PWS SM556 Customization Question

[Col_Crocs]

Looking to cut the PWS SM556 down to about 1.75"(A2FH length) and milling to proper time for a shim/washer free installation.

http://farm5.static.flickr.com/4060/4667718745_4c19daa521_b.jpg
Is the SM556 threaded all the way through from Point A to Point C?
My idea is to cut halfway before Point B and work from there to time.

Background on this strange idea:
The idea of installing a comp without a crush or peel washer has been simmering in my head for quite some time now and Ive finally decided to give it a go.
Primary considerations for comp choice were overall length (I would prefer the end result be no longer than the standard A2FH), some flash suppression capabilities, and amount of modification(s) needed.
Ive narrowed my choices down to 2 PWS comps, the SM556 and the FSC556 QDSS-NT4.
Between the 2, the SM556 seems to be the more ideal option. From what I can see, it appears to only require a straight forward length cut (to shorten to a little more that 1.75") and ofcourse, a bit of milling to time. While the FSC556 QDSS-NT4, though closer to my desired length, would probably require me to mill new wrench flats after milling down to time.

[glen]

Wait, according to USMCO3:

"The SM556 is only 1/10" longer than the USGI A2 flash hider. If you use a USGI A2 flash hider and a crush washer, it's the same length as the SM556 with a peel washer."

In this thread:

https://www.m4carbine.net/showthread.php?t=43080

Looking at your goals for this project I would suggest you also look into the Battle Comp.

http://www.battlecomp.com/

[Joelk]

Not sure about the SM556, but the FSC556 is threaded far enough to allow you to face the rear of the brake to time it without using any washers. I have done several this way for a clean instalation. You may have to lenghten the relief cut on the rear of the threads on the brake if the threads on your barrel have a shoulder at the rear.

[Col_Crocs]

glen: Thanks for the links! Ive been watching the Battle Comp thread as well and Im sold on getting one too.
The SM556 is actually the multiple suppressor mount version of the FSC556 which measures 2.2" long...
http://primaryweapons.com/store/pc/viewPrd.asp?idproduct=161&idcategory=6
While the "short" FSC556, measuring 1.85", is really the FSC556 for the QDSS-NT4 Suppressor.
http://primaryweapons.com/store/pc/viewPrd.asp?idproduct=98&idcategory=6
Though just 1/10" over my preferred length, I was dissuaded by the possibility of having to mill a new set of wrench flats on it. It doesnt have very much to begin with and I may not have enough left, if at all, after milling to time.
joelk: Thanks for the heads up on the relief cut!