Adjustable BCGs?

MadMardigan

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When shooting my 300blk 16" suppressed with a standard nickel boron BCG I had some malfunctions. I suspect it's the gas system.

Would it be better to get a BCG I can move between platforms since I have 3 (8.5" 300blk and 18" .223) to solve the gas issues, or should I sort it using a heavier buffer / spring combo?
 
What exactly is the nature of the malfunctions, and what direction is the gun sending cases? If your barrel was pointing at 12:00 and your stock was at 6:00.

If it is overgassed it should be throwing them forward of the ejection port, like 2:00.

I personally like cutting the gas with a gas block. I have never tried the adj. BCGs but that may be a good deal, too. Likely you would have to adjust it everytime you changed between the two, which seems like a pain in the ass.

That said, I have a 12.5" 5.56 that was slightly overgassed, in which I used an H2 buffer and JP chrome spring and it works great. But if money were no object I would go with a lighter buffer and an adj. GB.
Just feels way smoother and cuts down on the forward impulse. Just my opinion.
 
PSA 16" 300blk, PSA Nickel Boron BCG, Magtech 123gr supers, Griffin Armament Optimus. Smith and Wesson Lower, not sure on the LPK or buffer weight.

Sorry, should have been more specific. What malfunctions are you having? Of course I typed it before you posted the pic. Didn't refresh before I posted.
 
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try shooting the same loads unsuppressed. See if the problem persists.
If it doesn't happen again it's most likely a gas issue and you will need to get an adjustable block

Yeah, that would be the next step. I've just never seen a round get caught above the BCG like that
 
It's so quiet it's creepy.
I have a blk/9mm can and a 308 can.
The 308 can makes it sound like an air soft toy

The Optimus will do 9mm and up to 300win mag.
I'm going to get a 9mm ar soon, it's too heavy for my g17 for anything more then fun with how the balance goes. But worked great on the Scorpion I had.
 
Yeah, a double feed.
Mine was doing exactly that. But it was doing it suppressed or unsuppressed, supersonic or subsonic....
Maybe try cleaning the gas block and tube really well.

Also make sure the gas rings are spread out to 120 degrees each, and the BCG system is well lubed.
You'd be surprised how many people forget to lube an NP3 BCG

I do lube the bolt, I'll have to break it down for a cleaning.
 
Two questions, one, where does it throw cases when it functions?

Two, what mags are you using and how old are they?

Bolt over brass could easily be a mag lip tension issue.
 
Two questions, one, where does it throw cases when it functions?

Two, what mags are you using and how old are they?

Bolt over brass could easily be a mag lip tension issue.

Don't recall the direction, didn't check the brass deflector for impact.

New out of the package pmags
 
Two questions, one, where does it throw cases when it functions?

Very first question I asked in this thread, lol.
Seems to be the first question that should be asked if someone thought they had a gas issue!
 
Don't recall the direction, didn't check the brass deflector for impact.

New out of the package pmags

Do like @NKD said and see where it falls next time you shoot. Should be fairly consistent. That'll tell you all you need to know about gas operation.

How many times has it happened? It's a fairly rare jam as I understand it. New mags shouldn't be an issue, but ya never know. Do you mark them? I got a bad 40rd PMag out of the bag once. Gave me fits until I finally threw it against the wall at Wake Co and broke it...
 
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Very first question I asked in this thread, lol.
Seems to be the first question that should be asked if someone thought they had a gas issue!

Yeah, as I understand over gassing throws brass forward, under throws it's back farther. Though bolt speed will increase and you fire since it's less resistance on the bolt as it cycles.
 
Yeah, as I understand over gassing throws brass forward, under throws it's back farther. Though bolt speed will increase and you fire since it's less resistance on the bolt as it cycles.

Not sure exactly what you mean by this. Less gas makes bolt speed increase?
How is that possible? Resistance on bolt should be the same no matter what amount of gas it does or doesn't have.
Maybe I am missing something.
 
Not sure exactly what you mean by this. Less gas makes bolt speed increase?
How is that possible? Resistance on bolt should be the same no matter what amount of gas it does or doesn't have.
Maybe I am missing something.

Less resistance as the mag spring pressure on the bolt easies up, should have clarified.
 
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With the increased volume caused by a suppressor, does it cause the bolt to hang back / delay?

Shouldn't. Just more gas volume in the upper making the bolt move faster. That's where an adjustable gas block shines. Just don't turn it down too far...

To slow/delay the BCG you need mass or spring tension, assuming gas is a constant...
 
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With the increased volume caused by a suppressor, does it cause the bolt to hang back / delay?

Nope.

Gas is regulated by the BCG gas chamber excess gas is vented by the gas ports on the BCG = normal operation

Excess gas traped in the BCG gas chamber can not vent = charging handle fumes and wear on the gas rings on the bolt.

The return speed of the BCG is directly related to a quality charging handle stem, buffer weight, spring coil pressure and bounce back off the buffer tube and no damn nylon tip screw.....
 
Pistol gas on a 16" barrel......lends itself to functioning with subs rather than supers. This issue was discussed lots when the cartridge was new as there were only a few companies that had the gas port specs figured out to get 100% reliability with subs and supers. Everyone else was selling barrels that worked well with one or the other. Since the cartridge isn't new anymore many people are not aware how critical proper gas port sizing is for the BLK to work with both Supers and Subs.

Sent from my SM-N910V using Tapatalk
 
Pistol gas on a 16" barrel......lends itself to functioning with subs rather than supers. This issue was discussed lots when the cartridge was new as there were only a few companies that had the gas port specs figured out to get 100% reliability with subs and supers. Everyone else was selling barrels that worked well with one or the other. Since the cartridge isn't new anymore many people are not aware how critical proper gas port sizing is for the BLK to work with both Supers and Subs.

Sent from my SM-N910V using Tapatalk

Would a Gemtech / Bootleg bolt be a fix then?
 
I finally tore the gun down and get the round out. I was running a heavy buffer H3, swapped it to a 3oz standard.

Might have been the issue. Hitting the range tomorrow.
 
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