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Old 05-13-2009, 14:23   #35
Bringsteen
10mm Shooter
 
Join Date: Dec 2007
Posts: 101
New Data--Serious Velocities

As with my earlier post, I have already posted this, but I wanted to make sure that it was placed in a sticky.

The new data are interesting and a little confusing. Once again, I used 180 grain Hornady XTP's, new brass, handloaded each charge, and put a heavy crimp on the cases. As you can see, the 17 grain charges were slightly faster than the 17.5 grain charges.


Hodgdon Lil’Gun, 17.0 grains
_ 1)_1409.0_ 13.3
_ 2)_1402.0_ 6.3
_ 3)_1434.0_ 38.3
_ 4)_1371.0_ -24.7
_ 5)_1408.0_ 12.3
_ 6)_1397.0_ 1.3
_ 7)_1419.0_ 23.3
_ 8)_1373.0_ -22.7
_ 9)_1378.0_ -17.7
_ 10)_1366.0_ -29.7

__ High:_1434.0
__ Low:_1366.0
__ E.S.:_ 68.0
__ Ave.:_1395.7
__ S.D.:_ 22.9
__ 95%:_ ±17.3

Hodgdon Lil’Gun, 17.5 grains
_ 1)_1351.0_ -37.8
_ 2)_1399.0_ 10.2
_ 3)_1428.0_ 39.2
_ 4)_1414.0_ 25.2
_ 5)_1392.0_ 3.2
_ 6)_1337.0_ -51.8
_ 7)_1383.0_ -5.8
_ 8)_1381.0_ -7.8
_ 9)_1414.0_ 25.2
_ 10)_1390.0_ 0.2

__ High:_1428.0
__ Low:_1337.0
__ E.S.:_ 91.0
__ Ave.:_1388.8
__ S.D.:_ 29.8
__ 95%:_ ±24.3


What is frustrating is that the highest average velocity (1395.7) is actually lower than the highest average velocity using Accurate #9 (1400.9). But the maximum velocity with the Lil'Gun loads was higher (1434) than the #9 loads (1417). I will probably experiment with using a slightly lighter crimp and dropping down by a few tenths of a grain. It may be that compressing Lil'Gun in the 10mm doesn't do any good. Compression loads work for some powder/cartridge combinations, and not for others. I will also try to load them just a little bit longer, but the need for reliability dictates that I only stretch them by a few thousands of an inch, so it may not make any difference.
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