How much is too much?

AR/M4 AR General Discussion
1

Hey All: Can you help us out here?
My friend just got himself a new Bushmaster. We went to the range this afternoon. He had five loaded 30 round clips. After running through 3 of them in just a few minutes he was about to load up another when I suggested to let the barrel cool down some.

Neither of us know if that is necessasary or not. He’s never owned any kind of rifle before, and I’m not familiar with these black rifles. What are your opinions?

Thank you in advance.

2

You should really worry about letting the barrel cool. It is rifle made for heavy use so shoot on. Just make sure you are getting some training value out of the ammo you are exspending and not just blowing it.

3

Ok… a few quick points.

  1. An AR15 uses magazines, not clips.
  2. It is a combat rifle. It will take quite a bit more than 3 mags to heat up the barrel to the point of doing damage. I don’t usually worry about the barrel heat until it is time to put it back in its case and I want to make sure I don’t melt my carry case.
  3. I don’t think I can give you a definite number, but I feel confident that if he only has 5 mags, he could run through all of them before needing to let the barrel cool.
  4. He needs more mags. :smiley:
4

Most of my rifle experience is with precision rifles … I use the same adage with all of my rifles:

If it’s too hot to hold it’s too hot to shoot.

5

That’s why AR’s have handguards and more recently the option of foward verticle grips.

6

3 magazines is nothing. An AR that won’t run many more than that in a short period of time isn’t worth owning.

A certain drill at one particular class has students running 300+ rounds in a couple of minutes. Repeatedly.

For a precision rifle in that application, that’s probably okay. Outside of that context, void.

7

According to SAR, an M4 barrel (Colt, Mil-spec barrel steel, which is 4150 BTW) needs to be heated to 1100-1375 degrees F to make the barrels become soft and lose their heat treating, with structural failure sometime after this. In order to reach these kinds of temperatures it was found to have fired somewhere between 540-596 rounds in 3-3 1/2 minutes. BM claims to also use 4150 barrel steel (that is debateable according to some). FYI.

8

I few days ago when conducting my ammo/carbine testing I ran 12 mags with 28 rounds each through the Bushmaster M4gery on full-auto (fired in bursts) and everything was fine.

Rather than just blow ammo make sure that there is some training/ learning value going on. Practice some reloading drills, malfunction drills, strong hand/ weak hand, etc…