Adjustable Gas Block for suppressor question

[brandon41582]

I ordered a silencerco saker 762 for my grendel and my ar-15. I have a Precision firearms neptune VIII upper with a 20" fluted Bartlein 1 in 8 twist black nitrided barrel on a bushmaster lower with magpul m93A2 stock. Im still learning so please go easy on my lack of knowledge. Im assuming my stock is using a carbine buffer and spring. How do I know which size gas block to order ex..750 etc? How do I figure out what size gas system I currently have rifle, mid, etc? I believe my grendel is over gassed cause the bolt slams pretty hard and recoil seems harder than my ar-15. So do I need to get an h2 buffer also or will the adjustable gas block be enough to tame recoil for suppressed or unsuppressed? Any help is greatly appreciated.

[LRRPF52]

Weigh your buffer. If it's a carbine standard buffer, it will weight 2.9-3.0oz ballpark.

For a 20" gun with RLGS (Rifle Length Gas System-this is what you have currently with that barrel), I like to have a heavier buffer in the carbine extension tube guns.

Your gun is not over-gassed, it's probably just under-buffered and under-sprung at the moment, which is an easy fix.

The 6.5 Grendel has more recoil than the 5.56, all things equal, but with the optimum set-up, it will be very pleasant to shoot, especially the 20" RLGS guns like you have.

For suppressed use, you will want a heavy buffer. On 20" RLGS guns, you don't normally need an adjustable gas block, but adding one can help you tune the gas to be more tame when it drives the BCG internal expansion.

[brandon41582]

I will definitely weigh that buffer and will more than likely be getting a heavier one. Also the reason I thought it was over gassed besides bolt slamming, etc was because it ejects all the shells at 1-2 o'clock. If I did go with an adjustable gas block how would you know what diameter to get? I really appreciate the great info!!!!

[Grendelsbane]

I have a Govnah gas block which uses a plate with holes for quick & repeatable switching between port sizes. I ordered the plate with holes I knew to be undersized, and drilled them incrementally until I got the function I wanted.

I would still start with LRRPF52's suggestion of trying heavier buffers first. You've spent a fair amount of money to buy an upper exactingly built for accuracy, and I am pretty sure _I_ probably can't get the gas tube as perfectly placed in the receiver as a skilled assembler/ gunsmith.

As for gas block journal size, I'd call PF and ask them, or get out some calipers and measure it.

[brandon41582]

I'm definitely going to take y'alls advice and get a heavier buffer first. Save me some money instead of buying a block that may not necessarily be needed. How you like the Govnah? I've been looking at blocks for about a week now and that was one of the ones I've been eyeing.

[A5BLASTER]

My 6.5 has the jp scs and a syrac adjustable gas block on a 21 inch target crowned barrel and its very smooth shooting.

The scs my be more then you want to spend but it can be bought with a spring back to adjust it even more.

I love the syrac because its adjustment screw has a detent spring so no locking screw to mess with and a nice simple click adjustment to set the gas, and the allen head tool is nice and long to reach under the handgaurd to make adjustments.

[A5BLASTER]

You could also look on PF website and find the upper or barrel you bought and get the profile size and that will tell you what size gas block to buy.

[brandon41582]

I looked up the jp scs and yeah it's got a pretty good price on it but seems like it will be better in the long run. I use my rifle for hunting more than anything else so any upgrades I can make for it to be smoother/better I'm all for it. Syrac gas block sounds a whole lot easier to setup than Govnah.

[brandon41582]

You could also look on PF website and find the upper or barrel you bought and get the profile size and that will tell you what size gas block to buy.

I looked on pf site but didn't see that info. Shot them an email about a week ago but haven't received a reply either. Im sure they're pretty busy. Guess I'm just gonna give them call, probably easier that way.

[A5BLASTER]

You could post a pic of the barrel and gas block that came on it and maybe someone here could give you a far sure answer, but I went to the site and read it is a meduim weight barrel so Im think possible the same as hbar profile, hbar is .750 but thats not for sure.

[A5BLASTER]

Yea I love the scs got rid of the scratchy spring feeling and sound when chambering a round and reduced the recoil of my rifle a lil, I bought the heavy verison with tungston weights and the spring kit, the syrac block just works so dang easy to set plus it has a very tight fit on my barrel.

Between those two things it really made a diffrence in the recoil, if I had a muzzle break like most guys do im sure it would be even less recoil.

[K280]

I use the Syrac on my 20" Grendel along with a heavy buffer. I have to open it 6 more clicks to get it to cycle without the suppressor. A muzzle break has less recoil than a suppressor, but I don't care for the muzzle blast. My bolt 260 is even quieter than my Grendel and both are 20".

[SG4247]

I run the SLR adjustable gas block and the JP SCS on my 16" Grendel with the Phantom 308 can.

Its smooth as glass, i can basicall shoot it with one hand.

[brandon41582]

Awesome Thanks. I tried to order an JP ScS heavy but they were all on back order so I got an H2 buffer, new rifle and carbine spring. Shot rifle with H2 buffer & rifle spring. Cycled good but wouldn't lock back on last round so I switched rifle spring out w/carbine spring. Due to working so many hours I haven't been able to go to range to test it yet. Hopefully that will help but if not then will probably get a adjustable block next. I have a saker762 in jail right now. Hopefully will be able to get an TBAC ultra7 soon also. Did you get the phantom titanium or stainless? How you like it?

[SG4247]

Mine is the stainless, but I wish I had bought titanium.

Great can, very quiet with the Grendel round, most guys think I am shooting sub-sonic loads until they realize I am shooting targets at the 300 yard berm!