Sig MCX vs. MPX

[MMH]

If the objective is to shoot subsonic, what is the advantage of a 300BLK over the 9mm? Obviously the 300BLK will have more energy (if shooting the 220 gr. bullet) & better ballistics, but for a 200 or 300 yard shot, are the differences that significant? If going supersonic, then the advantages of the 300BLK are obvious, but then you also have the supersonic crack.

In particular I am asking these questions in reference to the SIG MPX & MCX.

[CanOfWhooppass]

Pros of 9mm, cheaper to shoot, quieter, bullets expand well at subsonic velocity, but 100 yard max practical range.

Pros of 300 blackout subsonic, flatter trajectory over distance and retained energy, but expensive and almost every bullet design punches clean through target with no expansion. Practical range pushes out to more like 200 yards.

300 blackout subsonic is far superior to either above, but not quiet and still expensive.

Personaly, I went 9mm SBR and use 147 hydrashock for defense. I also have a 5.56 SBR and 6.5 Grendel DMR for anything likely to reach past 50 yards.

Look at some trajectory tables and you will see that just about anything subsonic has a very short range for point shooting.

[TROOPER]

I like 9mm for price and simple logistics since I can use it in my handgun as well. Thus far, I've only ever shot at things that don't care about power... paper... soda cans... etc.

The big advantage of 300 BLK is that you can achieve significantly more power and range with a simple ammunition swap. With 9mm, you can switch over to 115 +P+ and still be no where nearly as powerful or realistic at 200 yards compared to 300 BLK supersonic.

If both are only suppressed, then I favor 9mm for cost, and just accept that it's going to be a little less effective on-target compared to 300 BLK.

[eastern_hunter]

Depends on the service you expect to see from the weapon. If for CQB defense, the 300 BLK is more potent than the 9mm. The 220 gr subsonic load tends to upset on impact and flat spin through the target ... at least that's what I've seen on deer. In a short barrel (1:7 twist 8.5") stabilization is adequate to suppress. Suppression w an Octane 9 is perfectly adequate for use in a confined space. Not as quiet as 158 gr Fiocchi 9mm in a 8" tube with the same can (the quietest I've found) but good enough.

Energy per unit surface area is better with the 300 BLK.

The 300 BLK is more costly to feed and is less a plinker than a weapon.

I have a 9mm upper for my 300 BLK SBR and both barrels have 3 lug adapters on them for the can.

[TROOPER]

If the objective is to shoot subsonic, what is the advantage of a 300BLK over the 9mm?

Pros of 300 BLK subsonic over 9mm subsonic
- More power.
- Slightly more realistic range.

Cons of 300 BLK subsonic over 9mm subsonic
- More recoil. Probably not enough to matter... but more all the same.
- Costs more per shot. Probably enough to matter.

The end-result is what you intend to use it for. If you anticipate shooting at a living thing with the intent of killing it, then the 300 BLK is probably better in every way. If you intend to shoot paper and inanimate only, the 9mm will probably be better... although with a slightly reduced realistic range.

[fishman]

If the objective is to shoot subsonic, what is the advantage of a 300BLK over the 9mm?

Pros of 300 BLK subsonic over 9mm subsonic
- More power.
- Slightly more realistic range.

Cons of 300 BLK subsonic over 9mm subsonic
- More recoil. Probably not enough to matter... but more all the same.
- Costs more per shot. Probably enough to matter.

The end-result is what you intend to use it for. If you anticipate shooting at a living thing with the intent of killing it, then the 300 BLK is probably better in every way. If you intend to shoot paper and inanimate only, the 9mm will probably be better... although with a slightly reduced realistic range.

I wouldn't call a 100 yard vs. 200 yard range a "slight increase." That's a 100% increase.
However, if your shots won't exceed 75 yards or so, the 9mm is cheaper and a little quieter

[CanOfWhooppass]

If the objective is to shoot subsonic, what is the advantage of a 300BLK over the 9mm?

Pros of 300 BLK subsonic over 9mm subsonic
- More power.
- Slightly more realistic range.

Cons of 300 BLK subsonic over 9mm subsonic
- More recoil. Probably not enough to matter... but more all the same.
- Costs more per shot. Probably enough to matter.

The end-result is what you intend to use it for. If you anticipate shooting at a living thing with the intent of killing it, then the 300 BLK is probably better in every way. If you intend to shoot paper and inanimate only, the 9mm will probably be better... although with a slightly reduced realistic range.

I wouldn't call a 100 yard vs. 200 yard range a "slight increase." That's a 100% increase.
However, if your shots won't exceed 75 yards or so, the 9mm is cheaper and a little quieter

I don't think either is a good choice past 100 yards unless you have enough time to use a range finder and chart.

If you think you are taking a 150yd shot that turns out to be a 175yd shot you will miss by about 15" with a subsonic 9mm or about 10" with a subsonic 300 blackout. Based on Fiocchi 9mm 158 and 300BO 208 Amax (personal favorites)

Based on the OP I was saying neither suppressed round is a good choice for 200-300yd shots.

I do think things like lack of retained energy and greater drop shortens the practical range of sub 9mm to be less than sub 300BO, but both are IMO inadequate to aim at mid size game at the OP'S ranges. I have no problems ringing steel with 9mm at 200yds once I get dialed in, but that isn't hunting. I agree with previous poster- it depends upon the intent.

Not hating on either cartrige, I own both.

[CanOfWhooppass]

The 220 gr subsonic load tends to upset on impact and flat spin through the target ... at least that's what I've seen on deer. In a short barrel (1:7 twist 8.5") stabilization is adequate to suppress.

I take you at your word, but dont dismiss the high end 9mm 147's. No longer cheap, but the extensive research in this caliber going back to the 80's has resulted in some great choices.

[TROOPER]

Well, I don't want to be shot with 9mm from 200 yards away, but that said, I still would feel wholly under-armed if I had to shoot at people 200 yards away with a 9mm.

Don't lose sight of the bottom line here: 9mm costs less to shoot and will also work in your pistol... 300 BLK has more power and range.

I'm confident that even a 22 LR could be made to hit a target some unrealistic distance away, but it's not a point-and-shoot affair, and in the hands of a lot of people -- most definitely to include myself -- the practical range is very much reduced. So too is the difference between 9mm and 300 BLK; yes, the bullet itself can be made to travel a great distance, but it just isn't practical.

Hopefully the OP's question was answered.

[jjasonjllim]

The ballistic I saw from ATK on their HST 9mm 147gr were on the margin of passing the FBI test at 12". And that's at 10 feet!

9mm has 56% of the energy of 300BLK subsonic @ 100 yds.

300BLK subsonic isn't designed for 200 yds. Look at the trajectory.

[HHsurfer]

The cost of magazines should also be looked at when picking between the two.

[Griz]

9mm = blowback
300 = gas op

I find the HEAVY 9mm bolt slamming back and forth to be a huge disadvantage when shooting on the clock like in a 3-gun or subgun match.

[jreinke]

9mm = blowback
300 = gas op

I find the HEAVY 9mm bolt slamming back and forth to be a huge disadvantage when shooting on the clock like in a 3-gun or subgun match.

The MPX is a gas operated firearm, NOT blowback.

[Griz]

9mm = blowback
300 = gas op

I find the HEAVY 9mm bolt slamming back and forth to be a huge disadvantage when shooting on the clock like in a 3-gun or subgun match.

The MPX is a gas operated firearm, NOT blowback.

I apologize, I did not know that!

[TROOPER]

9mm = blowback
300 = gas op

I find the HEAVY 9mm bolt slamming back and forth to be a huge disadvantage when shooting on the clock like in a 3-gun or subgun match.

The MPX is a gas operated firearm, NOT blowback.

I apologize, I did not know that!

A few things about this:

1 - some on the internet are reporting that Gen 1 MPXs are over-gassed. I haven't really found this to be true, but I can only compared to a suppressed blow-back 9mm (CX4 Storm) which tended to sandblast the user. I've also read that Gen 2 MPXs are less gassed, and therefore more pleasant. I own a Gen 1 and haven't even seen a Gen 2, so I don't know first-hand what the difference really is.

2 - the bolt of the MPX is extremely light-weight; it cycles really, really fast... less inertia to over come, and travel distance for a short 9mm round isn't much. Makes for a very fast cycle.

3 - the bolt of the MPX is extremely light-weight; this means that the action of shooting generates recoil from the mass of the bullet and gas ejecting out of the barrel... and the movement of the bolt inside of the receiver - both backwards to eject and again when returning to battery. But since there's less mass than a mass-dependent bolt lock-up (CX4 Storm), there's less "gun-jump" in your hand. Recoil is the same since it's still a 9mm, but you really notice the reduction in gun jumping in your hand.

Great system so far. No complaints.

[MMH]

The primary use would be to get some cheaper AR training (appleseed type of courses) while shooting subsonic. Really a quiet plinker. Sounds like a MPX would be a better overall choice.