Model 70 headspace advice

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I need some advice, I am rebarreling a model 70 push feed in 7mm rem mag. The action originally was chambered in this round and had a bulged barrel. I have another model 70 barrel that I set back and and then reamed a thou over the go gage. this is the first magnum barrel I have chambered. My problem is I cannot close a bolt on a factory round. The old barrel is chambered at least ten thou more than the go gauge and the round closes in it easily. Is this normal, is my assumption of chambering to minimally over the go gauge wrong. Thanks
 
Belted magnums gauge on the belt. Your fitting may be perfect on the gauge, but the body isn't part of the calculation. There is an incompatibility between your reamer and the factory round.
One solution would be to ream until the bolt closes on the factory rounds and hope a NoGo or Field gauge isn't accepted.
Or, forget about headspacing on the belt and treat the setup as if it were a rimless cartridge. When reloading belted cases, that's the better approach anyway.
 
Maybe the bullet on the factory cartridge is touching the lands of the rifling. Cover the bullet with magic marker and retry chambering the the round. Look for rub marks on the bullet.
 
Thanks, I was thinking the same but wanted to have some opinions before doing that, comparing the old barrel chambering to the new, it has been chambered deeper but still wont close on the no-go and will chamber the factory round. I've been headspacing on the rim tried two different brands of headspacing gauges as well. I've also tried bare brass as well as a loaded round, same issue. They seat deeper in the original chamber as apposed to the new one i've cut, rim depth is deeper as well. Both of my go gauges close on this shallower rim depth. I't seems I will have to carefully ream it deeper and keep it below the max. It just confuses me why the go gauge is not giving me an accurate chamber, I don't like unknowns. Unknowns usually mean something isn't right
 
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Because the headspace is on the belt, the body isn't all that important, and body chambering may be on the generous side. Shoulders may be blown forward on fireforming. FL sizing may eventually result in case separations.
 
You can torque the barrel down more than a .001 .Loosen the barrel. Use a feeler gauge between the barrel and action to determine how much you are out with both the head space and the brass.
When you take the barrel off make sure the abutment lugs on the action are not set back as well.You will see an impression of the bolt lugs on the abutments ,having a bulged barrel can cause this as well.
 
If the chamber is reamed toaccept the magnum (belted) "go" gauge and a piece of new brass still won't chamber, either the brass is wrong, the gauge is wrong, or the reamer is wrong. There is no proper scenario where this happens. I have seen reamers which were ground too short from belt to shoulder. I have not seen brass which was too long but it could happen.
 
Leeper said:
If the chamber is reamed to accept the magnum (belted) "go" gauge and a piece of new brass still won't chamber, either the brass is wrong, the gauge is wrong, or the reamer is wrong. There is no proper scenario where this happens. I have seen reamers which were ground too short from belt to shoulder. I have not seen brass which was too long but it could happen.
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I agree with this... and I have also seen reamers which were ground too short from belt to shoulder...
 
Leeper said:
If the chamber is reamed toaccept the magnum (belted) "go" gauge and a piece of new brass still won't chamber, either the brass is wrong, the gauge is wrong, or the reamer is wrong. There is no proper scenario where this happens. I have seen reamers which were ground too short from belt to shoulder. I have not seen brass which was too long but it could happen.
Click to expand...

This. Trying to find work around solutions for safety gauges isn’t how its done.
I’ve repaired other rifles with built-in headspace problems and they often stemmed from Bad Math in the layout stage of the build.
Or the reamer was out of spec.
Did you happen to purchase a used reamer?
 
OP stated his issue is he that can not close bolt on a factory round. So length to ogive, etc. comes into play, because there is a bullet involved. As mentioned above, the final chambering confirmation check is gauges, not brass, certainly not a loaded factory round. Get the chamber correct to between "GO" and "NOGO", when the bolt closes, then check with new brass. OP does not mention using a NOGO gauge, nor how he determined that he has reamed .001" past GO gauge length? If based on calculations and measuring before assembly, easy to make a math mistake or overlook thread crush, etc. As mentioned, if reamer, gauges and brass within spec, chamber stuff will all fit. Then deal with "throating" as a possible issue. Post #3 tells you how to identify if the throating is the issue; actually can be used to identify many issues related to fit into a chamber...
 
I don't know how to make it any more simple. If the bolt closes on a "go" gauge, it should close on a piece of new brass. If it does not, the chamber is, in some way, flawed. Determine where the brass is contacting and you will be better able to determine just where the problem lies.
 
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