About ramps?

[freewheeling]

I'm learning a lot of nomenclature but sometimes the stuff throws me. I understand that you can't use an upper with M4 ramps with a barrel that has rifle cuts, but I assumed that would be determined by length of the barrel. Apparently there are lots of rifle-length barrels that use M4 ramps and presumably some 16-inch barrels that have rifle cuts.

Are these always labelled as such, and what is more prevalent?

If I intend to use a 16-18 inch barrel should I be looking for an upper that has M4 ramps?

Is A3 a rifle designation while A4 is a carbine designation? Are both A3 and A4 "flat tops" with the only difference being the feed ramps?

 

[TrickyDick]

Majority of AR uppers are cut with the M4 feed ramps, as well as barrels. M4 feed ramp barrel will work with a rifle upper, but a rifle barrel will not work with m4 feed ramp upper. it's always best to check before you purchase though, it will save you a lot of headache.

 

[freewheeling]

Majority of AR uppers are cut with the M4 feed ramps, as well as barrels. M4 feed ramp barrel will work with a rifle upper, but a rifle barrel will not work with m4 feed ramp upper.

Thanks. So I can order an A3 upper and still use an M4-cut barrel? Are there any disadvantages to doing that. Feed problems, accuracy, caliber limitations, etc.? I'm thinking of getting a Wylde barrel with M4-cuts so can I use that with an A3 upper? Does it have to be a Wylde upper to get the benefit, or is Wylde chambering just a barrel-related term?

I've built a "multi-caliber" lower and am trying to sort out what these terms mean before I buy an upper/barrel etc.

 

[taliv]

i think credit goes to randal for that image, but i'm not sure

 

[TrickyDick]

Wylde is a special chamber that can take .223 rem,5.56x45 NATO, and .223 wylde. The Wylde cartridge to my best knowledge is a slightly longer .223 casing, but if you get a standard 5.56NATO barrel, it will cover .223 Rem and 5.56 Nato. however .223 rem barrels are only for .223 rem.

As for the multi caliber lower, it basically covers any cartridge that fits a STANAG Magazine outer diamensions. so a AR-10 in .308 magazine will not fit in there, but your .300 AAC, 7.62x39, 5.56 NATO, and any other mag designed fit the mag well will.

Hope this helped you.

 

[MK75]

taliv's picture is perfect, and has been tremendously informative for me as well.

 

[MrCleanOK]

If you're planning to use a barrel that has the M4 cuts in the barrel extension, you can get any upper receiver you want with confidence, because the M4 extension is compatible with both cut and un-cut receivers.

The rifle extension / M4 upper incompatibility isn't something that happens often, and is just something to be aware of in the unlikely event that you end up receiving parts that are incompatible. If you are ordering new production parts, chances are that they will work together just fine.

 

[freewheeling]

If you're planning to use a barrel that has the M4 cuts in the barrel extension, you can get any upper receiver you want with confidence, because the M4 extension is compatible with both cut and un-cut receivers.

The rifle extension / M4 upper incompatibility isn't something that happens often, and is just something to be aware of in the unlikely event that you end up receiving parts that are incompatible. If you are ordering new production parts, chances are that they will work together just fine.

I'd like to get the Wylde chambered barrel, but you know... I'll take what I can find.