bolt catch not working

[collin minchey]

OK i got the gun all together and went out to shoot some round through it  at the end of the rounds in the mag. bolt catch doesn't catch i  tried three times same thing over and over  what causes this also if you put a empty mag in and pull the charge handle back it catches the bolt :huh:

[imschur]

I moved this post. That other board is supposed to be read only but that permission appears to not be set. sorry for the confusion.

 

Did you try different mags? What kind of rifle? What's the history, a new build?, Bought new?, bought used?

[Robocop1051]

This can be a symptom of a new build (rough surfaces), an over gassed gun (cyclic rate faster than the catch can operate) or an under gassed gun (BCG doesn't get enough force to reach the catch).

They are listed in their level of likelihood. If your rifle is well broken in and you have gone past the "run it soaking wet" phase... Try a heavier buffer or an adjustable gas block.

If you are under gassed (rare) you might need to clean up your gas system. Check your gas block hole for obstructions. Run a pipe cleaner through the gas block and gas tube. Hit the BCG and chamber with some of that "FireClean".

Those three fixes should cover a majority of the issues you get with the 308AR

[mrraley]

What type of rifle and what type of bolt stop?

[collin minchey]

It's a new build pof lower and cmmg lpk with a cmmg upper I only have shot it 15 times since I got it put together what's the deal on running soaking wet do I just cover all working parts in oil

[Robocop1051]

Soaking wet is exactly as it sounds.

Many of us (myself included) start by soaking the BCG in full synthetic motor oil. I use Mobil1 5w50. Synthetic molecules are smaller than stanard, and will permeate deeper into the metal. When youre ready to shoot, just wipe it with a paper towel and install like regular.

When at the range put a heavy dose of your preferred lube all over the BCG, inside the upper receiver, across the trigger assembly, and it even helps to put a little inside the buffer assembly. Check out "Frog Lube".

The guys here will comment by saying "dripping". There will be a little bit of splashing involved after each shot. Don't be shy about adding more oil/lube as you shoot.

The reason:

You built a gun with parts that were never meant to be put together. That doesn't mean they won't work. It just means you'll have to put a little elbow grease into it. Keeping the rifle "soaking wet" will help the metal parts mate to eachother as you fire the rifle. The repeated motions will wear the parts till they reach a harmonious working relationship.

[98Z5V]

What type of rifle and what type of bolt stop?

What mrraley says - on a .308AR, just cut to the chase, and use the Armalite .308 bolt catch.  It's much beefier, where it needs to be, over the DPMS-type .308 bolt catch. 

 

If it's an AR-15 part, on a large AR, remove it and save it for a 5.56-based project.

[Robocop1051]

While you're at it. Grab yourself an AR-10A magazine catch too. Also a much beefier part, designed for the heavier format rifle.

[EasyEJL]

any machining need to be done with either for them to fit on a dpms style? i'm still waiting on my lower, so I have time to pick them both up

[98Z5V]

Nope.  They'll go right in.

[MaDuce]

 Breaking it in DOES dramatically improve the function. But there's a couple other things to cinsider. If you over tightened the buffer tube, you may have spec issues there.

 

 Another; the problem I myself had is one I've never heard of before. I ordered Armalite AR-10 carbine length buffer springs. Turned out that they coil up completely before the recoil buffer can even make contact with the butt. You can see here my DPMS heavy buffer compared with a brand new, unmodified fully compressed Carbine length AR-10 buffer spring. It's not as easy to see in picture as in person but there's a full 3 coils that need to be clipped before the buffer will even make contact with the butt.

 

Edited March 20, 2013 by MaDuce

[jrtMA]

Soaking wet is exactly as it sounds. Many of us (myself included) start by soaking the BCG in full synthetic motor oil. I use Mobil1 5w50. Synthetic molecules are smaller than stanard, and will permeate deeper into the metal. When youre ready to shoot, just wipe it with a paper towel and install like regular. When at the range put a heavy dose of your preferred lube all over the BCG, inside the upper receiver, across the trigger assembly, and it even helps to put a little inside the buffer assembly. Check out "Frog Lube". The guys here will comment by saying "dripping". There will be a little bit of splashing involved after each shot. Don't be shy about adding more oil/lube as you shoot. The reason: You built a gun with parts that were never meant to be put together. That doesn't mean they won't work. It just means you'll have to put a little elbow grease into it. Keeping the rifle "soaking wet" will help the metal parts mate to eachother as you fire the rifle. The repeated motions will wear the parts till they reach a harmonious working relationship.

I'm used to saturating ARs in CLP from military days but have never heard of such an oversaturation. This is not to say that I don't see your point. Especially considering I've never broken in a brand new AR like I'm about to. I have Frog Lube but would like to try your recommendation with the motor oil. Right now my AR-308 sounds so grainy and rough when I charge it back. So basically you're recommending completely soaking the BCG but how long should it be submerged for?

[98Z5V]

MaDuce, did you know that there's a difference in length of the AR-10 carbine buffer, and the DPMS LR 308 carbine buffer?  The Armalite AR-10 carbine receiver extension is also longer (7 5/8") than the AR-15 and other .308 AR carbine receiver extensions (7"). 

[MaDuce]

MaDuce, did you know that there's a difference in length of the AR-10 carbine buffer, and the DPMS LR 308 carbine buffer?  The Armalite AR-10 carbine receiver extension is also longer (7 5/8") than the AR-15 and other .308 AR carbine receiver extensions (7"). 

 

I didn't know that. Wish I did.

[Robocop1051]

@jrtmasp;

If you can give it 2-3 days, that should be plenty. I had about two weeks in between shoots, so I tied a string around the BCG and dropped the whole thing inside the oil bottle. Longer is always better than shorter, but no one is exactly sure how long that is. I don't see any harm with doing it more than once. It won't get soggy, so don't worry about leaving it in too long.

[survivalshop]

If you BCG is being locked back properly when the rifle is charged with an empty mag ., its working . I would check other things , as has been said , buffer , spring to proper specs , improperly gassed .