View Full Version : Question on common bolt lock culprits
I've recently begun to experience lock back issues with my AR. Before bringing my rifle into the local smith, I was wondering what common culprits cause bolt's to NOT lock back on an empty mag?
A quick break down, specs and back ground on my AR.
Mega billet upper and lower mid length build.
Rainier Arms complete auto BCG.
Mil spec buffer tube and ACS stock.
Recently installed Sprinco blue spring.
Spikes ST2 buffer.
BCM charging handle
PMags - pretty new and same result with six different mags.
Using Federal 55gr brass.
Recently switched bolt release from Phase5 back to original release because of bolt lock. Things functioned normal on two different days of shooting. Issued showed up last weekend.
At this point, I've filed a little off the action button to allow the catch to move further "up" the bolt. Not sure if that is going to do it. Also, with mag OUT, when charging the bolt to manually lock open, the bolt will not always travel far enough to clear the catch. I have to lightly press down the bolt for proper clearance.
I've thoroughly cleaned, scrubbed and lubed the BCG. Any thoughts and input greatly appreciated.
AMAC
Thomas M-4
03-14-11, 13:11
Also, with mag OUT, when charging the bolt to manually lock open, the bolt will not always travel far enough to clear the catch. I have to lightly press down the bolt for proper clearance.
It shouldn't be doing that. IDK off the top of my head what would be causing it but I would be inspecting the buffer tube and questioning the spikes buffer.Maybe try a standard buffer and see if it changes anything.
Also what kind of LPK are you using in your lower?
Who makes the barrel? I would dump that crap Spike's buffer and get a real H2.
I would also use another fully assembled lower and see if the problem continues. This will help you to narrow down if it is the upper or lower.
It is entirely possible that the "milspec billet" lower is not in spec and the bolt catch is too low to reliably engage every time.
I've recently begun to experience lock back issues with my AR. Before bringing my rifle into the local smith, I was wondering what common culprits cause bolt's to NOT lock back on an empty mag?
A quick break down, specs and back ground on my AR.
Mega billet upper and lower mid length build.
Rainier Arms complete auto BCG.
Mil spec buffer tube and ACS stock.
Recently installed Sprinco blue spring.
Spikes ST2 buffer.
BCM charging handle
PMags - pretty new and same result with six different mags.
Using Federal 55gr brass.
Recently switched bolt release from Phase5 back to original release because of bolt lock. Things functioned normal on two different days of shooting. Issued showed up last weekend.
At this point, I've filed a little off the action button to allow the catch to move further "up" the bolt. Not sure if that is going to do it. Also, with mag OUT, when charging the bolt to manually lock open, the bolt will not always travel far enough to clear the catch. I have to lightly press down the bolt for proper clearance.
I've thoroughly cleaned, scrubbed and lubed the BCG. Any thoughts and input greatly appreciated.
AMAC
alphapredator
03-14-11, 13:56
I had that problem, and found I had a rifle recoil length spring, replaced with carbine, and solved the problem!
Think I solved my problem. First, Iraqgunz, I hardly think the Spikes buffer is crap. Second, I failed to mention that I inserted a piece of plastic in the rear end of my buffer. There's some name for it, but it's purpose is to eliminate the "twang" most AR's make when fired. That little bit of space was preventing the full motion the BCG needed to travel. Silly me. :haha:
Now, a range test is needed to confirm. I'll keep you posted. Thanks for the input.
:)
Thomas M-4
03-14-11, 20:32
Think I solved my problem. First, Iraqgunz, I hardly think the Spikes buffer is crap. Second, I failed to mention that I inserted a piece of plastic in the rear end of my buffer. There's some name for it, but it's purpose is to eliminate the "twang" most AR's make when fired. That little bit of space was preventing the full motion the BCG needed to travel. Silly me. :haha:
Now, a range test is needed to confirm. I'll keep you posted. Thanks for the input.
:)
I am fairly certain that plastic POS was your problem of course you need to test to confirm.
The spikes buffer you might want to read this.
https://www.m4carbine.net/showthread.php?t=59176
That's my opinion and you have yours. BTW- my AR's and the ones I have built all work.
Think I solved my problem. First, Iraqgunz, I hardly think the Spikes buffer is crap. Second, I failed to mention that I inserted a piece of plastic in the rear end of my buffer. There's some name for it, but it's purpose is to eliminate the "twang" most AR's make when fired. That little bit of space was preventing the full motion the BCG needed to travel. Silly me. :haha:
Now, a range test is needed to confirm. I'll keep you posted. Thanks for the input.
:)
Think I solved my problem. First, Iraqgunz, I hardly think the Spikes buffer is crap. Second, I failed to mention that I inserted a piece of plastic in the rear end of my buffer. There's some name for it, but it's purpose is to eliminate the "twang" most AR's make when fired. That little bit of space was preventing the full motion the BCG needed to travel. Silly me. :haha:
Now, a range test is needed to confirm. I'll keep you posted. Thanks for the input.
:)
Nothing is wrong with twang. In fact, it serves as one more thing to indicate that the last round in a magazine has been fired (provided that the bolt locks back). Absence of twang=need to reload. For best reliability/functionality, avoid putting gimicky crap in an AR.
I failed to mention that I inserted a piece of plastic in the rear end of my buffer. There's some name for it, but it's purpose is to eliminate the "twang" most AR's make when fired. That little bit of space was preventing the full motion the BCG needed to travel.
Not busting on you personally, but the plethora of products designed to separate people from their money never ceases to amaze me. :rolleyes:
Derrick Martin of Accuracy Speaks says to grease the daylights out of the buffer spring. I tried it, and guess what, no twang.
Not busting on you personally, but the plethora of products designed to separate people from their money never ceases to amaze me. :rolleyes:
No worries. Just helping out the little guys! :D
Not busting on you personally, but the plethora of products designed to separate people from their money never ceases to amaze me. :rolleyes:
Transfer Devices.
A device designed to transfer money from YOUR wallet to THEIRS.
Transfer Devices.
A device designed to transfer money from YOUR wallet to THEIRS.
Good one. My keyboard is now covered in a mixture of Cheerios, Frosted Flakes, and milk.:lol:
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.