I picked up an 1957 model 70 recently. It started out as a .257 Roberts but was rechambered to 25-06 rem. I bore scoped the barrel and have found extensive fire cracking to at least midpoint down the barrel. When checking for OAL to trysome reloads using 100 gr. hpbt, I don’t find the lands until the bullet is pushed out of the case 1/4 in (.220 of push rod out of end of neck) . I’ve never seen this much free bore in any of my rifles. Heck of a jump. Have ordered a field gauge to check headspace. I’m now nervous about shooting. I know the barrel is cooked. Should bullets jump this far?