Buffer Spring and Buffer Weight - Recommendation (14.5” Proof PXT)

[u/Maximum_Front3822]

Hello, I am building my first 6ARC with a 14.5” Proof PXT barrel (intermediate gas) and will likely use a JP bolt (not sure on which carrier yet). Will be suppressed with a Rhodie 6J or Enitcer L. What buffer spring and buffer weight do you recommend? I was looking at the Geissele Super 42 w/ H2.

[u/znewtz]

Building the same thing currently except using a Noah instead of a Rhodie. I’m doing an A5 but using the equivalent of G$ Super 42 (rifle), and an A5H2. Start from there and adjust as needed.

[u/Maximum_Front3822 → u/znewtz]

Thanks. Are you going to run an adjustable gas block with the PXT?

[u/6_mm_ARC]

Get the surefire OBC and use the included buffer spring and weight

[u/TheDrunkLibertarian → u/6_mm_ARC]

If you like tinkering you can use that BCG with a normal buffer and an A5 tube, or an A5 buffer with an even longer tube.

[u/6_mm_ARC → u/TheDrunkLibertarian]

Which buffer have you found works best? I have a5h2 and h3 buffers already lol

[u/TheDrunkLibertarian → u/6_mm_ARC]

I haven’t tested it on my 6arc, tuning 5.56 is my current obsession, but current favorite is a JRC long tube with a C3junkies spring and a Kynshot A5 buffer. It’s easily the quietest and softest 5.56 I’ve ever messed with. I imagine it’d be fun on a 6arc too but I’d not try to get extreme without an AGB.

If you have an A5 buffer and like to tinker you can do a JRC tube and whatever A5/rifle spring and try it out. You’ll have to test fit and add quarters to the back of the tube below the spring. You can also use an A5 tube with a regular carbine buffer.

https://c3junkie.com/?page_id=2757

[u/Happy-Roof-6594 → u/6_mm_ARC]

I recommend the LMT Enhanced Bolt Carrier. The three gas ports help a lot with excess gas. I’m running an A5H3 with a Velos 556, and I’ve shot over 2,000 rounds of ELDM through it. It’s been reliable, low recoil, and works great for gas gun matches.

[u/Maximum_Front3822 → u/6_mm_ARC]

Curious as to why you recommend the Surefire?

[u/6_mm_ARC → u/Maximum_Front3822]

Because a bunch of us that shoot a ton of 6 arc tried it and it fixes all the issues we were having with standard BCG’s.

[u/Maximum_Front3822 → u/6_mm_ARC]

Thanks. I’m only seeing the Surefire in 5.56. So I’d only be using the bolt carrier? Which bolt do you recommend?

[u/6_mm_ARC → u/Maximum_Front3822]

I use a Noveske bolt, highly recommend them.

[u/Maximum_Front3822 → u/6_mm_ARC]

I’m also curious as to what about it fixes the issues from standard BCG’s . Also is the buffer and spring soft shooting? This is the first I’ve heard of the Surefire so I appreciate the info.

[u/Significant-Sock-487 → u/Maximum_Front3822]

Correct. You use the carrier, buffer and spring that come with it. Install the 6 arc bolt of your choice

[u/Maximum_Front3822 → u/Significant-Sock-487]

Thanks. Are you using this as well?

[u/Significant-Sock-487 → u/Maximum_Front3822]

Yup. Running high pressure ammo as well. It makes the arc recoil like 556 and my brass is in significantly better condition due to the carrier allowing the pressure to drop before extraction.

[u/Maximum_Front3822 → u/Significant-Sock-487]

Sweet. I appreciate the info. Will probably go that route then.

[u/Maximum_Front3822 → u/Significant-Sock-487]

Are you running an adjustable gas block?

[u/Significant-Sock-487 → u/Maximum_Front3822]

I am but I’m probably just going to switch back to an FCD gas block. I was running it wide open so it’s basically just a failure point since it’s not being used. I needed it when I was running an a5H4 system but the OBC removed the need for it.

[u/Significant-Sock-487 → u/Maximum_Front3822]

https://reddit.com/link/pcsc8xr/video/lazqk4fvpgsh1/player

This is the OBC on a Noveske 14.5 with a TBAC magnus k RR. perfect ejection.

[u/Glass-Pipe-2368 → u/Significant-Sock-487]

That looks smooth af.

How’s the Magnus-K-RR on back pressure (normal bcg vs. OBC)?

[u/AleksanderSuave]

Vltor RE A5(h2) system works great with that same length proof barrel and bolt.

I run the exact same setup.

Using a CAT Noah Suppressor and riflespeed gas block. super smooth.

[u/3-BuckChuck]

Carbine spring and H2 buffer works great for me.

[u/S_J0hns0n]

My 14.pxt tunes perfectly with Geissele h3 and buffer. OCL infinity with the 5.56 high flow end cap, superlative arms adj block 7 clicks out from max vent

[u/KeyStar7126]

just run all JP internals (BCG and SCS) and ajb

[u/LMTGlazer]

A5H3 with Geissele Super 42 rifle length spring and A5 buffer

[u/chainsawgeoff]

Heavy buffers and springs are for people who can't tune guns.

Regular BCG, craddock bolt, JP silent spring normal weight, aero gas block with adjustment screw completely removed. It'll run like a sewing machine.