How to "time" a flash suppressor to a barrel...

Creature · April 5, 2008, 10:32 AM

I have recently purchased a Bushmaster with a post-ban barrel. I am going to have the barrel sent off to be threaded (1/2-28) so that an A2 Birdcage flash suppressor can be installed.

Because the A2 birdcage requires that it be "timed" to the barrel when installed, is this timing something I can do myself...and if so, how is it best accomplished? Does timing really affect accuracy drastically?

Jimro · April 5, 2008, 10:57 AM

I think what you mean is that it is "indexed", at least that's what a machinist would call it. The A2 flash suppressor is solid on the bottom half, which helps it act like a compensator. So if you don't index it correctly then the solid portion won't end up on the bottom when you screw it in. If you know what you are doing you can install it yourself, I'd check ar15.com for instructions if you don't already have them.

Good luck, hope this helps.

Jimro

Creature · April 5, 2008, 11:12 AM

Understood. To be honest, I thought that it was a "harmonics" thing that required a bit of tuning when installing a flash hider with a closed "bottom".

Seems easy enough to do then...something I could do myself.

AMX · April 5, 2008, 11:51 AM

You index them with a crush or peel washer. The crush washer just gets flattened out as you screw the FS on. I don't care for crush washers myself. Sometimes you really have to crank on them to get the FS on correct.

The peel washer is what I use. You just peel some of it off with a razor blade. If you don't get it right the first time, peel a little more. The washers don't cost all that much so when you buy your A2 FS you could also pick up a washer or two. Maybe even one of each type.

Scorch · April 5, 2008, 12:38 PM

Quote:

How to "time" a flash suppressor to a barrel

You don't "time" it, you clock it to the barrel, same as indexing described above.

Creature · April 5, 2008, 01:11 PM

I am now educated. Hadn't heard of peel washers....

Thanks for the assist, brothers!

Wildalaska · April 5, 2008, 01:32 PM

Whoever threads your barrel should install the flash supressor properly

WildpartofthejobAlaska ™

Creature · April 5, 2008, 01:48 PM

Granted. But I want to learn the properly part for myself. Good stuff to know if I want to change the muzzle device later.

Speaking of which, a good crush/peel washer should preclude having to use loctite, correct? Is anti-seize a good idea?

DMK · April 5, 2008, 03:54 PM

Just to make it clear, strictly speaking a flash suppressor does not need to be indexed (clocked, timed, whatever). I have Vortex and M16a1 flash suppressors that just go on and get torqued to a certain spec (20ftlbs I think, I'd have to look it up) however that ends up.

A compensator gets indexed. The A2 FS is a comp (as are some Phantoms) as well as being a FS.

I use a crush washer. Torque it down until it is near spec, then align it so the closed bottom is centered at the bottom. Do not use Locktite! Anti seize wouldn't be a bad idea. I just use a tiny dab of moly grease (wheel bearing grease).

Do not overtighten your muzzle device or accuracy will be negatively affected. You are better off under torque than over torquing it.

Creature · April 5, 2008, 08:05 PM

Got it...very good to know. Thanks, DMK!

April 5, 2008, 10:32 AM	#1
Creature Junior member Join Date: April 8, 2007 Location: Virginia Posts: 3,769	How to "time" a flash suppressor to a barrel... I have recently purchased a Bushmaster with a post-ban barrel. I am going to have the barrel sent off to be threaded (1/2-28) so that an A2 Birdcage flash suppressor can be installed. Because the A2 birdcage requires that it be "timed" to the barrel when installed, is this timing something I can do myself...and if so, how is it best accomplished? Does timing really affect accuracy drastically?

April 5, 2008, 10:57 AM	#2
Jimro Senior Member Join Date: October 18, 2006 Posts: 7,097	I think what you mean is that it is "indexed", at least that's what a machinist would call it. The A2 flash suppressor is solid on the bottom half, which helps it act like a compensator. So if you don't index it correctly then the solid portion won't end up on the bottom when you screw it in. If you know what you are doing you can install it yourself, I'd check ar15.com for instructions if you don't already have them. Good luck, hope this helps. Jimro __________________ Machine guns are awesome until you have to carry one.

April 5, 2008, 03:54 PM	#9
DMK Senior Member Join Date: November 18, 2001 Location: Over the hills and far, far away Posts: 3,206	Just to make it clear, strictly speaking a flash suppressor does not need to be indexed (clocked, timed, whatever). I have Vortex and M16a1 flash suppressors that just go on and get torqued to a certain spec (20ftlbs I think, I'd have to look it up) however that ends up. A compensator gets indexed. The A2 FS is a comp (as are some Phantoms) as well as being a FS. I use a crush washer. Torque it down until it is near spec, then align it so the closed bottom is centered at the bottom. Do not use Locktite! Anti seize wouldn't be a bad idea. I just use a tiny dab of moly grease (wheel bearing grease). Do not overtighten your muzzle device or accuracy will be negatively affected. You are better off under torque than over torquing it. __________________ - Homeland Security begins at home: Support your Second Amendment - www.gunowners.org - www.saf.org - act.nraila.org - www.grnc.org

April 5, 2008, 11:12 AM	#3
Creature Junior member Join Date: April 8, 2007 Location: Virginia Posts: 3,769	Understood. To be honest, I thought that it was a "harmonics" thing that required a bit of tuning when installing a flash hider with a closed "bottom". Seems easy enough to do then...something I could do myself.

April 5, 2008, 11:51 AM	#4
AMX Senior Member Join Date: July 22, 2005 Posts: 129	You index them with a crush or peel washer. The crush washer just gets flattened out as you screw the FS on. I don't care for crush washers myself. Sometimes you really have to crank on them to get the FS on correct. The peel washer is what I use. You just peel some of it off with a razor blade. If you don't get it right the first time, peel a little more. The washers don't cost all that much so when you buy your A2 FS you could also pick up a washer or two. Maybe even one of each type.

April 5, 2008, 01:11 PM	#6
Creature Junior member Join Date: April 8, 2007 Location: Virginia Posts: 3,769	I am now educated. Hadn't heard of peel washers.... Thanks for the assist, brothers!

April 5, 2008, 01:32 PM	#7
Wildalaska Junior member Join Date: November 25, 2002 Location: In my own little weird world in Anchorage, Alaska Posts: 14,172	Whoever threads your barrel should install the flash supressor properly WildpartofthejobAlaska ™

April 5, 2008, 01:48 PM	#8
Creature Junior member Join Date: April 8, 2007 Location: Virginia Posts: 3,769	Granted. But I want to learn the properly part for myself. Good stuff to know if I want to change the muzzle device later. Speaking of which, a good crush/peel washer should preclude having to use loctite, correct? Is anti-seize a good idea?

April 5, 2008, 08:05 PM	#10
Creature Junior member Join Date: April 8, 2007 Location: Virginia Posts: 3,769	Got it...very good to know. Thanks, DMK!