Digital Dan
01-11-2014, 10:20 AM
In the spirit of tossing another log on the fire....
I backed into casting bullets, the motivation stemming from the acquisition of an ancient picket rifle which led to BP bullet guns, which led to casting bullets for more current cartridge guns. It went something like this: .38 picket rifle, .50 BP bullet gun (slug gun), .40 bullet gun also BP...and that's when the trouble started.
Next thing I know there's 600-700# of lead holding down my bench and a bunch of moulds for 1/4 bores, 7mm, .308, .357, etc. etc. etc. Production of bullets for the bullet guns started with pure lead (high temps) and hammer dies to swage them into useable projectiles. It baffles me that such tools are not more commonly used these days for paper patched bullets...they produce gems of near perfection and enable two part bullet building in a very simple but effective format. For those unfamiliar with the historical provenance of slug guns/bullet guns, they were the tool of the day during the heyday of the National Rifle Club back in the late 19th Century and early 20th Century. They are still used in competition. Common characteristics for the 40 rod competition (220 yards) is a bullet of 350-1300 grains with anywhere from 50-250 grains of BP. The guns mostly have scopes, some vintage, and weigh anywhere from 15 to 70 pounds.
An H.V. Perry rifle of .56 caliber weighing around 45 pounds:
http://img.photobucket.com/albums/v298/muddler/Guns/Black%20Powder/DSCN0187_zps19e3eed3.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Black%20Powder/DSCN0187_zps19e3eed3.jpg.html)
The .56 caliber "plinker bullet" of 900 grains on the far right, a .50 caliber of 800 grains (two piece) to its immediate left. The rest are picket bullet of various design philosophies save for the far left which is the 300 grain bullet I use for my .44 mag paper patching, something I began doing in the last century:
http://img.photobucket.com/albums/v298/muddler/Guns/Black%20Powder/9373f7cf-f2c6-4c61-abf0-bb5496cdeb2e_zps7b5ffe62.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Black%20Powder/9373f7cf-f2c6-4c61-abf0-bb5496cdeb2e_zps7b5ffe62.jpg.html)
My point in dredging this up? The recent thread discussion about RPMs and Litz articles etc. was a bit of a conundrum to me. The gist of most of Litz's published work deals with long range exterior ballistics and the cause/effect relationship between bullets used for such work and gyroscopic stability. It is interesting stuff to be sure and the fallout from misadventure is profoundly obvious at ranges of 1,000 yards or so. If not clear to you at this point, the significance of many of the phenomenons associated with the craft do not generally manifest until 600 yards or so, and in many cases much farther. I do not believe they are so important to cast bullet shooters in the main, though there are a few exceptions. One would be an annual competition out in Wyoming for BPCR guns that I understand to be called the "Wasserberger Mile" . If I have misconstrued anything about that endeavor that is incorrect I hope KW will chime in, but in short form I'd not stand still and pose at a target for those lads despite the breezy conditions common in Wyoming.
Point #2: A lot of the discussion about effects of gyroscopic stability effects is in my opinion, largely irrelevant to cast bullet shooters because of how the bullets are employed (short range) and bullet form (RNFB). The latter generally places bullet CG and aerodynamic center of pressure (CP) in close proximity. With shorter moments common to these designs gyroscopic stability factors (Sg) suitable for the task are found with slower twist rates and lower velocities. As example, the fastest twist of any of my bullet guns is 16". The .44 Mag is 20". Yes, the cartridge guns trend faster but with exception of the 7mm none are faster than 1:14". The larger bores find stability at these slow twist rate by virtue of their diameter, which when spun up to operating RPM achieve sufficient energy to stabilize by that virtue rather than spinning like a possessed demon.
Lest we lose a salient point in this meandering post, bullet guns can be used and have been at ranges much longer than 40 rods. Matches of 600, 800 and 1,000 yards are the stuff of record. They typically shoot at muzzle velocities near 1,100 fps to avoid transgression on the speed of sound and attendant drag effects. Yes, they figured this out in the 19th century. The "Mile" shoot boys shoot faster, but again, the bullet forms are amenable to minimizing transonic drag effects as are most all cast bullet forms. The commonly high weight of bullets used presented very high ballistic coefficients as well. Such things have not been lost on BPCR shooters.
The alloys used for cast bullets trend soft, especially for hunting purposes and bullet guns. It does not mean that hard alloys are bad, just that the desired effect(s) are easily had with soft alloys and in the case of BP, unlikely to be had with hard. That paper patch appears to protect such projectiles from the effects of barrel abuse and other misadventure seems to present conclusions of merit in that approach to achieving accuracy and higher velocity if one is so inclined. I'm not saying that is the only path, but it is a clue. Maybe a very finely finished bore is another alternative if one is inclined to use greasers?
One thing that doesn't change in the discussion is that if one builds a malformed bullet, or one that is grossly unbalanced, it won't work for squat at any range. If one tries to squirt a piece of lead "putty" out of a .300 RUM at 3400 fps they might have their work cut out for them and we might all learn something from it. Being of lazy nature, if I want to do that, the bullets will wear a copper coat and have a form suitable for plinking small targets at great distance, Wyoming wind notwithstanding. OR, I will stoke up a .45-110 with a 540 grain Money Bullet and take another path.
As I've found most of this path already paved I see little reason to reinvent the wheel. If your bullets are acting up, don't blame the bullet or necessarily the gun or even the cartridge. Anything is possible with cast bullets, it's just a matter of how one approaches the problem. First and foremost, make good bullets...
Dan
I backed into casting bullets, the motivation stemming from the acquisition of an ancient picket rifle which led to BP bullet guns, which led to casting bullets for more current cartridge guns. It went something like this: .38 picket rifle, .50 BP bullet gun (slug gun), .40 bullet gun also BP...and that's when the trouble started.
Next thing I know there's 600-700# of lead holding down my bench and a bunch of moulds for 1/4 bores, 7mm, .308, .357, etc. etc. etc. Production of bullets for the bullet guns started with pure lead (high temps) and hammer dies to swage them into useable projectiles. It baffles me that such tools are not more commonly used these days for paper patched bullets...they produce gems of near perfection and enable two part bullet building in a very simple but effective format. For those unfamiliar with the historical provenance of slug guns/bullet guns, they were the tool of the day during the heyday of the National Rifle Club back in the late 19th Century and early 20th Century. They are still used in competition. Common characteristics for the 40 rod competition (220 yards) is a bullet of 350-1300 grains with anywhere from 50-250 grains of BP. The guns mostly have scopes, some vintage, and weigh anywhere from 15 to 70 pounds.
An H.V. Perry rifle of .56 caliber weighing around 45 pounds:
http://img.photobucket.com/albums/v298/muddler/Guns/Black%20Powder/DSCN0187_zps19e3eed3.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Black%20Powder/DSCN0187_zps19e3eed3.jpg.html)
The .56 caliber "plinker bullet" of 900 grains on the far right, a .50 caliber of 800 grains (two piece) to its immediate left. The rest are picket bullet of various design philosophies save for the far left which is the 300 grain bullet I use for my .44 mag paper patching, something I began doing in the last century:
http://img.photobucket.com/albums/v298/muddler/Guns/Black%20Powder/9373f7cf-f2c6-4c61-abf0-bb5496cdeb2e_zps7b5ffe62.jpg (http://smg.photobucket.com/user/muddler/media/Guns/Black%20Powder/9373f7cf-f2c6-4c61-abf0-bb5496cdeb2e_zps7b5ffe62.jpg.html)
My point in dredging this up? The recent thread discussion about RPMs and Litz articles etc. was a bit of a conundrum to me. The gist of most of Litz's published work deals with long range exterior ballistics and the cause/effect relationship between bullets used for such work and gyroscopic stability. It is interesting stuff to be sure and the fallout from misadventure is profoundly obvious at ranges of 1,000 yards or so. If not clear to you at this point, the significance of many of the phenomenons associated with the craft do not generally manifest until 600 yards or so, and in many cases much farther. I do not believe they are so important to cast bullet shooters in the main, though there are a few exceptions. One would be an annual competition out in Wyoming for BPCR guns that I understand to be called the "Wasserberger Mile" . If I have misconstrued anything about that endeavor that is incorrect I hope KW will chime in, but in short form I'd not stand still and pose at a target for those lads despite the breezy conditions common in Wyoming.
Point #2: A lot of the discussion about effects of gyroscopic stability effects is in my opinion, largely irrelevant to cast bullet shooters because of how the bullets are employed (short range) and bullet form (RNFB). The latter generally places bullet CG and aerodynamic center of pressure (CP) in close proximity. With shorter moments common to these designs gyroscopic stability factors (Sg) suitable for the task are found with slower twist rates and lower velocities. As example, the fastest twist of any of my bullet guns is 16". The .44 Mag is 20". Yes, the cartridge guns trend faster but with exception of the 7mm none are faster than 1:14". The larger bores find stability at these slow twist rate by virtue of their diameter, which when spun up to operating RPM achieve sufficient energy to stabilize by that virtue rather than spinning like a possessed demon.
Lest we lose a salient point in this meandering post, bullet guns can be used and have been at ranges much longer than 40 rods. Matches of 600, 800 and 1,000 yards are the stuff of record. They typically shoot at muzzle velocities near 1,100 fps to avoid transgression on the speed of sound and attendant drag effects. Yes, they figured this out in the 19th century. The "Mile" shoot boys shoot faster, but again, the bullet forms are amenable to minimizing transonic drag effects as are most all cast bullet forms. The commonly high weight of bullets used presented very high ballistic coefficients as well. Such things have not been lost on BPCR shooters.
The alloys used for cast bullets trend soft, especially for hunting purposes and bullet guns. It does not mean that hard alloys are bad, just that the desired effect(s) are easily had with soft alloys and in the case of BP, unlikely to be had with hard. That paper patch appears to protect such projectiles from the effects of barrel abuse and other misadventure seems to present conclusions of merit in that approach to achieving accuracy and higher velocity if one is so inclined. I'm not saying that is the only path, but it is a clue. Maybe a very finely finished bore is another alternative if one is inclined to use greasers?
One thing that doesn't change in the discussion is that if one builds a malformed bullet, or one that is grossly unbalanced, it won't work for squat at any range. If one tries to squirt a piece of lead "putty" out of a .300 RUM at 3400 fps they might have their work cut out for them and we might all learn something from it. Being of lazy nature, if I want to do that, the bullets will wear a copper coat and have a form suitable for plinking small targets at great distance, Wyoming wind notwithstanding. OR, I will stoke up a .45-110 with a 540 grain Money Bullet and take another path.
As I've found most of this path already paved I see little reason to reinvent the wheel. If your bullets are acting up, don't blame the bullet or necessarily the gun or even the cartridge. Anything is possible with cast bullets, it's just a matter of how one approaches the problem. First and foremost, make good bullets...
Dan