Range Report: Comparing .36 Caliber Round Balls to Conicals

This test compared historically correct paper cartridges with conical bullets to loose round balls fired from the same weapon.

The paper cartridges were made using the same process I detailed in my post here except that I used the .36-caliber Colt Cartridge Works bullet made by Chris Beresovoy at Papercartridges.com using bullet molds sold by Mark Hubbs at Eras Gone Bullet Molds over 15 grains of Pyrodex "P" (3F equivalent).  The round balls were Hornady .375 swaged balls over 20 grains of Pyrodex P and a lubricated felt wad.  I ran a bore brush through the bore and wiped down the arbor after each table of fire.

Colt Cartridge Works Paper Cartridges

Using different loads of powder for the conicals and round balls may seem odd, but during the Nineteenth Century loose round balls were generally loaded onto more powder than was used in military paper cartridges in period, so I chose to follow this practice in order to compare the ammunition as it was actually used.  After all, this isn't about modern target shooting, it's about historical shooting, which means trying to do it the way they did.

For an explanation of the String Test Measurement system used in this comparison, read my blog post here.

Location:  Lytle Creek Shooting Range.
Weather:  52 degrees, wind variable, moderate to heavy from 1:00 to 3:00.
Range:  15 yards.  Shooting position:  Seated Supported.
Weapon:  Pietta Colt Navy.
Sighting:  Full Sight, 6:00 hold.

Table 2:
A.  Round Balls
String Test: 21.25 in./6 rounds = 3.5 in./round
B.  Conicals
String Test: 13 in./6 rounds = 2.2 in./rd.

Table 2

Table 3:
A.  Conicals
String Test: 21.75 in./6 rounds = 3.6 in./rd.
B.  Round Balls
String Test: 20.25 in./6 rounds = 3.4 in./rd.

Table 3

Table 4:
A.  Round Balls
String Test: 21.75 in./6 rounds = 3.6 in./rd.
B.  Conicals
String Test: 21.75 in./6 rounds = 3.6 in./rd.

Table 4

NB:  In each case, the "A" is the top target and the "B" is the bottom.  Table 1 was a different weapon and not part of this test, so is not shown here.

Conclusion:
As with previous tests I have done, I recognize this sample is not large enough to be conclusive, but it is suggestive.  The overall result suggests that the differences in accuracy between conicals and round balls is negligible in this weapon using these factors.  I am at a loss to explain the exceptional results for the conicals in Table 2, except to say that I actually fired the conicals first, even though I was shooting at the lower target (in the subsequent tables I shot at the upper target first).  It may be that the cleaner bore made the difference, although that seems unlikely since I brushed the bore after every table of fire, and yet I can think of nothing else that was different.  I think that if I soldered a 1/16 in. of brass stock onto the top of the front sight and filed the rear sight notch a bit more open on the left side it would bring the MPI to the IMPI with about a 2 inch group, which would yield a String Test measure of less than 2 inches.

I would also like to mention the importance of using Slix-Shot cones.  When I first got this revolver I had at least one serious cap jam (meaning one that required removing the cylinder to clear) per cylinder fired, and sometimes (often) more, using the factory-installed cones.  Since installing the new cones, that problem has almost disappeared, and, indeed, I did not experience even a single serious cap jam during this entire test, nor in the 36 rounds I fired afterward that day.