DI buffer tuning with supressor and Gemtech carrier?

[msh441]

1. Noveske lower/modded BCM midlength gas system upper with Spike's T3 buffer/standard buffer spring, BCM low profile gas block, full-auto BCG, BCM medium charging handle, Surefire SOCOM 556RC can.

2. Was a 16" barrel cut to 13" and gas port opened a hair by Adco. Barrel just clears 12.0 DD Lite Rail II.

3. Generally XM193 55gr. and 62gr. FMJ

5. Built the Gen III billet lower from Noveske parts bin. Purchased the upper from BCM and cut down the barrel as desribed.

1. IDK the Gas Port Size, and Adco is a bit secretive about their tuning. I had a good guess at one point, but that memory has long faded.

2. Gas Block/FSB Alignment on the Barrel is square and true.

5. Gas Rings look good

Looking to reduce/re-direct a little gas, so I purchased a Gemtech bolt carrier. Functions fine w/Surefire can in the 'unsupressed' setting. Short strokes in the 'supressed' setting (fails to eject casing and feed new round). IMO the little jet of gas re-directed out the BCG (instead of piling up inside and pouring out the reciever) is worth tuning the Gemtech BCG to work with this setup.

My first inclunation is tune it in the 'supressed' setting with the can attached (as that's how it's shot 99.9% of the time).

My knee jerk, gut reaction is towards finding the lightest buffer that'll cycle reliably (again, can-on and 'supressed' setting).

It's been a while since I've thought about the DI system, and wanted to make sure my foggy memory isn't way off on this one before I start spending $$$.

Thanks in advance.

[Smokin338]

Get this: https://www.kakindustry.com/shockwav...-buffer-system

[MistWolf]

How much does a Spikes T3 weigh?

As I see it, you have three options
1) Run it as is with the Gemtech in the unsuppressed position with the suppressor installed. It works and your plan is to shoot suppressed all the time
2) Ditch the T3 and go with a lighter buffer that locks back in the suppressed position with the suppressor installed
3) Accept that Adco got the port size right. Either sell the Gemtech carrier or set it aside for another project. Use a standard carrier. ALL AR carriers vent the gas through the side of the carrier instead of piling up inside and pouring out the receiver. That's what the two vent holes are for

[RedDawn]

If you don't want to swap out barrel for a reduced port size and run the BCM you have that leaves you with the buffer system. Vltor A5 is an option that may help and Sprinco has varying strengths based on the color of the spring that may help you be able to run the Gemtech BCG. Good luck.

[mig1nc]

My vote is the BCM A5 kit. It comes with the lightest A5 buffer and offers a wide operating range. https://www.bravocompanyusa.com/BCM-...ediate-shk.htm

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[msh441]

How much does a Spikes T3 weigh?

As I see it, you have three options
1) Run it as is with the Gemtech in the unsuppressed position with the suppressor installed. It works and your plan is to shoot suppressed all the time
2) Ditch the T3 and go with a lighter buffer that locks back in the suppressed position with the suppressor installed
3) Accept that Adco got the port size right. Either sell the Gemtech carrier or set it aside for another project. Use a standard carrier. ALL AR carriers vent the gas through the side of the carrier instead of piling up inside and pouring out the receiver. That's what the two vent holes are for

The T3 is a whopping 5.4oz (for reference, T2 is 4.02, and T1 is 3).

Been doing #1. Want to work towards #2. Likely to pick up the tunable buffer provided in the link above (Thanks Smokin338!)

As far as #3, not switching barrels. The shortened middy is a really pleasurable shooter, and has been really accurate barrel. Aware that all all carriers vent gas, but Gemtech seems to have a little different (better IMO) plumbing/routing. I notice significantly less buildup & seep out of the reciever as standard. In the 'Suppressed' position, there's a noticeable little gyser shooting out the side. Just oo bad it doesn't cycle (yet) in that position.

[BufordTJustice]

My vote is the BCM A5 kit. It comes with the lightest A5 buffer and offers a wide operating range. https://www.bravocompanyusa.com/BCM-...ediate-shk.htm

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This, or grab a PWS H2 buffer and try that.

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[themonk]

The BCM / Vltor A5 kit may work. I run one with a GT carrier and it runs great and some have said it's the smoothest SBR they have ever shot. But as a data point that carrier was designed for a slightly over gassed setup. I am running it with a BCM 11.5 ELW upper.

What's the gas port size from Adco?

Why dont you try a adjustable gas block like an SLR (instead of the GT Carrier)?

[tom12.7]

Please do not fall into the band aid over band aid, etc conundrum. That's not a good place to be in for obvious reasons. With the XM 193 at least, you could find yourself in a better position with a dedicated port for either using a standard carrier or LMT enhanced one with the A5H1-A5H2 non suppressed, towards an A5H2-A5H3 suppressed. That is using that SF can and a Colt rifle spring. The change between the A5 type buffer masses is not as coarse of an adjustment compared to the carbine action ones.
While a solution could be had with a gimmick action system, gimmick gas block, gimmick carrier, etc.. all the way through most other crap in the market. Is an easier path available as an option? Are these other complications really simpler than using a dedicated port with possible A5 action masses in the A5H1-A5H3 range overall?

[Clint]

In a marginal gas drive situation, a lighter buffer can help.

Try a milspec CAR buffer to see if that works.

Going further, It sounds like the gas port size is currently between normal and dedicated suppressed.

Measuring it may be helpful.

It either needs to be opened up to work with the SBC suppressed setting or reduced to work with a milspec BCG, both suppressed.

Again, the SBC is mostly useful for mixed suppressed use.

A dedicated suppressed setup does not need one.