The Firing Line Forums - View Single Post

Harry Bonar · April 6, 2008, 06:06 PM

Sirs:
Cartridge dimensions (saami) on the belt on the 7 mm, mag are: .220 - .008 which means a case belt could be .212
Chamber dimensions are .220 minimum, .227 max. This means your chamber could be .227 max.
Now, if you have a minimum case and a maximum chamber that you have a possible headspace of .015. Unconscionable!
Thia is why I feel the belted magnum case is the most dangerous case in the world. And, if we "headsace" on the shoulder we're opening a possible gap of .015 directly in front of the belt. Unheard of. This set of
circumstances can, at least result in stretched factory cases fired in this condition and, if reloaded and headspaced on the shoulder could cause a spectacular blow-up and possible injury or death to the shooter!
When I did chambering I made a .220 guage and headspaced on that and I do NOT use a no=go guage! It's .220 or nothing, with no play!
Also, the powder chamber on the belted case goes below the belted head belt area!
Many modern developers have deleted the belt on bottleneck cases and

wisely so.

April 6, 2008, 06:06 PM	#1
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	SAAMI specs Sirs: Cartridge dimensions (saami) on the belt on the 7 mm, mag are: .220 - .008 which means a case belt could be .212 Chamber dimensions are .220 minimum, .227 max. This means your chamber could be .227 max. Now, if you have a minimum case and a maximum chamber that you have a possible headspace of .015. Unconscionable! Thia is why I feel the belted magnum case is the most dangerous case in the world. And, if we "headsace" on the shoulder we're opening a possible gap of .015 directly in front of the belt. Unheard of. This set of circumstances can, at least result in stretched factory cases fired in this condition and, if reloaded and headspaced on the shoulder could cause a spectacular blow-up and possible injury or death to the shooter! When I did chambering I made a .220 guage and headspaced on that and I do NOT use a no=go guage! It's .220 or nothing, with no play! Also, the powder chamber on the belted case goes below the belted head belt area! Many modern developers have deleted the belt on bottleneck cases and wisely so.