556 SBR 10.5" vs 14.5"

[Just_me_mongo]

Hello gents,

I wanted to ask if anyone has experience with this caliber of SBR? I have built an upper in 10.5". I am running a 556 Spec War can on it. So far, I have tuned it to run with a can on it. It will not function w/o the can.

I have an adjustable gas block - which is barely opened up to function properly w/ a can.

Before - I have adjusted it to function properly w/o a can. It seems that I can only pick one.

I was curious if a 14.5" would be more forgiving? Is there a way to get it to cycle both with and without can?

Any input would be most appreciated...

Specs:

Yhm upper receiver
Rguns semi auto bcg
Seekins 223 wylde chamber 10.5" carbine gas
Jbo adjustable gas block
Trifecta flash hider
556 specwar can
Standard buffer & spring

[dm_graham308]

As far as making it run with and w/o the can on a 10.5 and 14.5" barrel; I think that every rifle is different. I have a little experience with suppressors (not a subject matter expert by any means) and most the rifles that were in the 10-12 range were running "position style" gas blocks like the noveske and different buffers and springs. A few ran fine both with and without the can without any modifications. All the rifles that I have use suppressors on were franken-guns, so I can't recommend any brands. I have run suppressors on my Army issue 14.5 colt without any issues or mods.

If you like the sound of the 10.5 with the Specwar, then I would try a "position style" gas block over the "micro adjustable" type. You might also want to try some different buffers and springs too.

Dave

[sidewaysil80]

Why not try a standard low-pro gas block and open up the gas port to .072"-.075"?

Rather than reinvent the wheel I am a strong proponent of copying NSWC Crane's r&d and going a little larger on the port to accommodate weaker powered rounds. With that being said I run a 10.5 w/ .072" gas block and have consistent/reliable function with my AAC SDN-6 on Or off. I also help setup a co-workers 10.3" MK18 clone and he went with .076" gas port to accommodate the wide variety of ammo he shoots. Again, no issues in terms of function.

[Iraqgunz]

Might want to fix those gas port numbers.

Why not try a standard low-pro gas block and open up the gas port to .72"-.75"?

Rather than reinvent the wheel I am a strong proponent of copying NSWC Crane's r&d and going a little larger on the port to accommodate weaker powered rounds. With that being said I run a 10.5 w/ .72" gas block and have consistent/reliable function with my AAC SDN-6 on Or off. I also help setup a co-workers 10.3" MK18 clone and he went with .76" gas port to accommodate the wide variety of ammo he shoots. Again, no issues in terms of function.

[BigWaylon]

Might want to fix those gas port numbers.

What, you think there's something wrong with a gas port bigger than your bore? I think a 3/4" hole in the top of my barrel would be fantastic.


To the OP...no reason you can't get a 10.5" 5.56 to run both ways. The upper I bought from PSA, and the lower I built with a standard PSA LBK, runs unsuppressed and suppressed without a hiccup. Granted, I get a decent amount of gas blowback when suppressed, but I tried the RTV and hole in CH band aids and it definitely cut down the amount in my face.

I just installed four SLR Sentry 7 AGBs on four SBRs last week, but haven't taken them out yet to tune them. Is expect them to function as before with the gas opened all the way up. Since I have enough cans to dedicate to each host, I plan on tuning the SLRs to function suppressed and have the bolt lock back. Not sure when I'd shoot unsuppressed, other to show somebody the difference...and if that's the case I'd just open it up a bit and not worry about it.

[sidewaysil80]

Sorry about the lack of zeros lol; fixed it. Although whats scarier is it happened four times as opposed to a typo/isolated incident...

[jerrysimons]

Try tuning it a little more, seems like it should work? Some specifics on what barrel brand, buffer, and spring set up you using might be helpful.

Should you still have problems getting it to run both ways, start with an Vltor A5 buffer kit and if that doesn't get you there add an LMT Enhanced carrier.