Hornady offers their traditional "Interlock" jacketed bullets for 45-70 as 350-grain RN and FP. Other than nose shape, is there a difference in impact performance and penetration between them? How tough -- penetrating -- are these bullets when compared with other non-premium 350-to-405-grain jacketed 45-70 bullets when loaded to the upper end of lever action 45-70 velocity?
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In .476-caliber Hornady offers a 400-grain XTP/HP bullet that the company rates as being satisfactory for velocity as high as 1800 fps. A friend owns a 475 Turnbull and is interested in these bullets as basis for a more moderate 475 Turnbull load. He is also considering Speer's 400-grain Gold Dot bullet. Both bullets are rated approximately the same in terms of achievable velocity without bullets becoming grenades -- that is, without explosive surface-only penetration. Which of these bullets will achieve deeper penetration @ 1700-1800 fps muzzle velocity?

I have never used the FP hornady 350's. The RN will work fine at any 45/70 'fast' speed. I have used them in a 458wm at 2400fps with satisfactory results. I have been shooting them for over 30 years for medium non dangerous game with good results. There are better bullets, however, for deer, elk, moose or black bear these work fine.

I shoot the 350 grain flatt nose, but looking at the latest hornady manual, Both bullets show 1800 to 2900 as optimal velocity for terminal performance.
I get great acuracy with the flat nose from my marlin. 3 rounds into 1.10 inches. I have done that more than once too.
And just a few weeks back I put around through a pop can at 100 yards with my scope on 4 power, got a little to close , and then my buddie did the same thing, we both had blod running down our noses , but the 2 holes were touching like a figure 8.
Both bullets are shown in the section for the marlin in the same book so I think it might be just a case of finding out witch bullet your rifle likes...tj3006

Naphtali

The 350 Hornady FN and RN are excellent bullets, and the operating range of the bullet is 1600-2400 fps. The RN has been around for many years made for the 458 Winchester. When the 45/70 Marlins really started getting popular, Hornady just simply flattened the nose and instant 45/70 bullet. At the time Hornady did this it made one of the finest 45/70 bullets on the market. Being designed for the 458 made it a perfect bullet for the Guide Guns where they could be ran around 2000 fps.

In my test work at the time using wet news print I found below 1600 fps impact the bullet did nothing, no expansion at all. At velocities of 1700-2000 fps IMPACT-the bullet performs like a premium bullet, perfect expansion, excellent penetration. In the 458 Winchester it give excellent performance up to 2400 fps, and above that it starts to come unglued. At 2700 fps in the 458 Lott it really goes to pieces.

I used it on moose, wildebeast, impala, bear, and several other species in the 45/70 Guide Guns and it gives perfect performance, and makes it very hard to justify using a premium bullet. I state for the money it is an excellent choice for a 45/70.

Michael