primer tube to top of powder charge
12-20-2004, 05:32 PM
#1
Thread Starter
Join Date: Dec 2004
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Posts: 75
primer tube to top of powder charge
i read somewhere that elmer keith (?) had experimented with 50 bmg brass that was modified to have a tube from the primer pocket to the top of the powder charge. I believe this was done in an effort to increase velocity. I'm not sure how it would accomplish this with standard loads. I do wonder if benefit's might be realized as far as barrel life, or even layering differnet burn rate powders in an effort to maximize velocity (flattened pressure curve). I think these might be accomplished by the thought (mind you not theory) that the powder would burn from the front of the case to the rear instead of being blown out into the barrel.
I realize that this would be very labor intensive to develop brass with said tube, hotter primers would be required to ignite the powder, it might be very hard on brass, the space required for the tube might negate any theoritcal gains, etc. but i wondered if it wouldn't allow for much hotter loads due to flattening (not lowering) the pressure curve. in other words, keeping the peak pressure for longer periods of time as the bullet passes down the barrel.
I realize that this would be very labor intensive to develop brass with said tube, hotter primers would be required to ignite the powder, it might be very hard on brass, the space required for the tube might negate any theoritcal gains, etc. but i wondered if it wouldn't allow for much hotter loads due to flattening (not lowering) the pressure curve. in other words, keeping the peak pressure for longer periods of time as the bullet passes down the barrel.
12-20-2004, 08:02 PM
#2
Join Date: Jul 2004
Posts: 91
RE: primer tube to top of powder charge
New one on me. Closest thing to that I've heard of is the .50 Caliber Spotter/Tracer. The parent case is the .50 BMG, but the brass is shorter. This brass has a tube that extends from the flash hole, 1/2 way or so into the case. This is to provide for a good, bright trace from the 800 grain projectile. For an explanation of this cartridge and a simple drawing check out Ammo Man, Spotter/Tracer
12-21-2004, 09:41 AM
#3
Giant Nontypical
Join Date: Feb 2003
Location: Texas - BUT NOW in Madison County, NY
Posts: 6,270
RE: primer tube to top of powder charge
In case you don't know, Elmer Keith was the dean of American handgun experts from the mid-20's until his death in 1984. He's given credit for the origin of the .44 Magnum cartridge. Elmer was just about the greatest advocate for big bores and big heavy bullets in rifles as well as handguns who ever lived, considering the .30/'06 barely adequate for shooting jackrabbits!
Prior to WWII, Keith and two of his associates Donald S. Hopkins and Charlie O'Neal, designed several wildcat rifle cartridges called the OKH (.280 OKH, .333 OKH and .334 OKH) series, and in these they also experimented with front igniton such as you have described. The .333 OKH is the direct predecessor of the .338/'06, and the .334 OKH is identical to the .338 Win. Mag., except for a .005" difference in bullet diameter!!
When Keith worked at Ogden Arsenal in Utah during WWII, he persuaded the Army Ordnance boys to test his front ignition ideas in the .50 BMG case. The conclusion was that while front ignition did permit higher velocities with less powder and pressures, it was not worth the extra effort needed to install the flash tubes and load the powder charges evenly around the tubes. So the idea was not pursued further by the Army.
Another person who played around with front ignition was "Rocky" Gibbs, designer of the Gibbs sereis of wildcat cartridges based on the .30/'06 case with the shoulders blown out and forward leaving a 0.25" case neck to hold the bullet.
Back in 1991, Wolfe Publishing Co. printed a booklet written by Roger Stowers entitled "GIBBS CARTRIDGES and Front Ignition Loading Technique. This gives about as much info as there is on this subject, and perhaps more than anyone would really care to know about it, since it is totally impractical for most people who reload ammo! However, the book is interesting for the descriptiopns of Gibbs' cartridges and the loading data given for all of them from the .240 Gibbs through the .338 Gibbs (the ultimate .338/'06 for sure!!).
Prior to WWII, Keith and two of his associates Donald S. Hopkins and Charlie O'Neal, designed several wildcat rifle cartridges called the OKH (.280 OKH, .333 OKH and .334 OKH) series, and in these they also experimented with front igniton such as you have described. The .333 OKH is the direct predecessor of the .338/'06, and the .334 OKH is identical to the .338 Win. Mag., except for a .005" difference in bullet diameter!!
When Keith worked at Ogden Arsenal in Utah during WWII, he persuaded the Army Ordnance boys to test his front ignition ideas in the .50 BMG case. The conclusion was that while front ignition did permit higher velocities with less powder and pressures, it was not worth the extra effort needed to install the flash tubes and load the powder charges evenly around the tubes. So the idea was not pursued further by the Army.
Another person who played around with front ignition was "Rocky" Gibbs, designer of the Gibbs sereis of wildcat cartridges based on the .30/'06 case with the shoulders blown out and forward leaving a 0.25" case neck to hold the bullet.
Back in 1991, Wolfe Publishing Co. printed a booklet written by Roger Stowers entitled "GIBBS CARTRIDGES and Front Ignition Loading Technique. This gives about as much info as there is on this subject, and perhaps more than anyone would really care to know about it, since it is totally impractical for most people who reload ammo! However, the book is interesting for the descriptiopns of Gibbs' cartridges and the loading data given for all of them from the .240 Gibbs through the .338 Gibbs (the ultimate .338/'06 for sure!!).
