Load for my New To Me 45 Govt Springfield Trapdoor

[Larry Gibson]

My experience with light weight bullets and RBs is the faster you drive them the worse the accuracy is. Best accuracy usually come at a velocity of 800 to 1050 fps.

Also, I never found Unique to be the best powder for such loads. I suggest switching to Bullseye or Red dot. Use a starting load of 5 gr and work up testing for accuracy at 50 yards. The use of a chromograph is also helpful. The max load will be based on when accuracy goes south or you've hit 1050 fps velocity of both.

[Rockindaddy]

Pirate: Instead of a small charge of Unique in a large black powder cartridge that may require a filler over the powder; try using a bulkier propellant like Reloader No 7, 5477, or IMR 4759. You will not experience a pressure spike. It is my contention that the over groove diameter Trapdoor Springfield's should have been called 46-70's Your .463" diameter boolits should work great! 1-20 to 1-30 slight tin/lead alloy will take Bambi off his feet!

[Larry Gibson]

Pirate: Instead of a small charge of Unique in a large black powder cartridge that may require a filler over the powder; try using a bulkier propellant like Reloader No 7, 5477, or IMR 4759. You will not experience a pressure spike. It is my contention that the over groove diameter Trapdoor Springfield's should have been called 46-70's Your .463" diameter boolits should work great! 1-20 to 1-30 slight tin/lead alloy will take Bambi off his feet!

Those powders are way to slow burning for use under the 155 gr collar button bullets Pirate mentions in his post #20.

[Pirate69]

My experience with light weight bullets and RBs is the faster you drive them the worse the accuracy is. Best accuracy usually come at a velocity of 800 to 1050 fps.

Also, I never found Unique to be the best powder for such loads. I suggest switching to Bullseye or Red dot. Use a starting load of 5 gr and work up testing for accuracy at 50 yards. The use of a chromograph is also helpful. The max load will be based on when accuracy goes south or you've hit 1050 fps velocity of both.

A very timely reply. I only have 40 boolits left and was planning of loading some more Unique loads tomorrow. I have both Bullseye and Red Dot. I will start to explore their use.

[Pirate69]

Those powders are way to slow burning for use under the 155 gr collar button bullets Pirate mentions in his post #20.

I think Rockingdaddy may have been referring to the 347 gn boolits that I was playing with earlier. Those are the ones I was/am considering for hunting.

[Chill Wills]

Pirate69 Wrote: " The barrel slugs 0.4605”. Average PC-ed boolit weight is about 347 grains. "

If I missed it I am sorry, but I didn't see how it was that you were able to measure the barrel slug that I assumed was pushed through the barrel.
How did you measure it?

[Larry Gibson]

A very timely reply. I only have 40 boolits left and was planning of loading some more Unique loads tomorrow. I have both Bullseye and Red Dot. I will start to explore their use.

For my small game load in my TDs I use a Rapine 460210 HB over 6 gr of Bullseye [no wad or filler]. The close to WC shaped "shuttlecock" bullet is quite accurate deadly running 950 fps. For general use I use a 270 gr Rapine [Accurate makes a replica] 460250 over 8 gr of Bullseye for 1050 fps. That gives excellent accuracy to 500 yards, the farthest I've shot it so far.

[Seeker]

http://www.gmdr.com/lever/4570g350_dat.htm
I use 12 grns. of Bullseye and it shoots a 2" group @ 100 yds.with my Henry.

[Pirate69]

Pirate69 Wrote: " The barrel slugs 0.4605”. Average PC-ed boolit weight is about 347 grains. "

If I missed it I am sorry, but I didn't see how it was that you were able to measure the barrel slug that I assumed was pushed through the barrel.
How did you measure it?

I used a micrometer. This is not a PC-ed boolet that was measured. It was a bare bullet fishing weigh that was driven through.

[Chill Wills]

I used a micrometer. This is not a PC-ed boolet that was measured. It was a bare bullet fishing weigh that was driven through.

Okay. These Springfield barrels are three groove and slugs need a fixture to get an accurate reading with a micrometer. You no doubt noticed there aren't two flats opposite each other to Mic'.
IF you are happy, I am happy too.

On a different train of thought....
A common complaint with these rifles are the barrels are oversized. However, there weren't any other 45-70's or 45 Govt. in existence before the Springfield. It is the standard or starting point the others worked from, right or wrong.
It is true today, the very common, almost bankable barrel numbers for modern 45 caliber rifles run 0.450" by 0.458". And that is a good thing!!!

My last thought is, regardless of barrel variation in these old rifles, black powder will bump up the bullet and can give very good accuracy. I've had 6 of them. They punch well above their weight for accuracy.

Enjoy your great old rifle!!!

[Pirate69]

Okay. These Springfield barrels are three groove and slugs need a fixture to get an accurate reading with a micrometer. You no doubt noticed there aren't two flats opposite each other to Mic'.
IF you are happy, I am happy too.

On a different train of thought....
A common complaint with these rifles are the barrels are oversized. However, there weren't any other 45-70's or 45 Govt. in existence before the Springfield. It is the standard or starting point the others worked from, right or wrong.
It is true today, the very common, almost bankable barrel numbers for modern 45 caliber rifles run 0.450" by 0.458". And that is a good thing!!!

My last thought is, regardless of barrel variation in these old rifles, black powder will bump up the bullet and can give very good accuracy. I've had 6 of them. They punch well above their weight for accuracy.

Enjoy your great old rifle!!!

I learn something new every day. Thanks for the information. I guess my measurement is not exactly correct. Would you expect the measurement by my method to over predict or under predict the actual diameter?

[Pirate69]

My experience with light weight bullets and RBs is the faster you drive them the worse the accuracy is. Best accuracy usually come at a velocity of 800 to 1050 fps.

Also, I never found Unique to be the best powder for such loads. I suggest switching to Bullseye or Red dot. Use a starting load of 5 gr and work up testing for accuracy at 50 yards. The use of a chromograph is also helpful. The max load will be based on when accuracy goes south or you've hit 1050 fps velocity of both.

Looks like Larry's experience is spot on. Loaded 10 rounds of 0.7 cc (5 gn) Red Dot and 1.0 cc (7.1 gn) Red Dot (Lee dipper). For some unknown reason, I "lost" one round in each of the groups at 50 yards. If we can look at 9-shot groups, the 0.7 cc loads gave a 3 1/4" group and the 1.0 cc loads gave a 2 1/4" group. Looks like some progress. The encouraging thing is that the sight setting for the 347 gn load matches fairly well with the Red Dot loads. I am down to only 20 boolits left to play with. Ignore the groups at the bottom of the cardboard. Starting to develop a 200 gn load for a S&W Model 629.

https://i.imgur.com/8UZ4eyJ.jpg

[Chill Wills]

I learn something new every day. Thanks for the information. I guess my measurement is not exactly correct. Would you expect the measurement by my method to over predict or under predict the actual diameter?

Without being there to see what you did, I have no answer.
There are at least two ways to measure barrel slugs made from odd numbers of grooves and both involve equipment more than just a micrometer.

[Pirate69]

Getting back to my 1873 45-70 Springfield Trapdoor again. I have played with some Unique, 2400 and Red Dot loads with cast boolits from a NOE 460-186-CB PB AP4 mold. The boolits used were sorted and 193.0 to 193.9 gn boolits were loaded. The Unique and 2400 loads are okay for banging steel at 50 yards, but they were not of the accuracy of the Red Dot loads below.

The loads below were fired from a bench rest. The boolits are PCed. The rounds were loaded slightly longer than the cartridge jam length and the final seating is performed on chambering. Cases used were previous fired, un-resized cases. The cast boolits are sufficient in diameter to seat and have some resistance to movement. A slight crimp was applied to prevent any movement from any applied pressure. Wolf Large Pistol primers were used. Rifle was elevated before firing to position powder against primer. The Red Dot powder was purchased in the mid 80’s for shotgun shell loading. Old powder.

Rifle was dry scrubbed with a bronze brush and cleaned with patches until only a slight color was detected before the first group. No further cleaning of the barrel was performed during the group firings.

Five shot groups were fired for all loads except for the 5.0 gn load. I loaded 10 rounds of this load to ensure that I was on the paper with enough rounds to shoot a five-shot group. I fired the first 5.0 gn round and verified that I was on the paper. Then I fired the remaining nine rounds. The first round was a flyer. No sure if it is a result of a “clean” barrel or just me. The 5.0 gn group is a nine-shot group, I eliminated the flyer.

Looks like my best accuracy is in the 5.5 to 6.0 gn range. The 5.5 gn group had one shot out of the group. If that shot is eliminated, the remaining four constitute a 1.6” group.

I have included the QuickLoad outputs for the loads. I plan to chronograph some loads to verify the data. I also want to shoot some 100-yard groups to see what that looks like.

I struggle a little shooting this rifle. The trigger is fairly heavy and I sometimes lose focus on the front sight before the trigger breaks. I have to back off, refocus and try again. Guess I could use a little trigger work.

5.0 to 6.0 gn loads: https://i.imgur.com/kVYVRyU.jpg
6.5 to 7.5gn loads: https://i.imgur.com/DbMqXQn.jpg

Group…..Gn….. ES,in…..X,in…..Y,in…..Width,in Height,in…..Velocity… .. ..PSI…. ..Ft-Lb…..Drop @ 100 yds
………1…..5.0……..3.1…..…0.0……2.0……...3.1……….....1.2…… …...1002…… ..3583…....431………….-9.6
………2…..5.5……..2.5…..…0.8……4.3……...1.8……….....2.4…… ……1062… …..4164…. ...483………….-8.7
………1…..6.0……..1.8…..…1.9……4.6……...1.8……...…..0.7…… …..1117…… ..4780… ....535………….-8.0
………1…..6.5……..3.4…..…0.1……4.8……...1.9……….....3.4…… …..1170…… ..5430…. ...586………….-7.5
………1…..7.0……..2.4…..…0.2……3.2……...0.6……….....2.3…… …..1220…… ..6113… ....638………….-7.0
………1…..7.5……..4.1…..…0.1……4.7……...3.5……….....4.7…… …..1268…… ..6826… ....934………….-6.6