Intermittant Feeding Problems With My Open Gun

[Austin Hemphill]

I got my open gun from Don at Kodiak Precision about 2 months ago, and for the most part it has been flawless. It is a 5" 4 port hybrid with a 4 chamber comp, and is an absolute delight to shoot. However, I have been having an extremly annoying problem with it lately. Once or twice in every hundred rounds, one round will fail to chamber completly. A slight bump on the slide will put it into battery. I am currently running a 9# spring and it has an aftec extractor. This feeding problem has never occured with the 1000 pieces of Lapua I have, and I have run them through the gun atleast 5 times. However, on my supercomp brass, this problem occurs. It didn't happen at all on the first firing of the starline, but only started on the second firing. I though it might be an extractor problem, and have swapped the springs around, and removed them one at a time, swapping positions, to no avail. I have also polished the feed ramp, with no improvement. The load that seems most reliable so far is 3n38 with a montana gold 124 jhp at 1.235". Any suggestions? I contacted Don about this, and he too thinks it may be extractor related. I miked the rims of both brands, and the starline is approximately 0.002-3" larger, but this is consistant with both new and once fired. I also chamber check my ammo, and have been inspecting the rims prettly closely. Are there any thing I may be missing?

[PaulW]

Well the fit of the aftec would be where I would check first. The firing pin stop MUST be relieved enough to allow the extractor to rock on the FP stop. I would also polish your chamber.

You can get a feel for how tight your extractor is by taking the slide off the frame then removing the barrel and slide a loaded round under the extrator. It should be firm but not take a lot of force to get under the extractor. I also bevel the bottom of the extractor so there are no sharp edges.

[.40AET]

I have 4 Aftecs in 2 guns and they run great. They need polishing! Don't polish the sharp part of the hook, that needs to stay sharp. The face of the extractor behind the hood and the under side of the face where the case will slide up needs polishing. I usually use a felt wheel and some rouge. Keep going until it shines like a mirror.

It sounds like you moved the springs around. Running one spring in the back hole will give you the least tension. After you polish it up try the one spring in the back and if it works then move it to the front hole to get more tension and see if the problem shows up again.

Good luck.

[scooterj]

The recoil spring could be suspect too. Check it, or better yet, change it and see what happens

[ipscron2000]

You didn't say anything about rolling your super brass. You said it ran fine the first use but not after that.

I roll mine every time I shoot it.

RJ

[benny hill]

Does not sound like a extractor problem. See if one side of the barrel hood is dragging in the side of the breach face.

[GuildSF4]

I agree with Benny, check for clocking of the barrel. From your description it sound like it is making it most of the way into the chamber, extractor is not a likely cause if it is making it most of the way into the chamber.

[Austin Hemphill]

Thanks for the suggestions. The FP stop is relieved for the aftec, and it seems to move freely. The hook is polished, and the rounds move freely under it, so it does seem to not be an extractor issue. I have also dropped all of the rounds I shot today into the chamber forwards and backwards, so it seems the rim is within the tolerance of the chamber. I have tried recoil spring from 8# to 11# according to the tester I have, with pretty much the same results. I have also tried leaving the lube on my ammo, with no improvement. Benny and Guild, how do I check for barrel clocking? The hood seems to have uniform wear on both sides, and after shooting, fouling seems the same on both sides.

[GuildSF4]

Thanks for the suggestions.  The FP stop is relieved for the aftec, and it seems to move freely.  The hook is polished, and the rounds move freely under it, so it does seem to not be an extractor issue.  I have also dropped all of the rounds I shot today into the chamber forwards and backwards, so it seems the rim is within the tolerance of the chamber. I have tried recoil spring from 8# to 11# according to the tester I have, with pretty much the same results.  I have also tried leaving the lube on my ammo, with no improvement.  Benny and Guild, how do I check for barrel clocking?  The hood seems to have uniform wear on both sides, and after shooting, fouling seems the same on both sides.

<{POST_SNAPBACK}>

The check for clocking:

Dry test: slow cycle the slide with no ammo if slide hangs up slightly out of battery grab the comp (be careful of muzzle) and twist the comp to one side then the other, if the slide goes into battery you have clocking.

Live fire in practice: when the problem occurs grab the comp (be careful of muzzle) and twist the comp to one side then the other, if the slide goes into battery you have clocking.

Clocking (ie one side of the hood is too tight) the direction you have to turn the comp to get it to battery tells you which side.

PS: a burr or oversize on the side of the hybrid section may cause this also.

Edited June 14, 2005 by GuildSF4

[J.L. Hardy]

Austin, check to make sure that there is at least .060 space between the hook of the extractor and the breechface. You can look up Bob's article on extractor fitting in one of the editions of front sight and he explains this in detail. I have found this alot lately. The case rim of super comp is a little thicker than both the armscor and TJ brass. Good shooting, J.L. Hardy