M4 feed ramps

[blacklisted]

I have a quick question.

Is it alright to use an upper with the M4 cuts with a standard barrel extension? It sounds like it could present a problem (if round were to feed from below, the tip could hit under the barrel extension). Should I even worry about this? I can't seem to find an A3 without the "M4 cuts".

It is almost 4AM and I'm pretty tired, so maybe I'm just delusional. Oh well, I'm sure someone knows the answer.

[avidone]

Ok, I give up. Who's the avitar picture this time?

[BigAL]

Will it work? Probably. On a properly running AR and mag the bullet tip will still hit the feedramps on the barrel extension.

Is it ideal? No. If you have a bad mag or some other problem that cause the bullet to feed low it will get hung up on the ridge between the barrel extension and receiver.

Plenty of A3 uppers w/o M4 cuts are available. Bushmaster sells 'em.

[Mute]

I have a quick question.

Is it alright to use an upper with the M4 cuts with a standard barrel extension? It sounds like it could prevent a problem (if round were to feed from below, the tip could hit under the barrel extension). Should I even worry about this? I can't seem to find an A3 without the "M4 cuts".

It is almost 4AM and I'm pretty tired, so maybe I'm just delusional. Oh well, I'm sure someone knows the answer.

Probably but I would advise against it.

[Pablo]

I think it's a really bad idea you will end up with a lot of malfunctions specially with heavy bullets. Fulton Armory has A3 uppers with rifle extensions same as carricozarmory.com

[blacklisted]

I think it's a really bad idea you will end up with a lot of malfunctions specially with heavy bullets. Fulton Armory has A3 uppers with rifle extensions same as carricozarmory.com

Thanks. I didn't think it was a good idea.

That picture is exactly what I imagined. I guess I'll just get a Fulton upper, I have Fulton lowers anyway. I was looking at CMMG, but they have the cuts.

[blacklisted]

Ok, I give up. Who's the avitar picture this time?

It's a secret!

[bwiese]

You should be able to find non-M4-ramped uppers easily. I'd bet Fulton has both.

So do you have a barrel yet? If you don't, get the barrel you want and then find an upper receiver to match (or buy the assembled 'barrelled upper' from a vendor already).

If for some reason you really have to have a certain type of upper and your barrel does not match it (in terms of ramped vs. non-ramped) an appropriate new barrel extension can be exchanged/installed on your barrel by a competent smith. (Randall Rausch at AR15barrels.Com could do this for you Ib believe.) He'll do headspacing at that time as well (new AR headspace is controlled by fitment of bbl extension to barrel) w/a standard new bolt as reference.

[blacklisted]

I've got a barrel picked out for this build (20" WOA Service Rifle Barrel), but I wont be getting it for a few months (I'm getting all the small parts first, then the barrel last). I'm pretty sure the extension has standard feed ramps.

Another thing I am concerned about is that the product description says: "Flats are machined on the barrel for our windage adjustable front sight base".

I don't want a front sight base, I'm planning on a gas block with the rail on top. I don't know if these flats will interfere.

You should be able to find non-M4-ramped uppers easily. I'd bet Fulton has both.

So do you have a barrel yet? If you don't, get the barrel you want and then find an upper receiver to match (or buy the assembled 'barrelled upper' from a vendor already).

If for some reason you really have to have a certain type of upper and your barrel does not match it (in terms of ramped vs. non-ramped) an appropriate new barrel extension can be exchanged/installed on your barrel by a competent smith. (Randall Rausch at AR15barrels.Com could do this for you Ib believe.) He'll do headspacing at that time as well (new AR headspace is controlled by fitment of bbl extension to barrel) w/a standard new bolt as reference.

[unimog_88]

I's say "DON'T DO THAT". It will tend to malfunction, easily.

[bu-bye]

Do you have a dremel and a steady hand.......

[C.G.]

Do you have a dremel and a steady hand.......

And "cajones"?

[CWM4A1]

Well, other has pretty much answered the question. Don't do it! you will most likely have your ammo jammed on the feed ramp. I know I can get a complete upper from globaltactical.com, A3 config with or without M4 feedramp cut for very attractive price (CMT/Stag). Just got a couple from them and have not decide which barrel to built yet.