I have to say, given the ones you mentioned, I would advise the 444. Here is why. First, the 444 is a standard cartridge, you can buy them right off the shelf in any reasonably good sporting goods store. That also means that you do not have the expense and risk of trying a ream job. Secondly, they have the flat meplat you mentioned for better performance on game. Most of the 35's have a pointed or roundnose configuration in their cast form. Also, 44 handgun bullets work just fine on deer sized game at longer distance where they are still at magnum handgun velocities. Third, although I love the 45/70, the 444 is more economical. The best cast loads for my 45/70 are with bullets in the 340 to 450 grain range, the 444 works very well with 232 to 250 gr bullets. At the same velocity the 444 kicks considerably less because it is throwing 1/4 to 1/3 less lead. In factory loads, or in reloads with jacketed bullets, the 444 is considerably flatter shooting than the 45/70. Loading to similar pressures I also think the 444 brass life is a little better than the 45/70, they have heavier walls.
The 35 Whelan is great in a bolt gun, but there have been some problems ( supposedly fixed) with the Whelan in the single shot, and the 35 Rem also has a small shoulder and soft brass. The 444 has a rim, no headspace questions.
If you actually wanted a 270, I would suggest an economy bolt from wally world, they are a good value. However........ if you have what it takes to join the few, the proud, the magazine capacity impaired..... world of handiholics....... welcome aboard! You really can't go wrong, we are happy to have you, we are all equal here....(but some are more equal than others
they have rims --troll ---troll
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I actually have and use 4 of the above mentioned, I just think that given your circumstances the 444 would be the best place to start. There IS no stopping.........