"Basic Handloading" by George C. Nonte, Jr. (page 113):
Chapter 13 Pressure:
Variables That Effect Pressures:
Bullets have an especially strong effect on pressures, and laboratory tests conducted for the NRA show quite clearly that different makes and types of bullets of the same weight may cause as much as 10,000 CUP spread in average maximum pressure with an otherwise standard load. This is the principle reason that when choosing a load from a manual published by a bullet manufacturer, you should not attempt to use a bullet of a different make or type. In the extreme, substituting one 150-grain bullet for another - with the same case, primer, and powder charge - may produce either an increase or decrease of up to 10,000 CUP in chamber pressure. With that 10,000 representing an average figure, the peak difference might well be 15,000 to 20,000 CUP. That much difference under some conditions is sufficient to convert a safe working load to a dangerous load.
George C. Nonte, Jr. entered the U.S. Army late in World War II and retired 20 years later, in 1964, as an Ordnance Corps Major. And was active in the military marksmanship program.
Following his retirement from the Army, he sporadically did private contract consulting work for a US government agency - and served as a consultant to gun manufacturers. He was a recognized expert in the firearms field. Nonte frequently gave court testimony as an expert witness on firearms.
In the 1950s he began a long career as a writer on handloading and guns, and was listed in the mastheads of more than ten firearms publications. He had written dozens of books on firearms subjects. Among them are Firearms Encyclopedia, Modern Handloading, Pistolsmithing, Black Powder Guide, and Home Guide to Cartridge Conversions. Nonte was a contributing editor to numerous gun and shooting publications, and authored more than a thousand magazine articles that were published in more than a dozen outdoor and gun magazines, including The American Rifleman, Guns & Ammo, The Handloader, American Handgunner, The Rifle, Guns, and Shooting Times.
The "Major George C. Nonte Award for Excellence in Firearms Journalism" is awarded annually, in Nonte's memory, by American Handgunner magazine. The first recipient of the award was Massad Ayoob.
"Ammunition, Demystified" - by Jeff Siewert (page 17-18):
War Stories #1
"I used loading data from one manufacturer for the equivalent weight bullet made by a different manufacturer. I picked a starting propellent load based on the projectile weight I was loading. ... imagine my surprise when I dropped the lock block on my Ruger no.1 and found the whole primer, cup and anvil, missing! I immediately ceased shooting that ammunition and rifle until I got the rifle taken apart, inspected for various and sundry loose metal pieces from the primer, and successfully put them back together. The ammunition was broken down, never to be fired in that particular arrangement again. I know I do not want to do that again! While the bullet weight is an important factor in selecting the powder type and weight for your firearm, the ability of the bullet to engrave by the rifling (think of friction and radial stiffness) also dramatically affects the peak pressure a given powder load will attain. Use only the loading data published by the bullet manufacture! Substitution of loading data for equivalent weight bullets can get you into deep yogurt!"
Jeff Siewert has been a ballistic engineer since 1979 and work on ammunition in virtually every caliber between .17 caliber up to 8-inch Howitzer. He has worked on bullets, propellants, ignition systems, cartridge cases, bullet barrel interactions, and rifling design.
Jeff has given classes in projectile design and ballistics and use of projectile design software for personal employed at the following operations:
Remington; Winchester; Federal; Swift; Nosler; Barnes; Armor Holdings; Liberty Ammunition; Sierra; IMI; Raufoss/Nammo (Norway); Norma (Sweden); Nexter (France); USAF Hill AFB; US Army ARDEC; NSWC Dahlgren; ATK; BAE; and General Dynamics.
Jeff has also been a reloader since 1983.
The primer Jeff blew out was with a 'starting load' of a very similar bullet from a different manufacture, and he (as one who designs ammunition for a living) says never substitute one bullet of the same weight and design for another manufactures load data! So the question here is who are you going to listen to, a bonified expert ballistic engineer or someone who says that they are no expert but their opinion is blah blah blah?
I personally emailed Lehigh Defense to ask them if I could use the load data for their .452 caliber 220 grain Maximum Expansion monolithic copper bullet to load their .452 caliber 220 grain Xtreme Defender monolithic copper bullet. The answer I got back was "NO!!!" They went on to explain that even though both bullets weight the same and are made of monolithic copper, the Brinell hardness was different and the data would not work safely even at a starting load. So even with two bullets made by the same manufacture it is not always safe to substitute load data for two bullets of equal weight!
Chapter 13 Pressure:
Variables That Effect Pressures:
Bullets have an especially strong effect on pressures, and laboratory tests conducted for the NRA show quite clearly that different makes and types of bullets of the same weight may cause as much as 10,000 CUP spread in average maximum pressure with an otherwise standard load. This is the principle reason that when choosing a load from a manual published by a bullet manufacturer, you should not attempt to use a bullet of a different make or type. In the extreme, substituting one 150-grain bullet for another - with the same case, primer, and powder charge - may produce either an increase or decrease of up to 10,000 CUP in chamber pressure. With that 10,000 representing an average figure, the peak difference might well be 15,000 to 20,000 CUP. That much difference under some conditions is sufficient to convert a safe working load to a dangerous load.
George C. Nonte, Jr. entered the U.S. Army late in World War II and retired 20 years later, in 1964, as an Ordnance Corps Major. And was active in the military marksmanship program.
Following his retirement from the Army, he sporadically did private contract consulting work for a US government agency - and served as a consultant to gun manufacturers. He was a recognized expert in the firearms field. Nonte frequently gave court testimony as an expert witness on firearms.
In the 1950s he began a long career as a writer on handloading and guns, and was listed in the mastheads of more than ten firearms publications. He had written dozens of books on firearms subjects. Among them are Firearms Encyclopedia, Modern Handloading, Pistolsmithing, Black Powder Guide, and Home Guide to Cartridge Conversions. Nonte was a contributing editor to numerous gun and shooting publications, and authored more than a thousand magazine articles that were published in more than a dozen outdoor and gun magazines, including The American Rifleman, Guns & Ammo, The Handloader, American Handgunner, The Rifle, Guns, and Shooting Times.
The "Major George C. Nonte Award for Excellence in Firearms Journalism" is awarded annually, in Nonte's memory, by American Handgunner magazine. The first recipient of the award was Massad Ayoob.
"Ammunition, Demystified" - by Jeff Siewert (page 17-18):
War Stories #1
"I used loading data from one manufacturer for the equivalent weight bullet made by a different manufacturer. I picked a starting propellent load based on the projectile weight I was loading. ... imagine my surprise when I dropped the lock block on my Ruger no.1 and found the whole primer, cup and anvil, missing! I immediately ceased shooting that ammunition and rifle until I got the rifle taken apart, inspected for various and sundry loose metal pieces from the primer, and successfully put them back together. The ammunition was broken down, never to be fired in that particular arrangement again. I know I do not want to do that again! While the bullet weight is an important factor in selecting the powder type and weight for your firearm, the ability of the bullet to engrave by the rifling (think of friction and radial stiffness) also dramatically affects the peak pressure a given powder load will attain. Use only the loading data published by the bullet manufacture! Substitution of loading data for equivalent weight bullets can get you into deep yogurt!"
Jeff Siewert has been a ballistic engineer since 1979 and work on ammunition in virtually every caliber between .17 caliber up to 8-inch Howitzer. He has worked on bullets, propellants, ignition systems, cartridge cases, bullet barrel interactions, and rifling design.
Jeff has given classes in projectile design and ballistics and use of projectile design software for personal employed at the following operations:
Remington; Winchester; Federal; Swift; Nosler; Barnes; Armor Holdings; Liberty Ammunition; Sierra; IMI; Raufoss/Nammo (Norway); Norma (Sweden); Nexter (France); USAF Hill AFB; US Army ARDEC; NSWC Dahlgren; ATK; BAE; and General Dynamics.
Jeff has also been a reloader since 1983.
The primer Jeff blew out was with a 'starting load' of a very similar bullet from a different manufacture, and he (as one who designs ammunition for a living) says never substitute one bullet of the same weight and design for another manufactures load data! So the question here is who are you going to listen to, a bonified expert ballistic engineer or someone who says that they are no expert but their opinion is blah blah blah?
I personally emailed Lehigh Defense to ask them if I could use the load data for their .452 caliber 220 grain Maximum Expansion monolithic copper bullet to load their .452 caliber 220 grain Xtreme Defender monolithic copper bullet. The answer I got back was "NO!!!" They went on to explain that even though both bullets weight the same and are made of monolithic copper, the Brinell hardness was different and the data would not work safely even at a starting load. So even with two bullets made by the same manufacture it is not always safe to substitute load data for two bullets of equal weight!