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powder filling case question

3K views 10 replies 7 participants last post by  Alpo 
#1 ·
how important is it that the powder is not at the bottom of bullet. Without measuring I'd say the .270 loads I am doing now are about 1/8" below the bullets. Leave it alone or do something?
 
#3 ·
different powders will yeild different case volumes with respect to min / max laods and projectiles.

sometimes you get compressed loads. sometimes you have freespace.

for instance i work up some trailboss 'cowboy action loads' generically, you can have between 70 and 100% case fill, but no compressed loads.


when i load 3006 using some powders.. the max loads will be compressed as denoted with a (C) in the laod data chart. some won't be. just depends.

rememebr.. always start at the minimum load and work up.
 
#5 ·
Are you using smokeless powder? If so, airspace is not a problem.

If you are using black powder, however, there should be NO airspace. You should compress the powder as you seat the bullet.
 
#7 ·
Air space in a cartridge is common in most loads for most cartridges. The claim is complete filling makes for better accuracy but I have not seen any testing that confirms that. If you look through a reloading manual you will see, by far, few loads are compressed (100% fill). It seems each and every recommended podwer and its powder fill in a cartridge varies all over the place. Nosler who publishes the fill percentage (they call it load density) for each load if you want to research it.

Now, Black Powder is a different matter. The loads must be compress or bad things happen. The same goes for Black Powder substitutes in granular form. Black Powder substitute pellets are a different matter and need to only be used in modern Black Powder guns designed for them. When used in other guns the pellets may never ignite. I helped a friend who tried to use pellets (as recommend by the clerk at a local gun store) in his 1800's black powder cap and ball replica rifle. He tired many times and the pellets never ignited. We checked flash holes and their diameters with no success. We even changed nipples. Finally I used some Pyrodex I had for my cap and ball pistol (that listed a load for rifles) and the gun fired perfectly. This was caused by bad advice from the gun store "expert". It pays to double check any info from any source other than manufacturers.

LDBennett
 
#8 ·
The small amount of space left in your 270 case if of no significance. That has been pretty well addressed.

Fructose based black powder substitutes, I cannot call them a replica as they are completely different from real black powder, have a significantly higher ignition temperature than the real stuff. When they are formed into pellets one can reasonably expect that the ignition temperature rises yet again. A regular #11 cap will not ignite them. While I don't know I suspect even a musket cap might have a bit of a problem igniting the pellets. The hole in the middle is for in-line ignition by 209 primers. The combustion method of most modern, in-line rifles differs considerably from flint or cap lock traditional rifles.

I don't even like the loose substitutes. They are more difficult to ignite, are worthless in a flintlock unless one leads with a small charge of black, they still corrode your barrel and lock and I have been unable to see any increase in accuracy. Velocity, yes. And I can see a good use for them in BP cartridges.....or as fertilizer.

I will have to exclude....what is it, Blackthorn? I have absolutely no experience with it. But T-7, Pyrodex, the old GOEX Clear Shot and ....one that was completely junk but I forget the name of it...they will corrode steel if left uncleaned, same as holy black.
 
#9 ·
Are you using smokeless powder? If so, airspace is not a problem.

If you are using black powder, however, there should be NO airspace. You should compress the powder as you seat the bullet.
Good stuff Alpo.

One reason IMR came out with Trail Boss smokeless powders is to have a higher load density.

Here's one that will make you look at it differently Todd.

Correct me if I am wrong on this Alpo. When cowboy action shooters are reducing powder volume for competition shooting there are some that theorize that as the cylinder in the revolver rotates the powder adjusts each time due to cylinder rotation and number of times under recoil ,and is therefore not always as consistent in the way the powder is sitting in each cartride as it comes into position. Therefore some argue that will cause inconsistencies with shot patterns becaue the smokeless powder burns will not burn consistently.

IMR created Trail Boss smokeless powder so that it fills the cartride more (primarily for handguns), or takes up moe space. Each granule looks like a donut so to speak. By filling the cartrige more the powder tends to be more consistent in how it rests in the cartrige.

IMO, what causes the inconsistency with shot patterns when they reduce the loads is two things. The first could be the lack of a dense load so to speak, and two the reduced velocity.

On your .243, not reaching a compressed load state is no issue at all. Your density will always be high enough and the velocity is pretty high so neither one is an issue. That is just how they develop the higher velocity loads.

Did I explain that right Alpo?
 
#10 ·
With the tiny amounts of fast powder in Cowboy and some target loads, where the powder ends up inside the huge case volume effects the velocity of the bullet. In some cases the difference can be hundreds of feet per second. Cowboy loads are sometimes below even target loads so the problem gets worse with them. Trail Boss was designed for Cowboy light loads. It is such that for the same energy produced on the bullet, the volume the powder takes up in the case is much greater than the regular powders like Bullseye, W231, HP38 and other target powders.

I think these Cowboy loads situation is a bit different than rifle cartridges with normal loads. The air spaces are quite different with the rifle cartridge closer to 80%+ and the cowboy and some target loads closer to 10% or less.

LDBennett
 
#11 ·
All right Jim. Here's some thoughts.

Cartridges, as a general rule, seem to like 75 to 80 percent loading density. That burns nicely and consistently.

Cowboy shooters, in an effort to 1) get as low a recoil as possible, and 2) to get as many loads for the least amount as possible, use both extremely light powder charges and extremely light bullets.

This, as you might imagine, leaves massive amounts of "empty" in the cartridge case. When you add in the fact that many of the cowboy shooters are using old cartridges, that were designed in black powder days, and therefore have large powder capacities, this just seems to be begging for a disaster.

With a normal amount of powder in the case, the primer flame sets the rear of the powder on fire and it burns progressively. With a itty bitty amount of powder in the case, it's all laying on the bottom of the case, the primer-flame flashes over the top of it, and sets the whole charge off at once.



The other problem is that, with a very small charge of powder in a very large case, it is possible to double-charge, and even triple-charge the case. This results in the gun turning into a handgrenade. Hard on the fingers.

For a long time, people that shot very light loads were in the habit of pointing the gun up in the air, before firng. This let gravity pull the powder to the rear of the case, and covered the flash hole. Then when you came down level powder was still up over the flash hole and you did not get the flashover. No one seems to know about doing that any more.

IMR developred Trail Boss, to be a BULKY powder. To take up LOTS OF SPACE in the older black-powder cartridges. You can load a light, low-pressure load, but still have a large amount of powder in the case. You don't have the flashover or the impressive detonation of your gun.

Most of my experience has been with pistol. I shoot it MUCH MORE than I do rifle. When I do do rifle, I use "normal" loads. Although I do shoot light cast-bullet loads in both 308 and 30/30, using eleven and ten grains of Unique, respectively. And, before I fire one of them, I point the rifle muzzle to the sky, to get the powder to the back of the case.
 
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