I suspect that the key to accuracy with a long freebore is the diameter of the freebore. If it is larger than the bullet diameter, it allows the bullet to enter the rifling canted/tilted, ruining accuracy to a certain degree.
If, on the other hand, the freebore is close to the bullet diameter, it keeps the bullet in alignment with the axis of the bore, and allows it to enter the rifling straight, thus accounting for rifles that shoot really well with excessive freebore. There are actually some who believe that the running start that freebore gives the bullet is conducive to accuracy, by allowing the bullet to come out of the case somewhat, before it has to enter the rifling. The theory is that the case/chamber alignment is not critical, if most of the bullet has left the case before it enters the rifling. This reduces the effect of case misalignment with the bore.
My own preference is for a short freebore. But, on the other hand, I have guns with long freebore that are really good shooters, and in some cases have convinced me that they are less tempermental as to load selection.

Kinda sounds like you are committed at this point. Shoot it and see. I have 4 wby rifles and I have loads for all of them that are under moa. Might actually be plus in the long run allowing a tad more velocity.

A long throat (or a long bullet "jump" due to deep bullet seating) does not always adversely affect accuracy., you just never know until you shoot a rifle. Both of my 7X57mm Rugers have very long throats:

This is with the M 77:


and this is the No. 1A:

Maybe it is time to get a different gunsmith to do your work.



I use a Sinclair OAL Gage and if I am not careful I can push the bullet in the rifling to far and get a false reading on length.

You might think about checking the OAL again when you get the rifle back from the Black Smith oops I ment to say Gum Smith darn I can't spell Gun Smith.



Good luck finding a new gunsmith.



But seriously I hope your rifle shoots one hole groups at 100yrds.

Took my OAL gauge over to my gunsmith's yesterday to check the bullet-loading length before I start work-up loads for my new .35 Whelen. The gun still has to be bedded and the magazine fitted, but the chamber and headspace are set.

To my surprise, the Nosler Ballistic Tips and Nosler Partitions I used for the gauge seated all the way out to the edge of the cartridge before contacting on the rifling. In fact, it has considerably more freebore than any of my factory rifles. If fact, it resembles the freebore on my friend's Weatherby rifles, which I sometimes load for.

The gunsmith said this is how the Precision reamer he rented was set up and there is nothing he can do about it.

I'm not really afraid of freebore. My guns that have a lot of it don't shoot any worse than the ones that have almost none. It's just that I am not used to a lot of it on a custom rifle.

I'll reserve judgement until I get it out to the range.

The larger the bore, the less freebore will affect accuracy. In addition, the softer the bullet, the more it will slug up to tightly fit the freebore and eliminate tilt. Try some of the Hawk bullets if you run into accuracy problems...they slug up very well.