Suppressed FAL

[AlaskanMBR]

I've always wanted to do it.



It's about f*cking time!



With the gas system opened up all the way, the carrier just barely kisses the lower. I've got a buffer on order, and plans to open the gas hole on the block a little on the breech side under the adjustment nut. When there's no can the gas setting is perfect (strong ejection) at fully closed.

It's not hearing safe but at least there's no concussion.

On the 21" barrel it is hearing safe, but just too damn long.

The barrel is 11.5" chromed, so I'm hoping the slick and short will help a lot with subsonics, which I hope to get to run in semi with the can.

:P

I may be dreaming, but we'll see just as soon as I can get my hands on some Trailboss.

The adapter is 9/16x24LH to 5/8x24 made by hi-desert dog- very nice but my one gripe is no wrench flats.

The can is a tactical solutions Karma 7- I got it to go on this gun:


FN PBR XP 308! Yes it is hearing safe, and even quiet, but not nearly as when I get some subsonic loads in it.

Scope is a Nikon Buckmasters 6-18x w/ BDC

[Tnguy]

What type of scope and power on the FN?

I have a YHM suppressor on my FAL Para, only get bullet crack. I haven't tried subsonic ammo in it yet.

Thanks!

[AlaskanMBR]

16" barrel on your para? How do you change your gas setting for suppressed and how well does it work?

I edited the original post- scope is a Buckmasters 6-18, I like it a lot.

[jaykden]

EXCELLENT!!!!!!!


i think it would be kickass to get a .35 cal suppressor for my .358 FAL.

[AlaskanMBR]

Oh yessss.... Anything suppressed is cool to me. I just got a 1/2x28 to 5/8x24 adapter so I could mount that can on an 11.5" barrel AR, I just tried it, works like a charm! Nothing but sonic crack. Hm... Crack. Is that why it's so addictive?



Hey Jake- you recognize that shorty front end?

[gman]

guns.connect.fi/rs/Reflex.html

For when you want the 21" barrel too.

[Artful]

Originally posted by gman
guns.connect.fi/rs/Reflex.html

For when you want the 21" barrel too.

You do know that those European cans, can't be imported except for .GOV buys - right.

I think OPS is the only one still making reflex cans in USA
http://opsinc.us/category.php@catId=30.html
but I could be wrong - keep in mind the barrel profile may have to
be changed to work with the reflex design. and OPS doesn't use
industry standard sound measurement for their "40 db reduction" either.

Nice looking gun - I doubt you'll get trailboss to cycle a FAL - only time mine cycled was when a bullet stuck in the barrel with the gas turned off - so watch for hole in the target.

but they are nice and quiet loads even if don't work the action
http://www.youtube.com/watch?v=wMIomwkvyBQ

[AlaskanMBR]

I've heard rumors of FALs cycling subsonic with one of the recoil springs removed, but they're just rumors. I'll get to see first hand soon...

...and hopefully without getting a bullet stuck in the barrel...

[jaykden]

Originally posted by AlaskanMBR


Hey Jake- you recognize that shorty front end?

i thought it looked familiar...

[Tnguy]

Originally posted by AlaskanMBR
16" barrel on your para? How do you change your gas setting for suppressed and how well does it work?

I edited the original post- scope is a Buckmasters 6-18, I like it a lot.

My FAL para is an 18" and it slings the brass 20 or more feet from the gun!

[AlaskanMBR]

Originally posted by Tnguy


My FAL para is an 18" and it slings the brass 20 or more feet from the gun!

How's your lower doing? You using a buffer? Do you adjust your gas when the can is on?

[stimpsonjcat]

I modded a spare gas plug to a smaller hole and tuned it to get normal extraction when installed.

It's hearing safe as near as I can tell.

5/64" was the magic number IIRC.

[AlaskanMBR]

You drilled it out and used it on grenade setting?

[stimpsonjcat]

Sorry, no, welded up the existing hole and then redrilled it smaller.

[W.E.G.]

Originally posted by AlaskanMBR
I've heard rumors of FALs cycling subsonic with one of the recoil springs removed, but they're just rumors. I'll get to see first hand soon...

...and hopefully without getting a bullet stuck in the barrel...

Be REAL careful about that.

Rifle projectiles can get real squirrelly at low velocities.

Goes without saying that you don't want to sacrifice an expensive suppressor to baffle strikes to "re-discover" that.

[AlaskanMBR]

No doubt. Just like my precision loads I'll only ever hand measure the charges, and use them at the same ambient temperature range they were developed for. Things are getting busy, it'll be a while before I get a chance to work any loads down.

I will get another gas plug and get it welded and drilled so I don't have to worry about carrier slap with full power ammo.

[gunplumber]

Originally posted by stimpsonjcat
I modded a spare gas plug to a smaller hole and tuned it to get normal extraction when installed.

It's hearing safe as near as I can tell.

5/64" was the magic number IIRC.

That's been my recommendation. What I haven't come up with yet is an adjustable one.

[jaykden]

if (more like when) Sean Parnell signs off on the AFFA (Alaska Firearms Freedom Act), i just might find some way to end up with a "made in alaska" supressor!

it is one thing going through all the crap for a MG. doing a transfer requires a ferry to juneau (nearest class3 dealer) , staying in a hotel for a night, paying the dealer HIS cost of $200 for the NFA transfer (very expensive, but still cheaper than flying alaska airlines up north for a cheaper transfer) plus the $200 to the BATFE.

all that plus the cost of a can kinda kills it for me.

[skuld]

Just make sure every thing is nice and concentric before pulling the trigger.

First shot out of my brand new suppressor, my first one, on my metric FAL and it hit the end cap!

http://www.flickr.com/photos/gandalf23/4311825120/

[TCustoms]

That sucks. Doesn't mean it wasn't concentric to the bore though. Easily could have been your ammo.

Great thread for me though as I'm considering a SBR PARA style build. Thanks

[ActionYobbo]

[AlaskanMBR]

That shorty FAL started out as a para, but I never really could get a good weld on the para stock so I got rid of it.

[srv656s]

So I posted a few pictures of my FAL with the suppressor attached and I'm glad I did:

http://www.falfiles.com/forums/showt...hreadid=295389

Apparently the consensus is that I won't be able to open up the gas system to bleed off enough energy and I'll beat the rifle to death with the standard gas system no matter how I set it.

I emailed Gunplumber and he Gunplumber suggested that I might be able to have someone make a custom gas plug with a smaller hole that would let less gas through. Unfortunately he hasn't done this before and didn't have any suggestions on who I could talk to.

Would anyone know anybody or anywhere I could talk to for this? I have no way of doing something like this on my own.

Thanks

Shawn

[shlomo]

Stuff like this always intrigues me.

What about sleeving the original hole, instead of making a new plug?

[tac-40]

What about sleeving the original hole, instead of making a new plug?

Playing devil's advocate here, since 50,000 psi does strange things to parts that may move. Would it be a possiblility that the sleeve could be forced loose and blow up into the gas block port? This would effectively lock the gas plug and block together until you could drive the sleeve back into the plug.

A simpler method would be to just drill and port the grenade side of a standard plug to a smaller than normal size. So instead of having a grenade setting, it would now be a suppressor setting. This would be very similar to what is being to gas piston AR's today.

[J. Armstrong]

Why not just drill the grenade side of the stock plug with the smaller hole. Instead of "semi/grenade" you'd have "standard semi/suppressed semi" positions.

[shlomo]

Originally posted by tac-40
A simpler method would be to just drill and port the grenade side of a standard plug to a smaller than normal size. So instead of having a grenade setting, it would now be a suppressor setting.

I thought this suggestion was elegantly simple and brilliant at first blush. But then I got out a barrel with a stripped block, and tried the plug in it. The original hole on the "A" side lines up with the access hole under the spring well and sight flange. My guess is that the gas coming up under the sight flange would do ugly things to it in short order.

Tac, my original suggestion was to sleeve the hole in the plug, not the one in the block. I imagined it as being something like a small cap screw shape inverted and pressed into a countersink drilled in the plug hole. Then the desired gas hole could be drilled.

[richbug]

Drill and tap the port in your existing gas plug to 8-32 or thereabouts. Install a set screw that has had an appropriate sized hole drilled through it. Test fire, if it works as intended, solder in place.

The setscrew will give more "bite" than a simple pressed in sleeve.

[shlomo]

Yep. Just been thinkin' the same and gauging hole to determine screw size.

ETA: the sample hole I have here (imbel plug) is right at .156. A #21 tap drill for a 10-32 screw is .159. Not sure that i wouldn't run the tap into the .156 hole, as I believe the #21 gives a 75% thread. Could be in error here, though, and would welcome a correction.

BTW--might be good to anneal the screw. Some are too hard to drill with HSS bits.

[Slow]

a thought


use a piston with a smaller diameter head. grind an extra for use with a can.

i think a plug is fairly hard materiel to tap

p.s. might need a short tube as well

[tac-40]

shlomo, you are right. Hadn't looked at it to see what you mean. So what about drilling a port 90 degrees out and adding a ball detent like a selector to the gas plug shoulder.? No impact on the sight flange and still a lot easier than making a new one. And I think a lot more secure than adding a sleeve/plug that could come loose.

[tac-40]

Or even simpleer yet, get a smaller diameter gas piston and let the pressure vent around the head. Or for the machinist guys, make a smaller one. Sort of reverse engineering a fix for an FTE. Slap on the supressor and toss in the correct piston. Viola, no problem.

[srv656s]

Thanks for all the great ideas. I'm still at a loss on how to get any of the suggested things. I think the smaller holed gas plug or a smaller diameter piston sound like great ideas, but don't know how I'd go about getting something like that.

Anyone have a contact that would be able to do something like that?

Thanks

Shawn

[mountainman]

I might try but am very very very backed up.

[shlomo]

There's a whole bunch of people on this board who could tackle this one way or another, including at least three of us in this thread.

Matter of fact, I have a stainless gas plug blank about half-finished in the lathe chuck as I write this. Turns out worth a flip, I'll report.

Meantime, 'splain to me what the issue is (residual back-pressure dwell on the piston from the effect of the can?), and how much smaller the port needs to be.

Discuss.

[Tyris]

Originally posted by J. Armstrong
Why not just drill the grenade side of the stock plug with the smaller hole. Instead of "semi/grenade" you'd have "standard semi/suppressed semi" positions.

This is what I was planning originally, but think that it needs to be plugged first.

-T

[Tyris]

Originally posted by srv656s

Apparently the consensus is that I won't be able to open up the gas system to bleed off enough energy and I'll beat the rifle to death with the standard gas system no matter how I set it.

Nah. It is not that bad with the standard plug as far as recoil goes. Try it and you will see, recoil is no where near HK-91/CETME levels. Probably two reasons for this: silencers act as great brakes, and the force on the bolt carrier was not terribly higher.

My intent for the small-hole was to help with the massive gas-in-the-face issues,

-T

[Tyris]

null

[Tyris]

Originally posted by shlomo

Meantime, 'splain to me what the issue is (residual back-pressure dwell on the piston from the effect of the can?), and how much smaller the port needs to be.

Discuss.

I've got the same can on my FAL. One of the problems we're trying to fix is to quiet down the FAL. The venting of gas straight to the atmosphere from the gas-block makes it a poor silencer host (but still worth it for shits and grins ).

The working theory is that a smaller hole in the gas-plug will still provide plenty of pressure to operate the action, and yet be quieter as we're venting less. I suspect there is something we've missed though and need in addition to the small hole gas-plug. We need a way to block or limit the venting to atmosphere from the adjustable collar.

Port size would probably need to be determined experimentally, starting very small, and going up until the rifle cycled reliably with the "silenced" setting on the collar.

I propose:

1. smaller gas-hole plug
2. a setting on the collar that provides complete blockage, meaning no gas vented to the atmosphere

With those two changes I think the FAL would make a kick-ass silencer host.

Your thoughts, gentlemen?

-T

[shlomo]

Originally posted by Tyris


I've got the same can on my FAL. One of the problems we're trying to fix is to quiet down the FAL. The venting of gas straight to the atmosphere from the gas-block makes it a poor silencer host (but still worth it for shits and grins ).

The working theory is that a smaller hole in the gas-plug will still provide plenty of pressure to operate the action, and yet be quieter as we're venting less. I suspect there is something we've missed though and need in addition to the small hole gas-plug. We need a way to block or limit the venting to atmosphere from the adjustable collar.

I propose:

1. smaller gas-hole plug
2. a setting on the collar that provides complete blockage, meaning no gas vented to the atmosphere

With those two changes I think the FAL would make a kick-ass silencer host.

Your thoughts, gentlemen?

-T

Well, for one thing, the notch in the end of the plug could be eliminated. That's what directs the excess gas to the vent hole. It would render the custom plug that much simpler to make.

[Tyris]

I love design simplifications

-T

[gunplumber]

Originally posted by richbug
Drill and tap the port in your existing gas plug to 8-32 or thereabouts. Install a set screw that has had an appropriate sized hole drilled through it. Test fire, if it works as intended, solder in place.

The setscrew will give more "bite" than a simple pressed in sleeve.

This has been done on garands and may be fine for determining size, but if it turns out there is an ideal size, it seems to me that welding would be easier.

[gunplumber]

another option it to change the focus to the piston (or combine with piston). One of the pistons POF prototyped for suppressors on their .308 AR had holes in it to vent any gas after it started moving.

[shlomo]

GP--

Would the piston venting have the same noise problem as the vent hole/gas adjustment sleeve venting that is the cause of the discussion?

I am not a "can" man myself, and am not really sure what the cause of the excess gas is. Again, is it the retention and backpressure of the can that amplifies it? Or just that these guys close down the sleeve all the way to prevent the noise of venting?

This is a bit intriguing, but I don't really have time to waste by running in the wrong direction.

[gunplumber]

Originally posted by shlomo
GP--

Would the piston venting have the same noise problem as the vent hole/gas adjustment sleeve venting that is the cause of the discussion?

probably, but I was thinking just about abating the over-pressured piston, not the sound.

Vent it into baffled handguards.

[Tyris]

Originally posted by shlomo
Would the piston venting have the same noise problem as the vent hole/gas adjustment sleeve venting that is the cause of the discussion?

I am not a "can" man myself, and am not really sure what the cause of the excess gas is. Again, is it the retention and backpressure of the can that amplifies it? Or just that these guys close down the sleeve all the way to prevent the noise of venting?

All silencers hold a volume of compressed gas for a moment, and dump it in both directions: back up the barrel via gas port, out of the chamber during extraction, and out of the front. In the FAL, addition of the silencer really did not make much of a difference as far as function, and I can deal with the gas-in-the-eye caused by the scope mount in other ways via plugs, or wrapping it with a cloth. The internals get dirty quickly, but I like the fal action as it is robust enough to tolerate this, ditto for an AK with a silencer. Both just keep on chuggin'.

My interest is completely in noise abatement for the time being. Mine ran just fine with no changes to the regulator settings when using the silencer, I found no need to open or close it. Function was excellent and I did not notice any big increase in recoil (I run mine a little hot on the gas anyways).

I am starting to doubt that a switchable gas plug (normal / silenced) can be made. As you pointed out above, gas hitting the under-side of the sight assembly would probably be bad.

Right now I think the easiest solution is a suppresed-only simplified gas-plug with smaller hole and no vent notch.

An ideal solution might be some method to incorporate a tune-able screw into the gas-system so it can be set from normal to reduced-gas. Like a noveske switch-block.

I don't have my FAL handy, so no idea if there is any room for such a solution to work, but it would solve the vent problem, and retain the tuning features of the fal gas-system.

Anyone want to hazard a guess if this is plausible?

-T

[ggiilliiee]

vent it into the suppressor...rite at the back of the unit ...give ya the back pressure ya need for cyclic ...

..and ya cant "silence" anything over 700FPS ...and yer not holding anything ..yer just slowing the gasses ...not trying to contain them ...gasses coming out are fine if they are below 700FPS ..
bet yer action makes more noise than the vent hole ...

[shlomo]

Originally posted by Tyris

An ideal solution might be some method to incorporate a tune-able screw into the gas-system so it can be set from normal to reduced-gas. Like a noveske switch-block.

I don't have my FAL handy, so no idea if there is any room for such a solution to work, but it would solve the vent problem, and retain the tuning features of the fal gas-system.

Anyone want to hazard a guess if this is plausible?

-T

One possible way would be to thread the main gas hole (the one in line with the piston axis) for a hollow setscrew that is drilled thru its own axis. The screw would be run in or out in the gasplug bore, so that its end partially occludes the gas vent hole. This would not be "field convenient", but it would be no big deal to set the gun up prior. The other trick would be keeping the screw from backing out. Maybe a jam screw on top of it, like the Schuster plug for the Garand that GP mentioned.

Was that clear as mud?

[Tyris]

Originally posted by ggiilliiee
vent it into the suppressor...rite at the back of the unit ...give ya the back pressure ya need for cyclic ...

..and ya cant "silence" anything over 700FPS ...and yer not holding anything ..yer just slowing the gasses ...not trying to contain them ...gasses coming out are fine if they are below 700FPS ..

The only way to vent back into the silencer would be to encompass the gas regulation system in a large integral silencer. While that would be all kinds of kick-ass goodness from an engineering standpoint, it is not within the scope of my immediate project which is to quiet down the gun with a removable can.

Regarding the 700 ft/sec -- Any time you add a silencer to a gun it makes a notable difference. It turns a ear-drum shattering 308 boom into a 1/4 second hiss from an air hose along with a supersonic crack. Well designed silencers work and I've found them worth the trouble.

I don't know where in Oregon you are Ghilliiee, but join me at the range for a day and you'll see why I like cans so much.

-T

[Tyris]

Originally posted by shlomo
Was that clear as mud?

No, that was fine, I follow you.

How about this: What happens if we incorporate the screw mechanism into the notchless gas-plug itself? Basically add an adjustable screw into the front of the gas plug. This avoids the necessity of drilling the gas-block, and retains the ability to adjust the gas on the FAL, just in a different manner than using the collar.

sound plausible and relatively painless with no major mods to the rifle?

-T