I have purchased G2 contender in 7x30 waters. I am interested in headspace but am not sure how to go about finding the headspace in my contender. I contacted RCBS to inquire about precision mic. They replied they don't make one in 7x30 waters at this time. ANY IDEAS !!! it's possible that I should just shoot it and see what happens. It seems to be in near new condition

7x30 Waters headspaces off the rim. It is the same as a 30/30.
Unless you suspect it was abused I would just shoot it.

M

If you reload and want your cases to last, you will want to treat the 7x30 Waters like any other bottlenecked case and headspace off the shoulder. This is achieved by backing off the FL sizing die.

The reason for this is that because the factory case headspaces off the rim, manufacturers pay little attention to the shoulder’s position, either on the case or in the chamber. If the tolerances add up right, head separations are certain after a few reloadings if you size the case to headspace off the rim.



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There is a simple test. Load a cartridge, and shoot it. If it goes off, the headspace is fine.

I know that sounds a bit snarky, but in a Contender the headspace is variable, but truly of little importance. If the firing pin is long enough to fire a primer, you are in good shape. Headspace is a measurement that ensures the case is fully contained in the barrel. You would need a huge gap between the frame and barrel in a Contender for it to be unsafe.

Long term, do as TX suggested and size so that it takes a small amount of force to close the action on a loaded round. You want to slightly compress the round in the chamber.

Jeremy

Have a look at this discussion, especially the animated image of a rimmed 303 round in an SMLE rifle and the use of an o'ring to take up the excessive head clearance to allow the case shoulder to move forward to fit the chamber. This animation and possible solution is identical to your 7-30 Waters case if indeed your Contender has excessive headspace.
If you read the whole post you will see my attempt to try and take the mystery away from the term headspace and simplify it down to just head clearance as being the focus. I hope you can see some clarity now.

http://forums.accuratereloadin...241023932#9241023932

Floor: I recommend you go to www.bellmtcs.com. Mike Bellm has a very good discussion of headspace as it pertains to the Contender action. Consistent headspace is very important to accuracy in the Contender action.

My advice is to not believe everything you read on the Bellm web site. Mike discusses headspace and would have you believe that just about every Contender and Encore needs to be fixed. It isn't so. Yea, after having shot a couple of different Condender frames and probably half a dozen Encore frames with a BUNCH of different barrels, there was nary a headspace problem.

On the other hand, Mike's kit to lighten trigger pull on Encores is excellent.

quote:

Originally posted by floor guy:
I have purchased G2 contender in 7x30 waters. I am interested in headspace but am not sure how to go about finding the headspace in my contender. I contacted RCBS to inquire about precision mic. They replied they don't make one in 7x30 waters at this time. ANY IDEAS !!! it's possible that I should just shoot it and see what happens. It seems to be in near new condition

Take the bbl. off the frame, place in padded vice chamber up, drop cartridge in chamber, lay machinist straight edge across bbl. face, measure with feeler gages case to strt. edge there is your headspace.

I would shoot it, then you'll have fireformed brass to work with. Have fun with it, a great little cartridge.

Put a empty fired case preferably from the gun take a .001 or A .0015 Feeler gauge between the cartridge head and the firing pin bushing which might or might not be sticking out a little bit off the beach block. Close the gun and see if you can pull the .001 feeler gauge out. The Ideal headspace is around .001 + or -. If its tight just slightly bump the shoulder back in the sizing die. Its a highly over thought process and for most of us if the gun goes bang and has enough accuracy to cleanly kill a deer its good enough. (For me anyway)Most of the Whiz-bang with Contenders has come from those wanting 100 yd. 3 shot,1 hole accuracy from a gun that is inherently not able to do that.

quote:

Originally posted by bobmn:
Floor: I recommend you go to www.bellmtcs.com. Mike Bellm has a very good discussion of headspace as it pertains to the Contender action. Consistent headspace is very important to accuracy in the Contender action.

+2

I've been shooting contenders for years, many different calibers. I get best accuracy with just a touch of crush on the brass.

Agreed !