.357 in a 9mm Can

[johnnywitt]

Ok, so the max CUP is 35000 for the .357 and the 9mm is 35,000.
so, why can't I shoot .357 Mag out of my Mk9k?
If I open up full auto with my Ti Bolt in my Uzi at >1600 rpm that would SEEM to exceed any pressure that would build up slow fire with a .Bolt 357 Mag.

Reason I ask is that I want to get a Ruger 77/357 and cut the barrel to 16" and mount a 3 lug on it like my sub gun has to hunt deer in Ohio with my Kid.
The only other thing is the diameter of the .357 through a .355 can as well and will the 3 lug hurt accuracy too much vs a screw on can.

[hyrulejedi86]

I'm looking to do a similar thing except I'm trying to get a hold of a Marlin 1894C in 357 to put my Octane 9 on. I've seen several posts in this forum and others where someone from SilencerCo has stated the Octane is capable of handling 357 mag. As for other companies I would reach out to them to find out what they say but I can't imagine it would be a problem. For 38 special you should be fine with any 9mm can on a rifle. The 9mm bore shouldn't be a problem with 38 caliber bullets, the 9mm cans all seem to have a large enough bore.

Where about Ohio are you? I'm West side of Cleveland and looking for the Marlin for deer as well.

[johnnywitt]

I'm looking to do a similar thing except I'm trying to get a hold of a Marlin 1894C in 357 to put my Octane 9 on. I've seen several posts in this forum and others where someone from SilencerCo has stated the Octane is capable of handling 357 mag. As for other companies I would reach out to them to find out what they say but I can't imagine it would be a problem. For 38 special you should be fine with any 9mm can on a rifle. The 9mm bore shouldn't be a problem with 38 caliber bullets, the 9mm cans all seem to have a large enough bore.

Where about Ohio are you? I'm West side of Cleveland and looking for the Marlin for deer as well.

I just visit Ohio with the Family occasionally and wanted to do some Deer Hunting There. I called Gemtech and they said don't do it (not Dr. Dater though). I'm just trying to figure out why. If I can shoot a burst of FA Fire with one caliber vs one shot slow fire with the other cartridge and both cartridges have the same max pressure CUP, I just don't understand. I think it's a Liability thing. Countrys run by friggen Lawyers.

[Fulmen]

Maximum pressure and muzzle pressure are not the same, the 357 holds a lot more pressure so for the same barrel length the muzzle pressure will be higher. And I don't think FA will increase the pressure in the can significantly. However, for a can to withstand FA use it must be able to withstand the load at high temperatures, and most materials loose strength at elevated temperatures. It's therefore not unreasonable to assume that such a can will survive slow fire 357 just fine. A long barrel will decrease muzzle pressure as well, so I expect this is precautionary thing to stop some joker from using it on a FA-converted 2" Desert Eagle or something

[David Hineline]

CUP is chamber pressure, it has nothing to do with the amount of volume of gas or pressure that comes out of the end of the barrel where the silencer is. Like you said yourself you don't understand so when you question the actual manufacturer of the device who does understand, you still don't believe them.

A silencer could easily be manufactured that could handle the 9mm and anywhere upto magnum rifle calibers, but it would not be lightweight like most 9mm silencers are made to be.

The product you desire for you rifle exists in the market place, just don't expect it to be a small light weight 9mm silencer designed for a handgun.

Looks like Ohio allows 38 special as a hunting caliber, or you could download 357 casings to a reduced power level that the silencer you have can handle.

[TROOPER]

I thought it was a volume-of-gas issue more than anything else.

I also do not understand how that works, but I do understand enough to know that a 9mm < 357 Magnum when it comes to how 'zesty' an individual shot is.

[Deathray]

Personally I don't see why it wouldn't handle it. I wouldn't worry about the volume of gas, the MK9K is a pretty huge can. And we're not dealing with all that much more propellant.

Yes you have about double the amount of propellant (though often not quite that much more), but you also have double the barrel length or more. PV being equal to NRT (yes I know that burning smokeless powder is not an ideal gas) would work out to roughly the same muzzle pressure assuming the same bullet, powders, etc...

You may even have lower muzzle pressure since it's entirely likely that all the powder will have burned before the bullet hits the muzzle.

[jlwilliams]

Like so many things, the correct answer is "It depends." The only way your going to get a better answer is to contact the manufacturer and ask them directly about the exact rifle and load you want to shoot.

If the can you have isn't going to do what you want, you have choices to make. You could either back it down a bit as far as what you do with that can. For example, it may be fine to shoot .38 specials through it so maybe you make that work. Or you may be saving up for another can. You may find that your 9mm can isn't the thing for .357 heavy subs, but maybe a different subgun can may be just the thing. Then again, you may be doing a form 1.....

If you haven't contacted the manufacturer already, that has to be on your list. There is a lot of knowledge here on this forum, but some questions have to be asked of the manufacturer. Even if someone here has the correct answer, it means so much more in writing or email from the maker.

[TROOPER]

There is some absurdity going on around here. 357 Magnum ≠ 9mm. Out of a rifle, 357 Magnum starts to behave like a 30-30. Out of a rifle, 9mm starts to act like it came out of a handgun.

Could you conceivably fire a 357 Mag through a 9mm can? Yes. People load subsonic 357 magnum and do this. They also sometimes have over-built cans. Sometimes they just risk it and it all works out ok. There was even a video of a Spectre being mounted on an AR. This doesn't make it a good idea.

I'd be surprised if a manufacturer says to go ahead and do it, because some yahoo is going to put full-house 357 magnum into their muzzle-grenade and get hurt.

As far as it being a rifle as opposed to a pistol, yeah, that matters, but the damnedest aspect of this analogy is how it so thoroughly works against the idea of doing it. 357 Mag genuinely benefits from more barrel length specifically because pressure doesn't taper off. Contrast this with 9mm where there isn't any practical difference between a handgun and a rifle as it pertains to performance.

That logic alone should warn you away from this idea.

[hardcase]

Liberty has a long list riffes comparable with the mystic. Night be worth a chance comparison look

[glocker17]

I use full power 357 through a 10.5" barrel Ruger 77/357 with an Octane 9HD, cleared it with Silencerco first. Tend to shoot more subs but occasionally will fire some full power 158's. I am guessing that by 10" muzzle pressure is at a safe level. Can is no worse for wear.

Pic is with ISIS can used prior to getting the Octane.

[savagetactical]

Personally I don't see why it wouldn't handle it. I wouldn't worry about the volume of gas, the MK9K is a pretty huge can. And we're not dealing with all that much more propellant.

Yes you have about double the amount of propellant (though often not quite that much more), but you also have double the barrel length or more. PV being equal to NRT (yes I know that burning smokeless powder is not an ideal gas) would work out to roughly the same muzzle pressure assuming the same bullet, powders, etc...

You may even have lower muzzle pressure since it's entirely likely that all the powder will have burned before the bullet hits the muzzle.

In a pistol, that much propellant makes a big difference. You are also making a bad assumption that all powders are equal. 357s use slower burning magnum pistol powders. When you use more slower burning propellant, the maximum pressure is the same but it stays higher as the bullet travels down the bore than a 9mm round fired through the same length barrel. This higher average pressure is why 357 can easily push a 150+ grain well pass supersonic velocities out of a pistol barrel while 9mm can barely break 1000 fps with a 147 bullet even out of a rifle. This higher average pressure is also why you can easily gain several hundred fps when shooting a 357 round though a carbine, while 9mm gains 50-100 fps max and might actually lose velocity due to bore friction.

For comparison, if you loaded a 357 with a 9mm's faster burning powder (using the same amount of powder as standard 357 load), the peak pressure would spike much higher and then probably drop below the muzzle pressure than with a magnum powder. However, the firearm probably would not survive the initial pressure spike.

[glocker17]

If the OP is using a 16" barrel it should be fine with a good quality can. If the Octane is fine on a short barrel 357 I would have to bet that even a lesser made can would be fine on a 16" barrel. Bore pressure drops of rapidly in higher pressure rounds like the 5.56 and the 357 with a lower quantity of faster bring powder will as well. Someone with Quickload can run a simulation for us?

John in NH posted some data years back that indicated a full pressure 357 in 14" barrel form produced a lower muzzle pressure than a 9mm 4" barrel shooting 147 subsonics.

[Fulmen]

The burn rate of the powder is in itself insignificant, by the time you reach the muzzle it's only the amount of gas produced that matters. And while all powders are different they are all in the same ballpark when it comes to gas production. But muzzle pressure alone isn't everything either, one must consider the total amount of gas as this will dictate the pressure inside the silencer.

A 14" barrel has more than 3 times the volume of a 4" and is comparable to the blast chamber of a medium size can. So the combined volume of the barrel and blast chamber will be 4 times the barrel volume for a 9mm but only 2 times for the 14" .357. This means that the pressure inside the blast chamber could be twice as high with a 357 even if the muzzle pressure is the same.

BTW: Your 357-loads are pathetic. My worst load is 18grs of WW296 behind a 180grs XTP, clocking out at 1390ft from a 6". Now THAT'S a MAGNUM baby.

[DKDravis]

Gas "production" from a given amount of powder is straight forward -- The combined mass of the gasses (plural) and unburnt/noncombustible particles is precisely the mass of powder involved .. (This i because the combustion process involving gunpowder is a self-contained process, it carries its own oxidizer in the "fuel" so to speak --

So you load a typical 9 mm with 4 - 7 grains of fast burning powder .. that produces 4 - 7 grains of hot gas/particle mixture .. No more no less ..

A typical "full house" .357Mag uses 12 - 20 grains of slow burning powder .. = 12 - 20 grains of hot gas/particle mixture .. No more - no less --

The muzzle pressures given the same barrel length will be very different, as will the amount of gas at that given pressure..

I will try to calculate the differences in QL --

As to the efficiency of the "can" this is sometimes influenced by the amount and pressure of the gasses, in the opposite way of what one might expect..

During a very elaborate and "scientific" test of a number of suppressors from European manufacturers (where I was a "consultant") we saw several of the .30 cal suppressors showing significantly higher sound-pressure reductions with .300WM, than with .308 ..
The absolute dB values were of course higher with the .300WM, but the "reduction" in noise was greater by up to 3,1 dB --
I.e the difference between a non-suppressed shot and a suppressed shot was 3,1 dB greater when shooting .300WM through the "can", than when shooting .308W through the same "can" -- Both rifles has identical 24" barrels .. 180 grain bullets were used for both calibers.

I think this has to do with the amount of "turbulence" and "gas-flow" obstruction that comes with more gas at higher pressures ..

[bgrayd]

I have a Marlin 1894C that I had threaded (by Tornado Technologies) for use with the SWR Trident. I only shoot 158 grain 38 special through it, and it sounds FANTASTIC!

You will not be disappointed with this combination

[glocker17]

BTW: Your 357-loads are pathetic. My worst load is 18grs of WW296 behind a 180grs XTP, clocking out at 1390ft from a 6". Now THAT'S a MAGNUM baby.

Thats not a 357 mag load, thats around 357 Maximum. Way over pressure for a mag, hence the higher than normal velocity. I use around 13.5gr with 180r bullets. Get about 1400fps in the 10" SBR. I don't think 18gr will fit at magazine length.

[Fulmen]

Actually these were loaded to the old CIP-pressure of 46.4ksi (it's currently at 43ksi) and fits in my 686 without any problems. The velocity is also probably higher than normal due to a 0,003 barrel gap. I won't deny that it's hot as hell, but it matches published reloading data and pressure ring measurements didn't indicate any excessive pressure compared to Federal American Eagle.