Fantastic explanation, Parashooter. Best I've ever seen! And the graphics were extraordinarily well done. Thank you, thank you, thank you! The rimmed case headspace is rarely explained in detail in modern manuals. My 1949 Lee manual is better, but still...

Of the ten rounds I shot this week, 5 Remington, 5 Winchester, all ejected with primers backed out about ten thou or so, and all were flattened except the 4 Rems that I reduced the load by 3 gr. Those still had nice rounded edges.
Both the Rem and Win are loaded to full case and at least slightly compressed loads.

I am planning to hand load my neck sized only brass per Hornaday manual using 3031 or 4320 which I have in stock, and 150 gr. v-max, but not sure if I should use magnum primers.

Now, I don't want anyone to stick their necks out un-necessarily, but I would like to ask for some advice..

As I wrote above, I did reduce the loads of the first four rounds I fired, AGAINST THE ADVICE I was offered, and I wanted to explain that.

I've been hand loading for only about a year, but I've been doing it with a lot of research done beforehand, logging everything, keeping targets, x-cell spreadsheets, etc. Trying to be scientific about it and not just hap-hazard.

I've hand loaded about 2000 rounds to date and have achieved some ridiculously small groups out of my 223, which, as you probably know, is perhaps the easiest round to load.

So my question is, was I taking a big risk in reducing loads by 3 grams (typo, that should be grains) and assuming it was safe to shoot?

The results were as I expected, but perhaps that was pure luck, so feel free to ream me if I screwed the pooch on that. Might help to keep me safe and around longer so I can pester you mercilessly with more questions.

Texas10 wrote on Aug 13^th, 2015 at 5:35pm:

If you reduce a typical .30/40 load by 3 grams (46.3 grains), you'll have no powder in the case. Be sure not to confuse grams and grains. Different systems.

You'll continue to see protruding primers until you put in enough powder to expand the case fully. With 150-grain bullets, that may require about 40 grains of 3031. Once the case is expanded to fit, neck or partial FL sizing can maintain minimal cartridge end play, eliminating primer protrusion even with lighter loads.

I grabbed 3 of the Winchester brass. The necks measured .340 at the mouth, .423 to .424 at the shoulder, and .455 about .200 above the rim.

And yes, that grams reference was a typo. Should be grains. 

I believe Hornady makes a sort of universal 30 cal neck sizing die.  The die is available from most suppliers(if in stock).  If you have a 308 Win die you can use that, Install die with about a 1/4 inch clearance from the shell holder and run a case into it.  You will see an obvious line where it stopped sizing the neck.  Adjust until sizing stops at the juncture of neck and shoulder.  A FL die works, the 308 case is fatter and will not contact the sides of the case.  Backing out your FL die until it just sizes the neck will work also.  The advice about annealing is spot on, it is easy to do and will extend case life, an issue since as you have found brass for a Krag is not easy to come by.

'RichWIS' - gave a good suggestion about using a .308 Winchester F.L. Sizing Die to Neck-Size .30-40 Brass.

Keith - confirmed your fired Brass is dimensionally typical for 'once fired Krag brass'.

The .30-40 Case Neck is quite long. It is not necessary to Re-size the entire case-neck, especially if reloading 130 to 165 grain bullets. With lighter projectiles, you may have to seat bullets Out, as far as practical, to have your reloads feed through the Krag action.

I am not a 'Precision Bench Rest Shooter' (BR does not appeal to me). I am a Military Match shooter. I have gotten good results from my Krags using Standard Dies, Neck-Sizing, using 'starting loads' of IMR-3031 & IMR-4895 with 180 grain and lighter jacketed spitzer projectiles (to keep pressures low), and standard large rifle primers (Winchester).

The .30-40 U.S. Army has been around a long time and is fun, accurate and easy to reload. There is a wealth of Data on this cartridge.

I applaud your efforts Keith.  I'm sure you'll knock us all dead at Perry next year.

For me, it's more about the fun of loading and shooting in the matches.  The Krag has been around for over a hundred years... and shooters have been successfully reloading, taking record game, and winning matches ever since... and doing it using simple tools and equipment to load, so I'm going to keep that tradition alive.  I use a standard Lee FL sizing die backed out 1 full turn to neck size.  I load 220 gr Hornady RN bullets over 40.0 grains of IMR-4350 and a CCI 250 Magnum primer, and I do alright with it... for me anyways!

Yup, I've tried that method in regular seating dies and you can get good results.  But my consistency using that method was never as good as I wanted it.  Now that I've got case runout down to below .002", the runout of my loaded rounds rarely exceed .004".  When they do I just set them aside for practice.  Something to remember.  The newer the brass, the less all this seems to matter.  But I'm now on my second loading.  As time goes on and I use these 500 cases over and over again, I think (I hope) these steps I take will be increasingly worthwhile.  But, only time will tell.  In any case, I've had a ton of fun "solving" this problem.