22-250 split necks

[burrhead]

I've been working up a load for my Remmy 700 in 22-250. I started with new Winchester brass trimmed to 1.902 and Hornady 50 gr. V-Max bullets over 36 to 37 grains of H-380. Neck sized. So far I've used 25 pieces of brass for two firings each. After the second firing nearly all the brass has split necks!! I bought this rifle used so I have no idea how many rounds have been fired through it but fired cases don't show anything unusual other than the neck splits. So, bad batch of brass? Bad gun? Suggestions?
TIA

 

[critter]

Could be a very hard batch of brass. Could also be a big difference in diameters between rifle case neck area and same in your reloading dies working the cases too much.

My first try would be a different kind of brass and see what happens.

 

[burrhead]

I thought about the neck area of the chamber being too big but the ID of the fired cases that didn't split is .224-.225. I have 40 pieces of once fired Remington brass; quess I'll try some of that.
Thanks.