My first upper... M4 ramp or not?

[Cameramonkey]

So Im starting to investigate building my first upper. Ive got a Bushmaster A2 style carbine, and am looking to build a flat top 20" free float upper with a scope for the range. Not going to be doing anything crazy like wanting sub-MOA at 500 yards. Just something in 5.56 for the range, and possibly varmints.

As I recall there is a difference between M4 ramps and regular, and mixing and matching doesnt always work. How do I tell what would be compatible with my lower? Its a Bushmaster XM15-E2S. Or now that I think about it, is it a mix/match between the upper and the barrel? (not at home to put my eyeballs on it.) And if it is the barrel/receiver, what are the benefits of the two ramp styles?

My plan is to start with this, and then eventually buy a new lower and use quality parts like a better trigger, etc. and end up with two rifles. But for now, I'll be happy with one rifle with interchangeable uppers.

 

[Maximinus Thrax]

http://i278.photobucket.com/albums/kk101/nasutton/gallery_18313_138_71257.jpg

See the above image. I'm not aware of any benefit of one vs. the other besides the fact that M4 feed ramps seem to be more common.

 

[JollyMon]

Best bet is to use one that has the m4 style ramps.... that is as long as the receiver and barrel are compatible you should be fine.


http://thearguys.com/ar-facts/m4-feed-ramps/

 

[Cameramonkey]

Thanks. Given Jollymon's article, I'm thinking rifle. My takeaway is the M4 profile is less prone to feed issues. though I may not have a choice as I'm budget conscious.

Guess I'll start with the barrel and work my way from there.

 

[milton]

Thanks. Given Jollymon's article, I'm thinking rifle. My takeaway is the M4 profile is less prone to feed issues. though I may not have a choice as I'm budget conscious.

Guess I'll start with the barrel and work my way from there.

What I have found recently, is that it is difficult to find a stripped upper without m4 feed ramps. If you buy a barrel without M4 feed ramps, then cannot find a upper without, you'll be in trouble. If you decide to do rifle, I'd shop around and make sure you can find an upper before buying the barrel.

 

[sig1473]

A2 Uppers(for Rifle extensions):
Upper Receiver, A4, Flat Top, USGI, Numbered
Upper Receiver, A2, USGI

 

[seedubs1]

Larue claims that there may be some accuracy benefits to running a rifle extension and upper due to the ramps being gentler on the bullets and potentially deforming the projectiles less.

That may be way down the chain of accurizing, though... And I'm sure there's a big long list to go through before you get to the point of that making a difference.

To the OP: Most common right now is M4. I'd just go that route for ease of finding parts.

http://i278.photobucket.com/albums/kk101/nasutton/gallery_18313_138_71257.jpg

See the above image. I'm not aware of any benefit of one vs. the other besides the fact that M4 feed ramps seem to be more common.

 

[gassprint1]

Your rounds will chamber so much better with the ramps. Alot less chance for miss feeds such as what happens in some pistols such as the hi point C9. The last i knew, non M4 receivers didnt exist anymore as that hasnt been milspec for years.

 

[Cameramonkey]

Larue claims that there may be some accuracy benefits to running a rifle extension and upper due to the ramps being gentler on the bullets and potentially deforming the projectiles less.

That may be way down the chain of accurizing, though... And I'm sure there's a big long list to go through before you get to the point of that making a difference.

To the OP: Most common right now is M4. I'd just go that route for ease of finding parts.

Given the quality of the barrel ill buy and other factors, you are correct. The ramp/bullet deformation is WAAAAY down the list of issues.

 

[halfmileharry]

IIRC....The ramps on the M4 were most efficient and reliable on full auto. Not to much difference other than that. Maybe a little as far as accuracy goes but I don't think it's as much of a factor as some believe.

 

[sig1473]

The last i knew, non M4 receivers didnt exist anymore as that hasnt been milspec for years.

Wrong, they absolutely still make non-M4 uppers.

 

[gassprint1]

Wrong, they absolutely still make non-M4 uppers.

Never said they didn't still make them somewhere, i said as far as i know they didnt.

 

[sig1473]

Never said they didn't still make them somewhere, i said as far as i know they didnt.

You are so lost. If you don't know then don't say they don't exist anymore If they don't exist anymore, then why are they still being made for the military?? This kind of misinformation really grinds my gears.......

 

[roadrunner681]

So? Question what is the difference?

 

[sig1473]

So? Question what is the difference?

It would help if you read the thread:

 

[roadrunner681]

It would help if you read the thread:

Thank you I had no idea there was different fed ramps I thought they were all like the m4 style