Handgun Forum banner
21 - 23 of 23 Posts

·
Registered
Joined
·
535 Posts
For any given projectile keeping the projectile caliber and mass constant, +P ammunition will increase the muzzle velocity over that which is achieved with standard pressure ammunition fired from the same firearm. Obviously, the greater the muzzle velocity, the greater will be the impact velocity for any given range and atmospheric conditions.

With modern JHP projectile technology, there is a somewhat delicate balancing act between impact velocity, expansion, and penetration insofar as terminal ballistics is concerned. As SouthernBoy pointed out, increased impact velocity will sometimes paradoxically decrease penetration by increasing the degree of expansion or by making expansion occur more reliably or sooner. In some short barreled handguns, muzzle velocity will not reach its potential maximum because not all powder is burned before the projectile leaves the barrel. So in some cases, a JHP that shows good expansion with a longer barreled weapon may fail to expand completely with a shorter barrel. Sometimes this can be dealt with by increasing the powder charge as in the Speer Gold Dot +P short barrel load.

There is also the matter of barrier penetration, which is a consideration for some. Barrier penetration will be largely dependent upon something that some have called "momentum density". This is the product of projectile weight and impact velocity divided by projectile cross-sectional area. Bullet weight divided by cross-sectional area is also called "sectional density" and this will be the same for all projectiles of the same caliber and weight. So the product of sectional density and impact velocity is a primary determinate of the ability of that projectile to penetrate a barrier. And for any given caliber, weight, design, and construction of projectile it will be increased by increasing muzzle velocity and thereby increasing impact velocity.
 

·
Registered
Joined
·
2 Posts
+P loads won't help much in a gun with a shorter barrel. I have never choreographed my Star Model 30PK but it has a barrel of less than 5 inches, and I would say the M miliary model is actually made with steel frame and longer barrel to take advantage of high velocity rounds. I know from 22LR High Velocity testing, the high velocity loads don't help much in a barrel with less than 6 inches, in order to be able to burn all the powder, otherwise gases have no time to push the bullet faster and are simply wasted..
 

·
Registered
Joined
·
790 Posts
+P loads won't help much in a gun with a shorter barrel. I have never choreographed my Star Model 30PK but it has a barrel of less than 5 inches, and I would say the M miliary model is actually made with steel frame and longer barrel to take advantage of high velocity rounds. I know from 22LR High Velocity testing, the high velocity loads don't help much in a barrel with less than 6 inches, in order to be able to burn all the powder, otherwise gases have no time to push the bullet faster and are simply wasted..
+P are tailor made for short barrels. Especially in older type ammo, well most of it is, but you get the ides.
It isn't going to get you to bragging velocities, but will make up some of the loss of an inch or two of barrel. +P isn't a magical velocity, usually 30-60 FPS depending on the barrel length, 30 being the majority of range, IIRC.
Modern powder and components don't suffer from the shortcomings you are stating any more, at least not to a large extent.
FWIW in this thread resurrection, I don't recall ever seeing a +P barrel. It says in the OM on all of them, and most say it is OK. Even the not so OK, the majority don't feed a steady diet of +P to guns anyway. It is expensive and tough on the shooter. A few for practice and in the near nonexistent need to use them is fine.
Poster Font Action film Event Fictional character
 
21 - 23 of 23 Posts
Top