30-40 Krag challenge/question

[Fishoot]

I recently bought a Danish rolling block that had been rebuilt with a nice sporter barrel and birdseye maple stock. The caliber was not marked on the barrel, so after some careful trials and measuring, the 30-40 Krag seemed right. I used factory 30-40 Krag loads from Remington. I pulled the bullets and reduced the charges by 10% since this is a 1860's vintage rifle. Test firing (with long string and behind cover) proved it was 30-40. So, I bought some dies and loaded some rounds using "The Load" described by C. E. Harris (13 grains of Red Dot) behind nominal bullet weights for the .30 caliber. Some rounds would not chamber. The once-fired Remingtons chambered fine, but some old used brass from various sources were iffy. Some would resize and chamber, some would not. My dies are old Lyman's in good shape. After trying headspace gauges I determined the rim depth was right. The gauges used were turned to be about a half inch in length and do not measure the shoulder length as in rimless designs. So, it seemed the depth of the chamber was short. To check this, I removed my shellholder and used an old one that had the rim cut removed (the part that grips the rim and allows the case to be pulled out of a die). I removed the decapping rod and turned the die in by small amounts until I was able to seat a sized case in the chamber. The die had to be turned in .016" further than normal to produce a sized case that would chamber. Since the shellholder could not grip the rim, I drove the resized case out with a .250" piece of drill rod and a hammer. This is a lot of work for resizing cases! Now for the question: How can I shorten a sizing die (presumably hardened)? I have a lathe, but I am sure my high speed steel will wilt when it hits the die. I know an alternative is to rent a reamer and deepen the chamber, but the customized die seems an easier way to go. I also thought about grinding a shellholder down a little, but there isn't much material here for grinding and still leave a sturdy rim to pull cases with. Any thoughts?

[fouronesix]

I've shortened several sizing dies to adjust for short chambers. Also as you stated, don't try to turn the die base down with a normal tool. It's best to chuck it up, set the lathe to a slow to med speed then use a fine grit grinder to remove material from the die. Then take a small diameter grinder head and put a rolled chamfer back onto the die base to help prevent catching a case mouth and ruining it. Don't overdo the rolled chamfer.... you may need as much sizing as possible near the case head/web as it will swell over time/number of firings.

An alternative method is to take a normal shell holder and take some material off the top. I've found it easier to take some off a die base than off a shell holder.