I recently bought a Husqvarna model 640 9.3x62 that I picked up today.

It came with a set of aluminum Weaver type bases I would like to swap out for either original Warne bases or Leupold. The bases are marked 35 and 55 but are also marked "Japan" so I don't know if they are original Weavers.

Does anyone know what the corresponding Warne or Leupold bases might be?

I doubt the rifle was factory drilled and tapped rather done by a local gunsmith.

I've used Warne bases and Weaver all steel Grand Slam bases on them.
Warne 898 and 829
Weaver 55 and 46 again these are the all steel Grand Slams. You will want to go to the Weaver and Warne website to double check the bases you must determine if your receiver is modified or not (hump is intact or milled off).
Leupold has a fitment chart on their website.

Absolutely get rid of the alluminium bases. They are meant for 22 RF and Tasco or Nikko Stirling scopes!

Leupold bases for the M98 would be fine.

I had Weaver steel bases & rings for my Husqvarna 9.3X57.

I now have the Parker Hale steel bases and rings for my 9.3X62 on a M98 Simson rifle. Very reliable.

How bulky are the Warne rings for a M98 action?

I have never seen aluminum Weaver bases fail on any big bore, and who said they were made for 22 caliber guns, that's not correct...The screws may fail the bases do not..I don't care for aluminum bases, but for different reasons being they can't be touched up with cold blue.....The weakness of bases is 6/48 screws and big bore rifle recoil, they need to be redrilled for 8/40s so they don't shere...

Ray

I appreciate your experience on the matter & do not wish to argue.

But if the screws are the problem, they would be the same for all bases, as the action is already threaded, right?. Do such screws fail for Warne, Leupold etc?

All else being equal, yes they will. One can make the argument that the addition mass of steel bases exacerbates the potential but probably not in any meaningful way. Aluminum bases like Talley light w eights are used in a lot of high end ultralight rifles like NULA with great success. I have a pair on my Colt Light Rifle in 300 Winchester that have survived hundreds of rounds.

i used for years weaver steel bases with no issues. we had two failures with aluminium bases and it was the screws ... no more screws without blue loctite ... it was on a 30-06 and a 9.3x62 ...

i really like weaver steel base with leupold qrw rings. worked great for me up to the 458 mag caliber.

Nakihunter,
Yes, in big bores I have seen 6x48 screws fail. Its a fairly common practice to replace 6x48s with 8x40s with all scope mounts, at least on this side of the big pond...I prefer it as Ive seen this happen on more than a few occasions.I also negates viberation from loosening screws such as in a saddle scabbard, or jeep etc.

I drill out the bases and the rifle and use a 8/40 tap..In some cases you don't even need a drill..You can buy a bit to drill out the bases in one pass for a couple of bucks and it leaves the needed edge in the base. Its a simple procedure and sometimes used on custom guns.

Same with all manufacturers of guns and bases, they can all shere.

Its just an option, an ounce of prevention is worth a pound of cure approach..