Hi Donner;
Your cast bullet load for your GG looks somewhat familiar.
I don't have a Guide Gun anymore having gone back to the Classic with the 22" tube. And I've owned most of the hot magnums all the way to the .458 Win Mag, and still own a .458 WM and a .300 Win Mag.
My current favorite load in the Marlin is a 465gr semi-hardcast at 1930 fps.
That load, or one very similar, flattened a trophy-class black bear at 70 yards a few years back. It has a very good ballistic rating from my Marlin at .465 BC. So, I thought a comparison with a .375 H&H shooting a 300gr Nos. Part.(.398 BC) at 2600 fps might be revealing:
300 H&H @ 200 yds:
vel.=2182/3170 ft-lbs
momentum = 93.5 lb ft/sec
TKO = 35
Marlin .45-70 @ 200 yds:
vel.=1630/2743 ft-lbs
momentum = 108.28 lb ft/sec
TKO = 49.6
It certainly would seem that while the old H&H is no slouch for Brown bear at 200 yds, and shoots flatter than the Marlin load, yet the older .45-70 in a Marlin wins the contest by a significant degree in momentum, TKO and frontal area of the bullet (by 50%), plus having the edge in sectional density.
There's also the fact that the Marlin can be (as you know) reloaded with one in the chamber, ready to fire in approaching a downed game animal. With one in the chamber and four in the mag, for my money I'd choose the Marlin over the H&H as a guide OR hunter of certain soft-skinned DG since shots would be far less than 200 yards.
That's my take from here...
Regards,
Bob
www.bigbores.ca
