AR15.Com Archives
 Finally got one!!
FreezinSig  [Member]
2/9/2012 2:27:38 AM
Picked up my first 556 gun today... after 5 years of drooling...

SIG 556 SWAT!!! This rifle was a new-old stock gun he has had for 4 years. He bought it way before the prices went down and had a price of $1800 on it. I offered him $1250 and he countered with $1305 with 2 Pmags. I took it!! I could have gotten a newer one cheaper, but he is great local shop owner and I dont mind spending a reasonable bit more locally.

Came with the Sig vertical grip and light, immedietly took it off and swapped on a magpul VFG.

Also had an extra Midwest Industries Flip up front sight and one of my AR height flip up diopter sights. Threw on a Primary Arms red dot as well. Looking into a Burris Prism with the 223 BDC.










This Flash suppressor has thread for a suppressor... which ones are compatable?
MANIST  [Member]
2/9/2012 7:28:22 AM
Being that yours came with the M4 pattern stock and early swiss gas block im assuming plus those midwest front sight and pmags. You did well especially helping out the locals, I always wished my swat classic had that stock setup as I hated the rattle trap non swiss folder.
Basenji703  [Member]
2/9/2012 10:35:33 AM
Very nice, hope you enjoy it and you did a good thing by helping out the local gun shop.
C_Swimm  [Team Member]
2/9/2012 11:26:25 AM
Congrats!

As for the flash hider mount, it was designed to be compatible with the AAC 18 tooth mount like found on their M4-1000 suppressor. As I understand it, AAC no longer makes can to fit their older 18T mounts, but they still make the mounts for people that still have the can. The 18T has been dropped in favor of the 51T and more recently the 80T (IIRC) mounts. Further, AAC supposedly doesn't condone use of their suppressors on SIG's 18T mount and will not warranty any of their cans that suffers a bullet strike while using these mounts. I tried one on My 556 with that mount without issue, but it didn't want to tighten fully. I guess this was a problem with the 18T design though and caused some to loosen during firing (even on their own 18T mounts) and result in a baffle or end cap strike. Sometimes the for the can to be tight on the threads, the teeth on the 18T mount would fall between the larger teeth so that can had to be backed off to the last tooth which caused it to not be bottomed out on the threads. This allowed the can to be loose and prone to loosening more during firing.

This was the reason for the 51T mount. The 51T design has finer locking teeth thus allowing the can to be tightened on the threads and the smaller teeth helped insure the lockup would be less prone to stop between teeth. To make matters more complicated, some people still had problems with the teeth not allowing the can to fully tighten on the 51T and the same problem started to occur hence the new 80T mount with even finer 80 tooth design.

I don't mean to sound like I am bashing AAC at all here. I still plan to get one of their 51T cans. I will make sure it locks on tight though even if I have to fit the mount to the can slightly. I just wanted you to be aware of the issue.

If you choose to remove the SIG factory flash hider/mount, be ready for a struggle. When I took mine off I locked the barrel into a padded vice on the flats near the chamber end. Then I used a wrench and 2 foot section of pipe as a cheater bar and it still took a lot of force to remove it. I even used a torch to heat the flash hider in case they used red loc-tite on it. I had to exert so much force I though I might twist the barrel. It moved my workbench that the vice was bolted too. But when it broke loose I saw no evidence of any thread lockers used. It appeared to just be torqued on there that tight. I thought I might break the gun, but it didn't. It still shot to the same point of aim after and functioned perfectly. I did however damage the wrench though.