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sound moderators

Posted: Mon Jun 10, 2013 2:06 pm
by @nd
Dont shoot me down on this one!
Are mods caliber specific,if i was to buy a mod for a .308 could it be used on a .223 and shoot a smaller round through it if the barrel threads are the same? Would it do its job at reducing sound and recoil.
i would not expect the opposite is possible and try to put a .308 through a .223 mod
The reason i ask is some web sites advertise the same mod with more than one caliber .223 to .308, i was led to believe they were all caliber specific or would you have to order it for the caliber rifle it is to be fitted to.

Re: sound moderators

Posted: Mon Jun 10, 2013 2:44 pm
by TJC
Cut n paste a reply for you from Zak Smith who knows a thing or two about suppressors:

There is nothing wrong with shooting a .308 suppressor on a .223 rifle, provided you do not exceed the manufacturer's intended usage for the suppressor (eg a lightweight .308 suppressor on full-auto 5.56 is probably not a good idea).

You will likely need a thread adapter so the 5/8-24 .308 suppressor will fit on the 1/2-28 .223 muzzle.

With regard to heat, there are thermal covers for this purpose.

We actually took some video of this exact setup (30P-1 on a .223 rifle) over the weekend; I just need to get the video online.

Re: sound moderators

Posted: Wed Jun 12, 2013 11:52 am
by GRSporth1
From the pressure and temperature perspective there should be no problem, however gasses will escape from the .308 moderator at about a 70% quicker rate than from a .223 moderator (due to the bigger hole in the front). Combine that with the smaller mass of gas that needs to escape (about 25 grains vs 45) and the pressure drop will happen over a much shorter time.

Therefore the recoil attenuation will be quite significantly less as a proportion of what is achieveable - however as a .308 with a moderator has more recoil than a .223 without one, that may not bother you.

Noise attentuation will also be lower, however as exhaust noise is not linear , I doubt you will notice that much of a difference.

Some moderators do allow interchangable baffles. Sorry I can't point one out offhand, but they do exist.

Re: sound moderators

Posted: Wed Jun 12, 2013 1:23 pm
by saddler
TJC wrote:Cut n paste a reply for you from Zak Smith who knows a thing or two about suppressors:

There is nothing wrong with shooting a .308 suppressor on a .223 rifle, provided you do not exceed the manufacturer's intended usage for the suppressor (eg a lightweight .308 suppressor on full-auto 5.56 is probably not a good idea).

You will likely need a thread adapter so the 5/8-24 .308 suppressor will fit on the 1/2-28 .223 muzzle.
Mmm - WHO says that suppressor threading is now caliber specific?

Your cut & paste may have been a reply to a more specific question...

My .223 moderator is threaded to fit a heavy PSS barrel....ANYONE that threads a barrel other than .22lr at 1/2"(x28/UNF/whatever) needs their heads looking at: in a lot of cases a tight fitting patch on a cleaning rod will hit resistance in the area where the barrel has been threaded if too much metal has been removed!!

Re: sound moderators

Posted: Wed Jun 12, 2013 2:53 pm
by AHPP
LOL! There will be a lot of very cross AR15/M16 owners out there now that you have revealed this. They'd better send the millions of rifles back to the factories to be rethreaded to something more sensible. Not to mention plenty of other guns that rock 1/2" muzzle threads.

And do tell us all about stress relief please.


:good:

Re: sound moderators

Posted: Wed Jun 12, 2013 3:42 pm
by froggy
Salut,

Sry I dont get it - Aren't AR's barell factory threaded to fit the issued A2 Flash Hider ?

Re: sound moderators

Posted: Wed Jun 12, 2013 4:18 pm
by saddler
saddler wrote:
TJC wrote:Cut n paste a reply for you from Zak Smith who knows a thing or two about suppressors:

There is nothing wrong with shooting a .308 suppressor on a .223 rifle, provided you do not exceed the manufacturer's intended usage for the suppressor (eg a lightweight .308 suppressor on full-auto 5.56 is probably not a good idea).

You will likely need a thread adapter so the 5/8-24 .308 suppressor will fit on the 1/2-28 .223 muzzle.
Mmm - WHO says that suppressor threading is now caliber specific?

Your cut & paste may have been a reply to a more specific question...

My .223 moderator is threaded to fit a heavy PSS barrel....ANYONE that threads a barrel other than .22lr at 1/2"(x28/UNF/whatever) needs their heads looking at: in a lot of cases a tight fitting patch on a cleaning rod will hit resistance in the area where the barrel has been threaded if too much metal has been removed!!
EDIT: 1/2" threads on OTHER than .22 dia- not JUST .22LR (was typing while on the phone earlier!!)
The comment was aimed at the folk that feel a 1/2" thread on a .308 is fine