Trouble getting SWC to feed in Kimber GMII

[gregj]

I thought I had a good load for my Kimber Gold Match II; Precision moly 200gr SWC, 5.4gr W231, OAL 1.245, crimp .4690 with mixed headstamp brass (except no R-P brass). This load worked great at the range with static targets, but under the stresses of a (USPSA) match, my Kimber became a jam-o-matic at a recent match. The round seems to get jammed going into the chamber at an angle. I absolutely know it's the ammo, because the last two stages I used my son's ammo, which is basically the same load but with Precision's 200gr RNF (OAL of 1.220). My GMII worked flawlessly. I'm using new Wilson ETM mags and my son was using new Wilson 47D mags.

I'm about to decide my Kimber Gold Match II just does not like SWC (chamber too tight maybe?) My son's Kimber Custom Classic Target has no problems with them. My GM does very well with RNF but SWC it feed jams at the most inopportune time. The jam is what I believe is called a 3 point jam, see attached pic.

I've tried Missouri Bullets 200gr and Precision Bullets 200gr SWC in the GM, with various OALs, and have not found a sweet spot yet. I've tried 1.245 to 1.220, and have not found an OAL I felt comfortable with. 1.250 and longer the nose of the bullet hits the barrel hood when manually ejecting a round (as in showing clear at the end of a USPSA match stage).

Mags are fairly new Wilson ETM 8 round mags. I have 5 of these, plus a couple of CMC mags. I have noticed that when a jam occurs, if I bump the bottom of the mag the slide will go into battery. I have not noticed jams with a particular ETM mag. Also, I have not noticed a jam with either of the CMC mags.

I've been running 5.4gr of W231 with a .469-.470 crimp in both SWC and RNF from Precision Bullets. The RNF run nicely at 1.220 OAL.

The throat on both the GM and Target are nicely done and polished.

My son competes with me at USPSA matches, and would really like to keep to one load for the both of us. But at this point, I'm looking at two different loads. :banghead:

 

[Walkalong]

I load those at 1.260 to 1.265 O.A.L., and they feed in my 1911's as well as my CZ97.

Won't hurt to try it.

1.250 and longer the nose of the bullet hits the barrel hood when manually ejecting a round

Unfortunately, the 1911 was designed to eject empty brass, and manually ejecting loaded rounds can be problematic. Worse case scenario is to eject the mag and drop the pound with it. Is that an option?

 

[MarcusT]

Whenever I've had that problem with 40 and 45 swc I've had to load them longer until they would feed properly but you have to make sure they are not too long and get jammed into the rifling.

 

[gregj]

Unfortunately, the 1911 was designed to eject empty brass, and manually ejecting loaded rounds can be problematic. Worse case scenario is to eject the mag and drop the pound with it. Is that an option?

At the end of a USPSA stage, the RO will ask you if you're finished to unload and show clear. This means dropping the mag and ejecting the round. With the SWC at a longer OAL, this is always problematic as it never wants to cleanly eject. Perhaps I could try and find an OAL that is just short enough to cleanly eject and long enough to feed reliably.

EDIT: I just made up some dummy rounds, seems longest I could get to feed and would still eject manually without hanging up was 1.255. I'll try loading a batch of these up and see what happens. <fingers crossed>

 

[MCMXI]

gregj, I had a similar problem with my Kimber Tactical Entry II that I shoot in USPSA matches. It ran like a well-oiled sewing machine being 100% reliable with 230gr FMJ and 200gr LRNFP (match load) ammunition, but it was unreliable with Western Nevada 185gr LSWC loads (OAL of 1.146"). I sent Walkalong a bunch of those bullets, and he was was kind enough to make up some loads to test in his 1911s and they worked perfectly for him. I ended up fitting a new Ed Brown barrel in the TEII that is more accurate with lead bullets and it also feeds and shoots the 185gr loads without problems.

Fast forward to last week when I was working on a new Kimber Raptor and I decided to make up some Western Nevada 185gr LSWC loads to see if the Raptor could handle them. I decide to load them a little longer than 1.146" and set the OAL to 1.180" after reading Walkalong's posts HERE. As I was reloading, I was using a Wilson max cartridge gauge to test a few loads and had the Raptor barrel on the bench. The first thing I noticed is how easily the rounds would chamber in the Raptor barrel if I held the barrel horizontally and simulated the feeding angle and pushed the round up and in. I then tried the same "test" with the original TEII barrel and the rounds wouldn't chamber anywhere near as easily. I could feel the round hanging up as the bullet made contact with the "roof" of the chamber. I then loaded some rounds in the magazine, and with the muzzle pointing in a safe direction I released the Raptor's slide ... eject, release, eject, release etc .... all of the rounds chambered effortlessly. My conclusion from all of this is that the original TEII barrel has a very tight chamber and is the most likely reason why it was never reliable with 185gr LSWC loads. The short OAL and tight chamber was causing a three-point jam.

If the chamber is tight you could have a gunsmith ream and polish it for you if you're set on shooting the 200gr LSWC bullet. You could even try polishing the chamber yourself. I get such good results with MBC's 200gr LRNFP that I won't be buying any more LSWC bullets but I do plan on shooting the remaining 200 185gr LSWC bullets that I have. I'll be putting all of those through the super smooth Raptor.

Western Nevada 185gr LSWC with OAL of 1.180" in the Raptor barrel.

Western Nevada 185gr LSWC in the original Tactical Entry barrel.

 

[gregj]

1858: Thanks for the info, and the link to Walkalong's testing, very informative. I suspected the cause to be a little tighter chamber in the Gold Match than in the older Target. I had taken cases of varying crimp and put them into the chamber of the barrel of the GM and the Target. Very un-scientific method, but it was pretty easy to tell the GM chamber was tighter than the Target.

I had recently polished the roof of the chamber a little (where the bullet hits the chamber in a 3 point jam), and it seemed to help some. I have more loads to test (also testing different crimps to try and minimize leading), but for peace of mind and reliablity at a match, I've pretty much come to the conclusion of having to load RNFP for the GM and SWC for the Target.

 

[Red Cent]

I have a Colt National Match that will feed almost anything. However, my go to bullet is this. Berry's Bullets.