I saw a post a while back about how you could substitute a DD barrel nut for the Steel KAC FF RAS nut, and save a lot of weight.

Is this true?

Can the nuts be swapped out with no problems?

How much is the DD Barrel nut alone going for?

Anyone know how much weight is saved?

I would also like to know since I was contemplating the same thing.

-Cap'n

greeno, I started to write the exact same thread this morning and ran out of time. good question.

Honestly, how much weight can you save?  

Is it worth the added expense?

Who cares.  If it ain't broke don't fix it.  I had a Les Baer FF tube which used an aluminum barrel nut.  Trying to torque the nut down to 40 ft. pounds, the holes ripped.  Granted it did not destroy the barrel nut, but it shows thats some things are meant to made of steel.

I asked DD....

"I dont think so."

I asked coldblue....

"I dont think so."

The aluminum nut for the DD unit IS sold seperately and this would save a quarter pound off the front of the rifle is my best guess.  If someone actually tries it and it works or even if it does not let us know here.

If you already have a FF RAS I see where you are coming from, but for those looking to buy a new FF rail I say just go with the DD.  It is every bit as good as a FF RAS and lighter too.  I like KAC stuff and I like the FF RAS but I like the DD better.

DeveL GreenO

My DD Barrel nut mices 2.062 inches.  I'll try to dig out my Tap and die set and see if I can ID the trheads.

Edit to say I am a dumb ass.  The threads are on the rai and the retainer ring I,m trying to mic the nut now.  I'll post back in a few.

The outside of the nut looks to be 1.875 inches but it is hard to get a real good number wihtout taking the barrel off.  It looks to be .75" thick (from the fron of the upper).  The holes almost have to be the same because the gas tube has to pass trough both.  Oh wait the index pin mics .203"  What other measurements would help?

I dont wanna pull my barrel... GreenO you are the one having problems with your upper... I nominate you to do it, cause I am lazy!

I am afraid the part that REALLY matters is if the pins line up with both the nut and rail.  That requires full removal.  The ring/cap on the DD nut could be used instead of the KAC ring/cap but the pins fitting into the KAC unit is the hard part.

good point devl.

Someone should make a KAC style nut out of aluminum.  The aluminum nuts work fine, old FF tubes used aluminum barrel nuts and I've never had a problem with them.

It's just funny when you look at the FF ras and the side walls are really thin (like .050in walls) when the barrel nut seems to weigh more than the FF tube. (it looks like someone was working overtime trying to lean down the design, but they weren't allowed to make the nut out of aluminum.)

The aluminum nut would solve three problems:
1. Weight (it would reduce weight, making it more competitive with the DD RAS
2. I wouldn't have to have one more part that can rust.
3. it would no longer need an odd anti-sieze that eliminates the bi-metal component reactions (wether or not these are a complete old-wives tale I don't know- but yes I have some special BS to dope the threads of uppers with prior to barreling.).