AR bolt release spring and detent channel problem

[ChCx2744]

Hello,

Sorry I haven't been as active but I found myself in a predicament this past weekend. I was wondering if someone could assist me in finding out why a certain spring and detent is giving me issues? The bolt release is stuck, as if the spring is half-way compressed and the release lever is just loose. Possibly scoring in the channel? Maybe a beaten up detent? This is the second time it's happened. First time I was able to remove the retaining pin out myself and clean out the gummed up oil/carbon in the spring and detent channel (Dirty buildup was the culprit the first time). It has happened again but I don't want to remove the retaining pin myself because it's already a bit scratched up from getting it out the first time. Would it be more plausible to have this serviced or just strip it and buy another lower? Money is not the biggest issue, but I'd like to have a functional, reliable rifle when I'm done without putting a hole in my wallet. I've stripped all but the stock and buffer spring retaining pin. Any help is appreciated.

 

[GeronPG]

I'd be surprised if it were dirt or gunk again, although a random piece of sand or grit maybe could get in there and bind up the pawl. You don't hear of it happening often.

Not sure why you stripped the whole lower; the bolt catch/pin/pawl/spring is it's own little system and nothing else in the lower is in the way or connected to it. Your lower looks "dry", too. Maybe you cleaned it? I keep mine well - lubed (oil clouds around the hammer and trigger pins)

The bolt catch pin is probably the most difficult pin to drive in and out without banging up the gun, but it can be done. Use tape on surface behind it (where the lettering is) and carefully drive the roll pin forward with a punch (3/32" I think) to remove it.

Check the bolt latch, gently stone or polish the sides of the bolt catch, if it's rough or binding. Make sure the hole in the catch isn't rough, so it can move smoothly on the pin.

Clean the hole that holds the spring and pawl with a pipe cleaner. Was it dirty? See if there's any roughness in there. They say sometimes there is roughness or leftover filings in the hole from manufacturing. Maybe the spring broke?

Reassemble: lube the spring and pawl, spring goes in first, pawl on top, then latch. A small nail or a WD-40 straw to line it up and hold it in place while you drive the pin in helps.

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Reinstall the roll pin from the back. A punch made for roll pins (with a little dimple in the tip) makes it easier to do without the punch slipping and marking up the gun. You really need a small hammer. In a pinch, a finishing nail can be used as a starter punch, using the head of the nail on the pin and driving the pointy end.

Hope this helps.

 

[GeronPG]

oh, and before you tear into the spring hole, make sure the bind isn’t in the upper slot the bolt catch rides in. it would be more likely to catch bits of dirt or brass shavings, but you might still have to remove the catch to clean it.

 

[a5werkes]

Seems like the bolt catch pin is going to require removal one way or another to evaluate internal channel and parts upon removal. Not marring the receiver is always the goal.
Usual cause is too short a proper sized roll pin, causing either the body of the punch or uncontrolled hammer taps to leave evidence behind. I fabricated a couple of different punches to move the body of the punch away from the side of the receiver which is the root cause of the misery; Brownells makes a purpose specific punch for this task but its still too short! Some photos of extended roll pin punch (drill rod stock from Brownells, tip turned to fit roll pin aperture) and a thin roll pin punch profile with a brass extension to move the hammer[-punch contact away from proximity of receiver side. Always some blue tape. Also more mfgs are substituting simple roll pin for simple hex head axle screw-photos of drlll-tap-install shown; really simplifies the situation going forward.

 

[BBBBill]

more mfgs are substituting simple roll pin for simple hex head axle screw-photos of drlll-tap-install shown; really simplifies the situation going forward.

^^^ One of, if not the best, upgrades for the AR lower.

 

[five.five-six]

I've had a dozen or more ARs and never heard of this problem. I'll consider myself lucky.