I noticed Wilson Combat now puts a 5/8-24 thread on their 11.3" 5.56 barrels. I’ve started seeing a couple other places doing that as well. They say it puts more thickness at the end of the barrel, which is good, but what if you’re running a dedicated QD 5.56 can?
How does this work if you have a QD 5.56 can? For example with the Surefire SOCOM, you can’t put a 5.56 can on a .30 cal FH/MB, yet, only the 6.8 & .30 cal FH/MB come threaded for 5/8-24. All of the 5.56 FH/MB’s are all 1/2-28.
Other than rebarreling the upper, the minor diameter for a 5/8-24 Class 2A thread (0.5742") gives you enough material to re-tap to 1/2-28 Class 2A or 3A. If you can’t find a place locally, Adco will thread barrels for $65.
https://www.adcofirearms.com/shopservices/shop_qnew.cfm?code=Barrel%20Threading
Additionally for your smith’s reference, here’s the Surefire thread spec.
Surefire did a run of 1/2-28 FH/MB for their 7.62SS cans. I had to wait 13 months from date of order but they came as promised. At the time I asked Garin @surefire if they were planning that for any other model and the response was negative. But you may want to check back with him. It’s been 15 months nod they may have something in the works for other models.