Oklahoma Hunting Forum banner
1 - 20 of 45 Posts

·
Registered
Joined
·
1,102 Posts
Discussion Starter · #1 ·
So, just some food for thought. Did a straight trade with a guy a few weeks back, my upper and ammo for his upper and ammo. The attached pic is what the bolt looked like and the handguard barrel nut was only hand tight.
The barrel extension looks good, but the bolt is trash. The bolt was so soft the bolt face was actually concave when placed face down on a table. I had to pry out the extractor because it was pinched in place. Somebody missed the heat treat kiln.

Be careful when buying/trading from unknown origins.
 

Attachments

·
Registered
Joined
·
1,102 Posts
Discussion Starter · #3 ·
I don’t know much about AR platforms but that don’t sound good
The bolt rotates and locks into lugs in the barrel extension. Because the lugs on the bolt were not properly hardened, evidenced by the mushrooming on the back of the lugs, headspace can increase to a point where you get into case head separation. A big Kaboom! That was compounded by the fact the barrel was well under-torqued. The guy I got it from did not assemble it, he got it from a friend. He shot about 20 rounds out of it before trading it to me. He was lucky he didn't get hurt and I'm glad I inspected it before I shot it.

Luckily nothing else was damaged and I was going to convert this to a 7.62x39 build anyways so I'm only out a spare bolt.
 

·
Administrator
Joined
·
14,234 Posts
You have to watch those $50 BCG's that come on sale around Christmas. Pretty much for the person that might shoot a magazine a year and call it good. If you get into volume shooting or competition, they won't last the weekend.
The old saying you get what you pay for rings very true in most gun parts. You have to remember there is about 50,000 PSI of pressure in that chamber when ignition takes place.
 
  • Like
Reactions: Bird (this time)

·
Registered
Joined
·
1,102 Posts
Discussion Starter · #6 ·
You have to watch those $50 BCG's that come on sale around Christmas. Pretty much for the person that might shoot a magazine a year and call it good. If you get into volume shooting or competition, they won't last the weekend.
The old saying you get what you pay for rings very true in most gun parts. You have to remember there is about 50,000 PSI of pressure in that chamber when ignition takes place.
Exactly! I took the barrel off this upper and decided to make it a "budget" 7.62 (hog slayer) upper since I needed to order a new bolt anyways. Got the new bolt and barrel this weekend and I've already run into another probelm. The barrel is of decent quality from a manufacturer I've used dozens of times and so is the bolt, however, the bolt was purchased at a steep, clearance, discount and I believe it may have shipped with an out of spec extractor. I'm getting perfect function and lock-up on an empty chamber. As soon as I put in a dummy round, it won't go into battery. So I guess it's either headspace, or the extractor (which is really common with 7.62 bolts as I've read.)

I just need to find some time one evening to take out the extractor and ejector so I can properly check the headspace to rule out an issue with the barrel. If that clears, then I'll go hunt down a new extractor. The extractor already looked out of spec to my untrained eye. It seemed seized up so I removed the O-ring to see if that helped and it sure didn't. At least extractors are cheap.
 

·
Administrator
Joined
·
14,234 Posts
The mil-spec stuff especially triggers are notorious for being out of spec.
In this pic of some I have here, the one on the right isn’t cut correctly. Looks like someone with a file made the cut. The left one is in spec.
What’s interesting is that the hammer on the right had a better trigger pull because there was less friction from the poor cutting job.

 
  • Like
Reactions: Bird (this time)

·
Registered
Joined
·
1,102 Posts
Discussion Starter · #8 ·
Oh yeah. I remember one of my first lower builds I used a factory DPMS lower parts kit. The upper was factory assembled. I went to an outdoor range for a function test and immediately heard an echo when I shot. I shot two or three times and it seemed like it was doubling. I put two rounds in a mag and after one trigger pull the magazine was empty. I looked down the firing line and I saw a firearms instructor who was teaching a CCW class and he was staring at me. I cleared the rifle and put it in my case and went home shortly thereafter. I was horrified.

After inspection, I found the disconnector was out of spec and contained burrs which were causing it to get stuck in the trigger where it pivots over the spring. This caused my rifle to double and shoot a burst each trigger pull. I replaced the disconnector and never had another problem. Even factory parts from reputable manufacturers can be out of spec.

I recently had a safety from CMMG which was not drilled correctly. It was rotating past "safe" and wouldn't rotate to a "fire position". Luckily my local store comped me a free safety, which dropped right in and fixed the problem.
 

·
Registered
Joined
·
5,338 Posts
(Insert jokes about gals here)
 

·
Registered
Joined
·
5,338 Posts
The mil-spec stuff especially triggers are notorious for being out of spec.
In this pic of some I have here, the one on the right isn’t cut correctly. Looks like someone with a file made the cut. The left one is in spec.
What’s interesting is that the hammer on the right had a better trigger pull because there was less friction from the poor cutting job.


So you did put the ugly but better feeling trigger back in, right? (Insert jokes about ugly gals here)
 
  • Like
Reactions: dennishoddy

·
Administrator
Joined
·
14,234 Posts
So you did put the ugly but better feeling trigger back in, right? (Insert jokes about ugly gals here)
No, those are take outs. I have replaced every trigger with a drop in Timney or a Rise Armament 3lb in all the AR’s and bolt guns.
Those in the pic are headed out to a guy today for a build he’s working on.
 

·
Super Moderator
Joined
·
11,253 Posts
I guess I gotta learn all this jazz now that I’ll soon have a -15. I’ve left my -10 factory as well.
 

·
Administrator
Joined
·
14,234 Posts
I guess I gotta learn all this jazz now that I’ll soon have a -15. I’ve left my -10 factory as well.
Once you get the lingo and acronyms down and see how easy they are to repair and modify it’s pretty easy to get hooked on them.
As an example, the designer Stoner built the rifle so a complete field strip including breaking down the bolt carrier could be performed with a loaded FMJ round as the only tool required.
 

·
Registered
Joined
·
1,102 Posts
Discussion Starter · #15 ·
Once you get the lingo and acronyms down and see how easy they are to repair and modify it’s pretty easy to get hooked on them.
As an example, the designer Stoner built the rifle so a complete field strip including breaking down the bolt carrier could be performed with a loaded FMJ round as the only tool required.
I'm terrified of bullet setback so I use the firing pin.
 

·
Administrator
Joined
·
14,234 Posts
I'm terrified of bullet setback so I use the firing pin.
If the bullet is crimped on the cannelure it's pretty easy to see if bullet setback has occurred.
 

·
Super Moderator
Joined
·
11,253 Posts
1 - 20 of 45 Posts
Top