I just got a pre-ban M4 flattop upper to put on a pre-ban CAR-15. The only problem was that the flash suppressor wasn't firmly screwed on. I took it to my local gunsmith and he told me that the upper had been put together with a peel washer and that I need to get a 'crush' washer instead.

Question: what is the difference in a crush washer and a peel washer?

Which one do I need to screw down the A2 flash suppressor on a PREBAN upper?

Where can I get which ever one that I need? Bushmaster has them both for about two bucks and some change, but they have a minimum order of $25 or something like that. I just ordered an offset pin recently in order to put the new upper on my old lower, not knowing I would need another $2 part. I had to order something else to reach the min, so I ordered my ARMS #40 for them. Sucks when you have to spend $100 to get a $2 piece!!!!!

(Oh yeah, Bushmaster doesn't give a description of what a 'crush washer' or a 'peel washer' is? Thanks alot! The former is $2.50, the latter is $2.95)

A peel washer is made out of multiple layers and you peel off layers until the flash hider indexes right.  It gets thinner as you remove the layers.  A crush washer actually crushes and gets thinner the more you torque on it.  It is beveled and flattens out.  I like the crush washer much better.  It is much easier to get things lined up and you don't have to pull everything apart to peel off another layer to get it to index.  CMMG is a good guy to deal with and he has crush washers.

IDHunt

Both will keep the flash hider in place if done properly.

I have never installed a crush washer so I can't comment on how easy those are.  I do have a Colt 16" 1x9 M4 barrel that came with the crush washer and it is kind of neat.

The peel washers have to be literally peeled away sections at a time until you get it indexed by hand to the point before you tighten it down to spec with a wrench.  I haven't done one of these in awhile, but I seem to recall bringing them to approximately 10 o'clock (facing the muzzle end) by hand for it to index properly at TDC or thereabouts with a wrench.  Haven't had one shoot loose yet.

The crush washer is simplicity itself; put the washer on, screw on the flash hider, index and torque to spec.

With a peel washer you might find yourself repeating the process a couple of times to get it right, peeling the wshe down to the appropriate thickness.

Bushmaster sells the crush washers for $2.50 each. It's worth it for the ease of use. And I think they look better, too [;)]

Posted by thompsondd...


Since when??? [>:/] I think you are mistaken.  They have a minimum [b]shipping charge[/b] of $6.95, but no minimum order amount.

So, both will work but a crush washer is simpler/easier?

Perhaps I am mistaken. It has happened before. Probably will happen again. That is probably how I wound up with 4 kids.

Now that I think about it, it was probably more along the lines of I didn't want to pay $7 to ship a $2 washer. I still think it sucks, whether its spending $100 or $7 to get a $2 part. But thats just me.

Both will work. Use the peel washer if you like tradition. Also you already have a peel washer. Just disassemble a remove a layer at a time until it assembles in the right position. The layers are thin. Use a sharp knife to separate a single layer from it. Torque is 15-20 ftlbs.

I found the peel washer to be simplicity itself.

I just put them in a vise and compress them sligtly and the layers will seperate slightly to make it easier to peel.

Then I peel, torque and re-peel and torque if neccassary.  

[b]The only thing I would like to know about Crush washers is how well they compare (as far as keeping the FH on in high-volume fire)  I usually torque my FH's to 35ft lbs and have never had one come off.  (at my unit the guys were abusing A2's and one of the FH's came off when the barrel got red on a night fire.-- I don't want mine to come off)[/b]

The crush washer has replaced the peel washer on military weapons for several reasons all mentioned above.

You can pay the $6.75 minimum shipping charge or you can drive over to the next gun show (at 35cents/mile + $5 admission) and save the shipping.....

-- Chuck

"You can pay the $6.75 minimum shipping charge or you can drive over to the next gun show (at 35cents/mile + $5 admission) and save the shipping....."


My area gunshows are 15 miles away meaning approx $9.50 to see a bunch of fags who are too cheap to buy or sell anytihing at reasonable prices. (example-- walk in with a ar-15 and you will hear "I'll give you $75 CASH RIGHT NOW" These bastards have no shame at all and have driven away all the paying visitors like myself- now theyre lucky to draw 400visitors in a weekend.

I think the BM shipping is a better deal.