Awesome, just picked up a 762RC for my scar as well.
Are you running the muzzle brake under there, I was curious how you installed it on the nonexistent scar barrel shoulder? I can't tell but it looks like your crush washer is still on there, I've read that will cause baffle strikes.
Snugged the muzzle brake on with the nut yes. I don't see how a baffle strike could take place. Looked down the bore before and after about 60 rounds and no issue. Granted that isn't much but I plan to check it frequently.
I put the muzzle brake on my Tavor in the same manor as it has that nut, yet to try it yet.
There are many sources that say you can't use the jam nut, because it's not completely flat and while it may seem concentric there's always that risk. It's not a risk I would ever take. I believe surefire has their own instructions on how to install their muzzle devices on a scar 17s so I would call them to verify. It would be a real shame for you to have a baffle strike on such an expensive can.
Good call on SCAR muzzle devices. Surefire did say to discard the locking nut and use the shims. They're getting back to me on the Tavor mounting because it also has the locking nut. Great customer service from Surefire by the way very impressed.
I put about 20 rounds through it with it barrel nut installed before it knew it was an issue... worked great but there will be no more of that. Surefire says the kit is in the mail so as soon as i have it on properly i will follow up!
Surefire told me they talked to IWI at shot show and it's still pending on what is right and what's wrong... So I think I might hold off on that for now.