Duplexing .45-70 with WC872 + heavier bullets

[iplaywithnoshoes]

I recently had some success duplexing H50BMG and a variety of kickers in a 405gr bullet in .45-70. I am curious now if a similar development procedure is possible with a 500-535gr bullet. I would figure that the additional inertia buys the powder time to burn a bit longer in the case and down the barrel. Initial guess: the kicker charge level that ensures complete burn will be lower than with a 405gr bullet?

Has anyone tried this method and what kind of main charge would be reasonable to start with? I am aware that this reloading subject is controversial but I am seeing that if done safely, it's an incredibly effective method and very interesting to experiment with.

shoe

[Wayne Smith]

Kicker charge of??

[iplaywithnoshoes]

Imr 4198.

[Char-Gar]

I have loaded lots of 45-70 rounds with cast bullet (400 to 500 grains) and WC 872. I use three grains of 3031 in the bottom of the case and fill the case with 872 to give slight compression when the bullet is seated and crimped. I get great accuracy, a complete burn, with no high pressure. I suspect the velocities are way below 1,400 fps.

[25ring]

I run this load in my trapdoor. 54grs WC872,4grs RL-7 kicker,.030 wad,466gr shortened minigroove bullet.Very accurate all the way to 1000yds.FWIW--Mike.

[Wayne Smith]

I've only done it in my Steyr - 8mm. Now that I have a scope on it I'll see how accurate it is!

[richmanpoorman]

Duplex loads are at best not safe. There is no reason for them and, as the OKH crew proved, of no advantage. In olden days duplex loads of 2400 and black were useful in reducing fouling. No need anymore with Alliant black.

[ballistim]

I use a duplex load of WC872 with an IMR4198 kicker in my H&R Buffalo Classic and Marlin 1895 that I learned about from member 9.3x62 AL several years ago, and it's the only load I use for 45/70. Good accuracy, burns clean, and with 32 lbs. of WC872 on hand I'll probably be using it for quite awhile.


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[iplaywithnoshoes]

I use a duplex load of WC872 with an IMR4198 kicker in my H&R Buffalo Classic and Marlin 1895 that I learned about from member 9.3x62 AL several years ago, and it's the only load I use for 45/70. Good accuracy, burns clean, and with 32 lbs. of WC872 on hand I'll probably be using it for quite awhile.


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Yep, I'll be trying WC872 in My Encore and Buffalo Classic as well. I also talked to him recently and got very good information on safe development. It literally melts and mops leading from the bore.
8 lbs will last me a couple months probably.

shoe

[Char-Gar]

Duplex loads are at best not safe. There is no reason for them and, as the OKH crew proved, of no advantage. In olden days duplex loads of 2400 and black were useful in reducing fouling. No need anymore with Alliant black.

This is simply not true. Duplex loads can be safe and are needed for a clean burn with ultra slow powders like WC 872 in large cases like the 45-70. The Oneal - Keith - Hopkins crew did use duplex charges of powder, but ignited the charge from the front via a brass tube installed in the case. The OKH experience should not be conflated with duplex loads in general.

[Hamish]

Duplex loads are at best not safe. There is no reason for them and, as the OKH crew proved, of no advantage. In olden days duplex loads of 2400 and black were useful in reducing fouling. No need anymore with Alliant black.

May I suggest you spend a little time with a site search and CastPics.

[iplaywithnoshoes]

This is simply not true. Duplex loads can be safe and are needed for a clean burn with ultra slow powders like WC 872 in large cases like the 45-70. The Oneal - Keith - Hopkins crew did use duplex charges of powder, but ignited the charge from the front via a brass tube installed in the case. The OKH experience should not be conflated with duplex loads in general.

May I suggest you spend a little time with a site search and CastPics.

To add to this: I get many suggestions from forum members to stick to homogeneous charges of powder. Anything slower than Trailboss and Unique (with the exception of H4198) typically leads my barrels at trapdoor levels and leaves unburned kernels. I found a duplex of H50BMG as a test powder with 4198 to be the cleanest load for my guns so far in .45-70 while maintaining trapdoor pressures and velocities and keeping leading to a minimum at the muzzle. I should end up with something similar with WC872.

[Freightman]

Good discussion,I use 3031 as a kicker and have for many years in my 45/70 never had a problem. I use wc860 and wc872 with almost equal results.

[TCLouis]

I need to try this as I have a bucket full of WC870 and AA8700 to burn up.

[rbuck351]

I have been using 5010 and several different faster powders such as red dot, unique, AA9 with good results in the bigger cases for several years. Just start with a case full of a powder you know to be to slow for the round you are loading and replace it one grain at a time until it cleans up burn wise or pressure starts to show. It's really little different than using a starting load and working up watching velocity and pressure signs.

[ballistim]

I have been using 5010 and several different faster powders such as red dot, unique, AA9 with good results in the bigger cases for several years. Just start with a case full of a powder you know to be to slow for the round you are loading and replace it one grain at a time until it cleans up burn wise or pressure starts to show. It's really little different than using a starting load and working up watching velocity and pressure signs.

Good advice here, having worked with 5010 using faster burning powders as a kicker while looking for clean burn without signs of pressure, although I never found the accuracy that I was able to get from WC 860 or WC 872, and as stated by someone earlier found little difference between those two powders as both worked well in 45/70 for me with a slightly compressed load.
I have two jugs of 860 & four of 872, and 8 lb. jugs of fast burning powders on hand, so I should be set for 45/70 for life.


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[Buckshot]

..............The following is what I came up with when first experimenting with duplexing the slow surplus WC872 & WC860 ball powders. This work commenced in April of 1996. Hard to believe it's been 21 years since then The below is just a synopsis and a small example of experimental loads.



The above rifle was used for testing. A MAS36 I rebarreled to 45-70.

R-P cases 2.10", WLRP, Lee 457-450 FNPB 8 lead + 1 Lino + 1 tin, Sized .459", .060" cardwad under slug, Taper crimp. All charges scaled, WC872 Lot # 48774 added through 18" drop tube, OAL= 2.955", duplexed with H-4198. Slight compression at boolit seating.

1.0 + 69.0 ....................2.0 + 69.0 .................3.0 + 68.0 ..................4.0 + 67.0

HIGH:....1410 ..................1446.........................147 1. .......................... 1522
LOW:.....1358 ...................1430 ........................1439 ............................1480
ES:........52.........................16.......... ...................32............................. ...42
AVRG:.....1383....................1439............ ............1453............................1496

1.0 = No real difference in powder litter compared to full charge WC872
2.0 = Visible reduction in litter
3.0 = Great reduction in litter
4.0 = As clean as with with regular recommended canister powders.

A couple of other loads for comparison. Both of these were fired in Feb of 1997:

Bullet: Lee 457-450 cast 20-1 lead/tin, paper patched with .002" 9# Onionskin, and tumble lubed with Lee Liq Alox. R-P brass, WLRM primer, card wad, OAL = 2.985", Taper crimp.

#1) Straight load (73.0grs) WC872 Lot 48774 Thru 18" drop tube.
HIGH: 1402
LOW: 1360
SD: 20.0
ES: 43
AVRG: 1380
Fired at 100 yards, benched: 1-5/8"

#2) Same load data as above EXCEPT: 5.0gr H4198 + 68.7 WC872 Thru 18" drop tube.
HIGH: 1556
LOW: 1540
SD: 6.7
ES: 16.5
AVRG: 1550
Fired at 100 yards, benched: 5 into 1-7/8", but 4 into 7/8" (one oval hole).

Primer flat across it's face, factory radius on cup not affected.

I tried duplexing in my 45-90, however it did not work out as well as with the 45-70. Before I could get clean burning I began to get more then desired casehead expansion. My theory is that the heavier charge of WC872 was possibly containing pressure at the base. In any event I gave it up in that case.

A shooting buddy had a Turkish M38/46 rebarreled to 35 Whelen and he was skeptical at first, but after seeing the results I was getting he tried it in that rifle. With a full case of WC872 and the Lyman 358009 cast boolit he got good accuracy @ about 1800 fps, but had the usual powder litter in the barrel. IIRC with 3.0grs of H4198 and a suitable load of WC872 (allowing the boolit to hold the same OAL) his velocity increased to right at 2000 fps, no powder litter and maintained accuracy or a slight improvement.

WC872 & WC860 powders work well for cast (and jacketed in some calibers) which have high(er) expansion ratios such as the 7x57 and especially the 6.5x55 Swede WITHOUT using a booster. For example in the 7mm Mauser with the RCBS 172gr cast boolit, 42.0 grs + Dacron yields about 1775 fps from a 29" bbl and burns clean enough to not be a problem, plus provides excellent accuracy. Ditto the 6.5 with 32.0 to 36.0 grs + Dacron and the Lyman 152gr boolit. Also in the 6.5 from my M38 Husqvarna with a Hornady 140gr JSP I get 2700 fps with a full load. In the 7mm with a 175gr slug you get close to the original ballistics of 2400 fps with usably clean burning.

Yes you can get your personal tookus in a sling via duplexing if things are not correct. In the 45-70 it's almost perfection. The main charge of slow powder isn't excessively heavy to get started moving, (and I believe as the booster ignites and involves the ball powder, the bulk of it also moves forward) plus when the slug has moved 2" the volume has doubled. I've never done the math but the slug in the 6.5 Swede (for example) has to move quite a bit further then 2" to double the volume, so pressure remains higher. Nothing magic about that 2" measurement. It's just a simple example to use.

Other then what my friend did in his 35 Whelen, I have no personal experience with duplexing in BN cases. If I was to try, naturally the place to begin would be with a case full of the slow powder under a light to medium weight slug for that cartridge. Plus a set of casehead expansion measurements with full power factory ammo should be on hand for comparison purposes before ANY duplexing takes place. I would NOT recommend any fast pistol/shotgun powders as an igniter, but rather a powder that ignites easily, but would be in the area such as the 4198 type powders, and of a bulky type. Maybe even IMR3031, but I've not used it.

I just checked and I did try WC860 in the 43 Spanish (Bertram cases) WLR primer Lyman 370gr slug. These were fired 8-99. The charge was 75.5 grs through an 18" drop tube. Rifle was a M1879 Argentine contract Rem RB with a 33" bbl. Stats were:

HIGH: 1627
LOW: 1589
SD: 14.7
ES: 37.2
AVRG: 1601

Fired at 50 yards, 4= 1" with the 5th about 3" away . Notes state, primers flat , factory radius not affected, no leading. There was some unburned powder present but not like in the 45-70. Actually the velocity was a bit higher then I suppose I'd like to see. Maybe I should try it again with like 65 grs and a GREX filler?

..............Buckshot

[kbstenberg]

I hope the OP doesn't mind a little thread drift on the subject.
You have throughn the kicker charge in the bottom of the case. How do you add the main charge so as not to push the kicker away from the primer hole?

[Buckshot]

............Simply drop the igniter charge and then dump the main charge on top of it. For the 45-70 or the .43 Spanish the igniter charge is sufficient to remain in place when the main charge is dropped.

...............Buckshot

You mentioned using a drop tube when throwing the main charge into the rifle case. Where could I go to learn more on the subject? So far I have never used compressed loads and would like to learn since I just got 8lbs of 872 and 860. Also how do you start to add the main charge of powder over the kicker so you don't move the kicker powder away from the flash hole?[/QUOTE]

You just add the igniter, booster, or Kicker' charge to the case. You simply dump it into the case. From there it's not so much that they're "Compressed" as you don't want them to mix, or intermingle with each other. They need to be such that they do not intermingle, or CAN'T intermingle. Assuming you're going to be carrying or transporting them, you don't want them to have the powders internix. If you have the igniter or base charge in the rear of the case, you want it to stay there and do what it's supposed to do, and that is to act as a supercharged primer. Nitrocellulose powders react to pressure. The higher the pressure, the more energetic they are.

As in ALL reloading at one end you have a 'Squib', where the slug doesn't make it out of the barrel, and at the other end you have a bomb. You do NOT want a bomb, but all cartridges from the factory, and all the ammo you reload is biased toward the BOMB end of things. The BOMB end is the most efficient end. A squib is the least efficient end.

You have a cartridge with a 'Starter" which is the primer and then a powder charge that is at the base and easily ignited. The ignited powder charge against the primer supplies the pressure required for the main charge to react against. In other words the main charge builds on the pressure started by the primer and the 'FASTER' powder to help the main charge to burn efficiently. That is why I recommend against a very energetic igniter charge. You want the igniter to make pressure, but not so much "ALL AT ONCE". You do not want a "Pressure Bubble". The igniter charge is supposed to supply pressure that the main charge can react to. All the igniter does is to easily ignite, and then build sufficient pressure that the main (and slower powder) can react to it, to propel the boolit efficiently through the barrel and on it's way to the target, whatever that might be.

If you peruse loading manuals for say the 30-'06 , you'll see loads like 28.0 grs of 4198. Then you will also see charges like 60.0 grs of some powder, and looking at the "Burn Rate Chart" it will be a very slow powder. The powders we are looking at for duplexing are MUCH slower then 4350, which is a maximum effort cannister powder in the 30-'06. There is no need to duplex 4350. It is ignited by a standard LRP. The powders we're looking at so far as duplexing is concerned, are those for use in the 50 BMG or 20mm cannon powder realm. The std LRP in the 30-'06 doesn't have the flame duration or temp to efficiently ignite and maintain the pressure required for efficient powder burn.

...............Buckshot

[Randy C]