Function Frustration... Please Help?

Discussion about rifles in 300 AAC BLACKOUT (7.62x35mm), hosted by the creator of the cartridge.

Moderators: gds, bakerjw, renegade

User avatar
JeffWard
Silent But Deadly
Posts: 237
Joined: Tue Jul 15, 2014 12:13 pm
Location: St Pete, FL
Contact:

Function Frustration... Please Help?

Post by JeffWard » Tue Jun 06, 2017 9:57 am

I own two 300BLKs.

My first is a 8.25" barrel with a 0.125 gas port, standard buffer and spring, standard buffer tube.
It runs perfectly with all supers, and subs, 147-220gr, locks back, ejects, everything. Suppressed and not suppressed.

My second... 7.5" barrel, 0.125" gas port, standard buffer and spring, standard buffer tube, BUT... LAW TACTICAL FOLDING STOCK.
It runs fine with supers, 110-150gr. With 220gr subs, it will eject, but not pick up a new round reliably. I assume the bolt isn't going all the way back in the recoil cycle? The suppressor doesn't fix it. I assume it will function WORSE unsuppressed due to less back-pressure?

I still need to test the new upper on my proven lower (no folder), and see if it functions THERE.

But what else should I look for? I've heard of drag being created inside the Law Tactical Folder... maybe lubing the inside of that?

Any "no-shit" fixes come to mind?
Guns are tools designed for dirty work both competitive and defensive. If I meet someone with a well worn gun, I hope their barrel is pointed the same direction as mine if the lead starts flying...

BulletFlight for Android
Guges Mk3
Member
Posts: 29
Joined: Sun Jun 04, 2017 3:09 pm

Re: Function Frustration... Please Help?

Post by Guges Mk3 » Tue Jun 06, 2017 10:41 am

I have been experimenting with a LAW folder on another build. I have noticed this...the Law Folder hinge is tight, really tight. I think it retards the action quite a bit.

A lot of break-in of the action is required. Only thing I can think of is a lighter buffer and "working" the travel path of the BCG with plug across the adapter.

dbltaps
Silent Operator
Posts: 54
Joined: Mon Apr 23, 2012 10:08 am

Re: Function Frustration... Please Help?

Post by dbltaps » Tue Jun 06, 2017 10:46 am

The Law Tactical Folding Stock Adapter adds a bolt carrier extension to your bolt carrier, which adds weight to your bolt assembly. I suspect that the added weight is the cause of your issues. You may be able to correct the issue by using a lighter-weight buffer spring.

dbltaps
Silent Operator
Posts: 54
Joined: Mon Apr 23, 2012 10:08 am

Re: Function Frustration... Please Help?

Post by dbltaps » Tue Jun 06, 2017 10:51 am

Also, since adding a suppressor doesn't resolve the problem by increasing the back pressure within your gas system, you may have an alignment issue with your gas block and gas port. Check to make sure the hole in the gas block is centered over your barrel's gas port. If it is an adjustable gas block, try opening it up a little when shooting the heavier subs. But since it is getting enough gas with the supers, I suspect it will be resolved with a lighter buffer spring (or a lighter bolt carrier, if you want to go that route).

User avatar
JeffWard
Silent But Deadly
Posts: 237
Joined: Tue Jul 15, 2014 12:13 pm
Location: St Pete, FL
Contact:

Re: Function Frustration... Please Help?

Post by JeffWard » Tue Jun 06, 2017 4:16 pm

Where do I get a lighter buffer spring than standard?
Guns are tools designed for dirty work both competitive and defensive. If I meet someone with a well worn gun, I hope their barrel is pointed the same direction as mine if the lead starts flying...

Guges Mk3
Member
Posts: 29
Joined: Sun Jun 04, 2017 3:09 pm

Re: Function Frustration... Please Help?

Post by Guges Mk3 » Tue Jun 06, 2017 4:37 pm

You can try this one for your needs...

http://www.brownells.com/rifle-parts/re ... 56149.aspx

...or just start cutting coils on a Carbine buffer spring.

User avatar
dellet
Silent But Deadly
Posts: 6536
Joined: Fri Nov 30, 2012 1:25 pm

Re: Function Frustration... Please Help?

Post by dellet » Tue Jun 06, 2017 5:43 pm

The adapter adds 2OZ.

If you are running an H2 buffer and FA carrier like it should have been to start then, then going to a regular carbine buffer and SA carrier will get back most of that, about 1 1/2 ounces.

With the port drilled out as big as it is, I would expect it work unless it was lighter bullets.

Switch the uppers out before spending any money.

Of course all these idea's could be worthless without knowing exactly what you are running for ammo, factory or reloads, what velocity it's running, and what suppressor you are using.
300 Blackout, not just for sub-sonics.

User avatar
JeffWard
Silent But Deadly
Posts: 237
Joined: Tue Jul 15, 2014 12:13 pm
Location: St Pete, FL
Contact:

Re: Function Frustration... Please Help?

Post by JeffWard » Tue Jun 06, 2017 6:52 pm

dellet wrote:The adapter adds 2OZ.

If you are running an H2 buffer and FA carrier like it should have been to start then, then going to a regular carbine buffer and SA carrier will get back most of that, about 1 1/2 ounces.

With the port drilled out as big as it is, I would expect it work unless it was lighter bullets.

Switch the uppers out before spending any money.

Of course all these idea's could be worthless without knowing exactly what you are running for ammo, factory or reloads, what velocity it's running, and what suppressor you are using.
I'm running a FA carrier, but a standard buffer. I have an H Buffer available. I THINK I have a standard weight BCG around... good idea.

220gr SMK commercial reloads running about 1000fps, Omega 30 suppressor.
Guns are tools designed for dirty work both competitive and defensive. If I meet someone with a well worn gun, I hope their barrel is pointed the same direction as mine if the lead starts flying...

Boolit_Head
Silent But Deadly
Posts: 349
Joined: Tue Aug 23, 2016 7:15 pm

Re: Function Frustration... Please Help?

Post by Boolit_Head » Wed Jun 07, 2017 12:15 pm

dbltaps wrote:Also, since adding a suppressor doesn't resolve the problem by increasing the back pressure within your gas system, you may have an alignment issue with your gas block and gas port. Check to make sure the hole in the gas block is centered over your barrel's gas port.
Every time someone says their gun won't function that is the first place my mind goes. I'm willing to bet that the percentage of issues coming back to this misalignment is very high.

User avatar
RAINS
Silent But Deadly
Posts: 542
Joined: Mon Sep 30, 2013 6:18 pm

Re: Function Frustration... Please Help?

Post by RAINS » Sat Jun 10, 2017 12:38 am

The only thing I might suggest is trying another sub sonic ammo.(if you have not already) Just pick up a box of UMC 220g. That stuff is hot for subs.(it's often supersonic in longer barrels) If your gun won't run that ammo you have a problem. Good luck.



R

Post Reply