I shot a 6.5-06 A.I. for twenty years and loved it so I am in no way knocking this cartridge but rather would like to throw something out there for those of you who have shot out your barrel or might want to improve your performance.
When I shot my last one out, I decided that since I liked the A.I. so much, why not try to improve on it since I was wildcatting anyway. I always used .270 cases because as most of you know, you will end up with a short neck when fire forming a std. '06 when fire forming to A.I. I didn't like the extremely short neck of the Gibbs case, so in a nutshell, that is how the 6.5 Sherman came about. I started with the .270 case to take advantage of the .046" longer case. (.280 also works). I blew the body taper out more than the A.I., moved the shoulder farther forward, and maintained the 40 degree shoulder. The result was a case that holds 75 grs. of H2O and still has a .300" neck. That is an approximate 5% increase over an A.I. and 11% more than a std. '06. I had a reamer built by Pacific and put a 4 contour, 26", 3 groove, 8 twist, Lilja barrel on a 700 Rem with an H.S. stock. I am getting up to 3200' with 140 Bergers, although that velocity is a little hard on cases. My hunting load is at 3150' with 1/4 minute accuracy and GREAT case life. Recoil is low and results on game are impressive.
Rechambering an A.I. would be simple as all the Sherman dimensions are larger. IMHO this is the ultimate 6.5 without going to a magnum and then your barrel goes south in a hurry. By the way, I have fired close to 1000 rounds so far with no signs of wear or loss of accuracy. Food for thought