Hello and thanks for the add to the forum, I'm looking for info of any kind on a rifle my grandfather left me. I always assumed it was just a custom built krag, however while having a conversation with my younger cousin he had mention my grandfather left him a 250 savage A.I. And had mentioned my grandfather stamped IMP on the barrel. I realized my barrel has the same thing so did a little research and compared a case I fired to a factory 30-40 krag round and sure enough the shoulder is completely changed.  I recently purchased a reloading press and cases and dies, I now realize I have the wrong dies and am going to have to buy a case formed for the 100 cases I bought.  Is it ok that I have been firing non A.I. Rounds through it? And if so is it ok to fire form the other 35 factory rounds I have? Does anyone have any loading info for 30-40 A.I. Or any loading equipment for it that they want to sell?

I will try and post pictures up after work or later tonight if I can.

I bought 100 unprimed new cases, so those will have to be resized, Amy more info on using 308 dies? I'd save a bit of money that way.

So you are suggesting I use my standard 30-40 does and load data for the new cases, fire form them, then reload them with a different die and different load specs possibly? Sadly I do not do any hunting, I however would like to in the future and it would mean the world to me to do it with this rifle.  I've never reloaded before ( at least since I was a little kid helping my grandfather) so I'm just taking as much precaution as I can.  I've read that with the improved case I can load a bit more powder then standard loads however I don't want to cause any damage to the rifle. I'm going to reload with 150gr bullets for 308

The barrel is stamped IMP in the same spot as the improved 250 savage my younger cousin has so I'm not sure why he would stamp this barrel if it wasn't actually improved, I'm not arguing with you by any means, just really really trying to make sense of all of this, I'd drive to a range in another state to shoot with one of you guys if you physically seeing the rifle made any difference, at 30 years old I don't have any real friends that reload or know a damn thing about anything other then ar15's. I appreciate the input and am very glad I came across this forum today.

The more I look the more I think something is up with this rifle. Today I got 100 unfired cases in, they are definitely different from my case. I wish it would let me upload a picture but the files are too large. There 100% is a visual difference in these cases though.

Class86act wrote on Mar 3^rd, 2017 at 2:56am:

I think brass manufacturers take a little liberty with Krag and maybe other rimmed cases.  Since these cases headspace on the rim they can give themselves more tolerance on the shoulder which has to be held tight on regular bottle neck cases. Your earlier photo is looks exactly like the before and after I get with Remington brass. I am with Parashooter and think you have a standard chamber.

You have not shown us the rifle, but some of the old conversions were A#1 hunting rifles. 

When Ackley "Improved" the Krag case, he shortened the neck and increased the powder capacity.  The ordinary Krag case has enough powder capacity for the unwary to get into trouble.  These are 110+ year-old rifles, NOT .308s, even though the powder capacity is similar.

Use fire-formed cases with just enough neck-sizing to hold the bullet in place.  Stick to ordinary loads only.  The deer, coyote, bear or paper target will never know the difference.

Make up dummies (no powder or primer) using your fired & neck sized cases and new bullets.  Try them in the rifle for magazine functioning before you mess about with load development.

For the benefit of those having trouble understanding the amount of body/shoulder clearance in a normal US Krag chamber, here's a photo showing a fired case and a new case. Note, the difference in shoulder position is absolutely normal.