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Suppressors Threading for suppressor ruin accuracy?

clyancey

Online Training Member
Full Member
Minuteman
Dec 7, 2010
123
34
La Grande, OR & Snohomish, WA
Hi all, need some assistance deciding what to do about threading for a suppressor:

A reputable gunsmith told me he is leery of 1/2x28 threading when it comes to accuracy because: 1) common sense says that having 0.138” (.5-.224)/2 =.138) of metal at the muzzle to hold/direct/stabilize the bullet isn’t much 2) he has personally seen how threading a barrel to 1/2x28 and simply adjusting how hard a thread protector was torque on (by hand) varied groups from over 2” to around 1” and 3) several customers have bought his uppers after growing accustomed to their accuracy (.5 moa or even better) being disappointed when they threaded the barrels for suppressors and lost accuracy.
The gunsmith said he will not do 1/2x28, would do 5/8x24 but wouldn’t guarantee accuracy and preferred/recommends/uses ¾ threads for his guns. But, as far as I know, there is only one suppressor on the market that is offered at 3/4x20 or 3/4x24 (Thunderbeast Arms) and it’s for 30 cal and I’m looking for a 22 cal.

Questions:

1) Do you think 5/8x24 will work (tons of other folks have used this….but then again tons of other folks are excited with 1 moa accuracy, so what do they know)?

2) Do you know of any other 3/4x24 threading suppressors? Or do you know of a Thread Over the Muzzle Break (TOMB) or Quick Detach system where the break/flash hider threads to 3/4x24?

3) A bit of a tangent but still a parallel thought: if the muzzle is so critical to accuracy, and is machined so thin while under pressure, and is so susceptible to how a can is torque on, wouldn’t a TOMB or quick attach system have the potential to be the best for consistency/accuracy (because the flash hider/break is permanent)? I know this goes against the current group think of threaded suppressors for accuracy rigs; but I don’t care about group think, I care about facts….so help me sort it out!

Thanks guys
 
Re: Threading for suppressor ruin accuracy?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 762frmafr</div><div class="ubbcode-body">Find another Gunsmith </div></div>

I agree
 
Re: Threading for suppressor ruin accuracy?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 762frmafr</div><div class="ubbcode-body">Find another Gunsmith </div></div>

Send the barrel to ADCO for threading.

A guy who used to work for KAC and posted on Ar15.com under the name of Cold Blue I believe, (it's been a while) he did some testing that suggested that less than 10 foot pounds was most ideal for accuracy. <of course that's not at all ideal for mounting a suppressor or a QD mount for one.

The single most important factor will be concentricity of the suppressor mount bore and suppressor bore to the barrel bore, and that is something the gunsmith determines when he cuts the threads.

My brother shot a 3 round group in our only take for POI shift on a video in the summer of 2010 with his 30-35 foot pound mounted Adco threaded CL CMV 10.5" barrel and those three rounds punched a one hole group at 25 meters (~1MOA)

It's not often we shoot 10.5" barrels for accuracy.

I've shot 1/3MOA 100 yard 3 shot groups with his similarly torqued Ops brake/Ops 12th model suppressor/ 18" WOA barreled SPR clone. Those were wtih 77grain SMK match ammo from HSM.

We actually had accuracy issues with the Ops /SPR combination initially that we traced to crush washer installation. The Crane procedure for this is to use shims and the crush washer to get the brake to time in less than 1/4 turn. Apparently when the washers crush more than 1/4 turn on the 1/2x28 thread, they don't crush as straight.

Resultant eccentric brake and suppressor apertures produce 2-4MOA groups. Our solution was to use a machined washer and shims instead of the crush washer.

To me these observations were a great reason to use shims and get away from the crush washer. Because my theory is if the crush washer crushes terribly out of square at 1/2 a turn- then it probably isn't crushing ideally square at 1/4 turn.

Eccentric apertures- even as large as an A2 compensators .334 bore- are able to cause some inaccuracy, so the crush washers save armorer time and degrade system performance.