Anybody ever rebarreled a 93 Mauser in 6.5x55?  My dad gave me his old 93 Mauser (7x57) which is in need of a new barrel due to excessive head space.  I've been considering sending it to E.R. Shaw to have all the work done, rebarreled, tap receiver, forge bolt handle and so forth.  I know it ain't worth much but it was the first deer rifle my dad ever had and I want to turn it into something useful for sentimental reasons.

I love old Mausers..........

As to the choice of 6.5×55 I am not in a position to advise. 6.5 CM seems to be all the rage.
As to dropping down from 7×57 to 6.5×55 I would be tempted just to put another 7mm barrel on the thing most likely in 7×57 form.
But that is just me.

I've considered keeping it 7x57 since someone gave me some RCBS dies.

If you reload, why couldn't you just adjust the sizing die to make up for the excessive headspace? I mean it's not like you have to full length size every time and set the shoulder all the way back to factory specs. All you have to do was incrementally screw the die in until the neck was sized enough to hold the bullet and leave the shoulder at the as fired length.

Because the casings split vertically along the side when fired. I had considered removing the barrel and cutting back the shoulder and breach face then reaming the chamber again but with that much work I might as well rebarrel it.

6.5 Swede or 7mm mauser will serve you well. both a great cartridges.  If it were my rifle i would go with 6.5 Swede