KAC RAS M5 on my heavy barrel Upper

[Frijolito1988]

So today I received my KAC RAS M5 rail for my 20'' DPMS upper. But it wont fit . Ive been told that this Rail might not fit Heavy barrel uppers ? Mine is a DPMS 20'' heavy barrel. This is the same rail that are issued on the USMC M16A4. I checked out KAC webiste but does not state that it wont fit heavy barrel uppers, am I doing some thing wrong here ?


The place where it wont fit is when I install the upper part of the handguard , it has a half moon metal that wraps around the barrel , BUT it wont hug it and fit on the barrel, or atleast I think this is the problem ? have you guys heard of this ?

[armygunsmith]

You won't get it to fit until you remove some material from the bushing that contacts the barrel near the front handguard support. I had a similar issue with a heavy CAR barrel and KAC carbine handguards.

[djleisure]

Dremel time!

[chuck762]

It willfit some heavy barrels. There is no standard on dimensions for what a HB should be. Some companies HB may be .500 in diameter and anthers may be 1 inch.
If I remember right the limit is .870 for the KAC to fit with no issues. I had one on an armalite upper that was just at the limit.

Some people installed them on AR10s and had to remove the locking piece that clamps on the barrel nut to get it to clear. Since it is just a roll pin I would try that first.

[Frijolito1988]

ah , darn. So if this where a normal pencil barrel upper it would fit fine? Il see if i have the balls to dremel it. LOL.

[Fobjoe]

I use an KAC M5 RAS on my 20" STAG heavy barrel. Fit without any problems. Are you installing correctly?

[djleisure]

I thought DPMS Heavy Barrels were .750 - is it a Bull maybe?

[Frijolito1988]

How does one remove this part ?

[djleisure]

Hammer time?!

[Frijolito1988]

Ah I see, it has a roll pin up top. Damn now i gotta get me self a good Roll pin removal tool set, dont wanna eff this up

[Frijolito1988]

Great succes!! Had to punch out 2 pins, it was real easy, took about 15 seconds each, now it fits perfect

[ElvenSoul]

good job

[fcr]

Good Tools last, never hesitate, learned that early from my Dad.

[Nessal]

Off topic, but how does the 20" HBAR feel when carrying it around?

[Frijolito1988]

good job

Good Tools last, never hesitate, learned that early from my Dad.

Oh yeah i was surprised how easy it was

Off topic, but how does the 20" HBAR feel when carrying it around?

The 20'' HBAR is on the heavier side, but im a big guy so im biased