SP at Logan with MP5 Submachine Guns!

[M1911]

The MP5SD really isn't designed to be used with typical 147 gr ammo. The way the gun is designed the integral suppressor sucks off a bit (actually, make that a LOT) of velocity in the process. (Part of this is why the integral can on those things are so effective... ) Typical l147 gr ammo can even cause
function problems in that particular gun. .

Thanks for the info. As I mentioned, cans significantly reduce the report even from supersonic ammo.

 

[Coyote33]

Lots of good points being made in this thread (cekim, ps2, gsg, others). Good job and good discussions, guys!

 

[GSG]

The magazines, where they held together with blue tape or red tape? If my memory serves me correctly, the blue tape means they're blanks, so nothing to worry about.

and . That's an awesome reference.

 

[mikem317]

I think you forgot on 9/11 they took away 2,973 American's freedoms, permanently. Forget that? But to say that politicians are terrorists? I think your drifting far from reality. But to go as far to say you hope someone would assassinate our elected leaders? I think you have deeper issues, and should seek help. McCain is far more of a patriot then you will ever be, and has sacrificed so you can sit on your PC and bitch about America. Get with reality, and take your tinfoil off.

"McCain" and "Patriot" are two words you'll never expect to see in the same sentence.

 

[GSG]

"McCain" and "Patriot" are two words you'll never expect to see in the same sentence.

I found the unexpected here

John McCain supports the 2006 extension of the Patriot Act

 

[abomb60]

The MP5SD really isn't designed to be used with typical 147 gr ammo. The way the gun is designed the integral suppressor sucks off a bit (actually, make that a LOT) of velocity in the process. (Part of this is why the integral can on those things are so effective... ) Typical l147 gr ammo can even cause
function problems in that particular gun. .

-Mike

MP5SD has a barrel port system that is specifically designed to bleed off gas pressure to drop a normal 115gr 9mm round to subsonic (see http://www.rimcountrymfg.com/guns.htm#guns for barrel example). If you look at a cross section diagram of the suppressor it has 2 chambers, the first for the initial gas venting (to drop velocity to sub-sonic) and a more traditional suppressor forward chamber to suppress noise.

Non-SD's need to use an external suppressor (obviously) but also need a new locking piece to be installed for suppressor use due to the changes in back pressure and chamber pressure caused by the can. You can't really go from suppressed to non-suppressed (and vice versa) without changing out the locking piece.

That being said the MP5SD is designed to only use 115gr ammo but a normal suppressed MP5 would benefit from a heavier bullet since the bullet will stay supersonic if it started that way and a subsonic bullet won't be slowed down by the design of the suppressor. A heavier bullet in an SD might slow the bullet down enough that it alters course and could cause baffle strikes in the suppressor.

And as a side note the link to the company above is a great source for certain HK parts if you have a clone you need to fix

 

[Gammon]

There are several SMGs on the market with suppressed barrels that will reduce the velocity of supersonic rounds to eliminate the sonic crack. The key is the suppressed barrel that can bleed off enough pressure to reduce the velocity of the round. Adding a suppressor to the end of the barrel will do no good as the round will then leave at super sonic velocities.

 

[drgrant]

There are several SMGs on the market with suppressed barrels that will reduce the velocity of supersonic rounds to eliminate the sonic crack.

Other than the MP5SD, what is there? I think it and the LRM169 upper are just about it. (Made famous by that hot russian chick shooting it... )

The key is the suppressed barrel that can bleed off enough pressure to reduce the velocity of the round. Adding a suppressor to the end of the barrel will do no good as the round will then leave at super sonic velocities.

I wouldn't say "does no good". A gun with a can on it, even without a velocity reduction, is still quieter than one without... There's easily an order of magnitude of difference. Obviously 147s are the quietest here, but there is still a benefit to running a can with standard 115 gr ammo, as well...

 

[jim/boston]

Thats Rob Silvers with his suppressed MP-5