1911Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
258 Posts
Discussion Starter #1 (Edited)
I just got my SA GI back from Springfield. The main reason I sent it in was to have some warranty work done for reliability. It was feeding poorly with 230gr FMJ ammo, and would not feed at ALL with JHPs. According to the invoice, the following was done:
  • Polished feed ramp,
  • recut the frame (I have no idea what that means)
  • gauged the breech face (@.480)
  • replaced the extractor
  • testfired with FMJ and JHP ammo
Now that I have it back, it runs FMJ just fine. I bought two new 7-rd Tripp Cobramags for carry.

I took it out today and ran some Winchester 230gr JHP ammo through it. The first mag fed well, with one hangup halfway through the second mag. I loaded up three more mags and this time nearly every other JHP round became hung up on the mouth of the barrel. This necessitated racking the slide to reseat the round in the chamber. Simply pressing on the rear of the slide would not work.

Below are some detail photos of the barrel and the malfunction. What would need to be done to prevent this from happening? I would like to carry JHP ammo for self defense.



















Here is the original thread: http://forums.1911forum.com/showthread.php?t=185897
 

·
Registered
Joined
·
346 Posts
its on the way in

looks like its going in try a heavier recoil spring, like a wolf 18 or 19 lb to shove her home or try polishing that little hump where they stopped polishing the throat,,,see how ruff it is.
 

·
Registered
Joined
·
42 Posts
Hard to tell from the pictures, but here's what I see far. It looks like the bullet nose is hanging on the barrel ramp (pushing the barrel forward), and it shouldn't be touching that ramp or just barely making contact only at the very top near the chamber. This really isn't a ramp like in the frame, but rather a clearance cut so the bullet nose misses the barrel as it begins to chamber. So with out more information I have two suggestions. First try some different magazines. Next I would also look at the extractor tension. I see your notes state that SA replaced the extractor, but that still doesn't mean it's tensioned correctly. There are some sticky's on the forum that explain how to check and retension the extractor, read that and follow them carefully. Also make sure there are no burrs on;) the breach face and around the firing pin hole, that might be stopping the round from sliding under the extractor.

From what SA claims they did I'm guessing the frame ramp was cut at the wrong angle so SA recut that to help feeding. Regardless of this I still suspect the magazines first and then the extractor. Heavier recoil springs may help, but that really just masks some other problem. The gun was designed to use a 16 lb. recoil spring and it should function properly with that. All that said you have to consider this is a Springer GI model and feeding JHP ammo is always touch and go. If everything is in spec. JHP should work, but that is with everything is spec. Before you go back to the JHP ammo retry some 230 gr. ball again.
 

·
Registered
Joined
·
76 Posts
Do not change the recoil spring or polish anything.

First, check the extractor to see if it has too much tension. Take the slide off of the pistol and slowly feed a cartridge up from the bottom of the bolt face underneath the extractor hook and see how much force it takes. The tension should be firm but not overly hard.

If the extractor is ok, try a Colt factory magazine. Cobramags are made to feed the round higher, more directly towards the barrel ramp. That isn't necessarily a good thing.
 

·
Premium Member
Joined
·
7,062 Posts
Belt,
I'd wager that the angle of the barrel throat is too steep.
I've found 19 degrees to be the absolute minimum.

My buddy Bob Rodgers has developed a simple means of measuring the throat angle. Perhaps he will share.
 

·
Banned
Joined
·
1,347 Posts
Yep. Chuck is right as usual. If you look at old military guns, they have very deep barrel throats, not wide like modern guns, but deep and at a less steep angle than the throat pictured.

I just reworked 2 guns built by very regarded pistolsmiths. Both had less than .030" ramp-throat jump and had too steep chamber throat angle.
Th guns worked OK, but were not smooth feeders. Now they are slick as snot.
 

·
Registered
Joined
·
6,322 Posts
Feeding JHP ammo

There was some good replies already discussed. Another thing I always check for, are loose fitting magazines. If a magazine shows a lot of vertical
play when seated, the mag will drop slightly once inserted in the frame. This can affect feeding. I suspect the reason is that some magazines may not be in proper spec. where they place the mag catch cut.
If you notice that your magazines do exhibit a lot of vertical play, one thing that may help is an oversized magazine catch. Evolution Gun Works sells one that is oversized, so it can seat magazines higher in the frame. I think they run about $25. I like their flat bottomed firing pin stops also....$15!
 

·
Registered
Joined
·
36 Posts
Yep I'd say the throat needs to be polished Its a simple job that can be carefully done in about 10 minutes and enjoyed forever. Do not go to deep check with a case to make sure there is still enough support on the bottom of the case and you will be fine . Just remember you can remove but not put back and the barrel throat should match the frame ramp.
 

·
Banned
Joined
·
1,347 Posts
gunman1911 said:
Yep I'd say the throat needs to be polished Its a simple job that can be carefully done in about 10 minutes and enjoyed forever. Do not go to deep check with a case to make sure there is still enough support on the bottom of the case and you will be fine . Just remember you can remove but not put back and the barrel throat should match the frame ramp.
The barrel throat should NOT match the feedramp. There should be a gap between the throat and ramp. A minimum of 1/32" is called for.
 

·
Registered
Joined
·
1,960 Posts
My compadre Chuck is the inspiration behind this vaguely Goldbergian-looking device. He proved, he didn't postulate, he didn't hypothesize or speculate, he absolutely PROVED that the angle of the barrel ramp has a lower limit for consistent feeding. So, how to avoid it? You can set up and indicate the ramp and get an accurate measurement with a protractor, but the process is slow. I figured if I could come up with a quick way to grab the angle, I'd just whack out a quick tool for the process. And due to variations in barrels between the rear of the lower lugs and the barrel throat, everything had to be adjustable. While not quite as accurate, I can still get within a degree, and that's plenty close enough. Use the machimist's scale to match the ramp angle and lock it in place. Then use a protractor to measure the angle of the scale off the base of the tool. 'Bout a minute-start to finish.:)




 
1 - 17 of 17 Posts
Top