Barrel heat in Mk18 profile barrels

[Clint]

The "government" profile varies quite a bit between various makers.

The original M16 barrel is .670 -> .600, but that is a fairly light barrel with the .625 gas block journal.

Colt continued this with many barrels, including those with the .750 gas block journal.

Most other makers start with .670 but taper to a different small dimension, usually between .660 and .600.

Is that not a normal gov profile? I don’t remember ever seeing actual measurements.

[GrumpyM4]

I can tell you that it doesn't take much for a MK18 Mod1 to heat up pretty badly. Gloves are pretty much a necessity.

In the linked video below, the shooting drills shown, when all added up, were enough to make the handguard very uncomfortable to hold.

[Sparky5019]

Question for the more experienced members or anyone who used a Mk18.

The barrel listed on DD’s website is 1.15 # (18.4 oz). This is very light. How did it hold up under sustained use, particularly when paired with the suppressor?

It doesn’t seem like a problem, as I haven’t heard about it.


I’ve got a nice 11.5” barrel that is 23.5 oz. It’s on my “generally chasing ounces” carbine, which when suppressed is heavier than I would prefer, particularly considering I will eventually add a laser/illuminator to the end of the handguard. I’m considering changing the barrel out to an 11.5 or 11.3 that is a little lighter.

The 5.5 oz isn’t that big of a deal, as it is better balanced than the 10.3. Before anyone comments on weight, I have a persistent left shoulder problem that when supinated in an aggressive hand-over-bore extended grip is perfectly fine, but I cannot slide my hand back into heel-to-magwell supinated grip as I used to do when using an AR for a while. Explanation offered due to the typically negligible weight difference that I wouldn’t have concerned myself with previously. The shoulder thing reared it’s ugly head again after a number of years being fine.

I have an older (2014ish) DD MK18 barrel that has seen 1000s of rounds of suppressed full auto and a 1000 or so unsuppressed FA. Surefire SOCOM RC suppressor. No major issues with heat over time. Accuracy is fine though it’s trending down over time as expected but still very acceptable. Any specific questions pm me.