Hot loads (noob question)


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g-nome
December 25, 2005, 01:15 AM
What's a hot load? Is this just a round of ammunition wherein the projectile (bullet) itself weighs more than typical and therefore requires a greater powder charge packed in as to propel it at the speed/velocity need be?
So for instance, a lighter round will not need nearly so much in the way of propellant grains and therefore is less taxing on the firearm? Creates less pressure, less heat and therefore allows a longer barrel life?
Do I understand this correctly or not?
Oh yeah one more thing; +P ammunition is what would be considered 'hot' as well correct? What's the +P stand for?

Thanks from the noob.

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antsi
December 25, 2005, 01:35 AM
Generally 'hot load' refers to more powder charge at any given bullet weight (which translates into more velocity).

In many loadings, heavier bullets actually take a smaller powder charge because they build up more pressure inside the gun. For the same pressure and caliber, loadings using heavier bullets will usually produce less muzzle velocity.

SAAMI or SAMMMI (don't remember the exact acronym) establishes standards for the pressure in a given caliber. +P means that the loading produces greater pressure inside the gun than the standard. This makes the bullet go marginally faster. Whether or not this makes the bullet any more effective at stopping an attacker is a matter of some controversy. It certainly helps them sell more bullets.

whm1974
December 25, 2005, 02:23 AM
When shooting "hot loads" or +P ammo keep in mind you will put more wear and tear on your guns.

-Bill

g-nome
December 25, 2005, 03:30 AM
In many loadings, heavier bullets actually take a smaller powder charge because they build up more pressure inside the gun.
Ohhhh so I had it backwards then.
And while still on this topic . . . So basically, if you want your barrel AND gun altogether to last longer you should generally shoot loads with lighter bullet weights? As this generates less pressure? And it's not the faster velocity that wears down a gun? Instead it's the pressure generated?
Okay so if I have it straight:
lighter bullet weight=less pressure=generally higher velocity with less pressure generated=lesser wear
Heavier bullet weight=more pressure=generally lower velocity with greater pressure generated=higher wear :D :what:

When shooting "hot loads" or +P ammo keep in mind you will put more wear and tear on your guns.
Oh yeah and the +P thing I was just curious on. And no, I don't think I'd EVER use such loads regardless of the type of firearm.

Thanks for helping a noob out it's appreciated more than you can know.

Cosmoline
December 25, 2005, 05:23 AM
"+p" is typically an official SAAMI designation and is perfectly safe in any firearm designated to take +p ammunition of that type. The designation is typically only used with certain kinds of handgun ammunition such as .38 Special and 9x19. I am not aware of any +p designation for rifle cartridges. There are "light magnum" loads in certain classic rifle cartridges which are similar to +p but AFAIK not officially sanctioned by SAAMI.

As far as wear and tear, higher-velocity rounds typically cause more wear and tear than larger, slower rounds. It takes less powder to generate sufficient pressure with larger bullets, but this means you load less powder. It does not mean larger bullets operate at a higher pressure. For, example, in a .357 Magnum the smaller, higher-velocity rounds have been known to cut into the steel on the topstrap. In rifles ultra-high velocity rounds most certainly wear down a barrel faster than slower, larger bullets.

antsi
December 25, 2005, 09:09 AM
Ohhhh so I had it backwards then.
And while still on this topic . . . So basically, if you want your barrel AND gun altogether to last longer you should generally shoot loads with lighter bullet weights? As this generates less pressure? And it's not the faster velocity that wears down a gun? Instead it's the pressure generated?
Okay so if I have it straight:
lighter bullet weight=less pressure=generally higher velocity with less pressure generated=lesser wear
Heavier bullet weight=more pressure=generally lower velocity with greater pressure generated=higher wear :D :what:
.

No, I've led you astray ;)

Most loadings with lighter bullets are loaded with more powder, and generally acheive similar pressures for a given caliber. With the same pressure, a lighter bullet will go faster and a heavier bullet will go slower. I don't know if you can generalize about which will put more wear on the gun, and doubt it will make much difference in most factory loadings.

Most factory loadings, especially in practice/range ammo, are not loaded with real extremes of bullet weight. For example, Winchester makes a 9mm practice ammo in 115 gr, and Speer's is 125 gr. You may find that your gun performs slightly better with one or the other, but you're not going to see a vast difference in power or recoil or anything obvious.

Some people do believe the +P loadings put more wear on the gun, due to more overall kinetic energy, banging the slide around harder, etc. Even with +P, though, how many rounds you shoot probably makes a lot more difference than ammo type.

Most +P loadings are premium defense ammo anyway, not practice ammo, so I hope you do not have occasion to shoot thousands and thousands of rounds of it.

I don't get too freaked out about wearing out a gun. Most modern quality firearms are good for tens of thousands, if not hundreds of thousands of rounds if they are properly taken care of.

Merry Christmas

Firethorn
December 25, 2005, 09:46 AM
If I remember right +P is the SAMMI designation means "within 110% of specified pressure limit for caliber".

Now, you can also get +P+ ammunition(usually handloaded or special order), of which the definition is "exceeds 110% of specified pressure limit"

Does anybody know of a link where I can see the SAAMI specifications for calibers? The reloading books are down at Dad's.

As for wear and tear: I'd say not to worry about it unless you're shooting +P or +P+. Standard ammunition is loaded to about the same pressure, thus the same wear.

JMusic
December 25, 2005, 10:16 AM
Gnome all good replies but to do justice to hot loads you could right a novel. Lets just say they are safe in almost all modern firearms in good condition. A Reloader's definition may be a bit different than factory so my statement is meant toward the later. In general a hot load will make a bigger bang than what you are acustom to in your specific caliber. If you really want to learn about the variable's look into the reloading section of this web sights. Lots of knowledge there. Merry Xmas
Jim

M2 Carbine
December 25, 2005, 10:37 AM
I consider a "hot load" to be at the top or slightly exceeding a maximum recommended load for a given caliber/pistol.

For instance the normal "full load" for the Makarov pistol is a 95 grain bullet loaded to 1,000 FPS.

A factory load using 115 grain bullets doing 1,000 FPS is available. I consider this load to be a "hot load" for this pistol and the factory recoil spring should be replaced with a stronger spring.

I hand load a 90-95 grain bullet loaded to over 1,125 FPS for the Makarov, which would definitely be called a "hot load" for the Makarov and a "over load" for the P64 and PA-63 9x18 pistols.

So what may be a "hot load" in one pistol could be a "do not use over load" in another brand of pistol.

Lupinus
December 25, 2005, 11:43 AM
Basicly a hot load is a round that will give more preasure then normal through adjusting the powder charge.

TallPine
December 25, 2005, 02:46 PM
In many cases, a "hot load" is used in a modern handgun (usually revolver) chambered in a vintage caliber like .38 special or .45 (long) Colt. Such cartridges were originally designed for black powder, and there are still some original guns around along with jillions of replicas. These can be fired with smokeless powder cartridges loaded to similar pressures as what black powder would have produced. Since the smokeless powder takes up less volume than the original BP, there is a little to a lot of extra room in the loaded cartridge.

For instance, a Ruger Blackhawk/Vaquero (and a few other quality brands)chambered in 45 Colt can be loaded up to 44 magnum levels or even a little beyond, using modern brass. But you have to make dang sure not to ever let those "hot loads" find their way into a vintage or replica gun :uhoh:

The 357 magnum is basically a "hot loaded" .38 special, but the case is about 1/8" longer so it will not fit in older guns. 38 +P is just a way to get more performance out of a modern steel 38sp revolver, but again those "hot" cartridges need to stay out of older (and some current) guns.

Similar situation exists with the 45-70 and 450 Marlin in rifles. You can load the 45-70 up to higher pressures/velocities in new Marlin rifles, but the 450 Marlin (same thing, basically) will not fit in older 45-70 rifles.

I suppose the same thing can be done with semi-autos, but since the pistol is basically designed around the cartridge it doesn't seem as worthwhile. A semi-auto normally has a certain pressure range that it likes to function at, but a revolver will pretty much work with any load from barely falling out the end of the barrel to just short of blowing up.

g-nome
December 25, 2005, 07:27 PM
Woot!
Wow the information continues to pour at THR!! :)
Okay I now believe I have a better understanding than when I initially asked this question. Thanks a lot people!

benEzra
December 26, 2005, 12:12 AM
Another way to look at it is that a "hot load" is a higher-energy load, regardless of bullet weight.

For example, the Cor-Bon 115-grain +P JHP load for 9mm stands about halfway between an average 9mm round and a .357 in terms of kinetic energy; muzzle velocity is 1300-1350 feet per second instead of the 1200-ish fps characteristic of standard-pressure 115-grain 9mm rounds. For defensive use, if all else is equal, more energy is generally better, so many police departments that issue 9mm's have issued +P or +P+ ammunition to go with them.

FWIW, Glock 9mm's are rated by the manufacturer for both +P and +P+ ammunition. S&W discourages +P ammunition in their aluminum-framed guns (probably over concerns about accelerated wear), but in moderation you are unlikely to wear the gun out. I own an S&W 3913LS 9mm, and use standard-pressure ammunition for recreational shooting and much practicing, but Cor-Bon +P is my defensive load of choice and I shoot enough of it at the range to be familiar with it and to ensure the gun is 100% reliable with it.

Jim March
December 26, 2005, 01:47 AM
There's a very interesting case history on bullet weights, velocities and gun damage that came out of the S&W "K frame" sized 357Mag guns.

The "K Frame" was originally meant for 38Spl. By the late 1950s better metallurgy meant they could be set up in 357Mag with minor design improvements by S&W and 357Mag K-Frame guns started shipping such as the model 13 (blue fixed sight 357), model 19 (blue adjustable sight 357), model 65 (stainless 13) and 66 (stainless 19).

All was well until around the 1970s, two things happened: the top performing loads in 357Mag were the 125grain "full house" loads doing more than 1,400fps from a 4" barrel and police adopted a new policy: practice purely with the same load and performance level that you carry for duty.

Prior to this, it was common for most or all practice to be done in mild 38Spl loads and very little 357 shooting would be done if at all.

Under the stresses of thousands of rounds of full-house 125grain, the K-frames came up with a problem: stress cracking at the back of the barrel.

It turned out that the same guns running the same overall power level ammo but 158grain instead of 125 wasn't such a problem (even if the net energy was the same). Why? Because the 125s were accellerating faster and at the point where they hit the back of the barrel they were already going like a bat outta hell. The 158s start out slower but boost up pretty good once IN the barrel.

Eventually the "bad rep" the K-Frames got led to S&W coming out with the L-Frame for those wanting an "unbreakable 357" and of late they've completely phased out the K-Frame 357, which I consider a crying shame.

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