Trap Door Bullet Trajectory?

[alfajim]

Now that I know my mfg. 3d Q. 1886 Model 1884 has no serial # records , I wonder if someone can help me understand the trajectory of the rifle.

I am shooting factory loads from Black Hills. See: http://www.black-hills.com/shop/cowboy-ammo/45-70/

405g bullet/1250 fps.

I recently took the rifle to its maiden outdoor trip (with me) to a 300 yard range in WI.

I was about 8 inches high at 100 yards. Original front sight. Original Buffington laid flat.

But, at 200 yards, I could not hit the target--regardless of where I held the sight.

I then ran out of ammo--and my shoulder was about done, too, after being preceded by 60 rounds of .30-.30.

Is this rather-authentic load still going up at 200 yards (I understand it was originally zeroed somewhere north of 300 yards)?

Some other phenomena known to this august group but as-yet unknown to me?

Thanks in advance.

Andy first thing you need to do is get a copy of Spence Wolf's book Loading Cartridges for the Original 45-70 Springfield Rifle and Carbine. It has all the proper loading and loading equipment. The bullet you are using is not very good in the trapdoor with the flat nose and if it does not have a hollow base it will not expand to fill the grooves properly.
Using the .405 bullet (1873) with the Buffington rear sight the leaf mudt be up and the slide down, line at base of open (window) lined up with 275 mark on slide it will be set at 150 yards with the lower peep hole and shoot +9" at 100 yards and -6" at 200 yards actual zero is 175 yards.
Hope this helps.

Jim