Couple questions about AR-15's

[22many]

Im new to the whole AR thing. I have AK's but the whole AR rifles seem to confuse me. Maybe you guys can answer a couple of questions I have.

First off is what is the difference between a AR-15 and a M4? Second, what is "twist rate"?

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[Visceral]

A M4 is a version of the AR-15. It typically refers to two features. An M4 AR15 has a 16" barrel or a specific medium profile that also has a section for attaching a grenade launcher. It also has feed ramps that are both in the chamber AND in the upper receiver. (The are longer and promote better feeding). The twist rate applies to the rifling on the inside of the barrel. It describes how tight the spiral is in terms of travel (down the barrel) per full twist.

 

[BKMDNO]

The AR-15 is basically the civilian model of the M-16. The M4 is the Carbine model that sports the 16" barrel with a cut out in the barrel to mount the M203 launcher, bayonet lug, and collapsable stock.

 

[stitchclimber]

A 1:9 twist rate is desirable for 55gr bullets, 1:8, and 1:7 allow for heavy bullets to be stabilized, 1:7 twist rates might have difficulty stabilizing lighter rounds such as 50gr hollow points.

 

[22many]

OK. Im starting to understand now. I ordered my first AR today and was reading the info and didnt understand the 1x10 twist rate.

 

[stitchclimber]

1:10 will be great for stabilizing 55gr and 50gr bullets, I wouldn't recommend firing 62gr bullets, they'll have trouble stabilizing

 

[22many]

Have you guys heard anything bad about the AR-15 in the 7.62x39mm chamber? Thats what I ordered today.

 

[stitchclimber]

Disregard what I said about twist rates. That data was for the standard 5.56mm AR round.

You got a 7.62x39mm which is the same round as the AK47 and SKS rifles. It is a good round, not as inherently accurate as the 5.56 (.223), but it has much more knockdown power.

 

[22many]

I wanted to run the same ammo in the AR as I do in my AK's. Figured it would be easier than having to buy 2 different sizes. Plus, it is a little bigger so I guess that helps. Ive also heard from a couple people to run quality ammo in the AR's. Is this true? Ive ran wolf ammo in my AK's with no problem but their not quite as refined as the AR's. I dont have a problem buying the higher quality ammo for the AR.

 

[stitchclimber]

Don't use a lot of steel cases ammo in your AR, it will eat up the extractor. and its really dirty. Try and find some brass cased ammo. (This is not to say you can't run wolf in your AR, but a steady diet of it is sure not advised, only AK's and SKS's can take a steady diet of Wolf)

 

[22many]

Thank you much for the input.

 

[Unka-Boo]

Don't use a lot of steel cases ammo in your AR, it will eat up the extractor. and its really dirty. Try and find some brass cased ammo. (This is not to say you can't run wolf in your AR, but a steady diet of it is sure not advised, only AK's and SKS's can take a steady diet of Wolf)

Shoot all the wolf you want, it is dirty, so be prepared to clean a little more often, but it will not "wear out your gun"......besides, the only brass cased out there besides Winchester and maybe S&B is gonna be Yugo surplus, which is corrosive....not something I'd subject a non-chrome lined AR to....

 

[wichaka]

......besides, the only brass cased out there besides Winchester and maybe S&B is gonna be Yugo surplus, which is corrosive....not something I'd subject a non-chrome lined AR to....

What??? First I've heard of this....

 

[Unka-Boo]

What??? First I've heard of this....

which part?

 

[wichaka]

"....the only brass cased out there..."

 

[PhysicsGuy]

Brass cased;

Winchester
Remington
Federal
Black Hills
Ultramax
S&B
PMC
Wolf Gold
Fiocchi
American Eagle
Hornady
Magtech

And the list goes on and on. There is far more brass stuff out there than steel cased.

 

[wichaka]

It's spendy, but it's out there......

 

[Unka-Boo]

pardon me while I remove my foot from my mouth............





But I still take issue with "steel case will ruin your gun".....internet myth...

 

[Doc In UPlace]

I have heard from some experienced shooter/reviewers that the steel-cased stuff, Wolf in particular, is OK.
I just don't like Wolf, darn the expense. I can't see why steel cases should be worse on extractors than anything else, the case probably expands in the chamber less than does brass (?) so where would this extra wear come from?

The extractors are expensive little doo-dads though, so it'd be good to know.

 

[stitchclimber]

Brass cased;

Winchester
Remington
Federal
Black Hills
Ultramax
S&B
PMC
Wolf Gold
Fiocchi
American Eagle
Hornady
Magtech

And the list goes on and on. There is far more brass stuff out there than steel cased.

don't forget we're talking about 7.62x39 here.