Duplex loads in 45-60

[shootlow]

Hello. New to forum and was wondering if anyone would be willing to elaborate on a post I read elsewhere in this forum calling for a duplex load of 8grs. Of 5744 under a charge of BP in a 45-60 repro?
Is this even safe?
Can you use 5-10 grs. Of any smokeless powder that is safe to load in this caliber to pull this off?
I have quite a few years of loading modern rifle and pistol rounds under my belt but just starting with big bore obsolete cartridges. Getting back to the old stuff as plastic guns have no soul. Thanks.

[Mike]

I have a 76 in 45-60 and could not get it to shoot with BP at all, so now it shoots 4759 only.
BUT we may have stumbled across the solution while trying to get a Highwall in 45-65 to shoot BP. The HW would not shoot the BP at all while shooting nitro very well. The solution, unsized lead bullets. When sized to the correct size for bore they work for nitro loads but not BP.
put them straight from mould on top of a case of 11/2 Swiss same performance as nitro.
The rifling in the  Ubeti guns is so shallow the bullet has nothing to grab,
 

[shootlow]

Thanks for the reply but I may not have been clear about what I'm after.
I'm looking for the best way to get a safe consistent smokeless load in the
1300-1500 fps range. I read that a duplex load may shoot cleaner than just straight BP and allow me to fill the cartridge case for consistency. Everything I read about using fillers says to be wary. Don't get me wrong
I'm not against using BP, I have other guns for that, my time at the
range is limited and I don't want to spend it cleaning the barrel every
4 or 5 shots.

[Advertising]

[larryo1]

I must stick my nose in here for a few comments.  First off,  Duplex loads can be very hazardous if one does not know for sure what they are doing.  Years ago, I diddled around with Unique and BP.  Good and bad results and not what one would expect for accuracy..  I was using my 45-90 '86 and my Sharps rifle.  Finally, I decide it was not the trouble or worth the effort to use this combination.  Were I you, I would stick to either straight BP or get a good smokeless to go with.  I have very good results in my .45-75 with 76 grains of Swiss 1½ or 22 grains of 2400.  But that is in MY rifle and she is a very fussy ol girl!  The best results that I had years ago was a duplex load in my old .45 Colt.  I used just a pinch of Unique and a case full of 2Fg and it shot pretty good.  I guess the best part was that things were cleaner using that load but that was about all it accomplished. There is alot of literature to be had if one is interested in following this idea.  I think that there is some in Phil Sharpes old book also.  You can use Google and get started if you desire but without any good information to start out, I sure would not go on a tangent and try before doing some research.  Hope this is of some help for you.

[shootlow]

Thanks for the info. Looks like the choices are either BP or live with
the loads in Lyman #49. The one's I've tried there are the reason why
I'm on this wild goose chase, they have been both inconsistent over the
chrony and marginal accuracy with a 300gr. Meister cast. Looks like
I've sat down to a meal I don't have time to eat. Well she can always sit
in the safe till retirement maybe I'll have time then.

[Coffinmaker]

I personally have little or no experience with duplex loads.  I have had some quality time with some folks who have lots of experience with them.  Some of that experience includes some ruined guns.  Elmer Kieth wrote at one time, at some length, about turning some of his
experimental Colts into scrap trying duplex loads.
None of the powder manufacturers will recommend duplex loads. 

There is however, one duplex load I am aware of that is successful.  Very Large Naval Artillery.  16"/50 rifles to be exact.  There is tiny amount of BP in the base of each powder bag to act as an igniter for the "big guns."

Unless you just happen to own or have access to a full blown ballistics lab.  SKIP IT.  No duplex load information from a hobby reloader is
to be trusted.

Coffinmaker

[Blackpowder Burn]

There should be no need to clean the barrel every 4 or 5 shots if you use the correct bullet design and lube - i.e., large lube grooves and good BP lube.  I shoot a 36 round Cody Dixon match with my 45-70 or 38-55 for two consecutive days (72+ rounds) without cleaning and rarely miss a target.  If I do, it's not the fault of the rifle or ammo.  If you use a bullet that carries enough of the proper lube, the bore is kept moist and fouling reaches an equilibrium.  I can clean my rifles with 4 or 5 patches and one swab with a bore snake.  After years of use, my bores are still bright and shiny.

Now, if you're trying to shoot the tiniest possible groups on paper at long range, it may make a difference to clean more frequently.

[OD#3]

I guess I'm going to be the lone voice who likes duplex loads with this rifle.  I started with the "1 grain of smokeless is equal to 3 grains of BP" rule of thumb with mine.  Starting with 5 grains of SR4759, then multiplying that by three directed me to lessen my BP charge by 15 grains.  Unfortunately, 45 grains of BP didn't quite fill the case enough.  Since many duplex loading recipes call for a much larger ratio of smokeless to BP, I broke that rule of thumb just a little and eventually settled on 50 grains BP with 5 grains 4759.  This is still a smaller ratio of smokeless to BP than a great many of the duplex loads others shoot regularly.  I don't remember what the velocity was, but it was about the same as my straight BP loads.  Accuracy was great, and fouling was nothing.

 I'd had pretty good success before with the PRS 385 Gr. Big Lube bullet and straight BP.  It carries enough lube to keep the fouling fairly soft, but I never did get a "lube star" with that long barrel, and those Big Lube bullets aren't known for their long distance accuracy.  And I wanted to be able to shoot some classic 350 gr. 45-60 bullets that don't carry as much lube.  Blowing and swabbing didn't interest me; this is a repeating rifle, after all.  My rifle holds 10 rounds, and I wanted all 10 in the magazine to retain their accuracy; straight BP with the smaller lube groove bullets wasn't doing that for me with such a long barrel--too much fouling.

With the duplex loading, I can shoot all day without fouling.  I still get the boom and smoke, and I can hit an 8 inch steel plate at near 300 yards when I do my part.  Granted, I hit that steel plate plenty with the straight BP and Big Lube bullets, but I hit it more often with my duplex loads.

I haven't experimented yet with smaller amounts of smokeless; I'm planning to do that next when I reload my latest batch of fired cases.  My goal is only to get rid of the fouling, and if I can do that with less than 5 grains of 4759, I'll be happier, and I'll feel better about loading 50 grains of BP in my duplex loads when the rule of thumb about duplex says I should probably load only 45 grains.

[dusty texian]

OD#3 sounds like you are getting good results from your loading. What rifle are you shooting your duplex loads in? Would like to hear more about your loading test. ,,,DT

[OD#3]

It is a run of the mill full-sized Uberti 1876, and I shoot cut-down 45-70 cases in it.  Some Uberti rifles need you to thin the rim just a little; mine didn't.  Not much load development with it yet.  I did the PRS big lube over 60 grains compressed 2f for a while and then tried the duplex load.  I prefer the duplex load, but I'm still not entirely comfortable with disobeying the "rule of thumb" on the ratio of BP to smokeless.  I may try three grains smokeless the next time, though I'm not optimistic that it will be enough smokeless to get rid of the fouling.  I'll let you know when I do.  The cases have only been washed for now.  I still haven't gotten around to really cleaning them and loading them back up yet.

[PJ Hardtack]

Duplex loads work! That's why the turn of the last century Shuetzen riflemen used them.

I wouldn't worry about 5 gr of 4759 as priming charge. I use it in both 45-70 and 50-70 loads when I want the clean burning results you mentioned.

I've got most of a can of 4759 left, but I hear that is a discontinued powder. Gonna hafta find a replacement. A rifle powder with the same burning rate oughta work, or a charge of pistol powder.

[OD#3]

Yes, 4759 is sadly discontinued.  Had I known it was going to be, I'd have bought the five cans the store had instead of just the one I bought years ago.  Still, I only use it for duplex loading, so at 5 grains or less a cartridge, I'm hoping it will last a long time before I have to explore other powders.

[shootlow]

Thanks to all that have shared their experiences. In the past month since
I started this post I have contacted Taylor's gunsmith, and talked to a good
friend of mine that has considerable experience with big bore lever guns. And I now realize that I was expecting way too much from this cartridge. The gunsmith explained that axial thrust against  the bolt is what prevents these newer rifles from obtaining the higher performance you would expect with the better metallurgy in the newer repros. The chambers are bored to original specs, there-by not allowing the brass to expand against the chamber walls when fired. (We both agreed that this is done to accommodate blackpowder shooters.)And my friend assures me that his 444 and 45-70 Marlin's are 200 yds guns at best with his handloads. So now I guess the big question is - what is going to be the best way to keep the powder against the primer? Toilet paper?

[PJ Hardtack]

The guys that write for the BPCN advise against the use of wads of any kind, especially in BN cases. It's your rifle.

When I load duplex 45-70 and 50-70, I don't use even a newspaper wad. I use enough BP to give the same degree of compression by reducing the powder charge 5 grs, the same amount of 4759.

[Silver_Rings]

Howdy Shootlow,

I am assuming you have a reproduction of the 1876, either a Uberti or Chappy?  If so it is easy to use a 300 gr lead bullet and get 1500 fps with smokeless powder.  If you browse through the load data for the 45-60 which is near the top of this forum http://www.cascity.com/forumhall/index.php/topic,36384.0.html you will find a number of loads that will match what you are looking for.

Silver Rings

[OD#3]

In reference to the assertion that the chambers are too generous for the cases to seal, I've never had a problem with that.  But I anneal my cases every time, so case obturation has never been an issue for me.  I just finished prepping some more cases.  Unfortunately, I have day-shift tomorrow, so it will be some time before I can reload them and fit in a range day.

I may be way off, but when it comes to the 45-60, I feel better knowing that the 1876 was originally chambered in 45-75, and that the action is designed for that higher bolt thrust.  It was why I went ahead and broke the "rule of thumb" on duplex loading and went ahead with 50 grains BP instead of 45 grains BP over 5 grains of 4759.  I believe that there is a greater margin of safety with the 45-60 when it comes to duplex and pure smokeless loads.

[shootlow]

Thank you gentlemen, OD #3 do you anneal your cases everytime before you reload? , or is it something you do once every 2 or 3 sessions? I know how to do it, just not the frequency.

[OD#3]

Most experts say that annealing is not needed for each reloading.  But for most of those guys, annealing is only done to prevent work-hardening induced case mouth splits (extending case life) and to recover lost neck tension (work-hardened brass tends to spring back too easily after resizing, while annealed necks more easily stay where you've resized them to).  But a lot of what I've read about that says that it may be the second reloading after an anneal to get good tension.  According to those sources, the neck tension is in its sweet spot and pretty consistent for a few more reloadings before one needs to anneal again.  However, the first rounds made after a fresh anneal will usually have a different neck tension than the ones reloaded during the "sweet spot" times.

Since my goal is only two things--improved case longevity and excellent sealing with low pressures--, I anneal every single time.  I'd rather not keep up with exactly how many times a case has been reloaded.  I sometimes load 200 rounds, shoot 100 of them, and then decide to load that 100 back up.  If I have to keep up with how many times a particular case has been reloaded in order to determine when to anneal, I'd then have to keep that new batch segregated.  The next time I may only shoot 50.  Then I'd have to segregate that batch, too. 

I just anneal every time, and I add the reloaded rounds back into my supply.  If I am consistent in my annealing process, the new stuff performs the same as the old, and I'm assured of good case sealing.   I must admit though, that this practice does not allow me to maintain an accurate count of how many times a particular case has been reloaded.  But I do inspect my cases thoroughly, and none have needed to be condemned yet.  My attrition rate is do to the occasional reloading blooper and "lost in the grass" events.

[sail32]

Lymans Reloading Handbook, 46th edition list duplex charges with 11% SR-4759 in the Ruger #1 and #3 section and in the
50/70 section.

I have loaded 3 grains of IMR-4227 under 27 grains of GOEX 2Fg, for my Uberti 1860 Henry and Pietta  1873 Colt copy.

The load kept the barrel clean and produced some black powder smoke..