W231 with 230 Zero, erratic velocities

[GregJ]

I thought I would test some rounds tonight, 5.2gr W231, with the 230 zero @ 1.24 OAL. Gun is 1911 5" (Gravitas Tactical). Rounds loaded on a LNL. The brass is all mixed headstamp. Sizing die is EGW-U. Crimp is .470.

I shot 3, 3 shot strings. CED chrono with the IR sky screen. Temp 40* clear/calm.

str1: 716.7, 766.2, 750.7 PF 171.2

str2: 649.1, 738.4, 746.7 PF 167.0

str3: 714.1, 720.4, 742.5 PF 166.9

Only string 3 made major. I just grabbed 9 rounds from the bucket, none were cartridge gauged, but cycled in the gun fine. The gun is pretty dirty, but that shouldnt have an effect on the first round of all 3 strings being lower than the rest. The only rest between strings was the time it took to save the string on the chrono.

I check the powder drop fairly frequently, and it's always spot on 5.2gr. I usually use WSF, but the W231 just seems to drop more consistently, and I dont think it's as temp sensitive. So I have been thinking of switching to it.

Suggestions for the inconsistent velocities?

Edited February 6, 2014 by GregJ

[GregJ]

I may have found the issue. Battery was too low to upload the data to the laptop. I'll try again with the new battery and see if that was the issue.

[CarbineTX]

Also try a larger sample size such as 5 rounds instead of 3. I like to at least 8 rounds. This should bring your power factor calculations between strings a little closer together. Check to see if all your rounds are as close together in OAL. Pistol rest or freestyle? Use a pistol rest to remove variablity in recoil and lost energy.