Anyone know if the factory Daniel Defense M4A1 upper has the barrel cut outs to accept the M203?

Found a picture online that shows it could work, but wanted to make sure

Thanks!

I'm not sure, but I wouldn't think it matters.  The M203 bolts up straight to the hangers on the RIS II rail and does not touch the barrel.  It was the whole purpose of the rail design in the first place.  A free floated rifle with grenade launcher attachment capability.

But wouldn't the barrel size prohibit the M203 from sliding past it to eventually meet up with the RIS II?

Found a video here:

https://www.instagram.com/p/BVyAK1Tl6Nl/

Thanks!

I don't know off top of my head which barrel profile DD uses on their factory "M4A1" uppers, find out which barrel they use, and we could tell you easy.

However, most of their barrels are "gov't" profile, skinny behind the gas block seat, which means they should be fine for mounting the M203. The M203 "flats" on the R0921HB profile barrel were necessitated because it is a medium contour barrel, and when originally designed, it was intended to be used with rifles with fixed FSBs and pinned gas blocks, so you couldn't "slide it on" from the front, either.

Given that free floating the M203 was the second most critical feature that the RIS II needed to have (the first was free floating the rifle's barrel...), chances are that even though >99.9% of people will never mount an M203 to a factory DD "M4A1" upper, that DD has nevertheless ensured that it is still capable of doing so, especially since they're not selling RIS II's alone any longer.  

~Augee

DD uses an M4 profile barrel with a pinned low profile gas block. The M4 barrel is correct for the non FSB Block II upper, but the gas block they use is not correct. The correct gas block is the Mk12 gas block.

The M203 will fit The DD M4A1 rifle. It would even fit if the barrel didn't have the M203 step down in front of the gas block seat because of the way it mounts to the RIS II.

Ahh, I thought you were talking about the M203 cutout in front of the gas block.

Thanks! Was able to get ahold of a M4A1 upper and it looks like it will work with the M203 :D