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Discussion Starter · #1 ·
Got my Surefire SOCOM flash hider (will be attaching a SF suppressor when it arrives). The instructions offer two options: Untimed or timed. They give no benefit one VS the other. Am I right to assume the only benefit of timing it will assure the SF suppressor unlocking mechanism will be in a convenient rotational orientation for quick removal? Seems that if you can leave it untimed, then why not and avoid adding unneeded parts (shims)? And if I do have it timed, why do some here say to leave off the spacer when the instructions for Scar 16 say to use it (reversed). I've read people say to leave it off, but I don't think I understand why it's not needed (that is, why do you think SF wants me to use it VS why do you think I don't need to). Thanks for any advice.
 

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Discussion Starter · #5 ·
No chamfered spacer on the 16; just use shims to index the FH & your good to go.
Would you elaborate? Why is the chamfered spacer not needed on the 16s? Does it cause a problem if used?

I've read the reasoning on the 17s regarding this topic (no shims/no nothing - use a flash hider not a brake - because of no shoulder, etc.), I've just not heard the reasoning for the 16s shims-only advice.
 

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Discussion Starter · #6 ·
timing is more crucial with brakes i believe you should be fine un less they provided u with shims
The instructions allow for it to be installed either way. That is, they provide shims if you decide to time it, or they say you can install it untimed without the shims. Right now I'm leaning toward an untimed/shimless install since it's the only method that both Surefire and the collective advice of this forum agree will work.
 

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Discussion Starter · #7 · (Edited)
So here's what I did and why:

[edit] Removed comments about hider hitting the barrel face when installed without spacer and shims. After further reading, that doesn't seem to be a problem.[/edit]

My final decision was to time it and follow Surefire's instructions.

(The Tapco AR tool was the only one I found that was thin enough to fit the Surefire flash hider, by the way. I used it in combination with a Sears torque wrench.)

Should I use the spacer? I did. Here was my reasoning:



  1. SUREFIRE'S INSTRUCTIONS SAY YOU MUST USE IT FOR A PROPER TIMED INSTALL ON THE 16S (CHAMFER FACING MUZZLE) - IN ALL CAPS. THEY ARE ACTUALLY YELLING AT ME TO USE IT.
  2. The barrel shoulder is so small (really just a raised edge), I did not trust the thin shims to not flex under torque without support from the spacer. I do not know precisely, but it appears that the raised edge where the threads end is only about 2/3 as wide as the shims, meaning the full force of the torque is only held by 2/3 of the shim's surface. On the SCAR 16s, the spacer seems to function as a support, sandwiching the shims between them and the hider.
  3. Finally, if the spacer is not needed, why bother to time it at all? No one is timing the 17s, so I can only figure that people are timing the 16s because there is no fear of baffle strikes when using the shims/spacers anyway.

I can only figure that many regulars here did not post up because there really is no solid reason not to follow Surefire's instructions for the 16s (or maybe the 16s forum gets so little traffic VS the 17s forum?). I am open to solid reasoning if anyone can provide insight and evidence to the contrary.

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