M1A suppressor info needed


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Spartan Gladiator
August 23, 2011, 02:15 AM
I am wanting to suppress an M1A SA9805 I just picked up, my concerns are

1-I have heard the muzzle thread size is .595" - 32NS 3A, very odd, if I wanted to put a Thunder Beast 338BA on it what are my options. I would like to keep the weapon as original as possible.

2- how to handle the over pressure on the gas system?

3- would the original front site have to go?

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dprice3844444
August 23, 2011, 02:41 AM
ask them to thread it for an m1a

Zak Smith
August 23, 2011, 03:10 PM
The problem with the M1A is that it has basically no shoulder behind the threads. This interface is important for single-point thread attach suppressors.

The best option would be to have a 5/8-24 adapter "permanently" affixed either over the existing threads, or over new threads.

The existing front sight is part of the flash hider assembly, that would have to be removed. It'd be under the radius of a 30/338 suppressor anyway.

We once made a custom working replica of a Vietnam-era M14 silencer and there was no problem with backpressure.

ATCDoktor
August 23, 2011, 03:24 PM
The Delta P Design 5/8X24 adapter or the M1a is what you need.

http://www.deltapdesign.com/accessories-store/m14-muzzle-adapter

It threads on to your barrel using the stock barrel threads and replaces the front sight base.

It allows the use of any 5/8X24" threaded adapter or suppressor.

Zak Smith
August 23, 2011, 03:26 PM
Make very sure it's straight and can never move.

Spartan Gladiator
August 23, 2011, 07:38 PM
thanks for all the good advise, that adapter looks like a good idea. ATCDoktor have you used it on the M1A with a suppressor?

ATCDoktor
August 24, 2011, 07:41 PM
ATCDoktor have you used it on the M1A with a suppressor?

Yes, I have a good deal of experience with the Delta P adapter for the M1A.

My M1A scout with AAC 762SD

http://i30.photobucket.com/albums/c307/ATCDoctor/000_0006.jpg

http://i30.photobucket.com/albums/c307/ATCDoctor/IMG_0273.jpg

http://i30.photobucket.com/albums/c307/ATCDoctor/011-1.jpg

http://i30.photobucket.com/albums/c307/ATCDoctor/046.jpg

Close up with the Delta P adapter with AAC's fast attach suppressor mount.

http://i30.photobucket.com/albums/c307/ATCDoctor/000_0007.jpg

All you have to do is remove the Flash Hider and replace it with the Delta P adapter (ensure that your muzzle face is square prior to installation of the adapter) .

You will need to remove your Front Sight and install it on the adapter as well.

IMHO this adapter (or the 5/8X24 M1A adapter from Smith Enterprises) is the only way to go if your gonna suppress the M1A.

I have read several accounts of suppressors being launched off M1A's using the factory barrel threads for suppressor mounting.

Here's a thread were a couple of posters speak to this specific problem:

http://www.silencertalk.com/forum/viewtopic.php?f=70&t=12792&p=407045&hilit=yhm#p407045

Spartan Gladiator
August 24, 2011, 09:21 PM
Thanks for the info ATC, being a newbie to the site I had seen these pics in another thread on THR of "which M1A would you pick"> I asked a question but forgot to call out your name. As luck would have it I now have my answer, I did want to know did you do anything to compensate the gas system for the extra presssure? I am confused on the squaring up your muzzle comment. How could it be unsquare? Are you saying that once the original sight is off ,the muzzle face might be unsquare? Does this adapter thread on or just clamp?

ATCDoktor
August 25, 2011, 12:43 AM
did you do anything to compensate the gas system for the extra presssure?

I use a Schuster Adjustable Gas Plug to deal with the increased gas pressure. I adjust it till it works suppressed and it does fine (unsuppressed as well). Theres still a moderate amount of gas thats pushed back down the barrel but it's tolerable.

Does this adapter thread on or just clamp?

With respect to attaching the Delta P adapter, it is splined to fit the splines on the barrel (just tap it on and tighten the castle nut and cinch down the set screw that keeps the castle nut from backing off).

I am confused on the squaring up your muzzle comment. How could it be unsquare?

Mass produced barrels (especially barrels for military rifles whose muzzles are designed for flash hiders/compensators that will cover the crown) can have muzzle faces that arent square. In fact, it's fairly common in mass produced "factory" barrels.

How an unsquare muzzle effects suppressing the M1A, is that once the castle nut on the adapter is tightened the adapter indexes on the muzzle face (when the castle nut is tightened it pulls the adapter tight against the muzzle face).

If it's not square the adapter will be canted and you may get a massive POI shift or worse baffle strikes with your suppressor attached.

The muzzle face on my Scout was not square and my POI shift with the suppressor attached was 2 feet at 100 yards.

I had a gunsmith square it and it was good to go after that.

I can not stress how important it is to ensure that the muzzle face is square on your M1A prior to installing this adapter.

I was lucky that my suppressor wasn't damaged.

With regards to suppressing the M1A, you need to manage your expectations with respect to suppression on this specific platform.

It will be a louder platform than a bolt gun due to the gas system and the action noise (not to mention the sonic crack of the bullet).

I'd rate mine as being about as loud as an unsuppressed 22 magnum.

Definitely quieter than without the suppressor but still (depending on where I'm shooting it) ear ringing loud.

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