45 70 trap door loads

geneo · December 2, 2007, 04:42 PM

My 45-70 trap door shoots about a foot high at 100 yards using a 405 grain bullet with 25.5 grains of Accurate 5744 powder. My sights are as low as they can be set so I'm thinking of going to a heavier bullet. I'm going to buy a bullet mould and a .458 sizing die but not sure which weight of bullet to get. Any ideas? Thanks

Slamfire · December 2, 2007, 06:28 PM

Your load sounds fine. I am using the same powder, same bullet weight, but slightly more grains of powder. I chronographed my loads to make sure I was not exceeding the blackpowder era velocities.

Ok, I think you are hosed. I am not an expert on trapdoors, maybe your lowest elevation setting is 200 yards. If so, about a foot high at 100 yards would not be that off. I can recall moving back from 100 yards to 150 yards with my 45/70 and the bullet drop was like a foot or something. I am used to the flat trajectories of .223, 308, 30-06, and the 45/70 has a rainbow trajectory.

But let us say you want a 100 yard zero, well I have tried in other rifles playing with different bullets, raising or lowering the charge. When you are talking about 12" off at 100 yards, you will find that it is an exercise in futility.

You need a taller front sight. That will push the muzzle down, because you sure are not going to be lowering the rear any more.

I recommend going to the SASS sight and posting your problem. Guys there might have an idea of what to do. I suspect your front sight is silver soldered into some permanent block on the barrel.

geneo · December 2, 2007, 07:21 PM

So if I go to a 500 grain bullet and 21 grains of Accurate 5744 i'm still going to be 12 inches high at 100 yards? I see that the 405 grain bullet and 25.5 grains of 5744 has a velocity of 1,440 fps and the 500 grain bullet and 21 grains of 5744 has a velocity of 1,161 fps. I thought maybe with the slower velocity and larger bullet it might get some of the drop I need.

I don't want to mess with the front sight, as this is an original 1878. Maybe I will just have to shoot low. Thanks

VaFisher · December 2, 2007, 07:35 PM

The slower heavy bullet will get you closer to zero but in order to be able to adjust, sounds you will need a higher front site.

December 2, 2007, 04:42 PM	#1
geneo Junior Member Join Date: December 2, 2007 Posts: 2	45 70 trap door loads My 45-70 trap door shoots about a foot high at 100 yards using a 405 grain bullet with 25.5 grains of Accurate 5744 powder. My sights are as low as they can be set so I'm thinking of going to a heavier bullet. I'm going to buy a bullet mould and a .458 sizing die but not sure which weight of bullet to get. Any ideas? Thanks

December 2, 2007, 06:28 PM	#2
Slamfire Senior Member Join Date: May 27, 2007 Posts: 5,261	Your load sounds fine. I am using the same powder, same bullet weight, but slightly more grains of powder. I chronographed my loads to make sure I was not exceeding the blackpowder era velocities. Ok, I think you are hosed. I am not an expert on trapdoors, maybe your lowest elevation setting is 200 yards. If so, about a foot high at 100 yards would not be that off. I can recall moving back from 100 yards to 150 yards with my 45/70 and the bullet drop was like a foot or something. I am used to the flat trajectories of .223, 308, 30-06, and the 45/70 has a rainbow trajectory. But let us say you want a 100 yard zero, well I have tried in other rifles playing with different bullets, raising or lowering the charge. When you are talking about 12" off at 100 yards, you will find that it is an exercise in futility. You need a taller front sight. That will push the muzzle down, because you sure are not going to be lowering the rear any more. I recommend going to the SASS sight and posting your problem. Guys there might have an idea of what to do. I suspect your front sight is silver soldered into some permanent block on the barrel.

December 2, 2007, 07:21 PM	#3
geneo Junior Member Join Date: December 2, 2007 Posts: 2	So if I go to a 500 grain bullet and 21 grains of Accurate 5744 i'm still going to be 12 inches high at 100 yards? I see that the 405 grain bullet and 25.5 grains of 5744 has a velocity of 1,440 fps and the 500 grain bullet and 21 grains of 5744 has a velocity of 1,161 fps. I thought maybe with the slower velocity and larger bullet it might get some of the drop I need. I don't want to mess with the front sight, as this is an original 1878. Maybe I will just have to shoot low. Thanks

December 2, 2007, 07:35 PM	#4
VaFisher Senior Member Join Date: January 24, 2006 Posts: 596	The slower heavy bullet will get you closer to zero but in order to be able to adjust, sounds you will need a higher front site.