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I've been going out pretty consistently and shooting about 20 rounds through my 1873 (1879) .45-70 trapdoor each week. I purchased this piece from a friend who's father owned it since the 1950s. The paper trail says it ended up as a shipment to the Oregon National Guard sometime in mid 1880 and eventually found it's way up to Tacoma where my buddy's dad bought it in the 50's.
Please correct any of my assumptions below.
As many of you know, the ballistic trajectory of a .45-70 is equivalent to that of a potato gun as can be seen in this graph below.
I take notes each time when messing around.
Using low pressure "Cowboy" rounds with a 405 grain solid lead bullet, these have a velocity of around 1400 fps.
So the day after I cooked my fingers 2 weeks ago (long story about messing around with old fireworks with the kids back by the firepit) I went out and had my best day yet.
I do have to adjust and shoot low, the picture shows my aim point in the red circle.
This target was set at 100 yards and I needed to group 3 in the first 5 shots within 3" of center to qualify for the 200 yard range (easy to do with scopes, not so easy with a potato gun!)
RSO qualified me with my first 4 shots.
I continued on shooting at the same target at 100 yards experimenting and I now know the sweet spot in the Buffington sights. It's LOW.
I was playing with the wind-age adjustment on the Buffington sights and a half crank CC moves the mark to the right (I was aiming dead center of target) as indicated by two shots in the upper left quadrant.
The two high shots are where they land if I shoot dead on bullseye.
And the red circle I photo-shopped in is the sweet spot to hit close or dead on center at 100 yards.
I have no excuse for the lower right shot. I think that was near the end of the shooting.
Please correct any of my assumptions below.
As many of you know, the ballistic trajectory of a .45-70 is equivalent to that of a potato gun as can be seen in this graph below.
I take notes each time when messing around.
Using low pressure "Cowboy" rounds with a 405 grain solid lead bullet, these have a velocity of around 1400 fps.
So the day after I cooked my fingers 2 weeks ago (long story about messing around with old fireworks with the kids back by the firepit) I went out and had my best day yet.
I do have to adjust and shoot low, the picture shows my aim point in the red circle.
This target was set at 100 yards and I needed to group 3 in the first 5 shots within 3" of center to qualify for the 200 yard range (easy to do with scopes, not so easy with a potato gun!)
RSO qualified me with my first 4 shots.
I continued on shooting at the same target at 100 yards experimenting and I now know the sweet spot in the Buffington sights. It's LOW.
I was playing with the wind-age adjustment on the Buffington sights and a half crank CC moves the mark to the right (I was aiming dead center of target) as indicated by two shots in the upper left quadrant.
The two high shots are where they land if I shoot dead on bullseye.
And the red circle I photo-shopped in is the sweet spot to hit close or dead on center at 100 yards.
I have no excuse for the lower right shot. I think that was near the end of the shooting.
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