AR build question

[Todd_ID]

I've finally got some parts coming for an AR upper build in .50 Beowulf.  My question is can someone tell from the below descriptions if I will need a barrel extension?  If there's a part missing (from me not ordering the right stuff) when the order comes Thursday I'm going to have to wait extra days before I can assemble it.  I ordered a free-float handguard that should have it's own barrel nut, but I ordered a barrel nut anyway, just in case.  But the stuff between the barrel nut and bolt face are new to me, so I figured someone on here will know just by looking at it that I either do or don't need any more parts and pieces.

http://www.bravocompanyusa.com/Upper-Receiver-Assembly-M4-Flat-Top-demo-p/flat%20top%20-upper%20-m4%20demo.htm

http://www.midwayusa.com/viewProduct/default.aspx?productNumber=911522

[h20hunter]

Oh yes, the Alexander Arms Beowulf. I think you will enjoy this. I have had a few chances to run a mag of rounds at bowling pins. It is a pretty big wallop when it hits. The recoil is actually pretty mild. Ammo sure isn't cheap.

[Heredoggydoggy]

Looks like the barrel is chambered and ready to go as is.  Your handguard should have a barrel nut on it.  Good price on the stripped uppers.  I don't have a .50 Beo. but my .450 Bushmaster is close.  Mild recoil and fun to shoot.

[Todd_ID]

Ammo isn't cheap, so I bought the dies for reloading when I ordered the parts.  I'm finding online that the barrel is set to go with any upper receiver, so I think it should be ok.  Still not sure about the difference between the M4 feedramps and A3 feedramps?  My upper receiver will have the M4 ramps, but I'm thinking that it should be pretty simple to dremel the feedramp interface between receiver and barrel extension to be smooth and polished.

Can't wait to put a thumping on some stuff.  I plan on shooting my spring bear with my bow, but the .50 will be on my back just in case I can't get to bow range!  Talk about a wallop on a bruin!

[JLS]

M4 feedramps will greatly reduce the misfeeds you may get.  I suppose you could dremel your own, that's what some companies appear to do based on the quality.

If you just shoot FMJ, it might not matter.  If you shoot soft point ammo the M4 ramps will reduce the small copper/lead shavings, which will lead to jamming.

Good luck

[Todd_ID]

I found this picture on the net showing the different combinations of upper receivers and barrel extensions.  These are of 5.56, and I know the 50 Beowulf ramp is different but not completely sure how much different.  I'm thinking that the Beowulf ramp with an M4 receiver may work fine just look funny.

[mb121]

Did you order a standard barrel nut?  If so you just wasted money as most of the free float rails use proprietary barrel nuts specific to manufactures designs.  Most do not intermix, my Larue barrel nut is completely different from my Daniel Defense, and both are completely different from the standard barrel nut for the regular M4/M16 hand guards.  Also DO NOT REMOVE the barrel extension, it is installed and set to spec by the factory and unless you know what you are doing you should not remove it and try to replace it.  As long as it is not a rifle extension on a M4 upper receiver you'll be good to go.  M4 feed ramps were created to solve malfunctions during rapid/full auto fire in Carbines, for the average user the M16/rifle feed ramps will do just fine.