SIG MCX review

[JCN]

That’s really interesting. I’d love to see more testing. My understanding is that the TTSX is the go-to supersonic bullet for short-barreled .300 blk. It’s surprising to see it can’t reliably penetrate soft armor. I wonder if this is the case for all supersonic .300 blk that isn’t specifically marketed as armor piercing, when fired from such a short barrel, or if this is specific to the TTSX. I’d be curious how some of the newer solid-copper stuff would do. If supersonic .300 blk out of a short barrel does generally have a tough time with soft armor, what are the advantages of supersonic over subsonic ammunition in something like a Rattler?

I do a lot of armor testing but I don’t usually post it online for reasons.

[WobblyPossum]

I do a lot of armor testing but I don’t usually post it online for reasons.

Totally understandable.

[Sensei]

Interesting. Is this the 110 or 120 gr? Do you know the velocity?

I’ve chronographed the 110s at over 2000 FPS from the rattler. They were definitely on the hot side though.

Your results a good bit off what I’ve experienced and seen with the 110 grain Barnes load. Take a look at post 1 and 10 here:

https://pistol-forum.com/showthread....Barrel-Lengths

The Rattler gave up 300 fps to a 9” MCX and came in at around 1825 fps. While this is enough velocity to expand in soft tissue within 25 yards and after many barriers, I’m not surprised that it chokes on soft armor. FWIW, I’ve seen other articles on the load that quote around 1800 fps for the 110 grain Barnes load out of a Rattler and 2100 fps from 9” barrels; none as high as 2K from the Rattler.

[JCN]

Your results a good bit off what I’ve experienced and seen with the 110 grain Barnes load. Take a look at post 1 and 10 here:

https://pistol-forum.com/showthread....Barrel-Lengths

The Rattler gave up 300 fps to a 9” MCX and came in at around 1825 fps. While this is enough velocity to expand in soft tissue within 25 yards and after many barriers, I’m not surprised that it chokes on soft armor. FWIW, I’ve seen other articles on the load that quote around 1800 fps for the 110 grain Barnes load out of a Rattler and 2100 fps from 9” barrels; none as high as 2K from the Rattler.

1800 versus 2100 were almost exactly what I got as well.

[Corse]

Your results a good bit off what I’ve experienced and seen with the 110 grain Barnes load. Take a look at post 1 and 10 here:

https://pistol-forum.com/showthread....Barrel-Lengths

The Rattler gave up 300 fps to a 9” MCX and came in at around 1825 fps. While this is enough velocity to expand in soft tissue within 25 yards and after many barriers, I’m not surprised that it chokes on soft armor. FWIW, I’ve seen other articles on the load that quote around 1800 fps for the 110 grain Barnes load out of a Rattler and 2100 fps from 9” barrels; none as high as 2K from the Rattler.

My results are for hand loads at or near max with a magnetoSpeed, so I imagine they are correct.

I think my results for factory loads are about what you stated.

[JCN]

My results are for hand loads at or near max with a magnetoSpeed, so I imagine they are correct.

I think my results for factory loads are about what you stated.

I wish Underwood would load them hot like that.

[JCN]

Got a factory 9” 300 blackout barrel off gunbroker for $750, which is a little more marked up from optimal pricing, but with availability being what it is, I’m okay with it.

I have the 16” out for cutting down to 9” as well… I might have that one cut to 11” because the gas block is further towards the muzzle.

[Corse]

Got a factory 9” 300 blackout barrel off gunbroker for $750, which is a little more marked up from optimal pricing, but with availability being what it is, I’m okay with it.

I have the 16” out for cutting down to 9” as well… I might have that one cut to 11” because the gas block is further towards the muzzle.

I have a 16” I was going to cut down to 10”, but for some reason I haven’t done it yet. Probably because they are so expensive.

[JCN]

I have a 16” I was going to cut down to 10”, but for some reason I haven’t done it yet. Probably because they are so expensive.

The local gun shop is asking $80 to cut down. The 16” blackout barrel seems like kind of an oddity in terms of what I’d use it for functionally.

I have a 16” blackout X95 that balances well, a 16” blackout MCX seems like it’d be super nose heavy and unwieldy.

The 16” blackout MCX barrel has a gas block in a different place than a 9” and the 5.5”.

I’m going 11” so I can use the handguard of my 11” 5.56 and just barrel swap.

[JCN]