45-70 duplex load

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  • Last Post 11 June 2019
loophole posted this 08 June 2019

My second centerfire rifle about 45 years ago was a Ruger No 3 in 45-70.  Since then I have owned about a dozen 45-70's.  I got one of the first Farmer Sharps and shot it in shuetzen matches and later on bought a heavy barrel Shiloh and started shooting 500 grain bullet.  Health problems prevent me from shooting except off a bench and my range is limited to 200 yrds.  I got out a Mod 63 some time ago and remembered why I really don't want to shoot heavy bullets much with a light sharps or my H&R officer's model.  I read my old reloader's manuals and noticed that a 350 grain bullet often shoots well in the 45-70, even though the twist is for heavier bullets.  I also remembered that I still have a 385 lyman mold and a Hoch mold I had made for paperpatched bullets which shot very well in the big Shiloh--less than 1" at 100 yrds with iron sights and black powder.  My 360 gr NOE mold just arrived and it looks great. Tomorrow I plan to cast a hundred or so bullets out of 40-1 allow.  My load worked out years ago was 5 gr 4750 under 62 grns FFg.  I  use 5744 now that my supply of the 4750 is used up.

Why a duplex load? I got started with duplex loads years ago.  Despite all the dire warnings, particularly on the Shiloh forum, I have found duplex loads safe, when done as Ned Roberts recommended and equal in accuracy at 200 yards as straight black, I can shoot all day without having to clean, and more importantly, bullets designed for smokeless often have lube grooves too small to carry enough lube for pure black loads.  I use Starline cases, Fed LR Magnum primers, and .20" of compression.  I don't have to resize cases for either of the 45-70 rifles I have now.  Just slight bell, compression die, and taper  crimp. I love NOE molds and the sizing tools they make. I hope the recoil with this load and a 350 gr bullet will be pleasant enough for my metal gong range. 

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Ed Harris posted this 08 June 2019

Duplex loads, substituting a bulky smokeless for about 10% of the BP charge GREATLY reduces fouling and speeds cleaning compared to straight BP.  I loaded 6 grains of Red Dot or 700X to 55 grains of FFg Goex in an original 1884 Trapdoor for years and it shot wonderfully.

Conventional wisdom was that the charge had to be compressed, using fiber wads or Cream of Wheat to keep the charge statified so that the powders didn't mix, but then when I went to Ruger and observed how they proofed the Old Army revolvers I realized that the powders could be mixed, if they were in correct proportions.  The Old Army was proofed with smokeless, using only a 10% black powder booster, evenly mixed in the measured charge, to aid ignition. The exact receipe must remain secret to protect the innocent, but I can tell you that the proof charge developed double the BP pressure, about 18,000 psi and drove a 250-grain Remington lead conical about 1050 fps.  I later developed a "hunting blend" of Goex 4Fg, Red Dot and Cream of wheat, which drove a 250-grain Remington lead conical to 880 fps at a measured pressure of 13,700 psi and I have used that load in my Old Army for years, cleaning with Ed's Red and having no rust issues.  Seven deer have fallen to the load in the last 25 years.

 

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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JeffinNZ posted this 08 June 2019

I shoot a duplex load in my .310 Cadet.  3.7gr H4227 (the smallest dose the Lee disc measure will throw) under 13-14gr Swiss 3Fg.  It burns so clean the bore is shiny after each shot.  I have shot 50 consecutive rounds without any form of cleaning and great accuracy.

Cheers from New Zealand

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loophole posted this 08 June 2019

And we get the wonderful aroma and smoke of real gunpowder!

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45 2.1 posted this 08 June 2019

Conventional wisdom was that the charge had to be compressed, using fiber wads or Cream of Wheat to keep the charge statified so that the powders didn't mix, but then when I went to Ruger and observed how they proofed the Old Army revolvers I realized that the powders could be mixed, if they were in correct proportions.  The Old Army was proofed with smokeless, using only a 10% black powder booster, evenly mixed in the measured charge, to aid ignition. The exact receipe must remain secret to protect the innocent, but I can tell you that the proof charge developed double the BP pressure, about 18,000 psi and drove a 250-grain Remington lead conical about 1050 fps. 

 

And here they warn you not to mix powders. Hahahaha! They have the equipment to do it safely though and we don't. Mixing is just that, a equally distributed mix. Layering (stratifying) is not a mix and gets us by quite well producing nice clean burn of the powder. It is also usually more accurate. I'm sure some BP guy will say his is more accurate, but there is a reason they don't allow duplexing in competition. Having done both, I know that reason. Duplex loads are clean burning and usually give superior accuracy.

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Dale53 posted this 08 June 2019

I was a serious Black Powder Cartridge Silhouette competitor for about 15 years. The local matches allowed both black powder or duplex loads (pyrodex was allowed also).

At any rate, nearly everyone used Duplex loads. Nearly everyone used 10% smokeless. My smokeless powder of choice was RL-7. Reloader 7 measures well, ignites easily, and the accuracy is excellent. My competition caliber was 40/65. When duplexing, I could literally shoot all day without cleaning. My first rifle was a 1875 Sharps and worked quite well. However, when Browning introduced the new High Wall, I immediately ordered one and that became my rifle of choice. I got groups at 500 yards off a bench that were quite impressive.

When our local association started shooting at Friendship, In at the NMLRA, the matches were NRA approved and allowed black powder or approved substitutes, only. I will tell you without fear of contradiction that the transition from duplex loading to black powder only was NOT easy. However, eventually, we learned to get excellent results with BP only. In all truth, duplex is much easier to run.

I also shot a good bit of 45/70 ammo in several different rifles and duplex worked exactly like they did in my 40/65.

All over the country I was repeatedly told that I was going to destroy myself and everyone around me if I continued to use duplex loads. Well, that is not true. In fact, Lyman had pressure tested loads in the #3 Cast Bullet Manual for duplex loading. Just like anything else in reloading, you must do it correctly. Done correctly, it is NO problem.

Just to be clear, after we signed up for NRA matches neither I nor my fellow shooters used anything but black powder or approved substitute. Even matches away from Friendship were shot with the NRA approved loads simply because we wanted to be competitive everywhere with approved loads.

However, if I were setting up a hunting rifle with black powder, today, I probably would use a duplex load. Life is just a bit simpler with duplex.

 

FWIW

Dale53

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frnkeore posted this 09 June 2019

I'm another, long time duplex loader. I only used 10% smokeless for one year. I did ok but, I'm a ASSRA member and the ASSRA has long range BP rules, that limit priming charges to 15%. I have used 15%, ever since (1987). My best 430 - 500 gr bullet, 45/70 load was 10.5 gr H110 and 70 gr of FG, using a LDPE wad and shot breech seated in a Douglas barreled,1878 Sharps Borchardt. Hard on the shoulder, even with a 16 lb rifle.

My most accurate 15% load is 5 gr 4759 and 35 gr FG, LDPE, breech seated, in a Hoch action, Douglas barreled .308 groove, 32/35 Stevens caliber. I won all my BP matches with that rifle, except 2.

I never had any problems, even using 6 gr 4759, 40 gr FG,, BSed in my factory, 32/40, Model 44 Steven. It's not a match rifle so, I never shot it a lot.

I only use Rem 2 1/2 primers for any 4759 or BP loads, even the H110 load.

Frank

 

 

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Larry Gibson posted this 09 June 2019

I've been using duplex smokeless/BP 45-70 loads for many years.  Mine are for duplication of the M1873 rifle 45-70 load and the 45-55 Carbine load with the 405 gr bullet. I worked both loads up for my TDs as per Spence Wolf's method.  I use 4759 (until what I have runs out) and Goex Cartridge or 3f BP.  I can shoot all day w/o using a blow tube or cleaning.  I have shot 100+ rounds through the carbine in a day w/o cleaning and accuracy held through out. 

I have also pressure tested both cartridges loadings and there is no indication of any potential problems. 

LMG

Concealment is not cover.........

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loophole posted this 09 June 2019

I also shoot duplex loads in my 40-65 sharps and I use them in my 1886 Winchester 40-65 because they do not crude up the action like straight black.  I have used some duplex loads in my 38-55 and 32-20, but I have not shot those enough to settle on loads.  I just use 7-10 % 5744 and slightly compressed FFFg.  .030 or .060 cardboard wads to adjust compression,  Years ago I also started using a 50-50 mixture of bee's wax and neatsfoot oil with a little set-up lube added for lube.  I have used a lot of SPG but my home made lube is just as accurate either with the duplex load or with the 5744 smokeless load I have used.  It's much less expensive and I melt it and pour it into the 450 lube/sizing press, let it cool, and resize and lube very easily.  Works great as a pan lube and also the best roundball patch lube I ever used.

Loophole

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Qc Pistolero posted this 09 June 2019

I don't shoot BP so I can't comment about it.But about your 350 gr instead of 500gr bullet,I can vouch for the fact that it groups very well at the short distance I'm using it.Still looking for that elusive MOA with it but a few of my targets came pretty close(1 1/4'' to 1 1/2'' at 100).The mould is Lee 457-340F unsized  lubed with 2 coats of LLA topping 29gr of IMR 4198.The twist of my gun is 1:18.

 

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John F. posted this 11 June 2019

Thanks for sharing, Ed -- good information, as always!  I am curious to ask how/what you lubed the factory

Remington 250 gr. lead bullets with?  I have heard of people putting SPG or similar in the cavity at the base of

the bullet for  use with BP, but have no experience with them.  They look like a good option, however.

Thanks very much for any info you can share!

John

 

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