I've seen many people referencing turning belts off of brass...this phrase is usually prefaced by the word 'just' as if to imply it's fairly straightforward to do, i.e. just turn the belt off and viola! Have any of you done this? and what was your method?
It's really plenty simple. When I was don't mine I had a little lathe I used to turn wood pins. Rigged up a jig to use a lee trimmer shaft and base to support the case and then am old chisel to do the cutting.
Since I had the little lathe I just used it. Could have set it up vertically in the drill press as well.
As usual just my $.02 Paul K
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001
Yeah, like rr said; lathe turn them off if you want to design a cartridge without them. very easy. Although a metal lathe will work better. They aren't needed anyway; no modern designed case uses belts. Headspace on the shoulder. What are you trying to do?
Posts: 17373 | Location: USA | Registered: 02 August 2009
Way back in the bad old days wildcatters were constantly turning off belts OR adding ON belts to come up with the "PERFECT CARTRIDGE".
As dpcd says, in todays world it isn't done all that much unless you are trying for a very specific case capacity, non-belted wildcat cartridge, and I would surmise, only in a large bore application...a "tweener"...something between the case volumes of a Weatherby 0.582" base and a 600 Jeffery or 700 NE.
It can be a lot of work to get "just the right case volume". Adding belts, turning off belts, turning down rims, adding extractor grooves, trimming to size, reaming...all for some one-off, you can't sell, can't throw away, give away, or bury, not to mention the evil thing keeps invading your day dreams, night dreams, watching football, baseball, hockey, or soccer, drinking enjoyment and love making....hahahahah
In the early '90's, my friend DJ came up with the "6MM DJ BMF" ( I'll let you guys figure that out). It was a 7MM Rem Mag necked to 6MM and blown out to a 40 degree shoulder. His goal was to push a 105 Berger VLD to 3600 fps. He turned the belts off of the cases. In the process of load development we learned two things. Berger 105s won't take it over 3500 fps and the primer pockets get loose quick when the belt is turned off. Sierra 107 MKs went past 3600 fps and stayed together. 8 twist barrel barely made it through 2 prairie dog hunts.
the primer pockets get loose quick when the belt is turned off
I would say the pockets got loose from over pressure that had nothing to do with removing the belt. The belt is in front of the primer pocket not around it.
As usual just my $.02 Paul K
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001
I'm sure you would know. When he cut the belt back in the chamber and made new brass, the primer pockets stayed tight longer. But the barrel went south at around 750 rounds.
Belts are used to regulate headspace and as a sales gimmick. It would be tough to regulate the headspace on a 458 Mag without a belt.
With a shouldered cartridge a belt isn't necessary for anything.
Ramrod is correct, primer pockets get loose from OVER pressure...belted cartridges get loose pockets from over pressure also. Once you get over ~65KPSI the chances of a loose pocket start going up 100%. It's the metallurgy of the brass that determines just where the point of deformation lies(malleability).
While the 350 Rigby sound cool. I have trouble going to that much trouble and expense when I have a 358 Norma sitting in the safe. The Norma has a 10% capacity advantage over the Rigby. Just doesn't sound as cool.
As usual just my $.02 Paul K
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001
