Headspacing belted magnums

[dgarvin1]

I understand that belted magnums headspace off the belt, supposedly leading to decreased inherent accuracy. I also understand that there is a way to set the headspacing during the reloading process to better improve accuracy.

I'm new to reloading belted magnums. How exactly do you do this, and how do you know if you've accomplished it? I can't seem to find any real concrete information on this technique.

Any feedback would be helpful. Thanks.

 

[243winxb]

You can buy a thingy like this. http://www.brownells.com/.aspx/lid=12897/GunTechdetail/Gauging_Success___Minimum_Headspace_and_Maximum_COL Or back the die out 1 turn, size, see if brass will chamber. If it will not chamber, turn the die down another 1/8 turn @ a time till it chambers. Works for bolt actions.

 

[rcmodel]

Back off the sizing die slightly until you are headspacing off the shoulder.

You should be able to feel slight resistance when you close the bolt on an empty sized case. It helps if you take the striker assembly out of the bolt so you can get a better feel.

I doubt it will improve accuracy any.
But it will definately improve case life.

rc

 

[BigBob3006]

Leave your full length sizing die as is. Beg, borrow, buy or steal a neck sizing die and use it. This will have the case head spacing on the shoulder like other bottle neck rifle cases. This has always improved accuracy for me and also extends case life.

 

[Walkalong]

Size the cases to headspace off the shoulder like rcmodel suggested. many folks do this.

There are numerous ways to set up the sizer to do this. The way rcmodel suggested is definitely the cheapest, and also one of the easiest ways.

http://www.thehighroad.org/showthread.php?t=504759

 

[dgarvin1]

Thanks

Wow, these answers are pretty consistent and very helpful. Thanks guys.

 

[gamestalker]

Belted cartridges only headspace at the belt for the first firing. Once they have gone through your rifle they are headspacing at the shoulder. I too was once under the impression as you are that they headspace at the belt. I was trying to locate information, much as you are, and spoke to an expert with one of the bullet manufacturers who set me straight on this. He stated that headspace isn't really a consideration with them except during the initial firing of new brass. I did some work on it and verified that prior to an initial firing there was .003" headspace, and after firing they were at near zero. I neck my brass so it is not quite the same as FL in this respect. However, even with consideration to the shoulder being set back with FL sizing, the degree of headspace at the belt is zero to minimal at most.

 

[cheygriz]

Definitely headspace on the shoulder, or even try neck sizing.

 

[rcmodel]

Belted cartridges only headspace at the belt for the first firing. Once they have gone through your rifle they are headspacing at the shoulder.

Not if you full length size them and push the shoulder back to factory spec again. Which all FL dies will do unless you back them off slightly.

rc