I love GT bullets! I shoot the 425 grain and they are my most accurate bullet out of my Cowboy (sized .460). However , the 4 or 5 month lead time keeps me from reordering. I know the old saying, “When is the best time to plant a tree? 20 years ago.”Old 45-70
Consider a lighter bullet. Check out GT Bullets and their 320 gr hollow point design. Only $28 for 100, less recoil with the same fps, the HP design is great for hunting, and more than you need.
If your eyes are like most, the tang sight on the 1885 or peep receiver sight on the Marlin is your friend! Oh, a longer barrel does not hurt helping keep the front sight in focus as well.
I want to try the 320 HP you mentioned. I think I may order some now. Thx for the reminder.