Does anyone have experience with an 8mm bullet in a 300Win Mag/ 338 case?
To me, this would be the perfect cartridge for my long-range kudu and gemsbuck hunting.
I have a 338 Win and it does not quite scratch the itch. A 300 Win with 200 gr bullets will not either.
My intention would be a 200 to 220 gr bullet at about 2800-2850 fps.

There are a few very similar 8mm wildcats in existance. the 8mmPoor Mans Mag which is simply the 8mm-338 win. There is also the 323 Hollis which is the 8mm-308 Norma and the 8mm-300Win. If you chamber the 8mm-300mag in a std length action (Mauser 98) you have to seat the bullets quite deep and end up with no more capacity than with the smaller cased 338. If you have a longer action and throat the barrel so you can seat the bullet out to approx 3.6 inch of overall cartridge length you can make better use of that case. The metric 8x68 is very similar ballistically. All 4 would be very effective with a 200 gr Partition or a 200 gr TSX. None of them will do anything the 338 can't do. There are a few good bullets for 8mm cartridges of this size but there are a lot more availible in 338 cal. The 338 will also handle the heavier bullets better

I would go 8mm mag and be done with it if I had to have a magnum 8mm.

I'd alse recommend the 8mmRemMag.

I'm just wondering what a 300 or 338WinMag necked down to 8mm would do that a 338mag wouldn't do...

WITHOUT the $150 die set.

I'm just wondering what a 300 or 338WinMag necked down to 8mm would do that a 338mag wouldn't do...
Point taken. Perhaps I must just get to like my 338 more, but somehow the magnum action Sako 75 SSS just has not become comfortable.

Karoo An 8mm mag is a very effective round no matter which variety you have. I like the 8mm bore and shoot an 8mm-06,an 8x68 and a 8mm Rem mag. I find the 8mm-06 to be everthing the std30-06 is and a little more. The 8x68 is a very fine round. It does what most of the 30 cal mags do with heavier bullets and what the 338 does with lighter bullets (for their calibre) and the 8mm Rem is quite a performer with a 26 in barrel and good handloads. If you decide you must scratch that itch give serious consideration to the 8mm-338 especially if you put it in a std mauser action.

Why not just buy or build a 325 WSM? Brass available as are dies, it'll scratch your 8mm itch.

Another vote for the 8mm Rem Mag. Great all around rifle cartridge.

I always fancied a 8mm wildcat on a 7mm Rem mag/338 Win mag case, better for seating heavy for caliber bullets than on 300 Win mag case. Fits in a Std action better than a 8mm rem Mag & probably does OK with 24" rather than 26" barrel. With the advent of the 325 WSM, its doubtful whether it is worth doing but theres no end of good 8mm bullets nowadays & I have a spare 24" 8mm barrel looking for some purpose & the 325 WSM won't clean up the original chamber. Its a good itch, needs scratching.
Steve.

Thanks for the replies.
The 325 WSM has not reached this part of Africa yet and is not a practical alternative as yet, but I'll study the options again.