444 qualifies but is not that much better than 375w or 45/70. It seems to me the best cartridge is going to be between 35 & 40 cal.
Straight case and nature of the ratio of weight is an obstacle rough to get past. The light bullets for these cals are short and stubby and spitzers add wieght fast. The spitzers are a lot more accurate at long range but you have to give up velocity. Any cal will do 95% of my deer shots. I'm not worried about those. I'm after something that will reach out and touch that big buck that walks out 200-300 yds in the clear. I have spent many years leaning on a 12g slug gun glassing the big buck that I had no chance of hitting let alone putting a kill shot on. Now that we have limited rifle I want to give one of those bucks a surprise. They been blowing me off for 50 years. My furthest shot to date was in WVa, 250yds with a 308/6x. The shot itself wasn't great but the opportunity to get that kind of shot is. Here in Ohio average shot in my area is under 100yds.
Never trust a man who rents pigs : Gus, Lonesome Dove
on my first trip to Africa, I fell in love with it and the people, at close to 76 now I don,t know I will make a seventh trip. we don,t know what tomorrow will bring, I would like to tho. and there I devolped a love for the cz 550 in .375 H&H