View Full Version : Dead Gun! Thoughts?
Was shooting an LMT. Fire 4 rounds and the 5th, the trigger won't move. Felt like the safety was on, but it wasn't. I clear the gun and push out takedown pin. The hammer is cocked and the trigger is frozen. I can't get the hammer forward. I suspect what the problem is, but can't see anything in the lower.
I get it home and pull the upper. I again inspect the lower but can't see anything that would jam the action.
I remove the hammer pin and hammer stays in place. I use a plastic hammer and punch and the hammer "pops" out. The trigger has a little movement now but not what it should have. I pull the trigger and sure enough, up against the back wall of the receiver, below the safety, wedged beneath the end of the trigger bar is a fired primer. That was what I suspected. I have heard of this, but this is a first for me. Called a buddy who is an armorer for a large dept. He said he has seen it a few times. So, I figure it is just what it is?
I was thinking about this issue and thought "Why don't they mill a bit out of the receiver so if any items get deposited it has some free space behind the trigger bar?" I decide to inspect different lowers. LMT and BCM look identical. Colt is a bit different but still has the same wall. Then I inspected one of my Sionics lowers and it is exactly what I was thinking. First there is substantially more room behind the trigger and also, it would have been easy to see the primer and remove it. I will attempt to attach some pictures. I hope I do it correctly and everyone can see what I am talking about. I wonder if this is the reason sionics milled their lower? Thoughts? Thoughts on this situation? Does it make sense? Makes me rethink grabbing an AR in an emergency without having a sidearm to transition to. Thoughts?
Pictures show LMT with trigger, then Sionics with trigger and then LMT with trigger removed.
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Were you using ammunition with staked primers? The Sionics modification is interesting; are there more brands like this?
I’m just speculating, as I am not a lower expert.
Perhaps that filled gap in the LMT adds some rigidity to the lower?
I was shooting reloads. I have looked at the following lowers: Sionics, BCM, LMT, Colt, Bushmaster, CMMP and a few others. So far, only Sionics has the cut. I doubt it adds much rigidity, but I am speculating as well. Perhaps I can ask everyone to look at their lowers to see if anyone else has the Sionics "cut."
I will probably call Sionics for their input. Being retired, I think I have too much time on my hands. However, I see no downside to the sionics cut. There is much more visibility. I think it is a better mousetrap???
Cheers, Steve
Makes me rethink grabbing an AR in an emergency without having a sidearm to transition to. Thoughts?
Many flavors of .223 and 5.56 come with crimped or staked primers so why not use one of those in a defensive gun? I don't think any of my 6.5 Grendel ammunition has crimped primers however.
I never noticed my Sionics being different. I will check it out after work.
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In 40 years of shooting I have personally only seen popped primers happen with reloads.
I’ve read about it & knew guys who used these, when they were available:
https://www.midwayusa.com/product/1003349235
In 40 years of shooting I have personally only seen popped primers happen with reloads.
Can happen to ammo like M193 fairly easily when firing in a .223 chamber. Depends on how 'tight' the chamber is but it does happen.
Popped primers, case mouths ripped off or split to hell, etc. Great way to ruin what 'could' have been perfectly good once fired brass to the point where it is garbage.
I’ve read about it & knew guys who used these, when they were available:
https://www.midwayusa.com/product/1003349235
Not bashing them cause I do have and like a lot of their older stuff (back from their early years) but it is fitting that they would make and sell such a thing cause their .223 chambers back then were tighter than hell.
Have sent more than a couple off to CLE to be rechambered so they do NOT make mil spec ammo puke primers so easily...
No issues at all with their chambers or popped primers IF shooting the proper ammo out of them.
Hammer_Man
11-20-21, 20:40
The Sionics lower appears to have a mil spec trigger pocket. The LMT has a neutered civilian trigger pocket to keep the alphabet boys happy.
I had thought that it was near impossible for the primer to pop out in factory ammo. That is why I called my friend. I will talk to him again to verify what ammo. He stated it was factory, dept approved ammo. I will follow up. My defense ammo is crimped, or at least I believe it is. (speer gold dot) If, as stated above, it is true about sionics having a mil spec trigger pocket, then I would assume that any arguments about reducing structural integrity is non existent.
The more I look at the sionics lower, the more it looks right. The additional visibility into the trigger pocket is beneficial. A quick push of the take-down pin, removal of debris, close upper and you are back in the game, class, training, range fun, fight. I see only benefits and no detriment.I look forward to other members reports of how their various lowers are milled.
Cheers, Steve
Out of spec chamber will pop primers. Used to be pretty common when AR-15 popularity was really picking up.
My only lower that's milled like the Sionics is a Geissele. BCM, Aero, Mega, Centurion, and PSA all have very minor differences. Of course Colt does it's own thing.
This appears to be Mil-spec??? Does anyone have a Sons of Liberty lower? I am curious how they are milled. So far we have sionics and geissele.
Cheers, Steve
jackblack73
11-21-21, 04:53
Isn't the Sionics milled that way to accommodate an auto sear (low shelf)? But without the third hole, of course.
This appears to be Mil-spec??? Does anyone have a Sons of Liberty lower? I am curious how they are milled. So far we have sionics and geissele.
Cheers, SteveAll SOLGW lowers are auto pocket cut. Always have been.
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Bingo!
The Sionics lower appears to have a mil spec trigger pocket. The LMT has a neutered civilian trigger pocket to keep the alphabet boys happy.
Yes, see above.
Isn't the Sionics milled that way to accommodate an auto sear (low shelf)? But without the third hole, of course.
Lower receiver milling patterns aren't the real issue here.
Popped primers can get stuck anywhere in the FCG and the results are the same.
The issues could be with the chamber, or most likely the reloads.
Fix that and the problem goes away.
I was shooting reloads.
Cheers, Steve
Glad someone showed up who actually knows something about lower milling. I learned something today.
Absolutely outstanding info from everyone. Thank you. As stated, I have had a few primers pop out from these reloads. They are only used for range days not for competition, training or self defense. I agree, this discussion has been very informative. Think I will stick with low shelf/ auto pocket lowers from here on out. Now to find some SOLGW lowers to build for my SOLGW upper that is on its way.
Cheers, Steve
Absolutely outstanding info from everyone. Thank you. As stated, I have had a few primers pop out from these reloads. They are only used for range days not for competition, training or self defense. I agree, this discussion has been very informative. Think I will stick with low shelf/ auto pocket lowers from here on out. Now to find some SOLGW lowers to build for my SOLGW upper that is on its way.
Cheers, Steve
Steve, I don't know if you missed the post from Clint a couple posts back, but it really doesn't matter much if you have a low shelf lower, or not. Primers can get wedged in a bunch of different places in the FCG, and I've even seen them getting wedged in the BCG and locking up the gun. The lowers you have are fine; just use better ammo when it comes down to serious use. You can still use the reloads you've been buying for range use, just keep your serious use and practice ammo separate.
I was shooting reloads.
There you have it.
Overpressure ammo can pop primers, doesn't matter if reloads or mil-spec, I had to pull down 1,500 rounds of linked IVI SS109 that was popping primers in a Colt 16" and a Colt 20". Also primer can get jammed in bolt lug recess not just in the fcg.
Steve, I don't know if you missed the post from Clint a couple posts back, but it really doesn't matter much if you have a low shelf lower, or not. Primers can get wedged in a bunch of different places in the FCG, and I've even seen them getting wedged in the BCG and locking up the gun. The lowers you have are fine; just use better ammo when it comes down to serious use. You can still use the reloads you've been buying for range use, just keep your serious use and practice ammo separate.
I didn't miss the post. I agree a primer can cause issues in both lowers. As stated, my reloads are for range time only. However, my point is that the "full auto cut" offers, in my opinion, better visibility into the trigger pocket and additional space for debris. My conclusion is that there are possible benefits without any downside or negative issues. Hence, moving forward, I will limit myself to using lowers that have the low shelf cut. I have no intention to replace all my LMT, Colt, BCM etc lowers.
Again, I want to thank everyone for a very informative and enlightening thread.
Cheers, Steve
I didn't miss the post. I agree a primer can cause issues in both lowers. As stated, my reloads are for range time only. However, my point is that the "full auto cut" offers, in my opinion, better visibility into the trigger pocket and additional space for debris. My conclusion is that there are possible benefits without any downside or negative issues. Hence, moving forward, I will limit myself to using lowers that have the low shelf cut. I have no intention to replace all my LMT, Colt, BCM etc lowers.
Again, I want to thank everyone for a very informative and enlightening thread.
Cheers, SteveI can't say I disagree at all with your thinking and conclusions. Cheers!
titsonritz
11-21-21, 16:11
Absolutely outstanding info from everyone. Thank you. As stated, I have had a few primers pop out from these reloads. They are only used for range days not for competition, training or self defense. I agree, this discussion has been very informative. Think I will stick with low shelf/ auto pocket lowers from here on out. Now to find some SOLGW lowers to build for my SOLGW upper that is on its way.
Cheers, Steve
Check out Big Tex.
https://www.bigtexordnance.com/product/solgw-loyal-9-stripped-lower-receiver-sons-of-liberty-gun-works/
"Limit 1776 per household"
Rifleman_04
11-21-21, 22:28
I see this happen a lot when people use military crimp removers and get overzealous and cut out half of the primer pocket.
You lose half of the depth of the pocket and half of the pocket wall adhesion on the primer as a result.
A primer pocket swage will remove a crimp and not completely ruin the brass by removing the primer pocket.
Absolutely outstanding info from everyone. Thank you. As stated, I have had a few primers pop out from these reloads. They are only used for range days not for competition, training or self defense. I agree, this discussion has been very informative. Think I will stick with low shelf/ auto pocket lowers from here on out. Now to find some SOLGW lowers to build for my SOLGW upper that is on its way.
Cheers, Steve
You won't be disappointed. I just finished a 13.7 build using a SOLGW lower and stripped upper. First time using them and they are now my go to. The attention to detail in the machining and finish is noticeable. I was going to cerakote this build but after getting the receiver set in couldn't bring myself to do it.
I see this happen a lot when people use military crimp removers and get overzealous and cut out half of the primer pocket.
You lose half of the depth of the pocket and half of the pocket wall adhesion on the primer as a result.
A primer pocket swage will remove a crimp and not completely ruin the brass by removing the primer pocket.
I've had the opposite experience. The super swager would ruin my pockets, where the hornady cutting tool was self limiting. I hand prime brass and sideline loose pockets to be shot in a batch where I'm willing to deal with a popped primer.
I've had the opposite experience. The super swager would ruin my pockets, where the hornady cutting tool was self limiting. I hand prime brass and sideline loose pockets to be shot in a batch where I'm willing to deal with a popped primer.
RCBS tools that do that are self limiting as well. Not possible to ream too much as the tools will only allow you to go so far...
Same here with the use of a hand primer. You can definitely 'feel' when the pocket is not right.
Rifleman_04
11-22-21, 16:42
Well I’m glad you guys are using self limiting cutting tools and aren’t dumb. The ones I saw were definitely not limited. I’ll see if I can find some in the bin and post a pic.
Well I’m glad you guys are using self limiting cutting tools and aren’t dumb. The ones I saw were definitely not limited. I’ll see if I can find some in the bin and post a pic.
You are not at all wrong about some guys using the wrong tool and going too far with it.
There are guys that will ream using whatever they have laying around instead of spending what 20 bucks? on something intended for the task and designed so you can't screw up.
I am guilty. Screwed up my share before buying the right tool to do it that way.
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