Which factory loaded subsonics will stay quiet in a carbine. I have an MP5 with a 9 inch barrel and want to get rounds that stay quiet in that. I was looking at ordering a case of American Eagle 124g subsonic, will those work out? My other options right now are Speer Lawman 147 grain TMJ Subsonic, 147 Grain Subsonic Winchester Training Ammo, Subsonic 147 grain FMJ Winchester Super-X, or Subsonic 147 Grain Remington UMC.

Find out whar barrel length the manufacturer used to label it subsonic and go from there, or buy a box of each to run thru your chrony for actual results and function in your carbine (this is more fun).

Sorry if it's not the answer you wanted, but it is the best way to find out.

AE 124 grain went super in G17 with Lonewolf barrel.
Most 147's should be subsonic.

Mine likes Fiocchi 158 grain best

Avoid the Winchester super x. it's pretty nasty on suppressor baffles

I went with Remington UMC 147gr, I will let y'all know how they preform!

The AEs are also supersonic in my M&P, not by much, but you can hear it and the chrony confirmed it.

doubloon wrote:http://www.ballisticsbytheinch.com/9luger.html

Great site to reference. I use it with reloading data to get a rough estimate on velocity increase.

http://www.hodgdonreloading.com/data/pistol

Yeah, it's not perfect but the real answer is buy a chrono.

If I'm not mistaken, I do believe the 147gr 9mm rounds were originally developed specifically for suppressed SMG's...

doubloon wrote:Yeah, it's not perfect but the real answer is buy a chrono.

He has a silencer. If he's going to buy and shoot the ammo for testing he doesn't need a chrono, he can just listen for sonic crack. Ammo with no sonic crack was subsonic.

PM me for some info on reloads for the MP5.

I don't shoot factory loads other than for EDC use.

147g will be the end result and reloading is YOUR FRIEND.

PM sent.

The Fiocchi 158 grain ammo has been very good in my MP5. You mileage may vary.

Conqueror wrote:

doubloon wrote:Yeah, it's not perfect but the real answer is buy a chrono.

He has a silencer. If he's going to buy and shoot the ammo for testing he doesn't need a chrono, he can just listen for sonic crack. Ammo with no sonic crack was subsonic.

Chrono is the way to go. With my reloads if I'm right at the point where they are subs vs super, I may have half of them going super with a crack and some not. Also if you are on the edge, weather, atmospheric pressure, etc can make a difference. I try to load mine at least 100 fps below supersonic at my altitude to be safe. I'd hate to buy a case of 1,000 and find half of them were super, If I paid a premium for subs.

hardcase wrote:

Conqueror wrote:

doubloon wrote:Yeah, it's not perfect but the real answer is buy a chrono.

He has a silencer. If he's going to buy and shoot the ammo for testing he doesn't need a chrono, he can just listen for sonic crack. Ammo with no sonic crack was subsonic.

Chrono is the way to go. With my reloads if I'm right at the point where they are subs vs super, I may have half of them going super with a crack and some not. Also if you are on the edge, weather, atmospheric pressure, etc can make a difference. I try to load mine at least 100 fps below supersonic at my altitude to be safe. I'd hate to buy a case of 1,000 and find half of them were super, If I paid a premium for subs.

+1, guessing isn't the way to go, and sonic cracks can be tough to hear when there's a braked AR nearby.

Conqueror wrote:

doubloon wrote:Yeah, it's not perfect but the real answer is buy a chrono.

He has a silencer. If he's going to buy and shoot the ammo for testing he doesn't need a chrono, he can just listen for sonic crack. Ammo with no sonic crack was subsonic.

I was eluding to "perfect" and a "real" answer but I tend to agree success is self evident once the sonic crack is eliminated.

I guess you guys shoot at different kinds of ranges from me. At our range it's never a problem to find a quieter area so you're not shooting right next to a guy with a .300WM. An I still say you don't need a chrono for this. It's not the end of the world if you pick some ammo and find out that it cracks a bit in cold weather. Most factory 147 will have some crack if it gets cold enough outside. And transonic cracks are not hard to hear if you know what to listen for. I even work up rifle subs without a chrono, very successfully. My approach to this has always been to buy 4-5 brands of 147, shoot them all in cool weather, and whichever one sounds best most consistently wins. Never been unhappy with the results.

5 boxes @ $20/box = 1 Chronograph

Right, so who would buy an unnecessary thing instead of five boxes of ammo? and if you buy the chrono you still have to buy the ammo.

Yeah, why would anyone want a chronograph when they can just make stuff up?

ThaDoubleJ wrote:Yeah, why would anyone want a chronograph when they can just make stuff up?

Wuh?

I buy the chrono to check ammo for consistent ballistics.

But I've never used it for checking subsonics.

ThaDoubleJ wrote:Yeah, why would anyone want a chronograph when they can just make stuff up?

What about "absence of sonic crack = subsonic" is made up? Unless you do some complicated math involving temperature, barometric pressure, elevation, etc. you don't actually know the precise speed of sound at your range during your shooting session. So what do you do when your ammo reads 1070fps on your chronograph? Assume it's subsonic? Or do you listen for some fucking sonic crack?

You might not know, but you can actually use a chronograph for things other than determining what rounds are subsonic in your gun. And who would shoot for 1070? I aim for 1000, then I don't have to worry about any of that hooha you're talking about. A chronograph can also be used more than once. In fact, if you don't shoot it, you can use it for many years. Hurling bullets, which aren't cheap these days, and sticking your ear out, is pretty subjective. Using electronics and numbers pretty much isn't.

ThaDoubleJ wrote:You might not know, ...

Dude ...

Don't see a need for a chrono if you don't even reload.