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Posted: 5/1/2008 2:54:18 PM EDT
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NEW HERE! Empty mag not locking. Shot for first time today. Mag will not lock bolt to rear. I'm using Kay magazines and one Labelle. When I look inside it appeares that the magazine spring is not strong enough to lock the bolt to the rear. Also this ar is NIB stag shoots awesome. But could it possible be that I need to run some more ammo thru to get the rifle to losen up? I took one magazine apart and streched the spring. Locked to the rear once then after that back to normal. I will be breaking it down in just a few minutes to clean everything. With being NIB I just wonder that not everything is loose yet. I would appreciate any comments or if there is a place on this site for this problem. THANKS |
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Will it lock with an empty magazine and pulling the charging handle back? If not then your bolt catch might be a bit too snug in the lower receiver and need a bit of stoning or your bolt catch spring/detent might need inspecting. If it's only not locking back on the last shot while firing, you're probably short-stroking and would need to clean the chamber and lube the upper very well. |
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By using a hard arkansas stone with honing oil, a.k.a. a knife sharpenning stone, you can remove and polish the sides of the bolt catch if needed and remove a very minimal amount of material and have a smoother finish than if you use a file. With the upper off, take a look and see if the bolt catch moves up and down freely. If it does not, then you need to see if its a bolt catch spring/detent problem (the detent should be against the bolt release, not down in the hole) causing the sluggish movement, or if the bolt release is rubbing on the lower receiver near where the roll pin retains it to the lower, or if its the catch itself rubbing in the lower creating the friction. I'm sure with a little investigating you'll find the trouble spot :) edit: theres one other thing to check first: with the magazine removed, see if you can lock the magazine open by pushing on the BOTTOM side of the bolt release while pulling the charging handle back. It's possible that on a new build you have the wrong buffer/spring combination and the bolt can't physically move rearward enough for the bolt catch to engage. |
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Something I just noticed. WOW Last round hold open. The weapon is fired. I just noticed that the hammer is against the bolt hold. Very hard for it to move. So here is what I think. When the round fires the hammer goes to the up position. Pushing against the bolt stop. Now like you said if I was to basically smooth that there should be no problems. If Im right. But here is the thing. With the weapon on safe that means the hammer should be down. Not up touching the bolt stop. Tried again still won't lock even with the hammer down. I read that a break in period might be the cause. By the way I have only put about 20 rounds through the rifle. |
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Shotgun the upper open and work the bolt catch by hand. The catch should move freely in the lower receiver, with only the spring tension pulling it back down (read cock the hammer back first). Now insert a empty mag into the opened lower and see if the mag follower makes the mag catch rise. If the catch will not rise, then either the mag spring is weak, or the catch spring and catch buffer where installed without removing blasting from the channel. You stated that stretching a mag spring allowed the the catch to work, so I would suspect that the mags you have, have weak/worn springs. |
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If the USGI mags are in good working order (read feed lips not bent, and the back U channel not cracked), then just replace the mag springs to rebuild the mag. Normal spring will work for the most part, but Wolf springs does offer extra tension units if that is the direction you want to take. They can be bought direct, or through companies like Brownells in single, three, and 10 pack units. |
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How hard is it to push on the bottom of the bolt catch to lock it open manualy? A friend just built his AR and had the same issue. It turns out that he has the wrong spring in the bolt hold open catch and the mag springs were not strong enough to overcome the too strong bolt catch spring. Borrow an unadulterated mag from someone and see if it works. Gringop |
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