I'm new to this forum and this is my first post. I have three rifles chambered in 30-40 Krag: one original 1899 cavalry carbine, one sporterized 1898 stalking rifle and a 1980's Browning copy of a 1895 Winchester.

I'm having problems with case necks splitting.

Background:

I have a slick sporterized Krag (headspace checked out by gunsmith) and an '80's Browning rendition of the 1895 Winchester. I reload the 30-40 Krag, and duplicate the original military load with 220 grain Hornady .308 round nose soft point bullets.  I'm using DuPont IMR reloading data to recreate the classic load of 40 grains IMR 4350 under a 220 grain round nose soft point. Hand loaded cases were trimmed to overall length of 2.304" +0.000/-0.0025". Bullets were seated to SAAMI maximum COL of 3.089". Brass was once fired. Loaded cartridges are not touching rifling. Cases are extracting easily. I also had some 180 grain Winchester SP factory loads on hand, and shot them to reclaim the brass for the mild 220 grain loads. Cases are properly head stamped 30-40 Krag and are NOT Enfields. Brass was either once fired or new. Dies are by Hornady.

Problem:

Had 7 case necks split from both lots. No other problems noted, just split necks. 20 Loads were shot between both rifles, cases randomly split from both. Not sure what's happening. Haven't had the problem before.

About half were new Winchester factory loads (180 grain bullets). The others were hand loads using the classic 40 grains IMR 4350 under a 220 grain round nose soft point.  Brass was once fired.

Has any one else encountered this?

Thanks.