compressed loads?

[mozeppa]

some load data lists "compressed" powder loads

such as blue dot in a 357 magnum.
how does one make such an thing as a compressed load?

any special tricks to employ?

[Vann]

Basically the case is full enough that the bullet actually presses down on the powder, thus you have a compressed load. If you go to Nosler's site and look at their load data the give a capacity percentage. Any thing over 100% is a compressed load.

In most cases there is still plenty of room to start the bullet in the case, and the bullet is loaded normally. Sometimes you have to lightly tap the case a bit to settle the powder some, in extreme cases you'll have to use a drop tube to get all the powder in.

[str8wal]

Ya, a compressed load just means you have run out of case capacity for the amount of powder and bullet style/weight being used.

[lar45]

Heavily compressed loads can sometimes need a heavy crimp to keep it all in place. I generally don't load more than 105% load density with ball powders like 296.
Heavily compressed loads of 296 have actually resulted in lower velocities, which could mean that it has lowered the burn rate.
There is nothing wrong with a compressed load, just as long as it's not too much much powder and your going over pressure...

[johnson1942]

after asking advice as to using reloader 7 on cast boolits in a pistol bullet and recieveing the advice that i could if i compressed the load, i tried it. my 38 special loves it. it is a 1871-1872 open top urberti colt type. i tried a lot of .38 roundballs reduced in size to .357 with a fiber wad between bullet and powder. the powder was compressed and i cant tell you how much, but alot. it shoots great and consistant and i really have a hard time finding unburned powder grains. the barrel is 7 or 7 and 1/2 inched long, in that area. i also tried last week 110 grain copper clad bullet and even compressed them more and then had a tight crimp to finish it. man did they shoot accurate. at around twenty yards they were all in a tight little group off hand. i felt like one of the shooters from the 1800/s. it made my day and the reloader 7 and compression really works and im sticking with it. i used it in my cowboy 45 long colt and i felt it was a little too much omph for the gun so im sticking with blackhorn powder in the 45 long colt. however for those of you with 45 long colts of the modern type as the rugers ect. i would absolutely use reloader 7 in them and compress also. i dont know what other powders you can compress but real black and reloder 7 love it. thanks again to the guys who recommened compressing reloader 7, again my 38 special loves it and it isnt to much for my cowboy gun.

[Blackwater]

Gunpowder is at least partially composed of wood, broken down chemically, but still similar in many ways, and wood is compressible, and so is powder, at least to an extent. I've found many compressed loads in both rifle and pistol tend to give stellar accuracy and great velocities. Like anything with regard to reloading, compression can be taken to a ridiculous extreme, but a bit of compression can actually do great, though as LAR noted, there's no magic to it, and the results CAN be either positive OR negative. Some seem to be afraid of compression, but if the burning rate of the powder allows it, that's never proven warranted that I've ever heard of. Once you reach a maximum load, adding more just to get compression is overloading. But if you simply use the right burning rate powder, compression just isn't a problem, though some just don't like the idea, tending, it seems, to equating it to "overloading," which it is not, if the powder's burning rate simply allows it.

[Vann]

I prefer a load that gives a minimum of 90% case capacity, the closer to 100% or up to 10% over the better. I know it can't always be done but one thing to consider is that the powder is going to settle after loading a fair bit. So a case that was full to the neck when first loaded with a powder like say Imr 4064 could settle down to about 80% full depending on how large the case is.