I may just be stupid and/or not thinking this through.

I bought a complete BCM upper receiver from someone here on arfcom with M4 ramps cut.  My intentions are to put a 14.5" (w/ perm FH) barrel on this lower.  Well, do I need M4 ramps on the barrel extension or will it work reliably if the barrel does not have cut ramps?

I intended on getting a DTI barrel assembly(affordability), but I just found out they arent M4 cut.  So, I am not sure what to do now.

Should I find a barrel with the cuts and move on(I dont know who to get this from now), or should I just sell the upper and get a complete upper assembly from one of our vendors.

Rod

You do not want to run a barrel without the M4 cuts with an upper receiver that has them.  You can run a barrel with M4 cuts in a standard upper (no cuts), but not the other way around.  If you are buying a barrel for an upper with M4 cuts get one with a barrel extension that has matching cuts.  Somewhere on here there is a thread with a picture that shows why this is a bad idea.  I'll see if I can find it.

ETA  The following thread was about the same issue and the picture that I was talking about is about 2/3 of the way down the page: m4 cuts on non m4 barrel.

Well, I didnt think it was a good idea.  Seems like the bullet tip would get caught as well as other issues that I havent even thought of yet.

So... where is a good palce to look for a barrel assembly.

Or, is someone interested in an upper!!  Yeah, I know that comment should go to the EE.

If I cant find a barrel PDQ, I will just order a compelte BCM barrel assembly.

Rod

You need a barrel with the M4 cuts in order for it to work with you cut upper.


Check here for some barrels with M4 cuts
www.bravocompanyusa.com

Rainier Arms

I picked up a 14.5 from ADCO about a year and a half ago and they did the permanent attachment of the flash-hider for me as well.

Just ordered a BCM upper assembly.

Will be putting the compete upper in the EE.

Rod