I picked up a spare diopter upper a few weeks ago and ordered a steel lower and M4 adapter for it. I put a spare Shockwave blade on a KAK tube on it for now. Last year, I bought a Sig SRD-556 suppressor (direct thread) for my 553 SBR and have been meaning to get around to taking the 3-prong flash hider off....honestly, I've been a bit scared to after having issues on my old 551-A1.

SO....I figured the new upper would be the guinea pig since there's no tax stamp on it (in case things went horribly wrong). Using a butane torch and monitoring temps with a laser thermometer, I saw the loctite flash over right around 500F. I stripped the upper down and put it in a vise, using some strips from an old leather belt right on barrel flats. A firm *snap* with a wrench on the flats of the flash hider and she came loose.

Some pics with the SBR and with the can mounted. Both have the 4-position gas regulator on them so hopefully, it'll work out nicely. I'm guessing the 0.9 setting is for suppressed fire since the stock regulator has the same 1.2/1.3 settings.

On to some pics...

Looks great. Thats interesting yours had any sort of thread locker on it, mine was just torqued on. Let us know how the Sig suppressor performs!
The .9 setting is definitely the one you want. I went with the Griffin Recce 5 on mine using their 3 prong.

Wow - looks great Dan!

Nice

Beautiful rifles, everyone!

Beautiful rifles all around!

This message has been edited. Last edited by: JoshNC,

Sure are purdy rifles.

just got my stamp today for my 553, any suggestions on best spot for engraving?? thanks

Which model did you get?

553p mine is a few serial#'s down from yours on the bottom

yeah, so Diopter? I think I'm going to put mine on the top strap or even on the leading edge of the rear sight mount if we can make it work