Why "hot loads" ?

You make my point! If a heavy load of some slow powder will improve things then it must be developed using a slower powder than Blue Dot! Trail Boss may be a lever to produce loads safely as max/min are purely volume based and can be used to find safe loads of other powders.

But this is rather off-topic. There is another thread on it!

Flyover_Country said:

I don't think that one could stuff enough slow-burning powder in the relatively small 9 mm case to make a carbine perform significantly better than a 4" service pistol. The slowest powder I see listed in my manuals for the 9 mm is Blue Dot, which would perform a little better in a carbine, but not a ton, it's not H110 for example. Most loads use powders no slower than Unique which pretty much tops out in a revolver length barrel and doesn't lose a lot when shot in a snubby.

Click to expand...

It can work the other way also. A small load of Universal or other faster powder will make the 30 carbine perform well in a handgun instead of breathing fire with the factory load.

grobin said:

Examples are the 9/10mm. The PCC is disappointing as 9mm is pretty much loaded for the shorty pocket pistols with 4" or less barrels. A load with a slower burning powder than communally used will produce optimum ballistics. But will not perform optimally on a shorty pocket pistol!

the 10mm is often less than 500Ft lbs and a few <400! 700Ft lbs is not uncommon.
.40 is typically <400 rarely ~500 occasionally <300

Meanwhile 9mm is commonly loaded <400 but quite a bit is between 400 & 500Ft lbs!

As you can see 9mm and .40 are about equivalent, with some unfortunate 10mm in the same range. To get the best out of 9mm and 10mm you need relatively heavy loads although there is no need to exceed SAAMI.

Click to expand...

It doesn't work that way, at all. Except for specialty subsonic loads, the powder is chosen according to case capacity and pressure, not barrel length. The 9mm doesn't have enough capacity for a slower burning powder like H110 to work. There's a reason why data like this doesn't exist.

This also addresses the myth that shorter barrels yield higher velocities with faster powders and slow powders are only appropriate to longer barrels. Completely untrue. As I said above, powder is chosen according to case capacity and pressure range, not barrel length. Slower powder also doesn't burn all the way down the barrel and muzzle flash is not unburned powder. "Fast" and "slow" are relative terms and most people seem to think the scale is much wider than it really is. In fact, fast powders like Bullseye are consumed before the bullet ever leaves the case. Slower powder is consumed by the time the bullet gets into the rifling. Slower powders produce more expanding gases and it's the expanding gases that accelerate the bullet down the bore. It is for this reason that with magnum revolver cartridges, the same slow powders that produce the highest velocities in 20" rifle barrels also do so in 3" revolvers. Powders like H110, Lil Gun or 300MP will yield as much as 250fps higher velocity in a 3" barrel than faster powders.

Muzzle flash is simply what happens when those expanding gases oxidize as they vent to the atmosphere. Faster powders may produce less muzzle flash in the .30Carbine but H110 was born in that cartridge.

Then why do we have cases where a loss of 75+fps per inch of barrel reduction occurs? Obviously some combustion is occurring in the barrel. My SIG 9mm with a 3" barrel has about the same muzzle flash and velocity as my 6.5" Blackhawk and my PC9! You are saying that cartridge manufacturers don't optimize to get the best performance in the most common barrel length? How come the new cartridges optimized for PCC? (I haven't tried any so far, the Federal was announced but apparently isn't shipping yet.)

I didn't say longer barrels didn't yield higher velocities, they typically do, to a point. Longer barrels allow the expanding gases to work against the bullet for a longer period of time. The greater volume of expanding gases, as occurs in magnum revolver cartridges, is why they gain 300-700fps in barrels up to 20" but pistol cartridges like the 9mm, don't gain much. It's a limitation of the cartridge. I said the same powders that yield the highest velocities in short barrels, also do so in longer barrels.

Maximum velocity is not always the end goal. Manufacturers often use low flash powders to reduce muzzle flash in handguns used for self defense. Most so-called "short barrel" loads use low flash powders and bullets that expand at lower velocities but people assume they use a faster powder for higher velocity in short barrels. It's not true and doesn't work that way anyway.

An extreme example would be Buffalo Bore's 340gr .44Mag load. Buffalo Bore uses a non-cannister grade of H110/296. This load yields well over 1400fps out of a 6-7½" barrel but also over 1200fps out of the 2¾" Ruger Alaskan. A faster powder wouldn't get anywhere near that.

The unfortunate reality is 9/10mm don't gain anything close to the expected velocity in longer barrels due to the shorty loads optimized for 3-5" barrels. Federal's release of a PC C optimized ammo supports this.

Recent review in American Rifleman reports a 221fps increase in a PC9 ~16" barrel over American ~ 3.4" barrel . That's a bit under 1/2 the expected (conservatively, could be more like1/3)!

Expected by whom??? Because I would expect no more than that. Actually 221fps is very good, because it's usually gonna be around 150fps. You're still clinging to the false belief that these loads are somehow "optimized" for short barrels and 'could' be altered to perform better with long barrels. It's just not the case. They're pistol cartridges and doing everything they can do given their design parameters. They lack the case capacity to do any more. To gain 300-400fps or more, you need a tall stack of slow burning powder in a cartridge that holds enough of it to work. In other words, you can't get there from here.

That's the increase I see with other calibers-except 10mm! I am able to get back to this now that it's warming up. So I'll see where I get to. If they aren't optimized for short barrels some one is screwing up big time and there will be no market for the new Federal ammo optimized for the PCC! I'M going to start with 10mm as I have a Blackhawk that will be good for developing loads and an Aero 10mm carbine. My 9mm SIG isn't really durable for developing loads, although not as prone to blowing up as my Glock.

You just don't get it. Have fun.

A better question is why does it bother you so much what others shoot in their gun? Are you paying for their ammo? Are you buying their guns? Why do gun companies build guns so strong that they can safely shoot hot loads and why do those same companies build these stupid tiny light weak guns that can't take regular loads and have to come with warnings about using special light loads.
What if a guy doesn't have enough money to buy several different guns so he chooses a caliber in a well built gun that can handle mouse loads up to moose loads. I just don't get why a few are so worried about what so many others shoot out of guns they bought and paid for with their only money not yours. Sorry rant over