Jap ammo 6.5 x 51

[vintage hunter]

Can we see a picture of the rifle ?...................

I'd rather see the case with the blown primer.

Actually if you round up the 6.5 jap. it would be 51 ie 6.5x50.8 !............

It depends on who's case you measure as to what length you get. A few thousandths one way or the other ain't gonna make no difference, 6.5 Jap is 6.5 Jap. As can be seen in Parashooter's photo at least some T38's lack a chamber step making an accurate determination of a standard case length difficult at best. The unfired cases I've measured(including a few WWII era Jap service rounds) range from 1.970'' to 2.00'' in OAL, the difference is in the neck portion only.
dlumpkin, regardless to what the gunsmith says you don't have an ammo problem, you have a problem with your rifle.