Post
by FredC » Thu Sep 17, 2020 2:40 pm
Hopefully the loose spots were just areas without as much leading. On your head space concerns, the real head space is in the rim area. The bolt receiver lugs can be worn or displaced with over loads. New old stock bolts can fix half of the issue at a modest cost.
Not too long before the site went down there was some discussion of a change in the distance from the shoulder to the rim. The change is not well documented and some of the data just does not look right. Since you are hand loading, just do neck sizing or minimal shoulder set back and you will get the best possible feeding and accuracy.
Butlersrangers did a thread on making a home made head space gauge. I do not remember all the details but it was not hard to do, and would give reasonably accurate results. On my sporter project I wanted .001 inch over minimum headspace and got his by measuring a bunch of brass to find the largest rim thickness in a batch of new cases. Once I had found one with .001 under max thickness I put in the chamber and adjusted the free play in the bolt till I got .002 play. This was done before the extractor groove was milled in by facing a shoulder on the back of the barrel that allowed the rim face to extend into the receiver. This particular receiver and bolt had .010 excessive head space and fired 30/40 brass OK before the conversion. All this being said shows that Krags can work with headspace past the original no/go and field gauge limits.
If you are pushing for best accuracy, members have shown on old threads how to hold cases back against the bolt when fire forming. The best ideas were put out there by Parashooter involving a loop of what looked like fishing line.