AA2520 and 257 Roberts and Ruger 77

[shastaboat]

Has anyone done any 257 Roberts loading with AA2520? I recently bought a used Ruger 77 in excellent condition and all my reloading data does not show any appropriate data above 44000 psi. Accuarte does not show any load data for AA2520 in the 257 Roberts but my Barns manual shows a max load of 42 grains with a 75 gr. bullet at 3403 fps. I loaded a test run and it only chrono'd at 3120 fps at absolutely no signs of excess pressure. Not a surprise but I think that in my Ruger I can push the pressure up quite a bit over the normal 45000 fps that most loads are listed for the 257 Roberts. Hogden shows 46 gr max for H335 which is a faster burning powder. I think that I can safely work towards loading 46 gr of AA2520, maybe above that and I suspect this may be a great powder in the 257 Roberts. Please respond if you have used AA2520 in the 257 Roberts. Thanks.

 

[Blackrock]

I have used IMR4831 and Alliant Reloder15 with Speer 75g hp bullets with great succes on Pdogs. AA2520 and Rel15 are close on burn rate. With 39.5g of Rel15 I get a CRACK-Splat on varmints. This proved to be more accurate than 41.5g.
This is in a Ruger 77 - .257 Roberts.

Work your loads up carefully and you might get better accuracy at lower than Max.
Hope this helps.

 

[shastaboat]

Reloader 15 is quite a bit slower powder. About like AA2700. Did you ever chronograph your load?

 

[Blackrock]

No I wasn't able to Chronograph these loads. I was looking for accuracy and backed down a full grain and and my groups tightened up.
Funny my burn rate chart is showing AA2520 and Rel15 together and AA2700 and Rel17 and IMR4350 close together. I am not here to nitpick just to share my experiences with the .257 Roberts.

http://www.hodgdon.com/burn-rate.html