INTERESTING THREAD ON AIR SPACE AND BP

[TAkaho kid]

http://www.theopenrange.net/forum/index.php?topic=2078.0

And continued here:

http://www.theopenrange.net/forum/index.php?topic=2098.0

[44caliberkid]

Good reading.  When I load 38-40's for my wife to shoot I just use enough powder for the bullet to barely touch it (or not touch it) instead of a compressed load.  I believe I could probably back it off even a bit more.   I've never noted any fall off in accuracy from the fully compressed loads, but I've never tested velocities.

[Cuts Crooked]

Read both threads. Here's what I left for consideration:

Interesting reading!

I will certainly change my recommendations on load advise to new BP shooters....just as soon as I see published data from a reputable modern ballistics lab indicating that the practice of loading BP cartridges with an airspace is safe in all possible calibers and bullet/powder combinations! 

[TAkaho kid]

I will certainly change my recommendations on load advise to new BP shooters....just as soon as I see published data from a reputable modern ballistics lab indicating that the practice of loading BP cartridges with an airspace is safe in all possible calibers and bullet/powder combinations! 

Likewise:

I will certainly change my recommendations on load advise to new shooters....just as soon as I see published data from a reputable modern ballistics lab indicating that the pratice of loading BP cartridges with cereal or other food products is safe in all possible calibers and bullet/powder combinations! 

Just funning you Cuts,

Again one test from long ago shouldn't stampede the herd to air space. This whole thread is about why we do things the way we do. In this instance should we really be afraid of air space? There is a good indication (not fact or proven) that the dreaded air space is not the great taboo we have been told it is. Does it need exploring? I would say yes. But under safe controlled conditions. Ballistics lab? Sure why not? How about getting a research fund going to accomplish this task?

Would I change my reccomendations to newbies? No, but I would indicate that there is some debate on the issue. Again we are relearning what had been learned over centuries. If we don't question or ask the simple "why" then we will never enjoy the full potential black powder has to offer and our sport will be the poorer.

[Delmonico]

It's always been my understanding that airspace between a heavy wad and the bullet is what is dangerous because of the air being compressed as the wad moves forward and the bullet not moving yet.  This is what blows the end off a shotgun barrel that has a wad stuck in the choke.

[Cuts Crooked]

...the essential diifference is that the

pratice of loading BP cartridges with cereal or other food products

has been a common practice for thousands of shooters for many years. Tha practice of loafding BP cartridges with air space has NOT been a common practice. I strongly suspect that there is a good reason.

(BTW, I saw mention in one of those threads of factory ammo with filler in it too)

[Dick Dastardly]

From my perspective and experience, Genuine Powder likes confinement upon combustion.  Air space is a variable.  Holy Black loading is given in VOLUME units for a good reason.  Density does vary.  Taking all that into account, air space is an easily managable variable.  Simply don't leave any.

A compressed load in my Browning 92 44 Magnum gives me a 2fps SD.  Now, that's very high quality consistancy.  I beg to buy a beer for the pard that can best that data while leaving an air space above the powder.  My gun will serve as the platform.  I don't buy beer easily. . .

DD-DLoS

[TAkaho kid]

It's always been my understanding that airspace between a heavy wad and the bullet is what is dangerous because of the air being compressed as the wad moves forward and the bullet not moving yet.  This is what blows the end off a shotgun barrel that has a wad stuck in the choke.

Hello Del,

Shotguns a bit diffrent. Remember you have an ounce or more of lead bearing down on that stuck wad at high speed (lots of mass/energy). Combine that with a thin walled barrel tube and its a burst barrel. I saw where some one over on the SASS wire wanted to know why he just couldnt push the wad out with the next shot. It dont work that way.

Interestingly the British Military adopted (though not in general service) a rifle developed by Westley-Richards. It was a capping breech loader using a paper cartridge. The cartridge featured a thick geased wad in the base. When the cartride ignited the wad was forced back against a brass plunger which acted as the breech plug. The wad then expanded to seal the breech. When the next round was fired the wad remaining in the chamber was pushed forward then out the barrel by the bullet upon discharge. There was no space between the bullet and the wad resting in front of it.

Best Regards

[Wild Ben Raymond]

Here's a question on air-space in BP cartridges. What about those bullets with deep hollow bases, even with some compression does the cavity in the base of the bullet get filled with powder or is there still traped air in there? If there is, how much can this hurt anything? Wild Ben Raymond

[TAkaho kid]

Here's a question on air-space in BP cartridges. What about those bullets with deep hollow bases, even with some compression does the cavity in the base of the bullet get filled with powder or is there still traped air in there? If there is, how much can this hurt anything? Wild Ben Raymond

If your using a wad - yes there is an air space. If not and your compressing then the cavity is filled with powder. Either way its not a problem. I shoot two loads with hollow base bullets. One is for the 45 S&W the other is my big paper patch load for the 45-70 and 45-90. I don't bother with a wad in the 45 S&W simply because I find it makes little diffrence in accuracy with pistol cartrdiges at CAS ranges. If I were shooting long range lever action with a solid based bullet then I would use a wad simply to protect the base of the bullet from damage. In the paper patch I use a grease cookie and use wads to seperate the lube from the powder and from the base of the bullet. Recovered wads are usually cupped were they have been forced into the hollow. Its not a problem unless they stick there and take a ride down to the target.

The other thing to remember is that cartridges are not hermetricly (sp) sealed some times you will notice a bullet wants to pop back out due to trapped air. After a while the pressure will equalize via leakage around the bullet and the primer.