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Joined: Thu May 10, 2012 1:30 pm
Posts: 9

Post Posted: Tue May 15, 2012 4:01 pm 
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Hello Gentlemen:

This is my first time posting here, though I've been lurking since the site first went on line. I've been a regular at 1911forum.com for many years, but from my observations there is a higher percentage of truly knowledgeable people here. I've just been hesitant to post, as I'm nowhere near your league. That being said, I'm hoping to get some guidance regarding a malfunction from people who are in the know.

Here's my situation:

I have a Springfield lightweight government model that I picked up at a great price (new) almost 10 years ago. It's been in the safe until about a month ago when I decided to get it ready for service, should I some day choose to use it for that. I did my usual complete inspection and adjustment, including adjusting extractor geometry and tension, cleaning up (or replacing) the fire control parts, installation of short trigger, etc., etc.

I've put about 250 rounds through it, and have experienced two different types of malfunctions:

The first is a nose down failure to feed. This pistol came with a ramped barrel, and three times I've had the first cartridge from an 8 round magazine dive into the front of the mag well, just below the barrel's ramp, and get hung up. In these situations the bullet wasn't in contact with the barrel's ramp (I could wiggle the barrel). I figure my only practical option here is to try a higher mag catch or use 7 round mags. I'm not sure there's much else I can do with a ramped barrel.

The second, and more perplexing problem, is a bolt over base type malfunction. When this occurs the bottom edge of the breechface dents the cartridge case at about the mid point and the bullet is pointing up. This only occurs when feeding the last cartridge from a magazine. I'm using McCormick Power Mags, all fairly new, and this has occurred with three of the five magazines I've been using. These mags all work flawlessly in every other pistol I use them in. I have no shok-buffer in the pistol and the slide can travel fully to the rear. The recoil spring is a factory 16lbs. I normally consider a bolt over base malfunction to be a magazine problem (the magazine spring not getting the cartridge against the feed lips in time for the slide), but could this be something else? I have tried my trusty, heavily sprung Metalform work-all-the-time-in-all-pistols magazines without malfunction, but my testing with those magazines has been too limited for me to state that they work flawlessly.

Any advice you have would be much appreciated.

Thank you,

Jim

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Joined: Thu May 10, 2012 1:30 pm
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Post Posted: Tue May 15, 2012 4:19 pm 
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I'm going to try to post a picture ... here goes:

Image

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Joined: Fri Jun 17, 2011 10:44 pm
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Post Posted: Tue May 15, 2012 9:15 pm 
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How did you determine proper extractor geometry and tension ?

Mark

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Post Posted: Tue May 15, 2012 10:43 pm 
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Hi Mark:

Your question has forced me to think carefully about how I would describe what I do to check/adjust an extractor and put it into words. Here's a quick explanation:

I ensure there is a radius on the bottom edge with a forward relief and that engagement with the rim is positive. I also ensure that the tip of the hook doesn't touch the inner diameter of the extractor groove on a cartridge case, yet the rim bottoms out inside the hook. I ensure that the front of the extractor hook is relieved to clear the forward bevel of the extractor groove, the pad doesn't protrude from the breachface, and there is proper cam out.

As for tension, I adjust by feel and then ensure it will hold a cartridge case under substantial shaking and a live cartridge under light shaking, but will drop the live cartridge if shook any harder. I then test by firing eight cartridges, one at a time, without a magazine in place to check for consistent ejection in the proper direction and the proper distance.

All that being said, the rim of the cartridge doesn't get up to the extractor in either of my malfunctions, so I don't think that has anything to do with it.

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Joined: Fri Feb 25, 2011 1:38 am
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Location: New Mexico

Post Posted: Tue May 15, 2012 10:48 pm 
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Check your follower for free movement in the mag first and foremost. Without the spring.

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Joined: Tue Apr 19, 2011 10:45 pm
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Post Posted: Wed May 16, 2012 4:02 am 
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Are you using standard 230 gr. ball ammo? Sounds almost like the follower is hanging up in the magazine.

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Joined: Mon Feb 28, 2011 4:34 am
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Post Posted: Wed May 16, 2012 7:07 am 
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May also want to look at the slide stop's internal lobe to make sure the rounds aren't hanging up on it as they feed.

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Joined: Thu May 10, 2012 1:30 pm
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Post Posted: Wed May 16, 2012 2:38 pm 
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Gentlemen:

Thank you for all the suggestions. Here's what I found:

Regarding the magazines, I disassembled them, removed the springs, and found that the followers move up and down the tubes freely.

I took a look at the slide stop's internal lobe and found some yellow/orange colored marks. Here's the best photo I could take with my cell phone:

Image

Should I remove some material from the lobe? If so, should I simply remove material from the areas that have the yellow/orange marks? Obviously, I don't want to remove anything that would reduce engagement with the magazine follower.

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Joined: Fri Jun 17, 2011 10:44 pm
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Post Posted: Wed May 16, 2012 3:40 pm 
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There you go I'd carefully file only where the bullet is striking the slide stop The magazine follower makes contact on the bottom of the slide stop lobe If you remove the slide and insert a magazine with a round in it you'll be able to see where its hanging up Let us know how it turns out

Regards,

Mark

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Joined: Sat Feb 19, 2011 8:38 pm
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Post Posted: Wed May 16, 2012 3:46 pm 
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Start at the right side (as shown in your photo) and taper that surface with the brass marks, removing no material at the right edge and making your taper heavier as you go to the left. You want to taper and polish that surface with the brass marks without changing the bottom of the slide stop.

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Berryhill Custom Guns, LLC

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