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Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 9:57 am
by JeffWard
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?

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 10:41 am
by Guges Mk3
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.

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 10:46 am
by dbltaps
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.

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 10:51 am
by dbltaps
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).

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 4:16 pm
by JeffWard
Where do I get a lighter buffer spring than standard?

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 4:37 pm
by Guges Mk3
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.

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 5:43 pm
by dellet
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.

Re: Function Frustration... Please Help?

Posted: Tue Jun 06, 2017 6:52 pm
by JeffWard
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.

Re: Function Frustration... Please Help?

Posted: Wed Jun 07, 2017 12:15 pm
by Boolit_Head
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.

Re: Function Frustration... Please Help?

Posted: Sat Jun 10, 2017 12:38 am
by RAINS
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.



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