I'm building a 270 win hunting/range rifle by combining a new Bartlein barrel and an old M70 action. I haven't shot it yet, and after reading the posts here on finding max COL I thought I would investigate and compare this new chamber to that on a factory M70 rifle of the same period (both late 40's). The headspace is correct, I checked with go/no go gauges.

Here is what I found: for a Berger VLD Hunting 130 grain bullet, I find that the bullet touches the lands at 3.255-3.257" in the factory M70, which is in the ballpark of my Lyman book's data for a 130 gr bullet (3.250), albeit specifically for a Sierra SBT. In the new barrel with the same Berger VLD, I measure between 3.197-3.200" which feels quite short to me.

Does this seem odd? Should I be concerned about safely shooting commercial 270 Win ammo?

I know Bergers may be different than Sierras, but .050 seems like a pretty big difference, especially on the short side. Had I loaded for published COL I would be that far into the lands. I assumed factory-built barrels would be on the long side; should I expect similar for custom work? Is this something I should have specified? I am concerned about shooting this rifle, as well as wondering what else might be poorly done, if this is the case.

Thanks in advance for any advice you are willing to offer-

Call your smith and ask him for the reamer diamensions, if you didn't send him a dummy round to set the throat, then he just used a reamer that possibly has a short throat, my 270 Win with 130 Berger Hybrids have an OAL of 3.256 and I'm jumping them .015!

Thanks for the suggestion; probably I am making too much of it. I'll get some factory loaded ammo and pull a bullet and see how that sits in the throat. If that is no good, I guess I can remove the barrel and see if there is even a throat there at all...maybe he only used a roughing reamer. He did mention that he didn't test fire the gun.

Just re-cut the throat a bit longer...............just don't go too far.

MM