17 February 2017
I’ll give myself a bit of an alibi here regarding accuracy. A group testing was with the target at 25 yards. I used a black 2 ¼” bull aiming at 6 o’clock. Both barrels have standard Contender iron sights. With my tired old eyes I do well to shoot 1 ½” groups at 25 yards with iron sights anymore. The Contender was rested o the sand bag shown and an additional sandbag (not shown) was used to brace/rest the forearm on, the position was steady. Looking down the sights through the screen we see;
After loading each cartridge the Contender action was snapped shut then the muzzle was raised to position the powder somewhat uniformly I the case. The Contender was then lowered level into the “V” of the sandbag rest.
45 AR; The 45 AR cartridges were tested in the 45 ACP barrel. Since the 45 AR cartridge is simply a 45 ACP with a rim test results would be applicable to an actual 45 AR cartridge. Notice in the cartridge photo above a slight roll crimp was also used. I had to size the front driving band/portion of each bullet .452 to get the loaded cartridges to chamber. Otherwise the bullets were sized .454 and were lubed with LLA (by Ed). The Extractor of the Contender 45 ACP held the cartridge in place so headspacing on the case mouth was not a problem. The medium roll crimp was the same as I do with 45 AR cartridges.
However, the 45 ACP Contender barrel is normally quite accurate with most all reasonable 45 ACP loads. In this case accuracy was actually poor with all 3 bullets. That may or may not have been due to the use of the extractor to headspace causing ignition problems. Additionally there was 16” of vertical impact difference between the loads. This caused other problems as the screens were hit by at least 3 bullets. I was able to repair the screens and continue testing. After repair a “reference” ammunition test was conducted to verify the consistency of the measurements. All was well, just nicked and scarred…….I have some of the 45-240H1s and 45-290H bullets left and in the near future will load them in the Webley cases (very similar to AR cases) and test in the 45 Colt barrel for accuracy.
All 3 bullets in the 45 AR test were loaded over the same 4 gr charge of Bullseye powder.
Note on the Oehler M43 PBL test data printouts the group is pasted onto the printout or the bullet holes are traced onto the printout. The M35P printout is pasted to the left of the M43s Shot Data and Summary fields for quick comparison.
Concealment is not cover.........