45-75 load info

[Mayor]

Howdy!

Anybody have any experience with Accurate Arms XMP-5744 in the 45-75? I will be using the RCBS 45-300-FN gas checked bullet (as it's about the only decent mould out there for this cartridge/gun combo). Im guessing I can start with Accurate's data for 45-70 (as there seems to be concensus that too low isn't a problem with this powder) and work up from there. I'm just wondering what results are lurking out there in somebody elses notes!

Thanks in advance!
Mayor

[NickSS]

I have used AA 5744 and 300 gr cast bullets in my 45-70s for several years now. I originally bought the powder due to an article I read that said it was possition insensitive in large cases. I have found this to be true. I mostly shoot the 45-70 at black powder ballistics and have settled on 29 gr of AA5744 with a 300 or 325 gr bullet. That powder charge seams to be a sweet one for several rifles I own in this caliber. It also duplicates the ballistics I get with black powder using the same bullets. 5744 is very similar too but slightly faster burning than 4198 with 4198 I use 31 gr but need a filler of dacron or styrofoam with that powder.

[fourarmed]

What rifle are you shooting your .45-75 in? If it is a '76 Winchester, I would regard the starting loads for a trapdoor Springfield as about maximum. If it is an Italian replica, I still wouldn't go much over that. The replicas aren't cheap, but they are replaceable.

[Mayor]

nickss and fourarmed:

Thanks for the replies!



fourarmed:
I actually own both a "Charter" (yea Chaparral) and a few Winchesters. But I think we are "assume"ing too much to think a "trapdoor" load (not 45-75 but actually 45-70) would generate the same pressure. Larger volume case here and bottlenecked, hence the 75 gr designation.

I went to AA's website a few days ago and submitted a request for load data help. As of this afternoon no reply email, so I called them. Silly me..........they sold to Western Powder a year ago (www.ramshot.com) and so I called them. So far no return call........maybe soon?

The "feeling" with xmp5744 is that there is NOT a problem with loading too light. I guess I will make an educated "guesstimate" of my own if no one on this forum has any insight soon:rolleyes: :rolleyes:

Dare I ask about 5744 in .577 Snider?:mrgreen:

[NickSS]

I guess I was reading fast and did not see the cartridge as 45-75 not 45-70. I have not loaded this cartridge but have loaded bottle neck cases with 5744 including a 44-77 Sharps and a 43 Mauser. I found that a good starting load is 25 gr with no pressure signs in those cartridges It works OK in the 45-70 too. Try it and let us know what you come up with as the 45-75 case actually has just about the same volume as the 45-70 it should not make a whole lot of difference. You should realize that Sharps loaded a 420 gr bullet and 75 gr of black in the 45-70 case way back in the good old days.

[Mayor]

Try it and let us know what you come up with as the 45-75 case actually has just about the same volume as the 45-70 it should not make a whole lot of difference. You should realize that Sharps loaded a 420 gr bullet and 75 gr of black in the 45-70 case way back in the good old days.

NickSS

Actually depending on what parent case the 45-75 is formed from I can get up to 72 grains (by volume) of black in it. I have not found the 45-70 to accept more than about 62. Of course I was asking about xmp5744 not black, just trying to clear up your statement.

As to the line above re: 75gr loaded by Sharps. Remember they were using compressed charges in balloon head cases. Modern cases will not allow that amount.

I will spend some time at the bench once we get a nice day and report back on my findings.

Thanks for posting!:-D

Mayor

[Mayor]

Accurate lists some new load info (must be new as of a year ago, before they sold the company). They list this load which is at the 18,500 cup recommended for trapdoors:

CLE 300 (L) PB 27.9gr 5744 (1405fps) to 31.0gr 5744 (1597fps)

this is for a 45-70 loaded to an oal length of2.550" firm crimp

I'm gonna start at 28 grains in the 45-75 with an RCBS 45-300 FN gas check bullet (one of the few moulds available that comes close to working in the 1876).

I'll reply later with my findings!

Mayor