Hornady Superformance not recommended in carbines?

**Eric Cartman** · 06-09-13, 09:27

So I"'ve read in three different posts that the Hornady superformance round is not recommended in carbine length gas systems. Can someone explain why? What will happen if I do?

**markm** · 06-09-13, 10:48

The ammo? Or the Powder?

I won't fire that ammo in any of my guns. I suppose the powder could be made to work with tinkering.

**ICANHITHIMMAN** · 06-09-13, 10:53

Originally Posted by markm

The ammo? Or the Powder?

I won't fire that ammo in any of my guns. I suppose the powder could be made to work with tinkering.

I'm with mark, to much pressure for my taste. Bang away with your bolt gun but no, no for the ar.

**Eric Cartman** · 06-09-13, 11:13

Originally Posted by markm

The ammo? Or the Powder?

I won't fire that ammo in any of my guns. I suppose the powder could be made to work with tinkering.

The ammo. So what could/would happen if I shoot it in my carbine? What about shooting it in a mid length gas system?

**Clint** · 06-09-13, 11:19

The Super Performance uses special power and has a pressure curve that is longer than normal.

The net effect in gas guns will be over gassing.

How much is difficult to say.

This can be dealt with in the usual ways.

http://www.hornady.com/ammunition/su...rated-firearms

**MegademiC** · 06-14-13, 22:21

if you graph the pressure curve, there is more area under it. The peak pressure isn't higher, but the average pressure is higher, meaning it will not adversely affect bolt guns, but result in higher velocity.

In the ar or any gas system, the higher impulse results in higher bolt carrier velocity. This will beat up the gun and may cause extraction issues, especially in a carbine. I have a 14.5" midlength that will not reliably cycle tula with an h2 buffer. I would imagine superperformance would cycle okay in such a gun. Heavier buffers will help.

I don't have experience with superperformance, just explaining the science and application of it. Id be interested to hear details of any issues users experienced.

**Coal Dragger** · 06-14-13, 22:24

I might have to play with some of this in my AR that has an adjustable gas block, I imagine that would probably work to dial in the gas system with the higher port pressure.

**highxj** · 06-15-13, 09:15

I have a friend at Hornady who I spoke with about this. It was in reference to their 5.56 55gr. GMX Superformance load. I had assumed that with the 5.56 designation it would only make sense that it could be safely used in a carbine. He says......nope, it'll pop primers.

I did shoot some in a BCM 16" mid length and it operated no differently than IMI M193, with no signs of high pressure. Velocity, however, was unspectacular.

**ICANHITHIMMAN** · 06-15-13, 10:20

Originally Posted by highxj

I have a friend at Hornady who I spoke with about this. It was in reference to their 5.56 55gr. GMX Superformance load. I had assumed that with the 5.56 designation it would only make sense that it could be safely used in a carbine. He says......nope, it'll pop primers.

I did shoot some in a BCM 16" mid length and it operated no differently than IMI M193, with no signs of high pressure. Velocity, however, was unspectacular.

Gene from LMT advised me against this in my rifle , he said they tested it and it was not safe for their guns.