Belted Mag Headspacing

[bajabill]

Do most people use the belted mag go gage, which essentially sets the headspace for the belt width dimension? Or, use a fired case - then how would you do this the first time?

also, if using a case, some options would be

unfired - probably not worth discussing
fired and not resized or neck resized
fired and resized with the shoulder set back slightly
fired and resized firmly to the FL sizing die

Pros and cons of these please...

[RWO]

I would use the belt "go" gauge to set the chamber depth. This should allow any factory round to chamber freely. Afterwards, I would adjust my FL sizing die to set a fired case shoulder back 2 or 3 thou. This would minimize brass working for max life.

RWO

[Der Verge]

What brass you use, as in fired or not, sized or not, should not matter, as long as the last load the case held was not extremely overpressure. There is always a little variance in brass from one make/lot to another, but the belt on a mag should be quite stable. I have set the headspace in a few belteds using brass, and never had a problem.

[Whelen Man]

I just went ahead a bought a go gauge. It'll work with all the belted mags. Mines already found a use a second time. That way you won't run into brass that might vary a little in the belt and have tight bolt closing later.

[bajabill]

the first take off I did I went and bought a go gage, took off 30-06 and added a 35 whelen. Now I am going to put the 30-06 back on so I guess I will use the go gage and verify all my already made ammo fits. I forget if I have rounds made from neck sized brass or not. I think for peace of mind, barrel switching and neck sizing may not be the best combination.

Now, I took off my 7mmRM and am going to add a 300RUM, I have a once fired case from a friend, I could resize this and use it as a starting point. I dont intend on using factory ammo ever. I just dont know if I want to spend $25 for every chambering I want to play with. In the near future I plan on getting a 6.5 swede, and either a 340 weatherby or 338rum or 338 edge. I can see the go gages piling up if I go that route.

[RWO]

There is no need to buy magnum " belt" gauges. They are very easy to make on the lathe.

The "go" or mimimum is 0.220", "no go" or max. is 0.227",

RWO

[Eric in NC]

There is no need to buy magnum " belt" gauges. They are very easy to make on the lathe.

The "go" or mimimum is 0.220", "no go" or max. is 0.227",

RWO


Step one - buy lathe....

[Der Verge]

I just went ahead a bought a go gauge. It'll work with all the belted mags.
All except .450 Marlin.

[PEI Rob]

WinMag brass can be any size from .218" to .212". If you can measure properly find a .218" and use a piece of tape to make a .220" gauge or just buy a gauge. You should set it at .220" and size the brass to headspace on the shoulder and forget about the rim yet know its in spec.

[efm77]

The guages aren't very expensive and definitely not as expensive as a lathe would be to make your own. I think it's safer to use the guages instead of a brass case because it's more precise. You know you've got the headspace right and then you can set your handloads to headspace off of the shoulder it you like.