AR-15 upper receiver

[slowyellow]

Trying to figure out what kind of upper receiver I need to order. I'm going to be using this barrel:

http://www.midwayusa.com/Product/688...teflon-pre-ban

The thing that confuses me is wether or not I need the "M4 feed ramps" Or what difference it makes.

And also I've read different things about wether or not I need to check headspacing, any clarification would be great.

[slow06]

What type of upper receiver do you have? It should have Standard or M4 cuts in it, IMO your best bet is just to match that.

One thing to watch out for is that if you have an M4 upper receiver you do not want "standard" ramps cut in the barrel. If the upper has "standard" ramps then it doesn't matter as much. Let me find the picture that shows the difference.

Edit: See below. You can see why the one on the bottom left would be a bad combo. With M4 ramps in the receiver and not in the barrel in theory rounds would have feeding issues. I say in theory because my AR has both and I have never actually experienced that problem.

[slowyellow]

What type of upper receiver do you have? It should have Standard or M4 cuts in it, IMO your best bet is just to match that.

One thing to watch out for is that if you have an M4 upper receiver you do not want "standard" ramps cut in the barrel. If the upper has "standard" ramps then it doesn't matter as much. Let me find the picture that shows the difference.

Edit: See below. You can see why the one on the bottom left would be a bad combo. With M4 ramps in the receiver and not in the barrel in theory rounds would have feeding issues. I say in theory because my AR has both and I have never actually experienced that problem.

I don't have the receiver yet, that's why I'm asking, lol. I ordered the barrel that I wanted and I'm going to match the receiver to it. So I guess I just need to wait and see what kind of ramps are in the barrel.

Thanks for the input though.

[slowyellow]

Just got off of the phone with DPMS, and they said that the barrel has M4 feed ramps. So looks like I'll just order an M4 style upper.

What about checking the headspacing?

[Chopped54]

What about checking the headspacing?

No need to check it....

[slow06]

I was hoping somebody else would come around and answer that part. I haven't assembeled my own upper yet so I don't know all of those details.

Chopped, you say no. Is that because they do it when they make the barrel? In your opinion, then, would you only need to check headspace on a barrel you make yourself?

[bronco71]

barrel is headspaced when the barrel extension is fitted to the barrel by the gunsmith/mfg., even when you buy a 'stripped' AR-15 barrel it comes with the extension on it so there is no need to check headspace. This is done so the milspec parts are all interchangeable without the need to check it. The only time it could normally be off is if severely worn parts are used...

[CJ]

barrel is headspaced when the barrel extension is fitted to the barrel by the gunsmith/mfg., even when you buy a 'stripped' AR-15 barrel it comes with the extension on it so there is no need to check headspace. This is done so the milspec parts are all interchangeable without the need to check it. The only time it could normally be off is if severely worn parts are used...

That's correct. Unless a part is either damaged or built wrong, it head spaces itself. It cannot be adjusted. I have never seen a barrel/bolt not head space correctly in any configuration. Given the way the lugs/bolt lock into an AR15 it will either fail to chamber (insufficient head space), or have excessive head space which you can identify on the cases from excessive growth.

[slowyellow]

Thanks for the info guys.