How is the Rem 721, 300H&H for long range shooting?
It is as good as the load and the shooter are as long as the rifle is accurate. The .300 H&H used to hold a few long range records IIRC. As far as MV and Energy go it has been surpassed. However you have the makings of a fine elk rifle if you do own one.
I like that 98 sporter as well, I especially like the Schnabel forend on it. That stock should finish out nicely. Plus don't believe some of the bull being put out here.
The 113 year old Mauser action has several limitations that more modern actions don't have.
1. The metallurgy is archaic using a soft steel that has been surface hardened using a carburization process. Metallurgy when Paul Mauser designed the model 1898 was more art than science.
2. The Mauser action is not particularly stiff with the huge thumb cut in the left side for stripper clip loading.
3. The action length limits the length of cartridge that can be used.
4. The magazine feed lips are machined into the receiver. While they work great for a 8x57 or 7x57 cartridge, they don't work so great for cartridges with other lengths or diameters.
5. The Mauser action uses a stock mounted recoil lug that engages a lip on the lower front edge of the receiver.
6. The lock time of the heavy steel firing pin is slow by modern standards.
7. Good triggers are hard to find for a Mauser.
If you are going through the expense of building a good long range rifle, start with a Remington 700 action purchased cheap at a pawn shop.
1. Yes the heat treat is old school, but this can be fixed (if needed) by re-heat treating the action. Companies like
Pac-Met and a few others can make the action suitable for todays high pressure cartridges. Besides not all M98 actions are 113 years old so not all actions have the same heat treat.
2. It is stiff enough to handle most magnum cartridges, I've seen several military actions built into .458 Lott and I'm sure that isn't the smallest. Again the action might have to re-heat treated but this can be done as stated above.
3 & 4. Any gunsmith worth his salt can easily fix both of these perceived problems. I've seen several old 1909 Mauser's made into rifles capable of shooting the H&H length cartridges. Plus if the action isn't an intermediate length it will generally feed and .30-06 based cartridge without modification. Several companies make different sized magazine boxes and followers because some many 98 Mauser's have been made into something else other than the 7 & 8X57.
5. Actually the recoil lug is part of the action, the front action screw, screws right into the center of it. What you are talking about is a cross bolt in the stock and they have been used with other rifles without integral recoil lugs as well. The cross bolt keeps the stock from cracking under recoil.
6. Yes they have a slow lock time, but it can be improved with aftermarket springs and firing pins. It will never have the speed of the M700 but it is more than adequate for most people.
7. Other than the M700 there are probably more triggers made out there for the M98 than any other rifle.
Midway has two pages of triggers for the Mauser action, though not all are for the M98.
The only real big detraction from sporterizing old M98 Mauser actions is the cost. It is far cheaper to modify a M700 or newer action than an old M98. However none of those rifles ever have the class and style of a properly customized Mauser action.
... then again he use to do work for the army and made hardness testers and automatic loading machines before the war and made several other creations for the US army for the war. 
