G27\33bbl accuracy probs

[mcsd2598]

I just purchased a G33 barrel(glock factory) for my 27 and the appropriate reloading equip to feed this beast. I got to test it today and got crappy results.

Background Info:
Factory ammo tested. Win white box 125 FMJ's(50 rds) and Win personal protection line. 125 HP's(20 rds).

Reloaded ammo tested. Speer brass. CCI small pistol primer. 125 fmj Star bullets. COAL 1.140. powder charges 7.8, 8.0, 8.2 8.4, 8.5 of power pistol. About 40 rds each charge.

I am a consistant upper "A" class shooter in GSSF and recently scored a 130 something with my 27 in Sub. And for a "control" portion of the test I fired 2-10 shot strings with my 40 barrel and 2 more strings with my 34. Both grouped very well, all in the A zone circle of an IDPA target at the same range. With the 34, groups were very tight. One string from each gun before and after testing the 33, so I knew fatigue wasn't a factor.

All rounds fired(factory and hand loads) out of my G33 barrel were all about 6-8" low and about 5-6" groups. Not very satisfactory. All handloads recoiled very close to duplicating factory. I had only one fail to feed. I believe this was a handload that was seated a little long, about 1.145, but could be mistaken. What's confusing is the factory shot worse groups than my first attempt at handloading for this caliber. Had I not fired factory ammo to test against I would have blamed my handloads.

I have owned about 7 Glocks in various calibers all but 2 were brand new. I've never had to really break in a barrel so I doubt that could be it.

My 2 theory's are: Bad barrel or barrel to slide match up. Or, the 357 sig round requires more barrel length to burn properly. I'm not real strong in any of the above theory's though. The barrel apears to be in spec, and I know the 40 barrel in the 27 functions well. So I doubt the slide components are out of spec. I haven't seen any post's about 33's shooting real low or inaccurate so I believe this could be isolated to my gun and or barrel.

Anybody have any thoughts. Have I missed anything? Should I send it to Glock?

[G33]

mc,

I think it might be the barrel; you seem to have tested all the other factors.
As you probably have read, I have used a lot of barrels in swap modes.

My experience with G33, G27, G23, G20 and G31 barrel exchanges is that given close to the same bullet weights, the bullet impact points were the same. Groupings were also about the same. Some were Glock barrels and some were aftermarket.
All were caliber conversions.

I guess I would give it one more try with factory ammo (just to eliminate reloading issues). Using bullet weights as close to the same as possible.

If still a problem, try for a barrel exchange from dealer?
Best of luck.

P.S. Had adj. sights put on the G20 just for the 10mm to .357 Sig conversion; never needed to change the sights.
P.S.S. My first barrel swap on the G27 took 3 tries before a barrel would work; but that was in 96 or 97.
;h

[mcsd2598]

Judging by the serial # I believe it might be one of the earlier barrels. If I remeber the # starts with L183XX. I'm gonna get a box of speer gold dots. If it don't shoot those well, I think I will send it back for exchange.

[roygun]

FYI when reloading 357 you must seat & crimp in two separate stations.In situations where the barrel has an unsupported section. it can cause case bulging at the base of the case. also check the case oal. due to high pressure of the round it can cause it to stretch like a rifle case. If you crimp too much it can cause the case shoulder to collapse in. Use your barrel to "chamber check" each of your reloaded rounds. Also check Accurate Arms for load data & Sierra for info. I had a few problems too reloading this round but now I get great performance with a low cost & accuracy to boot.

[rchrest]

Originally posted by mcsd2598
Judging by the serial # I believe it might be one of the earlier barrels. If I remeber the # starts with L183XX. I'm gonna get a box of speer gold dots. If it don't shoot those well, I think I will send it back for exchange.

Mine is L175xx and it shoots just fine, I'm not sure what to tell you... other than the fact that maybe you just need to shoot it some more to get the feel for the bigger snap.