I just stumbled upon the RRA "R-4" barrel profile. JT Distributing also has one that looks to be the same and is called the "EM-4" It looks to be an Hbar with the M203 notch in the barrel. Does anyone konw if this is the case? Or is it more like an M4 profile that is extra thick under the handguards? (pardon me, maybe the Hbar and M4 are the same diameter in front of the handguards, I am not too familiar with them)
If anyone has some specs (barrel weight, dia in front and behind HG, etc.) Also, if anyone knows if you can mount a 37mm M203 clone on one of these (more just curious) or if the extra thickness makes it impossible, I would like to know!
My M4 barrel heats up a lot faster than I like, and I think a chrome lined R4 is exactly what I am looking for.