Need SR4759 replacement for 45-70 duplex loads.

[Dick Dastardly]

First of all, I apologize for not hanging out here often enough. You folks are a great bunch and I enjoy your company.

I've been loading a duplex load for my Rem. roller 45-70 and am running low on SR4759 for my duplex load with FFg Swiss under a 500 grain boolit. I'm looking for a current manufacture smokeless powder to replace the apparently discontinued SR4759. I've been using some Unique but it doesn't work quite as well as 4759.

DD-MDA

[fouronesix]

5744 is the closest to 4759 I know of.

[John Boy]

Lil Gun & N-110

[Nobade]

Hi Dick, good to see you around these parts!

Yep, like they said above - 5744 is pretty close. 4198, N133, and 2015 work also. They're all about the same speed.

-Nobade

[Dale53]

Dick;
I have shot a considerable number of duplex loads with both the 45/70 and 40/65. My choice of smokeless is RL-7. It is the right burning rate, is fine grained, and measures beautifully. I have come to prefer 10% by weight of smokeless to the full charge of black powder. To clarify - if the proper charge of black powder alone (using the granulation and brand of your preference) is 70 grains, then the smokeless part (against the primer) is 7.0 grs. I then subtract that amount for the black powder which leaves 63.0 grs. of black powder.

SPG is a good lube for the duplex loads. I used Emmert's home mix with excellent results (50% Pure Natural Beeswax, 40% Crisco, and 10% Canola Oil. I later replaced the Canola Oil with Anhydrous Lanolin for longer shelf life (and loaded cartridge lube life).

In fact, I made up a powder measure from a shotgun press that dropped the proper charge of smokeless first, then the proper charge of black. I used the appropriate parts from a MEC shotgun press. It worked beautifully and took the "pain" out of dropping two different powder charges.

You can use a good bit more smokeless (the ultra long range Canadian shooters, using strong single shot actions, often use as much as 20%, I am told). I, personally, was happy with 10% after I did some experimenting. Each grain of smokeless, is equal to about three grains of black in effect on velocity.

You can shoot "forever" without cleaning, blowing, wiping or any of that mind numbing attention to detail that straight black demands. Clean up still requires a good black powder regimen. I use a good black powder solvent, dry carefully, then apply a good protectorate (Ed's Red). Then two or three days later, another application of Ed's Red just to be sure.

The matches in this area used to go with duplex loads almost exclusively. However, when the local shooters wanted to shoot in the National Matches they realized that they would have to learn how to manage black powder. We did, but I have not lost my appreciation for a good duplex load in black powder firearms. The NRA BPCR matches require straight black, of course.

At any rate, try RL-7 - you will definitely LIKE it, BIG TIME!

FWIW
Dale53

[MT Chambers]

4 numbers....4227

[Boz330]

When I fooled with duplex loads I used RL-7 as well. Seemed to work well for me.

Bob

[.22-10-45]

When I was playing with duplex in my .25-25 Stevens, I found PB cleaned the bore up to point of looking like a straight smokeless load had been fired..I was using 3FG Swiss as main charge..alas..PB is also being discontinued!

[RogerDat]

According to ADI powder equivalent chart SR4759 is equal to 2400, AA4100, and the N110 mentioned earlier.
http://www.adi-powders.com.au/handlo...quivalents.asp

The good news is that there are three other powders that are directly equivalent - the bad news is they are powders that are pretty hard to come by.

[ohland]

According to ADI powder equivalent chart SR4759 is equal to 2400, AA4100, and the N110 mentioned earlier.

SR4759 equivalent to 2400? Methinks the VMD is different
.09930 SR4759
.07420 HERC 2400

Burn rate (which will vary based on case volume, charge, bore / bullet diameter, and bullet weight)
43. 2400, Alliant
48. SR-4759

SR-4759 single base, stick powder
2400 double base, flake (is their a new spherical?)

[bigted]

I have used the IMR4227, IMR3031 and the above mentioned RL-7. of these three I prefer the 4227 myself as it provides a nice clean duplex load with no apparent side effects and worth mentioning here ... I NEVER go above the 10% rule. I also experiment with less then the 10% for the smokeless as my goal is just to provide a clean barrel free of fouling enough to provide the accuracy I like with no need to blow-tube or wipe every shot for optimum accuracy.

I always do the full case of BP under the boolit to find the beginning amount of BP to load and then subtract the percentage I use of smokeless powder to play with till I arrive at a good load combo for the duplex loading.

I guess another thing to mention is that I have always used GOEX in the 2F or cartridge configuration. I am sure that other powders and sizes would work the same.

4227 for me as it meters well and dips well for easy loading and weighing. I always weigh both the smokeless and BP to ensure a perfect load every time and to stay safe. I always load the smokeless first in a single case and follow immediately with the charge of BP to ensure I deal with a single case at a time so as to ensure no accidental doubles of smokeless and the rite on amount of black powder as well.

after I powder all the cases ... then I load the boolits ... or compress with a stem as needed.

[Dick Dastardly]

Thanks for the suggestions. I'm going to the new Cabelas and buy powder today while they have some left. They seem to have a good supply.

Best,

Dick