Mr. A is right...and we're really talking about the difference between a 308 and 30-06, 358W and 35 Whelen, etc...you always gain by "something" going to a larger case, higher velocity or heavier bullet weight.

The X62 has a nice large case capacity as is at 75 gr H2O...the only way to get more is to step up to a larger diameter case which brings in other costly mods and if you need/want more thump you need to go to a longer receiver and/or a larger case anyway.

As an aside...you could do a wildcat using a RUM case shortened to about 2.35", shoulders blown out to about 0.530" with a 0.350" long neck and 3.30" COAL and get 100-105 gr H20 for a very nice, high capacity case and still use the M98 action....more cost and why????

Basically a lot of money for not much gain and the x62 case has a large case capacity already, will kill anything walking the planet when you do your job...Mine is my "pickup Queen", open sighted, it rides with me most of the time along with a 50 round box of ammo, no matter what other rifle(s) I happen to also have with me. It's set in a Boyds walnut stock and Limbsaver pad, all camo painted. I can keep 5 rounds in a 2" circle at 100 yards even with my lousy old eyes. When I had it scoped for load development, it kept a mag full of 286 Hornady bullets touching at 100M with the H4350 load I now use at ~2425fs. What more could you ask for???

When I did my conversion I did it quick and dirty using an already threaded, chambered and crowned screw in and go shooting Lothar Walther barrel...I wouldn't even needed a finger nail if I didn't want to do the bridge grinding and other "stuff".

If you really want to get into this reloading stuff you need some software like "Load from a Disk" or "Quick load"...or go online to some of the links to the Powley computers...any one of the three will give you all the powders in the correct burning ranges and starting loads for "local" powders...plus load up on reloading manuals...every one I have(all available ones) have quite a bit of loading data for the x62.

As far as caclulationg goes all I did was compare the case capacities of the two cases, divide the larger into the smaller and multiply by 100 to get the percent difference...not complicated at all...du pont powders are linear as far as pressure increase goes...this has been understood for more years than I want to admit to...so it's not rocket science and you can deduce that information from just about any reloading manual for any cartridge...or Goto Accurate Reloading's reloading pages...the linear steps can be seen in all the different loads for all the cartridges. Go to a Powley computer and you can work out the step by step process at your leisure.

All this information may be way beyond your needs, but someone might find it usefull.

FWIW...from Load from a Disk...9.3x57/24" bbl/286 Hornady/52gr Varget/2266 at 51,430CUP...9.3x62/24" bbl/286 Hornady/56.8 gr Varget/2417 at 50,998CUP.

My 9.3x62 with the same bullet likes 4350 which gives the highest velocity and the lowest pressure(according to the manuals). Varget is a very close second and is more accurate and not far from 4350 as far as pressure and velocity go...but not enough to sweat in all the departments.

Luck on your quest.