Mags & bolt hold-open

AR-15 » Magazines

AR Sponsor:

Site Notices

TNVC Partners With Envision Technology - MARS Rangefinder Family, MARS-Lc!

[ARCHIVED THREAD] - Mags & bolt hold-open

Posted: 4/5/2006 6:45:36 AM EDT

What part of the mag is supposed to hold the bolt open after the last shot?
Follower or mag body?
If the bolt doesn't stay open was is the best fix? I thought of replacing the springs.

Posted: 4/5/2006 7:35:32 AM EDT

[#1]

The rear of the follower will come into contact w/ the bolt catch when the magazine is empty. You can see where this takes place. There is a cut-out at the back of the magazine on the top. The follower travels above this cutout and if you look inside your magwell, you'll see the little finger of the bolt catch protruding into the magwell where the top of the magazine would rest when inserted.

If your bolt is failing to lock back on an empty magazine, you may have a weak magazine spring as this is the driving force for the follower/bolt catch. Or you may have a defective follower (unlikely IMO) or a broken bolt catch.

HTH

Sly

Posted: 4/5/2006 8:28:01 AM EDT

[#2]

Quoted:
The rear of the follower will come into contact w/ the bolt catch when the magazine is empty. You can see where this takes place. There is a cut-out at the back of the magazine on the top. The follower travels above this cutout and if you look inside your magwell, you'll see the little finger of the bolt catch protruding into the magwell where the top of the magazine would rest when inserted.

If your bolt is failing to lock back on an empty magazine, you may have a weak magazine spring as this is the driving force for the follower/bolt catch. Or you may have a defective follower (unlikely IMO) or a broken bolt catch.

HTH

Sly

...or short stroking due to overpowered recoil spring / underpowered ammunition / leaking gas system.

Posted: 4/5/2006 9:45:50 AM EDT

[#3]

Does the problem occur with all mags (you said springs - like multiple)?

Posted: 4/5/2006 7:04:28 PM EDT

[#4]

Thanks for all the input.
At the range on Sunday none of my mags would hold open.
I use handloaded 68 gr or 75 gr HPBT bullets for match shooting, and only experience occasional failure tohold open. but Sunday I was burning up some surplus 55gr rounds. maybe that did it.

Posted: 4/5/2006 8:18:13 PM EDT

[#5]

I have some cheap steel mags I got a few years ago. On my AR's they often will not hold the bolt back after the last shot. These magazines are slightly smaller in the axis parallel to the barrel. They rock a bit and the follower will miss the bolt catch a lot of the time. I have tried different followers in the mags and it makes no difference.

Posted: 4/9/2006 3:13:24 PM EDT

[#6]

Shot a match today using my handloads. No hold open problems, even with the steel mags. It was probably the ammo I used last weekend.

Posted: 4/10/2006 5:23:26 AM EDT

[#7]

Gotgun,

This has been an ongoing issue for me with my older 20 rounders

Went shooting yesterday and used and brand new 30round out of the box. I wanted to eliminate the magazine variable from the bolt not holding open. Didn't matter what the ammo was, every last round held open.

Grabbed an old 20 rounder, nothing held the bolt back.

Took the magazine apart and stretched the spring. Walla. The bolt held open every single time.

I found my problem. Just have to go through all of them now and stretch the springs.

Posted: 4/10/2006 5:45:10 AM EDT

[#8]

Ben,
I know that took care of your problem, but it will happen soon again because of the stretching of the spring. The coils were not made to be stretched. You will be better off in the long term to replace the spring. Many suppliers have the springs for sale very reasonable prices. Just be sure if it is a straight mag you cut off 11/2 coils. Just my $.02.

Larry
C Products

Posted: 4/10/2006 6:58:31 AM EDT

[#9]

Larry,

True enough on replacing instead of "band-aiding" them. Since the magazines have to be taken apart I might as well do it right.

Thanks for your input.

Posted: 4/10/2006 10:16:40 AM EDT

[#10]

Quoted:
Ben,
I know that took care of your problem, but it will happen soon again because of the stretching of the spring. The coils were not made to be stretched. You will be better off in the long term to replace the spring. Many suppliers have the springs for sale very reasonable prices. Just be sure if it is a straight mag you cut off 11/2 coils. Just my $.02.

Larry
C Products

Yes thats true

Posted: 4/11/2006 3:17:33 AM EDT

[#11]

Quoted:
Larry,

True enough on replacing instead of "band-aiding" them. Since the magazines have to be taken apart I might as well do it right.

Thanks for your input.

Larry sells good springs at a good price. if you have not bought from him in the past give him a try, you will not be dissapointed.

[ARCHIVED THREAD] - Mags & bolt hold-open

AR-15 » Magazines

AR Sponsor:

Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.

Warning

Confirm Action

About AR15.COM

Stay Connected

Newsletter

Contact Us