Nothing at this point but there are certainly a lot of other calibers that do not provide any advantage over others. Besides, when I first envisioned this there was no 338 Federal only the rarely heard of 8X51 Mauser....
. When I was at the apex of my Marlin affliction I had close to 100 of them and about 24-26 just in 444 . I have since gotten the Marlins down to a more manageable number of 12-14 . I am well aware of the difference between the 06 and 08 cases and their derivatives . As to building on old Mausers that is of no interest to me I prefer to build on pre 1990 Rem 700's . Your opinion and mine vary widely and I'll stick with my own as it's worked for me for over 50 years .I am a Marlin lever gun fan. It is neat to have a .22LR in 39A, a .336 full rifle in .30-30, a .444 with 24 inch barrel. Now I just need an 1894 in .357.
They are all easy to carry in the woods. So are the Savage 99 and BLR. The 99 with the round bottom really fits in the hand. And both of them are strong and accurate.
The 8mm-06 is a whole different ball of wax than an 8mm-308, or a .358 Win. It has the powder capacity to match the bore. I own five or more 8x57s, from 1888 to M48, plus sporters, and an 8x60S. A 195-gr to 200-gr bullet at 2,500 to 2,650 fps hits hard at 100 yards, and at 400 yards.
To me, the reason to build something like these, or buy one, is the rifle itself. You might find a WWII bring back, engraved 8x57, 8x60S, or a ream out job to 8mm-06, which can be bought right, refinished, reblued, and own a thing of beauty which would be unaffordable today.
I'd rather have a BAR then a BLR fir a driven gun but then semi autos are not legal in the UK correct ? I have. Friend in Italy that shoots a fair amount of driven stuff and he seems to be found of Marlin levers in 444 and 45-70 .I do like the look of a BLR. I sometimes wonder if a BLR in .358W or .338 Federal would be a good driven boar / woodland stalking rifle.
Fast handling and good bullet using a fair bit of mass. Quick second if you needed and with enough thump for boar and big deer but not going so fast as to smash up roe / munties... Hmmm... project...
an 1893 Marlin in .44-40
The 8x60S and 8mm-06 don't give that much more performance over the 8x57IS. The 8x60S is a work around laws intended to disarm civilians, and the 8mm-06 was an economic modification to use plentiful K98 Mausers and .30-06 brass. Today, there are so many good 190, 200 and 208 grain bullets in .308, and a bear or moose hit with a 200-grainer from an 8x57, 8x60S, 8mm-06 or .30-06 cannot tell the difference. Complete penetration is complete penetration.