Free bore

[257wbycustom]

Hello i have a 257wby with no free bore oal length with 115 gr bullet is 3.24.I would like to try 120 gr parttion would this change my oal. My next ? is where can i get info for loading for a no free bore rifle

 

[martinbns]

I would start nearer the data for the 25-06 and work up gradually.