when is 9mm +p (+p+) using HS-6 powder?

[IM_Lugger]

I’ve seen a couple of places that indicate that 7gr is the max loads for HS-6 powder with 115ge FMJ. Is this the max load for HS6 for 115gr bulelt? Anyways would it be considered +p. if not what would be?

[Steve in PA]

I use this load in my Beretta 92FS and S&W 6906 and have been for several years now with no problems.

Hodgdon lists 6.4gr as max, 1117mv and 27,900 CUP.

The Hornady manual, which I refer to alot lists 6.9gr as max with something like 1240mv.

[caz223]

I've been using HS-6 6.8 grains with a 124 grain plated hollow point bullet for practice, and the book sez it's only good for 1169 or so. (Standard pressure.)
But remember, plated bullets will have less pressure than the equivalent jacketed bullets.
I also shortened up the OAL from 1.169 to 1.145 to insure good feeding in my CZ75b. (Notorious for short chambers.)
I would say this load is on the ragged edge for +p.
But due to the strength of the 9mm brass, it has shown no pressure signs whatsoever.
I really, really need a chrony to double check my self.
I'm in the process of switching to 147 grain bullets and power pistol, and going to drop velocity to 1000 FPS to keep it subsonic, and standard pressure.

[IM_Lugger]

But remember, plated bullets will have less pressure than the equivalent jacketed bullets

I didn’t know this. Why is that? I’m going to use Complete Jacketed (CMJ) Bullets aka total metal jacket is that the same as copper plated or is it still FMJ?

[caz223]

It sure sounds like plated.
It's plated, I'm pretty sure.
Are they less expensive than bulk FMJ?
FMJ usually has exposed lead at the base.

[caz223]

As for them having less pressure at the same velocity, I bet there's somebody here that can explain it better than I can.
I'll muddle through it best I can.
Everyone knows that lead bullets (Esp. swaged lead.) require less powder for the same velocity than jacketed.
It's really soft lead, that seals well in the bore, and follows the grooves very well.
The lead forms a molten 'plug' (Obturation.)at the base of the bullet where heat and pressure expands it slightly, forcing it through the bore with no gas 'blow-by' (Providing you use a fast enough powder.)
This leads the barrel.


Swaged bullets are basically lead wire, formed into the bullet shape.
It's dead soft. Basically pure lead.

'hard' cast bullets are poured into a mold, cooled, then quenched into cold water. This 'quenching' speeds up the cooling process, forming large crystals instead of an organized lattice. Whatever.
This raises the brinell hardness.
These bullets have more character, but if you use slow burning powder on an exposed base lead bullet, even a hard cast one without gas checks, you'll still get leading.
Because the swaged lead was squeezed out of a hole at room temp it really has no lattice of it's own.
Cast bullets are usually not dead soft lead, they are alloyed with other metals like tin, antimony, etc.
Lead alloys are funny. Just a tiny bit of a metal like tin or antimony radically alters the structure, melting point, and hardness of lead.

Now we come to plated.
Plated bullets are swaged .
That's right, pretty much dead soft.
Then plated in a bath of toxic and corrosive salts.
Sometimes they are plated, then 'struck' to artifically raise hardness by work-hardening. The same process done to steel would be drop forging.
The plating is thin, usually pure copper.
Since it's so thin, it's basically like case-hardened cottage cheese.
A really cheap made in china pall peen hammer.
http://www.rainierballistics.com/mainframe.htm
Rainier's website sez that you can load plated to lead velocities, or reduce jacketed by 10%.
Since the layer of gilding metal is so thin, it acts more like the lead underneath, except that the plating stops the lead from stripping off on the outer edges and leading the barrel.
It doesn't seal as well, but thanks to a convenient law of phyics, (Something about heat=pressure and vice versa.) it still manages to 'stretch' itself out when in the bore. Since the thin coating has no character of it's own, it doesn't 'bite' as well, and you'll never get all the accuracy out of a plated bullet. It doesn't have enough character.

Now FMJ.
This starts out with a jacket. A jacket of proper dimensions, very thick and it's mostly copper alloyed with a small amount of zinc.
No idea how it's made, but it looks exactly like the bullet you're shooting except for the fact that it's hollow, and is open at the end.
It's positioned nose down and has lead injected into it. Sometimes at room temp (Swaging.) other times it's simply poured in.
It's dead soft, but the jacket is hard.
Hard enough to bite into the grooves.
Hard enough to retain it's shape in the barrel.

JHPs are the same thing, except that the bullet has an open nose, and the lead is injected into the nose.
Or it's swaged into the jacket, then the jacket is formed into the nose shape of the JHP. (Better yet.) Most modern ones are made this way. This raises the hardness of the lead core.
The thick jacket, consistant dimensions, and work hardened nose of the JHP make it more accurate than the plated variety.
Also, the JHP has another thing that helps accuracy. No off-center bubbles or 'voids' in the bullet nose.
You can see with this many construction variables and proprietary secrets, there are no hard and fast rules.
But you can draw a few conclusions based on their construction.
Swaged lead is the cheapest.
JHPs are the most expensive.
Plated is somewhere in between.
Pressure is actually regulated by friction, not the gasses themselves.
Dead soft lead has no character of it's own. It 'forms' itself to the grooves in the barrel and changes shape while in flight. Due to this, it has the least resistance, and therefore, the lowest pressure is generated at the same velocity.
Matter of fact, most people compensate by using very fast burning powders with lead bullets. Which is good.
Plated is next. It's dead soft lead with a thin coating over it.
This dead soft lead and thin coating only has slightly higher pressure than lead. It tries to hold it's shape, and that's what generates slightly higher pressures.
Hard cast lead has higher pressures than plated!!!! (IMHO!)
Bet you didn't know that.
People compensate by teaming it with slow burning powders, and putting gas checks on it.
Hard cast doesn't act like lead, it kinda acts like soft bronze or copper.
The cost of making quality hard cast lead bullets is in the alloys.
When it hits the rifling it stays together and retains it's shape better than dead soft lead. It takes more effort to push it into the rifling.
As a result, it generates more pressure.

Jacketed bullets retain their shape well, but take the most effort to push through the rifling. The bullet retains it shape the best, therefore it flies the best. Also, because it tends to center itself to the best of it's ability before the grooves cut into it, it is theoretically in better alignment in the barrel.
Sorry for the book.
Someone fairly smart could have said that in a short paragraph.

[IM_Lugger]

It sure sounds like plated.
It's plated, I'm pretty sure.
Are they less expensive than bulk FMJ?
FMJ usually has exposed lead at the base.

no there’s no lead exposed, it is totally covered hence complete metal jacket...I know they're made differently then FMJ's and ARE cheaper.

btw thanks