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Bolt Stop vs. Top Left Cartridge in Magazine

2055 Views 9 Replies 5 Participants Last post by  maddie
The Question: Should the bolt stop touch the top left cartridge in the magazinel? On three SA M1A receivers pushing down on top left cartridge makes the outside end of the bolt stop move out slightly indicating the stop is touching the cartridge case.

On one as the bolt goes forward the contact causes the bolt to push down on the bolt stop which depresses the cartridges far enough into the magazine that no cartridge is stripped and the rifle ends up with an empty chamber, and won't release the bolt with a full magazine in the rifle.

Should the bolt stop be resting on the receiver when the follower isn't sticking up there?

I've been thru all my references and can't find this mentioned, nor can I figure out why my new M1A receiver is positioning the magazine so the top left round is pressing up on the bolt stop.

I've modified the really bad bolt stop by grinding off material from the contacting point, but something ain't right here. As my buddy says "Heck, the Chinese can produce these!"

-- Chuck
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Just wondering if you got any good feedback on this as yet. My LRB is doing the same exact thing, but to the extant that the bolt stop is catching the bolt every other round!

Gary --

I got no feed back on this other than your response.

As I noted back in March the M1A (tm) rifles I examined all let the bolt stop touch the top left cartridge, but only one moved it enough to interfere with feeding. When the bolt would come forward it'd depress the bolt stop which in turn depressed the top left cartridge back into the magazine so that the bolt didn't strip the next cartridge from the mag and put it in the chamber.

I ground the part of the bolt stop touching the cartridge case leaving the rear portion which contacts the follower of an empty magazine alone. Put a couple hundred rounds thru her since then without problems.

-- Chuck
Thank you very much. I am fighting the exact same issue! I am going to order a new bolt stop to grind on, but also a new magazine release lever. I would rather mill one of these down .020" or .050" then slim down the bolt stop. However, if that does not work, I'll hog away the extra bolt stop. Those are a PITA to install, since the 2 I tried all needed the roll pin shaved down to function properly.

I can probably get a photo of what I ground off next week. Wasn't much, had to remove/install several times to get it right.

-- Chuck
If I am reading your description of your problem with the bolt stop correctly, I have a couple ideas that might be of help. I checked one Springfield M1A and two Armscorp M14s I have built myself.

On my rifles the bolt stop does not make contact with the left cartridge when released, even when I press the bottom of the bolt stop upward from outside the receiver. The bolt stop rests on the far left side of the firing pin retracting bridge, there is a small ledge cut into it for this purpose. I have noticed some bolt stops are larger in their dimensions than others especially in the area that makes contact with the bolt and extending forward. This could be the cause of your problem and your grinding them down seems just what is needed to fix the problem.

You also indicate the bolt when moving forward presses down on the bolt stop. On my rifles the bolt does not make contact with stop once the bolt is released. When I was fitting the bolts to my Armscorp receivers, I had problems with the receivers not being within specification in a few areas. One of the areas out of spec that affected the bolt was the receiver bridge bolt support surface. This is the curved bearing surface that supports the upper back ridge of the bolt, it is right behind the cartridge clip guide.

On the Armscorp receivers, this area was not beveled enough and caused the bolt to stick when it was retracted and the bolt was hitting the bolt stop until I enlarged this area with a Dremel tool. I did not have the problem with feeding like you have, but you can still check this. Check this area to see if it is causing the bolt to move downward and hit your bolt stop. If this is happening this area needs to be enlarged so the bolt does not stick or move down. I hope this is of some help to you.
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Top left round contacts the bolt stop on mine. This rifle is new and will not feed from the left side, at all. Right round chambers, fires and left round feeds halfway and jams hard enough to tilt the bullet in its case. What is the cure and is anyone else having this feeding problem as well?
My almost new Springfield M1A just started doing this this weekend. It will still usually feed from both sides as long as the first round out of the magazine is on the right side of the magazine. It won't feed the first round into the chamber if it's on the left side.
This receiver is serial 1595xx.

To fix the problem I ground off a bit of the bottom front of the bolt stop, maybe a quarter of the the thickness for half the length. This was by trial and error until the top cartridge stopped raising the bolt stop.

There's something well out of spec here, but the slight modification cured everything.

I'm sure I could send the rifle to Springfield for repair, but don't have the time.

-- Chuck
Thanks. The bolt stop appears to be the problem on mine, too. I don't have the patience to send mine back to Springfield and wait on it, so I guess I have a project for next weekend.
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