I have a brand new never fired Surefire SOCOM-556-RC that was approved last month. Prior to the can being approved, I purchased an all Colt M4A1 upper from a fellow ARFcom member. The upper came with a FH556RC-1/2-28 (4 Prong) Flash Hider already installed.

The can will not fit all the way onto the 4 prong and I'm curious if anyone has ever experienced this before?

The can fits onto my other Surefire Socom adapters just fine: 3P, SFCT, SFMB, & Closed Tine Warcomp.

Here are some pictures. You can see how far the can will slide on before it basically would have to be forcefully pushed on. You can also see where it has taken some of the finish off of the 4 prong.

Thank You in advance, I appreciate any helpful responses/information. Maybe it's out of speck? Maybe it's a really good fake?







Here are two photos showing how the Closed Tine Warcomp fits and locks up fine.

Aren't those like $100 per prong?

It appears from the first 3 photos, that the adapter is deformed near the base of the prongs on the left due to improper installation. Instead of using the wrench flats, someone used a blackout type tool when tightening. My guess is this deformation is causing the issue. Or the deformation around the wrench flats. A caliper and some comparisons to you other devices would help.

Edited to add: in thinking about it more, unless the front end of the tines are splayed or something, it's probably the latter. It interfaces only near the front behind the ridge and at the larger diameter at the back near the wrench flats.

Make damn sure you check them with an alaignment rod before shooting. It will take 5 months and 400 bucks if you get a baffle strike to get your an back from surefire

Clean that up real good and then color the entire thing with a sharpie. Put your can on off a few times and see where the marker is being rubbed off.

No problems with my 4-prong and SF Mini

This would be my guess as well.  The wrench has displaced some of the material where the wrench flats are and the can is catching on the little "ridge" of metal.  I did this on one of my Surefire FHs.  If you can force the can on it should wear down (not sure if thats smart) or maybe try filing the extra material down.

which way is the main washer on? the convex side goes against the barrel facing towards the breech and the timing shims go between the flat side of washer and the muzzle brake. don't forget check the installation with an alignment rod