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So I took the SBR out yesterday. No issues of any kind. Get home and I noticed my bolt release catch seems loose. Then I realize that it's under zero spring tension. Today, I pop the pin out of the bolt release to see what's going on and it turns out the plunger hole has mushroomed a tad on the lower portion of the hole, locking the plunger and spring into the hole, obviously due to contact with the bolt catch. I checked and rechecked and everything on the receiver is in spec right down to 0.001", as is the bolt catch itself (which is Daniel Defense).

 

So take your best guess as to what's up here. This lower has just under 700rds through it. I want to think that there may have already been a burr on the lower and that use just exacerbated the problem, but I want to hear what you guys think as well. 

 


Also, I took a pick and pulled out a tiny burr from the hole and everything's fine now. My concern is that it may do it again though.

post-28103-0-35359600-1435012347_thumb.jpg

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I have built lots of ARs never seen this

I would suspect a burr in an over the counter lower before suspecting an operational issue.

the bolt lock only has the pressure from the mag follower  applied to it, that is not a bunch.

I guess it is possible the diameter of the hole could be small from a worn tool in manufacturing.

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Couple of quick easy fun fixes.  Yep ... I have never seen this type of bo bo.  1) Mix up some two part liquid steel or type gunk and fill up the void and re drill out the hole.  2) same but using high temp bondo.   Hope this helps.

 

Minor problem.  The platform will run just fine without the BCAG.  Hope this helps.  HB of CJ (oldest coot) Hundreds of AR15 builds, assisted uncounted many many M16 rebuilds.  Why it happened?  I dunno fur sure.

 

Edited by HB  What is a BCAG?  Heck if I know.  Opps.  How about a bolt stop group.  BSG.  Or bolt hold open group?  BHOG.

Edited by HB of CJ
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Couple of quick easy fun fixes.  Yep ... I have never seen this type of bo bo.  1) Mix up some two part liquid steel or type gunk and fill up the void and re drill out the hole.  2) same but using high temp bondo.   Hope this helps.

 

Minor problem.  The platform will run just fine without the BCAG.  Hope this helps.  HB of CJ (oldest coot) Hundreds of AR15 builds, assisted uncounted many many M16 rebuilds.  Why it happened?  I dunno fur sure.

 

Uhhh no.

I'm no AR expert, but no.

 

He can clean the plunger hole with the correct size bit, blow out with compressed air, and use a dab of grease in the hole.

Then polish the plunger (chuck it up in a drill) and reassemble.

 

There is no reason to start mixing up JB Weld!    shocked.gif

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Well children, respectfully, I am the AR15 build expert here and when you have built way over 200 AR15 rifles and long ago and far assisted in rebuilding uncounted many many truly beater worn out M16 rifles from basic training USA in which all sorts of non messy fun easy and educational ways of fixing really worn out and out of spec M16 lowers ... some the way I just alluded to, then perhaps you can come up with a better way.  Until then, defer to better judgment, experience, knowledge, wisdom and all of that useless knowledge stuff obtained from the mists of time. smile.pngsmile.png

 

Besides, goofing around with your AR15 is fun and easy.  Or you might consider calling up Daniel Defense, a premium builder and manufacture and asking them to take care of it under warranty.  Helpful hint ... they might just do what I have already suggested.  Working on AR15 rifles is fun and easy.  No big deal with the liquid steel and re drilling that pesky bolt stop group plunger hole.  Or just remove the group and run the platform without it.  Same thing with lots of stuff on the AR15.  Nice but not necessary.  Hope this helps.  Not to be taken seriously.  HB of CJ (oldest coot) smile.pngsmile.png

 

Edited by HB again.  Sorry.  The above sounds too harsh.  Not meant to be.  It was supposed to be funny.  It was not.  Shit.

Edited by HB of CJ
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Thanks for the input, gents. Like I said earlier, I've compared everything in the area to the blueprints and to my Aero lower (who I believe makes Spike's lowers anyway?) and it checks out perfect with respect to both. I'll call it a fluke. For right now I think I'm going to run it as is after the burr removal and check up on it again after another 500rds to make sure it's not a reoccurring issue. I'd like to keep tinkering around with it to a minimum since it's a registered lower.

Edited by W8lifter
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Yep ... missed totally the SBR stuff.  Sorry.  Might not be a good idea to send it back.  The paper work would be incredible.  Go ahead and fix the burr.  It might last, it might not.  Eventually you might have to address the underlying problem with the plunger hole.  Or ... maybe not.  Enjoy. HB

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Thanks for the input, gents. Like I said earlier, I've compared everything in the area to the blueprints and to my Aero lower (who I believe makes Spike's lowers anyway?) and it checks out perfect with respect to both. I'll call it a fluke. For right now I think I'm going to run it as is after the burr removal and check up on it again after another 500rds to make sure it's not a reoccurring issue. I'd like to keep tinkering around with it to a minimum since it's a registered lower.

Spikes lowers are pretty good at holding mil spec tolerances.

Speaking as a person who has manufactured AR15s and parts for years I think it is very unlikely the bolt catch detent  recess is in error

I would bet what you have done already is all that will be nessesary

SBRs and pistol length barrels cycle very fast, the bolts unlock very early,bolts strike the catch at a little higher velocity than a conventional length operating system, as the bcg rebounds with a little more energy.

Even so I doubt it is an operational issue.

I think you are good to go

jim

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Yep ... missed totally the SBR stuff.  Sorry.  Might not be a good idea to send it back.  The paper work would be incredible.  Go ahead and fix the burr.  It might last, it might not.  Eventually you might have to address the underlying problem with the plunger hole.  Or ... maybe not.  Enjoy. HB

There is no relevant paperwork other than including a copy of his Form 1 or 4 and state issued ID. He can send it to any 07FFL/02SOT for work and have it shipped back to him.

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Yep ... missed totally the SBR stuff.  Sorry.  Might not be a good idea to send it back.  The paper work would be incredible.  Go ahead and fix the burr.  It might last, it might not.  Eventually you might have to address the underlying problem with the plunger hole.  Or ... maybe not.  Enjoy. HB

There is no relevant paperwork other than including a copy of his Form 1 or 4 and state issued ID. He can send it to any 07FFL/02SOT for work and have it shipped back to him.

 

Thats correct, its as simple as simple gets.

But sending a gun out that carries a tax stamp may make one a little uncomfortable 

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I had the exact problem with my factory CMMG .308 AR. No explanation as to why, but once the plunger and spring were removed and and the hole cleaned up and deburred, the problem has never returned.

That right there is a what I was hoping to hear someone say lol

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I would guess that the BHO lever pin channel is drilled off axis and part of the lever is hitting the hole when activated. BHO lever casting itself may be out of spec.Tough to guess without seeing it in action.

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Soft ass Aero receiver that came off the line faster than chinese shoes during the panic. Run it to death and then melt it in the camp fire.

Care to elaborate on that? Never heard of that being an issue with Spike's or Aeros. I bought the lower this past December from PA after waiting for them to get them back in stock so I'm pretty sure it wasn't made during the panic period.

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They crank the shit out so fast and order aluminum from different distributors. They are well known pieces of shit. Just googleaplex SPIKES SUCKS and about a million defects show up. They cranked them out so fast during the original panics that they lost track of their objectives. They never slowed it down and have really slutted out their once good business. Never buy from a company who sells blemishes and discount bin shit. I am biased of course. We don't build pieces of shit up here.

 

https://si-defense.com/shop/ar15-receivers/556-lower-receiver/

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They crank the shit out so fast and order aluminum from different distributors. They are well known pieces of shit. Just googleaplex SPIKES SUCKS and about a million defects show up. They cranked them out so fast during the original panics that they lost track of their objectives. They never slowed it down and have really slutted out their once good business. Never buy from a company who sells blemishes and discount bin shit. I am biased of course. We don't build pieces of shit up here.

 

https://si-defense.com/shop/ar15-receivers/556-lower-receiver/

 

Are there really cases of "Soft ass" Aero receivers?

 

Would suck if true.

 

You could buy a shopping cart full of Anderson lowers for the price of that SI-Defense lower.

I know.... billet., but still.....

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Soft ass Aero receiver that came off the line faster than chinese shoes during the panic. Run it to death and then melt it in the camp fire.

This made me laugh.."run it to death and melt it in the camp fire" haha.gif

 

In all reality, you could just try what spartacus pointed out first. If it happens again, then gut the lower and see if anything else may be able to be seen that you cant see when its assembled. Never seen this type of issue.

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Wow. Stress abounds. Mullllllllllltttttiple Spikes/Aero lower and uppers built here. Not one of them have sucked. I had the exact same problem as the OP on a CMMG Billet lower and upper. This gun shoots 1/2" MOA every time I take it out, even after fixing the "problem". I would recommend removing the plunger and spring, remove any burrs, stop worrying, and shoot the crap out of it.

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  • 10 months later...

Sorry to necropost, but I completely forgot I ever had this problem until I was out shooting today. I've now more than doubled the round count of the rifle since this occurred and this problem has never happened again. Must have just been a random burr I guess.

 

Case closed.  

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