I have had this old Rem.722 .257 Roberts for quite a while now and it has proven to be a pretty fine shooter with jacketed. So,decided to see if it would be worthwhile fiddleing with it so that I might use it in the hunter class and some postals this summer.
One bullet that I was hoping would work was the RCBS 257-120 but according to the Greenhill tables, it was out of the upper limits for both weight and length in a 10” twist. A freind happened to have this mould and lent it to me to try. I'm figuring that if it fit and it could be pushed fast enough, it may work ok.
To make a long story short, I shot some at fifty yds cast from alloy of about 11-12 BHN and loaded with 14,15 and 16 grains of IMR 4227. Not so good, no groups to speak of, 16 grns was scattered.
So, I'm thinking, alloy could be too soft, why not try heat treating. So I cast some more and dropped them into a bucket of water, then let them age overnite. The BNH inceased to about 15.
Yesterday, I shot the same series of loads, again at fifty yds. Below are the results. The five shot group with 16 grns of 4227 were similar but these two targets were the best of the lot.
Only fifty yds to be sure but it appears that this bullet, heat treated, might have some possibilities. The real test will to be at the 200 yd. line of course.
In light of the above long winded tribe, the question is, after heat treating by dropping in water, do I have to size them right away or can I store them and size them as I need them. Seems to me I have read something about this destroying the hardness of the bullet if sized later. This method seems to be more convenient for me than to use the oven quench later.
Another challenge, the quest continues.........