Range Report 01MAR2026: Comparing Burnside Bullets

I have three different bullets for my Burnside carbine: 350-grain flat-nosed bullets at .553 in. I bought from S&S Firearms; those I make with a mold from Accurate Molds which come out at .563 in and weigh 390 grains; and some new ones I just got from Buffalo Arms which are a near-perfect match for the originals and are .553 in. and weigh 365 grains.  I will refer to these as the S&S, the Accurate, and the Buffalo bullets, respectively, below.

Left, S&S bullets; Right, Accurate Molds bullets (just the far right four).

Left, Buffalo bullets; Right, Accurate bullets.

I had already done a test firing of the S&S bullets and the results were quite poor, so today's project was to compare the Accurate and Buffalo Arms bullets to that original test firing of the S&S bullets to see which worked best.

All of the cartridges were made up in roughly the same way, however, as the pictures above will show, I recently acquired a batch of nylon cases (which are no longer being made, incidentally), and since I was out of the brass ones, I elected to use these for the Buffalo bullets.  All cartridges were loaded with 45 grain of Swiss 2F powder under a card wad.

Shooting Conditions
65 degrees, wind 5 mph from 3:00, humidity 40%.
Range: 25 yards.
Firing Position: Seated rest.
Aiming: A half-sight 6:00 hold (but see below).
For reference, the black dots on the targets are 3 in. in diameter.

Results
Previous Results with the S&S bullets:

The results from the previous session with S&S bullets.

Rounds: 5
String: 27.5 in.
String Test: 5.5 in./rd.

Table One: Accurate Mold

Table One: Accurate Mold.

Rounds: 8
String: 30 in.
String Test: 3.75 in./rd.

Table Two: Buffalo Arms bullets

Table Two: Buffalo Arms bullets.

Rounds: 15
String: 37.25 in.
String Test: 2.48 in./rd.

Conclusions
As should be obvious, the bullets I bought from S&S firearms performed abysmally.  Yes, that was the first time I had ever fired my Burnside, but that is not a valid explanation.  As a result, let's compare the other two.

First, let me start by saying I cheated.  I fired all eight of the Accurate cartridges using the same aiming point--6:00 on the black disk; I only fired 8 rounds because although I brought ten, two simply refused to chamber.  That is because of the brass cases, not the bullets; the brass cases are notorious for not fitting.  I have about 30 brass cases, and have had to set aside ten of them as not fitting at all, even without a bullet inserted.  I thought these two fit, but when I tried to load them they didn't, so I'll have to work on shaping the bad brass to make it useable.

But when I started firing the Buffalo Arms cartridges I saw the first one hit very high, so I adjusted my Point of Aim slightly lower for the next batch of shots, which you can clearly see bunched in the middle of the group.  Seeing that these were still slightly high, I aimed slightly lower still for the last batch of shots, which, as you can see, are almost all in the same hole right on the aiming disk except for the one flyer to the left, and that was me--I felt my hands shake as I fired.

Had I tried aiming off, I believe the Accurate Molds cartridges would have achieved a String Test much closer to that of the Buffalo Arms cartridges, but looking at the tightness of the groups, I think the latter would still have gotten a better score.

I purchased the Accurate Molds mold because someone I respect greatly told me I needed a bullet that was at least .56 in. diameter for accurate shooting, and I think that when I start working on the right Point of Aim for this carbine these bullets will work beautifully.  The fact is, however, that with this carbine, at least, the .553 Buffalo Arms bullets are superior.  I suspect that my friend--who really is an expert, with a lot of experience--is accustomed to other carbines that may be a bit worn, whereas I am lucky in that the bore on my carbine, while not bright, has solid, crisp, sharp rifling that indicates it is not much worn.

I am thrilled with today's results.  My personal goal is to achieve sub-3 in. String Test results, which the Buffalo bullets did, and the Accurate ones probably would have had I aimed off.  I believe that with practice I may be able to approach the sub-1 in. String Tests I get with my Smith carbine.

I was pleased, too, with the nylon shells, particularly given how rare the brass ones are and how poor their quality is.  There were no misfires, they seemed perfectly fine after shooting, and they cleaned up very easily after shooting with just soap and water.  We shall have to see if they changed shape when I try reloading them.

The Buffalo Arms bullets seem to me to be the best possible choice for this weapon.  I am extremely unhappy that the S&S and Accurate bullets have the wrong shape, whereas the Buffalo Arms bullets are near-perfect analogs of the originals (the cannelures are different, but can't be seen when loaded), which matters a lot to me, and they shoot so well there is no reason not to prefer them.

This carbine is interesting to shoot.  It is not as simple nor as fast to operate as my Smith, and the fussiness about accepting cartridges is a very serious problem.  It is, regardless, quite easy to use, handy, well-balanced, and accurate.  I certainly prefer it to the Sharps.

The next thing is to work up detailed ballistic information, aiming points, etc., and then I believe a head-to-head shoot off against my beloved Smith carbine will be called for.  I am pretty sure that the Smith is still the best carbine of the War, but I am impressed with the Burnside and think it will be very close.  The biggest difference I see right now is that it is much easier to remove spent cases from the Smith because of the way they protrude from the breech, whereas removing the spent Burnside brass is significantly more finicky.  Note, however, that even after 23 rounds, without any cleaning or oiling, I experienced zero stuck cases despite claims I have read that they become hard to remove.  Another problem is that the loading lever sometimes needs to be struck gently to close, another problem the Smith never has.

Range Report 15FEB2026: .45 Caliber Rifle Shoot Off

My Martini Henry and Springfield Trapdoor with correctly packaged ammo.

People often like to compare Snider-Enfields to Trapdoors since they were both conversion rifles, and that makes good sense as long as they compare the Snider to the 2nd Allin Conversion Trapdoor, but the later Trapdoors were purpose-built rifles, not conversions, and were in .45 caliber, not .50-government or .577 Snider.  So the real comparison to be made for later Trapdoors is the Martini Henry in .577-450.  Both were purpose-built (not converted) single-shot rifles chambered in .45 caliber.  Both of my rifles were made in the mid-1880's, too, making for a perfect temporal match.

The most significant difference between these two rifles is the cartridges:  The MH cartridge was loaded with 85 grains of R.F.G.² powder under a 480-grain bullet which achieved a Muzzle Velocity (MV) of 1,353 f.p.s., while the Trapdoor cartridges after 1880 were loaded with 70 grains of 2F powder under a 500-grain bullet which achieved a MV of 1,317 f.p.s.  Thus, the original MH has a Muzzle Energy of 1,942 ft.-lbs., compared to the 1,926 ft.-lbs. for the Trapdoor; a frankly trivial difference.

My MH cartridges are loaded with 85 grains of 2F Swiss powder under a 475-grain grease-groove bullet (unpatched) and achieve a MV of about 1.340 f.p.s.  My Trapdoor cartridges are nearly perfect analogs for the originals, with 70 grains of 2F Swiss powder under a 500-grain bullet and achieve a perfect match in MV for the originals.

My MH cartridges.

My .45-70-500 Trapdoor cartirdges.

My plans for today were somewhat nebulous, I just wanted to shoot the two rifles head-to-head and see what results would be.

Shooting Conditions:  38 degrees, mostly cloudy, winds 8-20 m.p.h (highly variable) from 3:00, humidity 80%. All shots were fired at 100 yards from a seated unsupported position using a full sight picture.

A word about the targets:  The target shown in ToF 1 is my recreation of the British qualification target from the 1860-70's scaled down for 100-yard shooting.  The other targets shown are recreations of the US Army qualification targets used in the 1870's and 1880's scaled down for 100-yard shooting.  My thanks to Bob Beck for designing the US targets for printing.

Note that the number of rounds I wrote on the targets for two of the pictures below (ToF 2 and 4) is incorrect, so I added the corrected information to the pictures.

ToF 1: Martini Henry.

Table of Fire 1: Martini Henry
String: 35.0 in.
Rounds: 9
String Test: 3.9 in./rd.

ToF 2: Trapdoor.

Table of Fire 2:  Trapdoor
String: 74 in.
Rounds: 13 (note the correction)
String Test: 5.7 in./rd.

ToF 3: Martini Henry.

Table of Fire 3: Martini Henry
String: 38.0 in.
Rounds: 8
String Test: 4.9 in./rd.

ToF 4: Trapdoor.

Table of Fire 4:  Trapdoor
String: 29.0
Rounds: 11 (note the correction)
String Test: 2.6 in./rd.

Conclusions
Let me start off with excuses:  I shot very poorly today, and have achieved much better scores with both of these rifles on other occasions.  I don't know what was different, but I am extremely disappointed.  The wind was pretty strong and quite variable, but at 100 yards that shouldn't have made this much of a difference.

In ToF 1 with the MH I was aiming at the bottom of the center black square; in ToF 3 with the MH I aimed at the bottom of the center black oval.  In ToF 2 with the Trapdoor I started by aiming at the bottom of the center back oval, but seeing how high the rounds were printing I aimed the last round at the bottom of the outer circle, which resulted in a bullseye; I took this same point of aim in ToF 4 with the Trapdoor which gave me a much better elevation (and thus a much better String Test), as the picture shows.

Actually, the best group of the day was ToF 2, but that was the worst String Test of the day showing once again that group size is a meaningless metric.  Had the Mean Point of Impact for that group been lowered to the middle of the target that would have resulted in the best String Test of the day.

The differences in these points of aim once again shows us that the Trapdoor has a battle-sight zero of 200 yards, while that of the MH is 100 yards, which makes quite a difference at these short ranges.

The clear conclusion is that my Trapdoor using my ammunition, is more accurate than my Martini Henry using my ammunition, but the difference is small enough that this can't be taken as truly definitive.  Moreover, the sample size, both the number of rounds and the number of rifles, is too small to make a broader generalization.  Frankly, my analog for the .45-70-500 cartridges is closer to the originals (literally perfect, in fact) than is my analog of the .577-450 cartridges (which are only fairly close), and that may explain much of this difference.

Another issue which may relate to the cartridges is that of the 20 rounds of .577-450 I tried to fire, 3 rounds failed to load--I just couldn't get them to seat into the chamber of my MH.  I'm not sure why this is, but I'm sure it has to do with the way I load them so I have to get better at the loading process.  Conversely, the .45-70-500s all loaded perfectly and easily.

What do I think about the two rifles after this process?  I think that, objectively, the Martini Henry is a better rifle if for no other reason than that there's no hammer to cock, which simplifies the manual of arms.  Balanced against that, however, is the lack of a safety on the MH, a point often glossed over in other comparisons.  And while the hammer of the Trapdoor does have to be brought back to half cock before opening the action, this is a nearly automatic action which takes place without thought or effort as the shooter lowers the rifle from the shoulder (for an experienced shooter), and so really doesn't add any time to the loading process.  Likewise, bringing it to full cock happens automatically and without thought or effort while raising the rifle to fire, and so, again, takes no additional time.

I did not do a time comparison for loading, and the videos I have seen showing people making such comparisons have usually done by people who fumbled a bit due to a lack of experience.  Another problem I have seen in such videos is that the person doing them often flips the door up without controlling it, which causes it to fall back down, which naturally adds to the loading time.  If you lift the door to a fully open position without just flipping it up and aim the muzzle down slightly as you do so the door never flops back down.

Frankly, I enjoy shooting the Trapdoor more than the MH.  It is more comfortable and the manual of arms (once I had drilled both of them enough) seems more natural.  On the other hand, the sights of the MH are quite a bit easier to see, making for a slightly faster, clearer sight picture, a very important point.

I have no real final conclusion about the objective merit of these rifles.  They are both excellent pieces of ordinance, well suited for their day and intended use, and my observations here relate to my subjective impression of both.

Range Report 01JAN2026: .45 Colt in a Reworked Remington Conversion

My 5-in. Remington New Model Army with reproduction ammo.  Note the reshaped web on the loading lever.

Introduction
I posted an article in May of 2025 discussing black powder conversion revolvers in which I compared my 8-in. Remington New Model Army to my 5-in. Remington (both Piettas, fortunately) when using a Howell conversion cylinder loaded with .45 Colt ammunition.  You can read that article HERE.  Unsurprisingly, the 8-in. Remington significantly outshot its shorter-barreled cousin--the longer barrel makes a real difference in both accuracy and muzzle energy; a more subtle difference, however, lay in the fact that the 8-in. Remington had been reworked by Gary Barnes (https://cartridgeconversion.com/home-page) to make it more accurate, while the 5-in. revolver was shot directly out of the box for that trial.

I have since had the short-barreled NMA reworked by Mr. Barnes (see the photograph above).  He did a trigger and action job, corrected the angle of the forcing cone to 11 degrees, refinished he grips, and ground out the web of the loading lever to make it look more like Remingtons of the period.  See the example below taken from A Study of Colt Conversions and Other Percussion Revolvers by R. Bruce McDowell.  This article will discuss my testing of the reworked revolver.

A Remington police model conversion revolver, shown with both the conversion cylinder and the percussion cylinder.

Ammunition
The ammunition used for this test was my hand-loaded recreation of the M-1873 government load, with a hand-cast bullet from a custom mold designed to replicate the original over 30 grains of Swiss 3F powder; the biggest differences are that I am using Boxer-primed cartridges rather than the government's Benét-primed copper cartridges and that I am using 3F rather than 2F, as the originals did (I plan to do more comparisons of performance using the 2F powder another time).  When fired from the 5-in. barrel these cartridges produce a Muzzle Velocity of 822 feet/second, for a Muzzle Energy of 383 foot-pounds (23 ft.-lbs. higher than a modern M1911A1 shooting .45 ACP FMJ government issue!).  To learn more about the historical ammunition and how I recreate it, read the article I posted HERE.

My recreation of the original ammunition and Franklin Arsenal cartridge packet.

Shooting Methods and Conditions
Most of today's shooting was done at 15 yards shooting offhand (one handed, of course) according to the revolver Manual of Arms from CPT Stanhope Blunt's 1889 Instructions in Rifle and Carbine Firing for the United States Army.  I shot one table of fire, however, using Blunt's instructions for "snap shooting," in which the sights are not used.  This more closely replicates real combat shooting with a revolver:

    832. Owing to the unsteady support that the hand gives to the weapon the methods of aiming previously prescribed for the rifle and carbine cannot be advantageously followed; this is especially true of the practice mounted, where the motion of the horse and the very limited time available for the delivery of the fire permit neither the steadiness nor deliberation so requisite for success with the other arms.

    833. The best results will then be obtained by following the method of snap shooting; for which the pistol should be held raised and then quickly projected at the mark and fired without pause or any effort to align it upon the object, the action being somewhat similar to that employed in throwing a missile from the hand and from the same raised position of the arm. (Blunt 1889 p. 309.)

He then gives the specifics of practicing this skill, recommending that troopers start by aiming at small black circles painted on their barracks walls (id. p. 310), and goes on to say:

    838. The clasp of the thumb and second and third fingers should be firm, the first finger being on the trigger and the little finger underneath the end of the handle. If the clasp is too high up on the handle the muzzle will be elevated; if too low, the muzzle will be depressed. The clasp should not be so tight as to communicate tremor to the pistol, yet sufficiently firm to sustain, when firing with ball cartridges, the force of the recoil. After the discharge the position of raise pistol will be resumed.

    839. These motions will at first be executed rather slowly, the instructor correcting the positions if necessary, and the motions quickened as the soldier acquires the habit of leveling or projecting instinctively the pistol in the same manner that the forefinger would be pointed at an object. (id. p. 311.)

All aimed shots were taken using a full sight and a 6:00 hold (not the snap shooting, obviously) without attempting to aim off.  For reference, the black disks on the targets are 3 inches in diameter.

For the purpose of comparing accuracy in today's testing I used the String Test, a method dating to before the Civil War which takes into account both group size and the distance of the group from the center of the group to the point of aim in a single measurement.  All historical shooters should be using this process to gauge their accuracy--please, no more "group size" numbers!  To learn more about the String Test and how to use it, along with a video link, see HERE.

Results
I shot 5 Tables of Fire consisting of 12 rounds each, 4 with aimed fire and 1 with Snap Shooting.

Table One, aimed fire.

Table of Fire One: Aimed Fire
Rounds: 12
String: 28.25 in.
String Test: 2.35 in./rd.

Table Two, snap shooting.

Table of Fire Two: Snap Shooting
Rounds: 12
String: 51.5 in.
String Test: 4.29 in./rd.

Table Three, aimed fire.

Table of Fire Three: Aimed Fire
Rounds: 12
String: 30.0 in.
String Test: 2.5 in./rd.

Table Four, aimed fire.

Table of Fire Four: Aimed Fire
Rounds: 12
String: 33.5 in.
String Test: 2.79 in./rd.

Table Five, aimed fire.  Note that the holes on the right side were from a neighbor with poor aiming control, and not part of this string.

Table of Fire Five: Aimed Fire
Rounds: 12
String: 34.0 in.
String Test: 2.83 in./rd.

Conclusions
When I shot this revolver before it was modified I achieved a string test of between 3-5 inches/round; today I achieved results between 2 to 3 in./rd., which is a significant improvement.  Note that I consider my own personal standard to be that I should be able to shoot a string test of less than 3 in./rd., and that all aimed tables of fire achieved that result today; even the snap shooting went well, with all the hits in an area less than the size of a man's torso, so this represents a perfectly acceptable combat shooting result.  I would say that Mr. Barnes' work has made a significant improvement and that this revolver is capable of excellent accuracy.

The 30 grains of 3F was perfectly controllable, much more so than the up to 40 grains I have tried previously.  In addition, the revolver held up very well and suffered none of the damage the heavy loads I have previously used caused.  I didn't clean the revolver at all during testing except to wipe off the base pin after each cylinder of fire.

Range Report 07DEC2025: A Tale of two Colts

Colt 1860 with Johnston & Dow pasteboard cartridge packets.

I went to the range today and threw away some J&D and R.L. bullets at high rates of speed through my Uberti 1860 Army and Pietta 1851 Navy.  As usual, the 1851 functioned flawlessly: easy to load, no misfires, no cap jams even though it’s a god-damned-Colt (that’s becoming a single word in my lexicon), etc.  And, also as usual, the Uberti 1860 was a pain in my butt, with several repeating problems such as some bullets not seating deeply enough to allow the cylinder to turn, a weak hammer spring failing to set off caps, etc.  Both revolvers have been significantly reworked by Gary Barnes at Cartridge Conversions, with the Uberti also having had a lot of extra work to eliminate as many of the typical Uberti flaws as possible, such as the short arbor syndrome, etc.

1851 Colt Navy with cartridges and accessories.

Having said that, the 1860 can certainly shoot.  Although not as accurate as my Pietta Remington New Model Army, it consistently outshoots my 1851 Navy (even though the 1851 is a Pietta and therefore significantly more functional).  I shot about 60 rounds of each today, but the examples below are typical of the results I got.

The Army was loaded with Johnston & Dow bullets over 25 grains of Swiss 3F powder.  The Navy was loaded with Richmond Labs bullets over 17 grains of Swiss 3F powder.  Both kinds of cartridges used Crossen one-piece nitrated envelopes and were dipped in the Ordnance Department tallow and beeswax grease recipe.

All shooting was done offhand using a 6:00 hold at 15 yards.

Table Two: Colt 1851 Navy.

Table Two:  Pietta 1851 Colt Navy
String: 47.0 in.
Rounds: 12
String Test: 47.0/12 = 3.92 in./rd.

Table Three: Colt 1860 Army.

Table Three:  Uberti 1860 Colt Army
String: 22.25 in.
Rounds: 12
String Test: 22.25/12 = 1.85 in./rd. 

That difference in accuracy is extremely significant, and I don’t have an explanation for it.  It’s not a Pietta v. Uberti thing since my Pietta Remington NMA outshoots the Uberti Colt, so it’s either some specific flaw in my Navy, or the Navy’s are just generally not as accurate as the Army’s (which I do not believe), or my load is at fault (although both are shooting authentic loads), or I simply don’t shoot the Navy as well as I do the Army.  Just as a benchmark, I consider any String Test under 3.0 inches/round to be acceptable shooting.  Both shoot a little high, as one would expect, but I am pulling left slightly, and that is, I think, on me.

Range Report 17AUG2025: Buckshot Trapdoor, .45-70-500, & Martini Henry

Following in the footsteps of my friends Keith Katschke and Kyle Schmittle, I made up a batch of buckshot Springfield Trapdoor cartridges and tested them on paper.  I also shot a comparison between the Springfield Trapdoor and Martini Henry, with an interesting result.  We will discuss both tests below.

Buckshot Cartridges

Extant Buckshot cartridge.

Experimental buckshot cartridge. 1879 Ord. Dept. Report p. 331.

My reproductions of Trapdoor buckshot cartridges.

These cartridges were used both for prisoner control and for foraging.  They were tested extensively in period, as attested to in various reports from the U.S. Ordnance Department.  As the picture above shows, they consisted of a regular cartridge case loaded with 40 grains of rifle powder and three greased round balls made of soft lead.

I knew from my experience making gallery loads for the Trapdoor (see HERE) that .454 round balls weighing 141 grains each worked well with the modern brass, so I used these again.  Following the Ordnance Department description I loaded 40 gains of Swiss 2F powder (which has given me exactly the correct velocity with the full cartridge loads), then a .46 card wad (not mentioned in the records, but I didn't know how long I would be storing these before use and didn't want to contaminate the powder with grease), and three balls which I had greased with my standard mix of lambs tallow and beeswax.

I used a dowel to seat the first two balls firmly on the powder, and found that the last ball would barely fit--less than one-third of the ball fit into the case.  I tried seating the balls with my Trapdoor seating die, but found that they got stuck up in the die, and some were damaged removing them from the die, as can be seen on the third from the left in the picture above.  Because of this, I switched to using a hammer and a wooden dowel to press in the last ball, which led to uneven seating depths, as the picture shows.  Next time, I will use the powder compression die to compress the powder by about 1/8th of an inch before loading the balls.  I then crimped the cases as normal to hold the balls in.

I tested the resulting buckshot cartridges at 50 yards from a seated unsupported shooting position.  The target shown below is a reduced-size replica of the original Trapdoor qualification target shown in Captain Stanhope Blunt's Trapdoor musketry manuals.  I used a 6:00 full sight hold for aiming, and the results are pretty remarkable.  The center of the 18-ball group is slightly high; if I had been shooting at 100 yards it would have been spot on, but I was concerned about the group spreading too much at that distance, so next time I will aim about 6-8 inches lower at this range.

It isn't clear in the picture below, but all 18 balls hit the target, with one flyer at the very edge.  A closer examination showed that at least two of the balls went through the holes of other hits.  I conclude that these would make for excellent hunting loads for small game... or escaping prisoners.  For reference, the target is 23.4x16.5 inches.

6 buckshot cartridges, 18 hits.

Comparing the Springfield Trapdoor and Martini Henry Rifles
I shot ten rounds each of my government-loaded Springfield Trapdoor .45-70-500 cartridges and Martini Henry .577-.450 cartridges at 50 yards to compare their accuracy.  To see how I load the Trapdoor cartridges go HERE, and to see how I load the Martini-Henry cartridges, go HERE.

My reproduction Springfield Trapdoor cartridges.

My reproduction Martini-Henry cartridges.

I scored accuracy using the nineteenth-century String Test, which you can learn more about HERE.  I used a full sight picture with a 6:00 hold for both Tables of fire from a seated unsupported shooting position.  For reference, the black circle on the targets is three inches in diameter.

Springfield Trapdoor.

Springfield Trapdoor
10 rounds
String 33.5 inches
String Test: 3.35 in./rd.

Martini Henry.

Martini Henry
10 rounds
String: 22.5 inches
String Test: 2.25 in./rd.

Although the Martini-Henry String Test is more than 1 inch/round better, note that the battlesight setting on that rifle is 100 yards, while that of the Trapdoor is 200 yards.  Given that disparity, the trapdoor naturally shot a little higher than the Martini Henry, which shot close to the sights, just a little high since it was 50 yards), exactly as one would expect.  From this, I conclude that both rifles shot just about the same, and both are excellent analogues for the originals.

The Krag Jørgenson: Working up a Load

 

My 1896 Krag Jørgenson and Mills Belt

I was recently fortunate enough to acquire an 1896 Krag Jørgenson rifle in nearly pristine condition.  I loaded 20 rounds of ammunition, with five rounds each of 4 different powder loads to determine which shot best in my specific rifle.  10 rounds of each would be more precise, and I will test later with that many when I tune these results, but my goal was to get a rough idea of where to start.

As always, my goal is to attempt to match original ammunition as closely as possible, but that is difficult in this case since they used smokeless powder and modern powders are different.  I was told that IMR 4350 is very close to the Dupont powder used in period, so I used that along with a Hornady RN interlock bullet weighing 220 grains since it is a very close match to the originals.

Original Krag .30-40 cartridge design.

My reproduction cartridges.

I will post a detailed discussion of my loading procedure later, but the key here is to note that I made four different loads:
Load I:    34.5 grains
Load II:    36.5 grains
Load III:   38.5 grains
Load IV:  40.5 grains.

Load IV came closest to matching the velocity of the original cartridges at just over 2,050 f.p.s., with the originals coming in at 2,000.

I shot each Table of Fire at 100 yards from a rest, with a 6:00 hold using a full sight picture (this will be important below) on the black disk shown on the target pictures below, with the disks being 3 inches in diameter.  The day was bright and sunny, temperature 85 deg., wind from 3:00 at 10-15 m.p.h. with 27% humidity.

I will show the target pictures below along with the string test results.  I will show the Figure of Merit for tables 3 and 4 only since the FoM is tedious to go through, and these (representing Load III and Load IV respectively) were the best of the day.

To learn more about the Figure of Merit and how to do it, along with a link to a calculator to do all the hard work for you and to a video I made showing the theory behind it, go here:
https://historicalshooting.blogspot.com/2021/01/calculating-figure-of-merit.html

To understand the String Test, go here:
https://historicalshooting.blogspot.com/2020/12/the-string-test-measure-for-historical.html

Table of Fire One: Load I
String Test: 27.5 in./5 rounds = 5.5 in./rd.

Table of Fire 1: Load I.

Table of Fire Two: Load II
String Test: 9.5 in./5 rounds = 1.9 in./rd.

Table of Fire 2: Load II.

Table of Fire Three: Load III
String Test: 8.25 in./5 rounds = 1.65 in./rd.

Table of Fire 3: Load III.  Note that all the spots are from a neighbor trying out birdshot at 100 yards!

Table of Fire Four: Load IV
String Test: 9.25 in./5 rounds = 1.85 in./rd.

Table of Fire 4: Load IV.

So, from these results, it would seem that Load III gave the best results with a String Test of 1.65 in./rd., which is, incidentally, far, far better than I have ever achieved with any other rifle at 100 yards.

Next, however, we will consider the Figures of Merit for Tables 3 and 4, which will show that the mean radial deviation of Load IV was slightly better than that of Load III.  Remember that the FoM only determines the consistency of the group, not how close it came to actually hitting the spot at which you are aiming, whereas the String Test takes both factors into account, just not as precisely.

Here is the target diagram and FoM calculations produced by Rob Enfield's FoM calculator (see the link above) for Load III:

Load III FoM target diagram.

Load III FoM calculations.

Here is the target diagram and FoM calculations produced by Rob Enfield's FoM calculator (see the link above) for Load IV:

Load IV: FoM target diagram.

Load IV FoM calculations.

Thus, from these results we can see that both loads III and IV are excellent, with very similar String Tests and Figures of Merit.  In this case, however, the String Test results actually tell us something important that gives the lie to the seeming superiority of Load III when trying to reproduce the original cartridge:  The Krag sight was designed with a 200-yard battlesight, meaning that at 200  yards you should hit precisely on your point of aim when using a full sight picture.  Since I was shooting at 100 yards, an accurate reproduction bullet should hit slightly high, as these with Load IV did when using a full sight.  This fact, combined with the fact that Load IV came closer to the 2,000 f.p.s. muzzle velocity of the originals, shows that Load IV is a superb reproduction of the original cartridge.

Springfield Trapdoor .45-70-500 Case Volume and Compaction

Original M-1881 .45-70-500 cartridge dimensions.

Introduction
I recently had a conversation about my recreation of the M-1881 .45-70-500 Springfield Trapdoor cartridge and how similar it was (or was not) to the originals, with my interlocutor arguing that the volume of original cases was different from that of modern Starline cases, meaning the powder compaction necessary to load the cartridges was different.  This led to the analysis below aimed at determining how close the cartridges actually are to one another.  Note that this applies only to the later brass solid head cases used from the 1880’s onward, not to the original copper “folded head” (what today are called “balloon head”) cases.

Original M-1881 .45-70-500 cartridge.

My reproduction M-1881 cartridges.

I use a SAECO government bullet mold that produces bullets which are very close in design, weight, and dimensions to the originals.  I load them over 70 grains of Swiss 2F powder in Starline brass, compacting the powder to a depth of 0.61 in.  You can read a detailed explanation of how I load my cartridges, including a link to a video about it, HERE.

Since water has a density of 1 ml./gram, a friend of mine filled an original UMC brass case with water and weighed it, comparing it to a Starline case to determine the volume.

Weight of a UMC solid-head .45-70 case:
Empty: 11.22 grams
W/water: 16.16 grams
Volume: 4.94 ml

Weight of a Starline .45-70 case:
Empty: 12.89 grams
W/water: 17.79 grams
Volume: 4.90 ml
(Courtesy Justin Huzuga, pers. comm. 11JUN2025.)

Difference in Volume: 0.04 ml.

Length of an original 500-grain bullet: 1.31 in.
(1877 Rules of Management p. 43.)
Length of a SAECO 500-grain bullet: 1.29 in.

Difference in Length: 0.02 in.

Analysis
Ordnance Department records say the M-1881 cartridge had a MV (muzzle velocity) of 1,315.7 fps (1887 Rules for Management p. 45), whereas my recreated cartridges have an average MV of 1,315.6 fps—an entirely negligible difference, as are the differences in case volume and bullet length noted above, all within the margin of error. I know from some of Brett Gibbons’ work that Swiss powder produces almost exactly the same MV of British RFG powder, making me think it was extremely similar to the military powder in general of the period. I know the Dupont powder used in the M-1881 cartridges might well be different from the British RFG, but it was, at least, a starting point. I hypothesized that changing the degree of compaction would significantly change the MV, and that if my Swiss 2F was at least close to the Dupont powder and gave the same MV then that would tell me the compression would be about the same. Since the volume of the cases is almost identical, as is the length of the bullets (and hence the depth to which they need to be inserted), this test seems to confirm that Swiss is very similar to Dupont and that the compaction is about the same.

Source:
U.S. Ordnance Department. Rules for the Management of the Springfield Rifle, Carbine, and Army Revolvers. Caliber .45. Washington: Government Printing Office, 1887.