View Full Version : M1A Flash suppressor tool?

May 16, 2008, 04:05 PM
Is there a special tool used to remove the flash suppressor on an M1A???
How do you remove that thing?

May 16, 2008, 04:33 PM

May 16, 2008, 04:45 PM
There is a special tool, and a gotcha. The gotcha is the itty-bitty little locking set screw that enters the front of the front sight base (not to be confused with the front sight base screw) and engages the top notch of the flash suppressor nut. If you don't remove that set screw, you'll never turn the FS nut. The locking set screw is not a standard hardware store item, either, so use a high-quality Allen wrench to remove it, carefully.

You may find the FS nut to be difficult to turn. If so, you should restrain the flash suppressor in a very, very, sturdy vise. I had to upgrade my bench and vise when I encountered several Sheriff's Department M14s on which I was working. They were the toughest nuts to break free I've ever put a FS nut wrench on. My then-existing setup had too much "spring" in it for the torque I had to apply.

[Shameless Plug] Fulton Armory has a high quality FS nut wrench, as well as a popular book that covers every aspect of M14-type rifle maintenance, including your M1A. The book, The M14 Complete Assembly Guide, also available at Midway USA, Brownells (who also carry a FS nut wrench), and elsewhere. [End Shameless Plug]



May 16, 2008, 04:57 PM
Hi Glen if you have problems, just send it up, no charge.

WildgratisAlaska ™

May 16, 2008, 05:04 PM
So first I remove the little Allen screw. Then I can unscrew the FS??? Or do I have to loosen the Crown Nut in order to loosen the FS?
Is the Crown Nut just a lock nut for the FS?

Thanks for the help, this is extremely helpful information!

May 16, 2008, 06:18 PM
OK, Glenn, here you go.

Remove the little itty-bitty Allen set screw. Do not lose it!!!

Clamp the front end of the rifle, just behind the front sight, in a sturdy vise. It's very likely you won't be able to generate enough torque just holding the rifle in your hands, or between your knees. I have run across FS nuts that weren't even finger-tight, but that's the exception.

Using the FS pliers, unscrew the FS nut until it hits the front of the window in the FS in which the nut is seen. When the FS nut hits the front of the window, tap the FS forward until the rear of the window hits the back of the FS window. You must cushion the blow of your hammer with a wood block or somesuch. Do not struck the front sight itself, rather the base, as close to the FS body as possible.

When the FS has gone forward as far as it can, unscrew the nut until it once again hits the front of the window. Tap the FS forward. Repeat until the nut is completely disengaged from the threads on the barrel. By this time the FS is generally "loose" enough that it can be pulled forward off the barrel.

The FS is located by three slots in the barrel, which are engaged by three splines on the inside of the body of the FS, much as the rear ring of the M1 Garand's gas cylinder engages three slots on the barrel. The purpose of the FS nut is to keep the FS from sliding off the end of the barrel.

To replace the FS, hold the FS nut in the window as you slide the FS onto the barrel. At some point you will be able to engage the barrel threads with the FS nut. Tap the FS rearward until the front of the FS nut window stops on the front of the nut. Screw the nut further on until it hits the rear of the window. Tap the FS rearward again until it stops on the nut, then further tighten the nut. Repeat until the FS is fully seated on the barrel. There is a shoulder on the ID of the FS that will "stop" on the muzzle of the barrel. Continue tightening the FS nut until it is snug, then tighten the nut until one of the slots of the nut is on the top. You will be able to verify this position by ensuring that the slots adjacent to the top slot are symmetrically disposed on either side of the FS window. You will need the FS nut pliers to complete this tightening process. You want the nut tight, but not "gorilla tight"! You may need to restrain the FS at this point just as you did during the loosening procedure.

Replace the FS nut locking set screw. The tip of the screw will nestle down into the FS nut's slot. Be sure you are using a fresh, new, high-quality Allen wrench, engaging the set screw head in line with the screw. If you booger up the Allen recess in the set screw, there will be H*ll to pay getting the stub of the screw out, particularly because of the angle of the screw.

Remember that the FS slips on, it does not screw on. The FS nut screws on, but it should not be used to "pull" the FS rearward. Tap the FS. It's all too easy to strip the threads on the barrel if you try to use the nut to "draw" the FS rearward.

[Shameless Plug redux] This procedure is lavishly illustrated in the referenced book ;), along with anything else you want to do to or for your rifle.[End Shamless Plug].

Does this help?


May 16, 2008, 07:25 PM
You're the man!!!
THANK YOU for you help!!!

May 16, 2008, 08:53 PM
You're very welcome; all I respectfully request in return is that you consider Fulton Armory (http://www.fulton-armory.com/) for your M14/M1A/M1 Garand/M1 Carbine/AR-15/AR-10 needs :) .

Best regards,


44 AMP
May 16, 2008, 11:40 PM
Sometimes we didn't have the pliers in our toolkits, instead a pivoting hook spanner (castle nut wrench) was used. It worked.

May 16, 2008, 11:56 PM
While it's always preferable to use the proper tool, sometimes resort can be made to thoughtful expedients. But, for goodness' sake, don't use a punch & hammer :eek:!



May 17, 2008, 06:58 AM
That looked like another '' Shameless Plug '' for the Fulton Armory, where is the best/cheapest place to pick up the book - The M14 Comp. Ass. Guide? Probably the Fulton Armory right. I've never done business with Fulton, that will change right quick!
If I were to pick from one of the two AR books, which would you suggest? The Owner's or the Assembly version?

May 17, 2008, 07:02 AM
I'm sorry I never responded to your very generous offer, THANK YOU!!!
I'm going to give it a try myself, I love learning more about these rifles and pistols.
Again, much appreciated!

May 17, 2008, 09:01 AM
Glenner, right now if you can get your order up to $50, shipping is free ('till the end of the month) at Fulton Armory.

The two AR books are very different. The Owner's Guide is aimed at the history, configuration, operation, maintenance, etc., of the AR rifles. The new third edition includes a section on .308 ARs.

The Assembly Guide shows how to put one together starting from the teeniest roll pin (that, by the way, is the roll pin that secures the gas tube to the front sight base). It's got hundreds of pictures showing every step of the process.

Look, guys, I'm here to help if I can, not to sell stuff. Once in a while, the best help is to suggest you get something. I'd have to be an idiot :p not to suggest getting it from the outfit that I thought was so good that I wanted to be a part of it. In this case, The M14 Complete Assembly Guide is without peer; if you have an M14-type rifle such as an M1A, you should have a copy, whether you get it from Brownells, Midway USA, Delta Press, or even Amazon.

Very best regards,


May 17, 2008, 10:06 AM
But, for goodness' sake, don't use a punch & hammer !

Why not, Ive done it, works fine

WildbutuseaNYLONpunchAlaska TM

May 17, 2008, 07:05 PM
After spending some time at the Fulton Armory site, it should be no problem to spend some money there as well.
Looks like a great place to do business!!!
Thanks for the heads up Walt.

May 17, 2008, 07:15 PM
Why not, Ive done it, works fine

We've seen too many flash suppressor nuts defaced if not ruined by intemperate use of punches. Using the punch does make it a little more difficult to get the nut properly tight and aligned perfectly with the notch at the time.

If it works for you, fine, but I can't recommend it when the proper tools are available for not a lot of money. After all, an M1A is now a $1500 rifle; a few $25 tools would seem to be a rational investment.



May 17, 2008, 07:19 PM
Looks like a great place to do business!!!

Thank you.



August 3, 2008, 05:33 PM

I am attepting to remove a flash supressor from a match M!A. Inspection reveals that there is no set screw securing the castle nut. I tried a nut tool , then a drift punch to no avail. I noticed a bit of discolorization between the rear of the castle nut and the supressor...I believe it's Loctite.

Two questions.

What now?

Where would a set screw assortment for the M1A be available.



August 3, 2008, 08:06 PM
First, be darn certain that you have no set screw. Second, the use of flash suppressor lock nut pliers is strongly recommended. The punch method will often leave a badly marred nut. Make the investment.

Third, unless you are securing the rifle in a very, very rigid vise bolted very, very rigidly to a very, very rigid workbench, the torque you apply is wasted. I know this from personal experience. I had a nut that was defying me greatly until I bought a new, heavy vise and mounted it to the strongest, most supported place on my workbench. What had been impossible became too easy for words.

Fourth, 350 degrees should loosen any LocTite. I prefer a heat gun as it's less likely to set my workshop on fire, compared to a propane torrch.

So, here are the steps:

1. Make sure there is no set screw.
2. Use flash suppressor lock nut pliers.
3. Secure the rifle in a rigid vise right at the gas cylinder area. You can usually swivel the vise slightly so that the balance of the rifle is supported by the workbench.
4. If necessary, use a heat gun to produce ~350 degrees F to loosen any LocTite present.

When you replace the flash suppressor lock nut, do not use LocTite!

You may wish to invest in a copy of The M14 Complete Assembly Guide to be your reference in this as well as all matters relating to the maintenence, repair and upgrading of your rifle. You can find the flash suppressor lock nut pliers, flash suppressor lock nut set screw and the Guide and everything else you need for the M14/M1A (and all the US Gas Operated Service Rifles) at Fulton Armory (http://www.fulton-armory.com/).



August 3, 2008, 08:11 PM
The flash suppressor lock nut set screw is a special screw not found at Lowes, hardware stores or even fastener supply houses. The use of a conventional set screw is strongly discouraged.



August 3, 2008, 11:15 PM
and look for a "dog-point headless socket set screw" it should be a UNC/UNF thread, not metric.

February 13, 2011, 08:23 PM
What if you want to carry the rifle without the flash hider?

Using the instructions above can you just remove it and safely shoot, or is there some sort of threaded cap that must be purchased to protect the barrel threads?

Know this is an old thread but it has good info.

Ron B

February 13, 2011, 08:42 PM
Yes, this is an old thread indeed. 900+ days old.

An M14/M1A will function without the flash hider in place. However... the flash hider is also serves as the base for the front sight. Without a flash hider installed, you'll be shooting the rifle sans front sight.

However, SEI does make a replacement Gas Lock Front Sight unit though, if you want to go that route.

Another option is to have the flash hider milled down, so only the front sight base remains. Some of the Chinese M14 clone rifles has this done to comply with import restrictions back in the 90's. You would still require the use of the castle nut and the set screw to hold the unit onto the barrel.


I know of no protective cap for the muzzle of the M14/M1A barrel.

You could just have the barrel cut down below the threads, re-crowned and then use the SEI gas lock front sight.

February 13, 2011, 09:18 PM
Fulton ARmory offers a gas lock with dovetail for the standard front sight. They also offer a front night sight to fit the dovetail.



February 13, 2011, 10:27 PM
Thanks very much for your helpful.

I have ordered a second FS with a castle nut wrench for sixty bucks and change.

Finally a SAFE firearm project for a Dremel!:D

I'll use the Dremel with a cut-off wheel to "mill" the new FS.

Thanks again,
Ron B