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Ar10 bolt stop problem

jcwarrior87

Sergeant
Full Member
Minuteman
Sep 6, 2009
819
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Selah, Wa
Well I broke my bolt stop today. Ar10 mega lower. Wondering what I should replace it with just a standard one or......... this is on a 6 creedmoor that will only be shot suppressed

Thanks
 
Make sure your buffer tube isnt too long for your buffer. Most broken bolt catches are caused by buffer overtravel
 
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Standard tube with a jp silent capture and lantac bcg.......

Can you explain plan how you have to much travel?
With the charge handle pulled all the way to the rear, you should only have 1/10-1/8” clearance between the bolt and the stop.

Sometimes you have to shim the buffer to limit travel by putting washer/washers or shims in the bottom of the receiver extension.
 
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You have JP SCS so it's likely not your problem. But for a normal buffer setup, pull bolt to rear and hold it. Buffer should be just behind the catch. With a lot of setups, it can go back further, therefore gaining more momentum before slamming into catch.
 
So who makes the best bolt catch? You know the ones that don’t break? I’ve seen some S7 tool steel ones from V7
 
So who makes the best bolt catch? You know the ones that don’t break? I’ve seen some S7 tool steel ones from V7

Sure you want to do that? I'd rather the bolt catch break to tell me there's an issue rather than an indestructible catch breaking the aluminum lower.
 
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Make sure your buffer tube isnt too long for your buffer. Most broken bolt catches are caused by buffer overtravel
or from being over-gassed. I think over-travel is probably the biggest culprit, IMHO. exacerbated sometimes by too strong of a buffer spring, accelerating that buffer on rebound right into that bolt catch. AR-10's are a lot more violent than the AR-15, so everything needs to be balanced, tuned just right, otherwise you'll end up with chronic parts breakage. Buffer, spring, travel, gas, etc.
 
With the charge handle pulled all the way to the rear, you should only have 1/10-1/8” clearance between the bolt and the stop.

Sometimes you have to shim the buffer to limit travel by putting washer/washers or shims in the bottom of the receiver extension.
quarters are frequently mentioned as the just-right-size shim for this situation. no joke.
 
Here is the one I just got after @Lawless was nice enough to inform me of the same situation after I broke my PSA bolt catch

S7 BOLT CATCH NP3 308/DPMS/SR25

SKU: BCS7308NP3/KIT


I just wish PHASE 5 would make an extended one to fit my 308 like my 223.
 
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Sure you want to do that? I'd rather the bolt catch break to tell me there's an issue rather than an indestructible catch breaking the aluminum lower.
AR-10 bolt catches have been known to break. I’ve never heard of a lower breaking because someone put in a properly made steel bolt catch. (Not MIM)
Have you?
 
AR-10 bolt catches have been known to break. I’ve never heard of a lower breaking because someone put in a properly made steel bolt catch. (Not MIM)
Have you?
I've never a bolt catch break in a rifle that didn't have some other issue. I'm just saying I'd rather fix the root cause than put a band-aid on it and turn a more expensive part into the weak link.
 
With the upper and lower seperated... and a empty mag inserted... Wear your safety glasses, fully depress the BCG into the buffer tube.

Then measure the distance between the bolt catch and the bolt face... it should be around 3/16"... Distances excess of that figure can allow the BCG to just get enough momentum to be abusive on the bolt catch.

Or your OEM one was faulty.

It is possible you have some sort of tolerance stacking going on.
 
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I've never a bolt catch break in a rifle that didn't have some other issue. I'm just saying I'd rather fix the root cause than put a band-aid on it and turn a more expensive part into the weak link.
I agree. I hope OP can figure it out.
 
One issue I've had in an mws lower, twice, is the hole for the bolt catch plunger got peened on the edge, sticking the plunger and letting the bolt catch bounce around. Gave me some sporadic malfunctions. It had a few chips taken out of it from being hit by the bolt and carrier.
 
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One issue I've had in an mws lower, twice, is the hole for the bolt catch plunger got peened on the edge, sticking the plunger and letting the bolt catch bounce around. Gave me some sporadic malfunctions. It had a few chips taken out of it from being hit by the bolt and carrier.


Good point... check for free and proper "travel" of the bolt catch etc in the lower.
 
You guys have been super helpful. When I get back from vacation, I'll be tossing in a v7 catch and checking everything else, I know I need to tune my buffer spring. It was not strong enough to push the bolt all the way back in to battery so I bet I had some over travel going on.

The over travel makes a lot of sense, my lantac bolt is HEAVY so any extra speed is just you to make it that much harder to stop.
 
... I know I need to tune my buffer spring. It was not strong enough to push the bolt all the way back in to battery so I bet I had some over travel going on.
if it's a new BCG, that could just be gas ring drag, which goes away quickly once broken in. Put some light oil on the gas rings, and the inside of the carrier bore. You should give it a chance to break in before deciding to put in a stiffer buffer spring, which will increase the impact velocity of the bolt on the bolt catch.
 
So I checked it this morning before we left, and I have a jp 2 weight buffer this allows the carrier when compressed all the way out of the upper there is about an 1" between the bolt face and stop.....
 
So I checked it this morning before we left, and I have a jp 2 weight buffer this allows the carrier when compressed all the way out of the upper there is about an 1" between the bolt face and stop.....
one inch!!! holy cow! that's why your bolt catch broke. that's way too much. I think you have the wrong-length buffer in there for that buffer tube.
 
one inch!!! holy cow! that's why your bolt catch broke. that's way too much. I think you have the wrong-length buffer in there for that buffer tube.

An inch ?! ... oh yeah, that would break a bolt catch
 
I think I have the wrong scs in it. It only has two weights on it..... all my other ones have 3.... (and I didn't build this thing, bought it in the prs here)
 
So I checked it this morning before we left, and I have a jp 2 weight buffer this allows the carrier when compressed all the way out of the upper there is about an 1" between the bolt face and stop.....
o_O Do you have a rifle receiver extension?

YIKES!

I have zero experience with JP SCS but dat ain’t rite yo.
 
Standard tube with a jp silent capture and lantac bcg.......

Can you explain plan how you have to much travel?
Dumb question...(and not trying to insult your intelligence) but Are you using the poly spacer that came with your scs? It should’ve been part of the kit, but might have looked like junk. It is needed when running rifle length and not carbine.
 
Dumb question...(and not trying to insult your intelligence) but Are you using the poly spacer that came with your scs? It should’ve been part of the kit, but might have looked like junk. It is needed when running rifle length and not carbine.
Here is the rifle length spacer. I believe you have to trim it to fit properly. I can’t remember
 

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I have got this figure out. It was just a bad catch. The spring is set up exactlyike it should be (called jp to get it perfect)
 
Here is the one I just got after @Lawless was nice enough to inform me of the same situation after I broke my PSA bolt catch

S7 BOLT CATCH NP3 308/DPMS/SR25

SKU: BCS7308NP3/KIT


I just wish PHASE 5 would make an extended one to fit my 308 like my 223.

You mean like this one??
FullSizeRender 4.jpg

 
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