Some more info for anyone interested...
I had posted this over on the Accurate Reloading forums and from there was made aware of a member having similar pressure problems with a .35 Whelen, rebored by JES in 3 groove, 1-14 twist like mine. JES states his .35 rebores are .349 bore, .359 groove.
Someone suggested it might be a tight bore so I slugged mine and came out with the quick sketch you see below. Notice it's not drawn to scale and I was able to get a caliper reading across a land and a groove.
It's 3 groove rifling so each land has a groove opposite, each taking up about 60 degrees of the circumference. I was able to measure the slug at 3 locations, all came out to .349.
Am I correct that to get the groove diameter (which should equal bullet diameter) I would add .004 (assuming average groove depth of .005) and arrive with .354?
This is .005 less than bullet diameter of .358.
I measured the Federal bullets and they are indeed .358. Interestingly enough the Remington Corelokts measure .356.
I am waiting on a call back from JES to see if I have made a mistake, the idea of 3 groove, not having lands or grooves opposite each other, is a bit perplexing.
Interested to hear thoughts from this community.
N.B. I just spoke with Jesse at JES, he told me my method of measuring is incorrect. he starts with a .349 hole and then rifles .005 deep for a groove depth of .359.
He thinks it may have been the Federal ammo and is going to get some to test.
thanks,
Rob
