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11/20/2019 5:07:11 PM
Posted: 7/25/2009 1:01:00 PM EST
I am an idiot.

So.
I'm telling a group of guys not to pull the trigger when then upper is off and "CLICK!!!". I pulled the trigger thinking the safety was on and away flew my large paddle off the bolt catch.

Made me mad. But my fault, and I have spares. The lower is a factory assembled unfired new one.

So.
Today I'm at home trying to tap out the roll pin to swap out the bolt catch. I've rebuilt and assembled ARs for years. I start tapping, meet some resistance, and whack the heck out of the punch. I see what I thought was a scratch on the receiver. I get mad, but don't realize that the punch is inside the receiver hole, so there's no way that's a scratch dummy, it was a crack. So I whack the punch again and...




So.
After the wife comes running to see if I've broken a body part as I'm screaming very loud after she heard me hammering, I have a beer. I take some pictures. Have another beer or three, and start posting. I like to think I know alot about our favorite weapon system. I've never seen this.

Can't think of how to fix it. Could I weld or JB Weld some goo onto it after driving in the roll pin? Just sorta stuck with a lower that won't catch or lock the BCG?


I am an idiot.
Link Posted: 7/25/2009 1:15:14 PM EST
you could have someone tig weld it with the pin in...or just redrill it after...a good welder could patch it up....
Link Posted: 7/25/2009 1:37:53 PM EST
Not the end of the world event!
Go easy on yourself.
It's a teachable moment for readers on this site.

Read above comment.
You do have another AR for backup?
Link Posted: 7/25/2009 3:39:56 PM EST
it just pivots on that pin. there's not much stress on it. the real work is done by the part in the slot. it would probably hold up as is, but epoxy and paint wouldnt hurt.
AND its fixable, for 125$ or so (new lower). which gives you a perfect reason to build a dedicated .22lr. or ... yeah... a dedicated single shot .50bmg! its... honey... i'm saving money by recycling this lower!
Link Posted: 7/25/2009 8:21:34 PM EST
Thanks, guys, I'll get with a welder.
Have backups to backups to those backups to well, it's the evil BRD.
Hmmmm, she might just buy in..., nawwww, I've used that line before.
Link Posted: 7/25/2009 9:17:14 PM EST
Who's parts?
Link Posted: 7/26/2009 2:18:37 AM EST
Did'nt we just have a thread where a guy did this to his lower 20 some time's to prove what happened to your's. Would'nt
Link Posted: 7/26/2009 7:29:17 AM EST
hey yoteslayer and op

in the thread demonstrating dry firing the lower that member stated he always tested his newly assembled lowers this way to assure the bolt catch is not defective

the op in this thread states this broken bolt catch occurred on a new unfired lower

could the bolt catch have been defective destined to fail?

i would really like to know what company made this bolt catch could be a warranty issue
Link Posted: 7/26/2009 7:42:17 AM EST
[Last Edit: 7/26/2009 7:43:20 AM EST by 556Cliff]
Originally Posted By YoteSlayer69:
Did'nt we just have a thread where a guy did this to his lower 20 some time's to prove what happened to your's. Would'nt


Yes I did.


Link
Link Posted: 7/26/2009 9:02:07 AM EST
Originally Posted By CRS188:
Thanks, guys, I'll get with a welder.
Have backups to backups to those backups to well, it's the evil BRD.
Hmmmm, she might just buy in..., nawwww, I've used that line before.


Most receivers I see are made from 7075 aluminum and this is what Lincoln Electric says about welding it...

8. How do I weld 7075?

Most aluminum alloys are weldable, but there are a fair number of them that are not, including 7075 aluminum. The reason 7075 is singled out in this example is that it is one of the highest strength aluminum alloys. When designers and welders look for an aluminum alloy to use, many will start by reviewing a table that lists all of the aluminum alloys and their strengths. But what those newcomers don't realize is that few of the higher strength aluminum alloys are weldable - especially those in the 7000 and 2000 series - and they should not be used.

The one exception to the rule of never using 7075 for welding is in the injection molding industry. This industry will repair dies by welding 7075 - but it should never be used for structural work.
Link Posted: 7/26/2009 12:50:30 PM EST
Link Posted: 7/26/2009 2:08:05 PM EST
Meh, use it for a .22lr AR15. The bolt catch doesn't work on those anyway. Consider it a lesson learned.

Posted Via AR15.Com Mobile
Link Posted: 7/26/2009 2:18:28 PM EST
[Last Edit: 7/26/2009 2:19:25 PM EST by ColtAllure]
Originally Posted By CRS188:
I start tapping, meet some resistance, and whack the heck out of the punch.


I think this is the teaching line from this teachable moment.
Of course we've all done it, usually to our regret.

Link Posted: 7/26/2009 3:04:52 PM EST
pm sent.
Link Posted: 7/26/2009 3:33:21 PM EST
Originally Posted By YoteSlayer69:
Did'nt we just have a thread where a guy did this to his lower 20 some time's to prove what happened to your's. Would'nt


I was just thinking the same thing
Link Posted: 7/26/2009 3:40:01 PM EST
Originally Posted By bookertbab:
Originally Posted By CRS188:
Thanks, guys, I'll get with a welder.
Have backups to backups to those backups to well, it's the evil BRD.
Hmmmm, she might just buy in..., nawwww, I've used that line before.


Most receivers I see are made from 7075 aluminum and this is what Lincoln Electric says about welding it...

8. How do I weld 7075?

Most aluminum alloys are weldable, but there are a fair number of them that are not, including 7075 aluminum. The reason 7075 is singled out in this example is that it is one of the highest strength aluminum alloys. When designers and welders look for an aluminum alloy to use, many will start by reviewing a table that lists all of the aluminum alloys and their strengths. But what those newcomers don't realize is that few of the higher strength aluminum alloys are weldable - especially those in the 7000 and 2000 series - and they should not be used.

The one exception to the rule of never using 7075 for welding is in the injection molding industry. This industry will repair dies by welding 7075 - but it should never be used for structural work.


Yes, exactly, and how "structural" is the ear that retains the bolt catch? I'd weld it in a heartbeat, probably using 5356 filler with a bit of a risk that the color wouldn't be spot on after re-anno.
Link Posted: 7/26/2009 5:45:08 PM EST
[Last Edit: 7/26/2009 5:45:34 PM EST by 2FALable]
I'd be willing to bet that since the roll pin really doesn't take stress nor does the receiver there that you could put in a new catch and pin, then layer and sanding shape JB Weld to that, then gunkote or duracoat it and it would hold unless you had to pull the bolt catch again.
Link Posted: 7/26/2009 5:59:41 PM EST
Where are we at on this site about dropping names? I think I saw a thread about this but didn't read it. So if a mod wants to delete this, obviously they certainly can.

The lower was a brand new unfired LMT. The warranty might apply, but it was my mistake in pulling the trigger, and bolt catches are cheap. It was also me that didn't pay attention to driving out the roll pin, because I'd done it dozens of times before and got lazy, and busted the ear with the punch. I feel it was my fault, so no need to bother the company.

I don't think this is a slam on the company as I broke it by doing something stupid. Twice.

Learning experiance indeed. I have pulled the trigger without the upper probably hundreds of times on dozens of lowers. Espicially when in the Army and hadn't been told not to. Once I learned not to after buying several of my own, I stopped doing it.

I've installed the bolt catch. I'll be shooting it later this week in order to break in the gun. I'll see if it holds up.

To those asking via IM, I'm not interested in selling it. Thank you fo the offers, but I'm keeping it.
Link Posted: 7/26/2009 6:03:08 PM EST
Meh, use it for a .22lr AR15. The bolt catch doesn't work on those anyway. Consider it a lesson learned.


Link Posted: 7/27/2009 1:48:44 PM EST
I thought it would be a DPMS part.

So you were hitting the ear of the receiver with the punch when it broke off and you were not on the roll pin?
Link Posted: 7/27/2009 1:57:49 PM EST
Originally Posted By CRS188:
Thanks, guys, I'll get with a welder.
Have backups to backups to those backups to well, it's the evil BRD.
Hmmmm, she might just buy in..., nawwww, I've used that line before.


There is a pretty durn good chance that the lower is 7075 Al, which is a non weldable alloy, so be sure to let your welder know that. It's most likely unless you have a cheap lower made of 6061 which is weldable. Wanted to get that out there before you or someone else tried and messed things up even worse trying to TIG it. No real way to tell either besides calling whoever made the lower and asking which material they used and going from there.

Link Posted: 7/27/2009 7:57:41 PM EST
If it's a forging, which it appears to be, then it will be 7075.
Link Posted: 7/27/2009 9:19:38 PM EST
I say buy you a Bohica .50bmg upper and put on there. You won't need a bolt catch on that and you'll have an awesome gun!!!!!!!!! just file down the broken and the unbroken tab and gunkote the lower.
Link Posted: 7/27/2009 9:27:27 PM EST
The main alloying element in 7075 Aluminum is zinc. That is what makes it so impractical to weld. (Think about what happens to the zinc coating of galvanized steel when welded.) If you can find a company that specializes in repair welding zinc alloy series aluminum, I bet the cost for the repair will be far greater than buying several brand new lower receivers!

You might try using this stuff here. I have had luck using this type of product to repair "pot metal" castings that were "unweldable".

If you give it a try, please be sure to give us an update on your results!
Link Posted: 7/28/2009 2:50:26 AM EST
[Last Edit: 7/28/2009 2:52:11 AM EST by shamayim]
Maybe I'm a bit off base here, but unless the manufacturer of the lower specifically included a warning against snappinbg the trigger w/o an upperin place, I would think you could recover damages on the broken piece. I've owned a Colt SP1 for over 30 years, and can assure you that I've accidentally let the hammer hit that wall 8-10 tmes over the years. Maybe more. That piece should have stood up to only two hits.

Sure, we all know we shouldn't snap the hammer on an uncovered lower, bu the simple fact is that the field is covered up w/newbies who don't know this.

I'd at least talk w/the company about this.. Two snaps is a hell of low count to break a reciever totally in half.
Link Posted: 8/3/2009 1:17:01 AM EST
Link Posted: 8/3/2009 7:49:59 AM EST
Good thing that lower wasn't SBR'ed.
Link Posted: 8/4/2009 3:51:12 PM EST
Originally Posted By Pro2AinPA:
Good thing that lower wasn't SBR'ed.


+100
Link Posted: 8/4/2009 4:44:51 PM EST
Let me get this right. He freaked it up by doing something he should not do, and you think LMT should be the one to replace the lower and eat the expense? God, what are you smoking? I am glad the OP does not have this attitude. He is at least man enough not to even ask someone to pick up after him. NO gun manufacturer that I know of warrants their stuff against outright misuse and abuse. Maybe they would have replaced the bolt catch if it had been returned (providing they built it in the first place and it was not built from a stripped lower) but when he broke the lower receiver it trying to replace the bolt catch himself, the maker would be nuts to feel obligated to replace anything. And the OP is smart enough to realize that. Good for him. Boo on you for even suggesting that the lower maker should be responsible.
Link Posted: 8/4/2009 8:07:26 PM EST
Originally Posted By shamayim:
Maybe I'm a bit off base here, but unless the manufacturer of the lower specifically included a warning against snappinbg the trigger w/o an upperin place, I would think you could recover damages on the broken piece. I've owned a Colt SP1 for over 30 years, and can assure you that I've accidentally let the hammer hit that wall 8-10 tmes over the years. Maybe more. That piece should have stood up to only two hits.

Sure, we all know we shouldn't snap the hammer on an uncovered lower, bu the simple fact is that the field is covered up w/newbies who don't know this.

I'd at least talk w/the company about this.. Two snaps is a hell of low count to break a reciever totally in half.


YOU are the reason why my handguns are covered in stupid safety warnings.
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