Load for my New To Me 45 Govt Springfield Trapdoor
I recently purchased an 1873 Springfield Trapdoor 45 Govt from a fellow Forum Member, and I am very happy with it. I am currently in the process of developing a 100-yard load that anyone can shoot without recoil worries. Boolits are cast from a NOE 460 mold and PC-ed. The final bullet diameter is running about 0.463”. The barrel slugs 0.4605”. Average PC-ed boolit weight is about 347 grains. My desire is to use Unique powder for my loads.
I have tested some loads and will be settling on a load between 10.0 grains Unique and 10.5 grains. The last 5-shot group using 10.0 grains Unique gave me a 4.3” group: 2.1” to the right and 7.0” low of the POA. The last 10.5 grain load gave me a 4.35” group: 2.4” to the right and 6.2” low of the POA. Both loads were fired on the same target. The spread for both loads (10 rounds) was 4.9”; centered 2.3” right and 6.4” low of the POA. These were fired at 100 yards. Target Calc was used to measure the groups and determine the group centers.
The 0.463” PC-ed boolit allows me to seat the boolit without resizing a fired case. The boolit can not be seated with finger pressure, needs a little extra push from the press. A very slight crimp is added. The boolits are seated to a depth slightly greater than the COAL jam depth (2.545”) and the chambering completes the final boolit seating. I can feel a slight fit of resistance as the trapdoor bolt is closed and the boolit is pushed against the lands. QL indicates chamber pressure should be about 10,444 psi and 1118 fps. Since the boolit is against the lands, the chamber pressure should be a little higher than projected by QL.
A bit of Dacron filler is used over the Unique powder. It probably is not needed but I am using it anyway currently.
The original front sight produced POI groups that were high when using the rifle’s battle sight. Two fabricated front sights were also provided. I switched out the original sight for the shorter of the two additional sights and got the current groups that have a low POI. I can now adjust the Buffington flip-up sight to get the POI where I want it and finalize windage. I would love to be able to just use the battle sight, but I guess I would need to file it down somewhat to get the POI up. May try the other, taller front sight, to see how close it brings me to the POA.
This has been fun so far.
As you can see, I am sparing not expense on targets.
https://i.imgur.com/gvHkDJB.jpg