I have a 14.5 Triarc TRACK 2.0 barrel for my Radian build, also bought a 16". With the 14.5, SF flash hider and washers my SOCOM suppressor does not clear the rail.

However with a crush washer there is clearance and even plenty when the can is unlocked. I wanted to share these photos and measurements to hear your thoughts on rather this would be good to go or not. The 14.5" looks a lot better than the 16", only downside is the foot work and turnaround time for a pin and weld.

Top, Side and bottom. Both side measurements were pretty much equal.







This will be a recce build utilizing a Razor HD for 500yds and in. Probably half and half suppressor use and I would like to avoid any accuracy issues due to suppressor and rail contact via barrel flex. Go or No Go? Any technical input would appreciated.

The gap between the RIS II and SF RC on my Mk18/CQBR Block II is about 0.110" or 2.79mm when locked.

No issue at all.

Edit: That said, definitely don't use a crush washer for your final P/W -- very real chance of alignment issues. Use a solid spacer or get one custom cut if necessary.

^ Good copy on crush washer. I’m going to hit up D. Wilson or ADCO. A solid spacer should be something they have on hand/ by request with the p&w service.

Throw a couple more of these on there.
https://precisionarmament.com/accu-washer-muzzle-device-alignment-system/

This.


You'll have zero functional issues with that clearance. I recently had a Colt .govt profiled barrel cut flush with a Ras.

Nice, thanks for the link. Couple of these would work perfectly in place of the crush washer. Exactly what I need.

I used an additional thick Surefire shim that I had on hand to get this closed tine flash hider on the end of a 13.9 barrel with a BCM MCMR 13. The BCM MCMR is 13.4 inches at the 3 and 9 o'clock positions, so I had to push it out a little and I have had no issues. Except for black carbon being blown all over my FDE rail.

13.9 with BCM_3 by James H., on Flickr

Well just FYI for those interested. D. Wilson does not recommend shimming to length and uses the bare minimum shims for timing. I'm guessing ADCO will be the same likely.

I may just send in my 16" Triarc barrel and have it cut down to 14.7 ~ 14.8" (need to sit down and do some measuring to verify).

If we're talking about a stack of multiple individual shims, then yes... you don't want an excessive number of shims as you're increasing the probability of misalignment the more you add.

However, if you're only using a single solid spacer and the bare minimum or no individual shims, it shouldn't be a problem in theory. That's assuming the spacer is concentric with the bore, not ridiculously long and you still have enough threads for a proper installation. I'd imagine something like the included SF beveled spacer roughly doubled in length would be perfectly fine.

John Thomas of Retro Arms Works made a custom spacer at 5/32 of an inch for this 13.7 inch barrel that he also pinned/welded a Surefire Warcomp to in order to achieve a legal 16 inches in overall barrel length. It was well worth the money as John is a true craftsman and does outstanding work and you can barely tell that it is pinned. The spacer, pin/weld work, and shipping was under $100 and was about the same price or lower than what most others charge just for the pin/weld job. In my picture above, there are only 2 of the initial indexing shims and those are followed by the 3-4 other thinner shims for timing. I checked the alignment with a Geissele suppressor alignment rod, no issues, and have fired around 150 rounds suppressed with no issues.

13.7 inch barrel w/ pinned Warcomp done by John Thomas:
Pin and weld job by James H., on Flickr

Yeah, I would get in touch with John Thomas.

Admittedly, I only used him once to refinish some Colt carriers (which came out great), but every post/review of barrel and P/W work I've seen from him was top notch and he has extremely fair prices.

Precision Armament makes the accu-Washer Muzzle Device Alignment System. Many different sizes of shims to choose from.