if you have a marlin 45/70 you certainly will benefit from casting and reloading your own bullets and ammo,
you can reduce the cost of ammo by over 60%, this rapidly pays for, or amortizes the cost of the molds and other components
I can certainly recommend, you do so and use a lead alloy of 95% wheel weights and 5% pure tin,
and use gas check bullets in the 300-400 grain range, with the 300-350 grain being the preferred weights for deer hunting in my experience.
I think youll find 45 grains of imr 4198 to be a very decent load, I used that with a 350 grain 45/70 for decades in my marlin for deer hunting
you might also try 45 grains of RL7 another well known accurate load with the 350 grain cast bullet
start with a 40 grain powder charge , and work up with either powder used 1 grain at a time,
a couple guys I load for both found the 40-41 grain powder charger more accurate in their marlin 45/70 rifles with that bullet and unlike my marlin,
they got better accuracy with the lower powder charge.
don,t worry about power or penetration even at a 40 grain charge it zips through deer effortlessly, even with velocity in the 1400-1500 fps range
all of us generally sight in to hit a couple inches high at 100 yards making hits on deer out to 150 yards very easy.
Id point out that worrying about long range trajectory is wasted time its been decades since Ive shot, or had the opportunity too shoot, a white tail deer at over 150 yards,
keep in mind hunting in florida may differ from other areas, but around here shots over 100 yards are rarer that honest politicians that never break a promise







http://www.neihandtools.com/catalog/index.html

theres also a 300 grain mold that works rather well with similar charges of those powders in a 45/70 if reduced recoil is preferred


https://www.midwayusa.com/product/17...nose-gas-check