I recently had a “post ban” AR15 made pre ban by having the muzzle brake removed and having an A2 flash hider installed. I noticed that there was not a washer installed on the barrel before the flash hider. I took the rifle back to where I had the work done and they said that the washer is just used as a “timing” spacer to get the flash hider to line up correctly when it is installed. I was told that factory thread jobs on AR15 barrels are not matched to flash hider attachments and therefore the spacer washer has to be used. Any and every AR15 that I have seen has a washer on the barrel in front of the A2 flash hider.
My question is: Do I need that washer on the barrel with the A2 flash hider or is the above correct?? I thought the washer was a “lock” washer to prevent the FH from getting loose.
Any and all thoughts would be appreciated.
Thanks.
The factory crush washer isn’t a lock washer per se, but it does provide some preload that will keep tension on the threaded joint. It’s very hard to time threads perfectly. Perhaps the guy just got lucky, or maybe he shaved the back of the FH to time it. If you want a washer to make it look “correct” take the FH off and put one in, it’s easy.
deuce,
The M16A1 came with a lock washer. That flash hider had slots equally spread around the thing so timing wasn’t necessary.
A2 guns had the lower slots removed and the upper slots closer together. They were timed with a peel washer.
Most current guns come with the Crush washer. I prefer the old peel washer, but I don’t replace any of my factory assembled crushes with peels.
Is it ok to NOT have a washer on the barrel?? Would I be doing any damage to my gun by not having one on the barrel?? Just curious if it is a functional thing or not. Thanks for the replies.
It would have been better if you replaced your entire barrel with one that was factory threaded.
Your gunsmith doesn’t know what he is doing.
As long as it is timed properly and torqued to about 15 or 20 pounds it is perfectly fine. Peel or crush washers don’t aid in locking the FH - they are only used to time it
How do you time it ?
I use a crush washer. The gunsmith that installed his might have…
A. Got lucky
B. Tried several FHs until he found one that timed correctly
C. Over or under torqued it
D. Machined the FH for a precision fit
By timing it he means that the flash hider is seated correctly in the proper position with the slots in the flash hider lined up correctly.
A washer IS NOT required. And if he indexed the flash hider, you won’t need one. As someone else said the M16 and M16A1 had a lock washer. Early A2s had peel washers and current A2s,A3s, A4s and M4s usually have a crush washer. Both a peel washer and crush washer just make it so that you can get the flash hider/comp to index correctly.
When I have my machinist/gunsmith friend profile barrels or thread them for me (or help me do it) for my guns I always index the threads so that I won’t require a washer. It’s only another 5-10min of lathe time. Does he know what he’s doing? Yep, he was a machinist before he was a gunsmith. Typically a machinist to a gunsmith like what a master mechanic is to a tech at Jiffy Lube.
Notice no washer:
I know that is what is meant, but how does one achieve this on a consistent basis? What little I have seen is that it only screws on perfect about half the time, and when it doesn’t its just gets torqued until it does line up. Is this normal or is there some magical ninja trick that some know that I have not seen;)?
Two ways to do it without using any washer:
The hack-fu non-gunsmith way is to remove metal from the back of the flash hider.
The gunsmith/machinst way is using a lathe to remove metal from the barrels shoulder (where the flash hider butts up against it) so that the muzzle device stops exactly where you want it without requiring any type of spacer/washer when you reach the torque spec.
Thank you for all of your replies. gotM4, thank you for clearing up what I was trying to say. If its safe to shoot without the washer, I will consider myself lucky and carry on. It sounds like from what you said, I am good to go and thank you again for your help.