My Trapdoor Loads, Technique and Equipment

[Don McDowell]

Well there's two things that Wolf sorta missed with his .096 flashhole when compared against the Berdan primer. The flasholes in a berdan primed case are seperated, so the flame actually hits the powder in 2 places, and the primers of that era were considerably weaker than the smokeless primers we have today, and that last bit is why so many folks find better accuracy from either large pistol primers , and or using an over primer or under powder wad, when deadnuts serious about accurate blackpowder loading.
The Springfield manual on the 1873 is a good read for trapdoor nuts as well.

[Larry Gibson]

Chill

I reread my post and see where the confusion is and it's all my fault. Why I put "Sharps" after the 2nd mention of "Remington- Hepburn" I have no idea. I have edited the original post to say "Remington Hepburn rifle" which it was. My apologies for the mistake and further confusion over what you were saying. Thanks for the catch and correcting me.

Larry Gibson

[Larry Gibson]

Larry I gotta tell ya....this is what I want to read. Love all the background info and the way you bring it to life with the wanderings. Please continue when time allows and keep writing it just the way you're doing. Now just to help you avoid anyone having a stroke about typos....paragraph 4 : I think you meant the 405HB mold was casting .464 perhaps and not .454 ? Paragraph 7 and 10 you made mention of shooting 8 inch bullets.....I think you meant 8 inch targets. See....I do read very closely and I'm not a nitpicker. Meanwhile I'm perched on the edge of this chair! Many thanks! Audie...the Oldfart...

Made all the correstions.....you guys are keeping me straight and it was sorely needed.....Kudo's......

Larry Gibson

[Larry Gibson]

DeadWoodDan

Don't hesitate to ask questions about the TD loads if you have any as this thread is where we want to learn, all of us.

Larry Gibson

[Larry Gibson]

Larry did you try the blackpowder loads without drilling out the flasholes and using a regular large rifle primer instead of the magnums? I've found the fouling to be a touch drier and harder with the magnum primers.
Interesting side note on duplexing, in it's beginnings it was totally opposite of what it is today. When they first duplexed it was using blackpowder to help the milder blackpowder primers ignite the smokeless powders , as the primers during the cross over time that were used in blackpowder were a good bit weaker than the primers used with smokeless. The blackpowder primers would not regularly ignite the smokeless at that time.
Thanks for enlightening the confusion of the mentioned in the first post, it was a head scratcher.

No I have tried the BP loads with regualr flash holes. I prepped a hundres WW cases as per Wolf's instructions and just went with those. Good point you bring up here on that. I will have to try them. My duplex loads are in cases with regular flash holes. My gallery loads are in both, I'll touch on that further on.

Larry Gibson

[Don McDowell]

Looking forward to reading your exploits Larry.

[oldfart1956]

C'mon Larry.....I'm having withdrawl symptoms! Anyways, still patiently waiting and I do have a host of questions but I want to read first. No sense me muckin' about and messing up a good read. And make sure to let us know (as you have already) the things that didn't work as well. I'm constantly changing/modifying/twaddeling about with this old gun and its ca'tridges. That being said it's still been very consistantly accurate and shockingly so for a 129yr. old gun despite my tampering. Audie....the Oldfart..

[Chill Wills]

Chill I reread my post and see where the confusion is and it's all my fault. Why I put "Sharps" after the 2nd mention of "Remington- Hepburn" I have no idea. I have edited the original post to say "Remington Hepburn rifle" which it was. My apologies for the mistake and further confusion over what you were saying. Thanks for the catch and correcting me. Larry Gibson

Hey Larry, Thanks for the reply and double thanks for adding this kind of in depth entry to the mix. If someone thought I was holding your feet to the fire, that was not my intent, I just like to understand. Keep 'em coming.
Michael Rix

[Barnacle Brad]

Larry, thanks for this thread first of all. I appreciate your work and words as well. I appreciate the work Spence has done and Pat continues through Wolf's Western Trader. Your fan base is increasing!

I have maybe a silly question. I am interested in bullet obturation. I know that Wolf's objective was to replicate the accuracy of the TD by loading to the Arsenal standard using BP, soft lead alloy and Arsenal spec bullets. The loads he developed were designed to shoot accurately through any TD. IMO, bullet obturation is the key.

Now, I have been told or read or imagined that BP is required to provide the pressure needed to upset the bullet base.The scope of Wolf's work has limited the discussion to BP, although he does tempt us with some smokeless loads. I am spoiled I guess, because I want to achieve consistency and accuracy with both BP and smokeless.

So as I sat contemplating this obturation thing it occurred to me that if you could inspect bullets having been fired with both types of powder, you could measure this and see the rifling on the bullet. The problem is once that bullet touches anything, your data is ruined. Then I wondered - and here is the question finally - have you fired into a water tank and recovered the bullets? Would the impact with the water ruin the data?

I am still in the process of working on the bp loads. I am pleased so far with what I have accomplished, but I want to be able to look forward to playing with smokeless also. Is there any hope?

[oldfart1956]

Larry I wasn't gonna ask any questions for a spell but I just noticed a problem and figgered I'd ask. Normally while at the range I clean between shot strings for each different loading. My procedure was always to run a Hoppes patch downbore then run a damp patch with a square of copper mesh over it to clear any possible leading. I am getting some minor leading for the first couple inches in front of the chamber....working on that. What I hadn't thought of was...where does the lead go? I have the gun upside down on the bags so figgered the lead would either stick to the copper mesh patch or fall free of the breech. Ummm...nope. While prepping some fired cases today found lead stuck to the mouth of several cases. Mind you it ain't from not flaring the case mouth. I'm real careful about that. I've apparently deposited a sum of lead in the chamber. GAARRRH! Next time I'll use a bore-snake and pull it from breech to muzzle....hindsight is 20/20. The problem now is clearing the chamber of this lead deposit. Can't get to it with a cleaning rod...rear of the breech prevents that. So I'm sittin' here looking at the flex-shaft on this Dremel tool and wonderin' how bad I could gammahooch up this chamber by fitting a cleaning brush on the end of the shaft and spinning it in there. Any ideas? Thanks...Audie...the befuddled Oldfart..

[Don McDowell]

The original composition of the 45 government bullets were 16-1, and used a lube made from bayberry wax and graphite.This like many other things have been lost in the translation from then to now, and noone for sure can tell you where things got distorted. Even as late as the 1950's Lyman/Ideal suggested #2 alloy as being fine for most blackpowder rounds, but try that today and watch the "experts" come unwound.

Oldfart, take your cleaning rod without a tip threaded on to it, run it down into the action of your rifle, then attach an over sized bronze brush that has a patched soaked in turpentine or kriol to the rod, pull it back until resistance is felt and then twist and pull it toward you, push it out take off the old patch and repeat until there's no grey shows up on your clean patches.

[Larry Gibson]

Barnacle Brad

Re obturation; yes in days of old it was thought that was the way to go, a hold over in thought from the ML rifles with bullets. Thus the 45-70 was developed with the 405 gr bullet and was expected to obturate to "take the rifling" as sealing the bore wasn't a serious consideration yet. Then it was found that a fully obturated bullet sealed the bore and left less fouling. It was found that the 405 gr bullet did not have the mass for effective sealing of the bore through obturation with the full service load let alone the carbine 45-55 loads. That led to the development and adoption of the M82 500 gr bullet. It has the mass to obturate under the 70 gr service load. It became renowned for it's much better accuracy that the 405 gr 45-70 load.

Note; let's remember the HB in the 405 and 500 gr service bullets is to control the weight while maintaining external dimentions. It is not there to aid in obturation ala mine' style HB bullets. The manuals refer to the HB as a "cavity" or "dish".

We have learned since that it is much better for accuracy with either kind of powder if the bullet "fits" the throat to begin with and does not have to depend on obturation to seal the bore. Spence rpelicated all there was about and that he could of the service 45-70 loads. They depended on obturation and his loads do also. That's why I took the tac I did to increase the accuracy. Sometimes depending on obturation (in our case using a bullet less than groove diameter) can give quite good results as with the original service loads and those developed to replicate such service loads by Spence. However, I think we can pretty much agree that having the bullet "fit" to begin with is the prefferred method for best accuracy.

While I've shot pistol bullets into water for inspection with success the faster the velocity the harder water gets and the more damage done to the bullet. I have recovered some of my 45-70 bullets that were fired into snow. They showed the bullets "took the rifling" quite well they were still not of groove diameter.

Larry Gibson

[Larry Gibson]

Don nails it; "Oldfart, take your cleaning rod without a tip threaded on to it, run it down into the action of your rifle, then attach an over sized bronze brush that has a patched soaked in turpentine or kriol to the rod, pull it back until resistance is felt and then twist and pull it toward you, push it out take off the old patch and repeat until there's no grey shows up on your clean patches. "

Only thing I would add is to use a conical rod guide on the rod at the muzzle to protect the crown.

Larry Gibson

[oldfart1956]

Thanks guys! Heading to Clearfield this weekend and I'll stop in at Bobs and pick up some larger bronze bore brushes. Mebbe a 50cal. and perhaps a .54 just to be sure. Another thought I had was...why didn't I just leave the last empty case in the gun while swabbing? That would have caught the lead....duhhhh. And I agree on using the bore protectors to avoid crown damage! Again, many thanks. Audie..the Oldfart..

[Don McDowell]

The lead just sticks to the cleaning patch and doesn't go anywhere anyway.

[Larry Gibson]

PART III:

I had several reasons for developing duplex 45-70 loads. Maintaining accuracy w/o cleaning between shots or every 10 shots or so was foremost as I didn’t want to carry a lot of cleaning equipment with me on “walk about” shoots where upwards of 50 shots would/could be taken. I also really detested the use of the blow tube between shots. Increasing the “power” of the loads was not a consideration at all. I wanted simply to lessen the fouling while maintaining original ballistics within the psi range safe for TDs and perhaps improving upon accuracy.

The smokeless powder charge against the primer aides in ignition alleviating the need for drilling the flash holes and other makes of cases with thicker walls can also be used. The smokeless charge, if sufficient, also “blows out” of the barrel most of the charcoal residue from the BP. This can be seen easily seen by looking from the breach end down the bore after several regular BP rounds have been fired. This residue (BP fouling) builds up and not only destroys accuracy but also can prevent the chambering of a bullet with a tight bore riding nose. The blow tube softens the residue in the leade allowing the bullet to be seated. However, after sufficient rounds fired w/o swabbing or cleaning and chambering, even with the use of the blow tube, will be difficult. [Note; this is why a true M1873 bullet is not a bore rider and the M1882 bullet’s nose is smaller than the bore in diameter sp both will still chamber even after many rounds have been fired] With an efficient smokeless ignition charge there is little charcoal fouling left in the leade and bore so the use of a blow tube to “keep it soft” is no longer needed.

Additionally with most of the charcoal residue blown out I have found accuracy of a 405 gr bullet that fits the groove diameter and not depending on obturation to fit the bore will not quite but almost as accurate to 800 yards as the M1882 500 gr bullet.

In developing my own duplex loads I followed Spence’s advice and use IMR 4759 (SR4759) as the smokeless powder in my duplex loads. I had picked up a hundred once fired R-P nickeled cases to use as they would, if useable, allow a quick identification of the duplex load vs a smokeless of straight BP load. Those cases would chamber in my TD so they were close to “fire formed”. I cleaned and NS’d them. I used standard WLP primers and did not drill the flash holes. Actually nothing other than cleaning and inspecting was done to the cases. I started off using 5 shot test strings with 4 gr of 4759 against the primer and (using Spence’s bulk formula of 1 gr 4759 = 2.8 gr FFG) reduced the amount of GC (GOEX Cartridge) by 11gr to 59 gr. Care bust be taken that the seated bullet still compresses the total powder charge. I have not found the compression die to be needed with the 500 gr bullet and probably is not needed with the 405 gr bullet But I use it anyway. I compress the powder so the bullet, at a cartridge AOL of 2.55” for the Lee 405HB, just sets on top of the powder. I use the taper crimp die to just put a slight taper crimp on the case mouth. Additional test loads to, increasing the 4759 1 gr per test while decreasing the GC approximately 2.8 gr per test, 7 gr 4759 and 50 gr GC were loaded.

Shooting the 5 shots in each test load and inspecting the bore showed that 7 gr of 4759 did indeed “blow out” most all of the charcoal (black streaks) residue and fouling. The barrel was cleaned between test strings. I also found that accuracy steadily increased as the 4759 was increased. Velocity was lower than the 1340 - 1350 fps I was looking for to duplicate M1873 service ballistics. I then kept the smokeless load at 7 gr and began increasing the GC in 1 gr increments. I found that with 7 gr 4759 under 52 gr GC in the fire formed R_P nickeled cases with the 16-1 Lee 405HB the velocity was right at 1340 - 1350 fps, just where it should be to match original ballistics out of the 32 ½” original TD rifle barrel. I have subsequently pressure tested that load (Oehler M43) and found the psi to be 20,300 psi(M43), well within the psi MAP of 28,000 for the TD. The ten shot psi test had an SD of 10 fps and an ES of 30 fps.

That has been my standard M1873 BP duplex load for use in my H&R Officer’s Model. I have a M1879 “R” Type III (3rd form) rear sight on it and a Beech front sight along with the factory tang sight. With the rear sight set at 100 yards and using the blade of the Beech front sight the POI is just above POA at 100 yards. I generally can hold 10 shots into 2 – 3 moa with the M1879 rear sight (I do better with the tang sight of course). The range regulations have proven quite correct to 1000 yards.

I next wanted a 45-55 carbine load with the 405HB at 1150 fps out of my H&R LBH Carbine. I took the tang off the LBH (why it was put there is beyond me!) and installed a “C” M1879 Type IV (4th form) rear sight with a blade front sight. I dropped the 4759 charge back to 5 gr (thinking it shouldn’t take as much smokeless to blow the BP residue/fouling out of the shorter 22” carbine barrel proved correct) and loaded 42 gr GC over it. Care must really be used to make sure the bullet does slightly compress the powder. The 405HB had to be seated under 2.55” OAL for some slight compression just as the original 45-55 w/o a wad in it. I left the 4759 charge at 5 gr and increased the GC until 49 gr gave 1138 fps at 15’ with an SD of 6 and an ES of 18. These were loaded with the 405HB cast of 16-1 and sized .4615 and lubed with my beeswax/olive oil lube. I have since switched to the 457124 Lyman cast of the same alloy. It gives almost identical ballistics and is easily identifiable as the 45-55 load by the different bullet.

These duplex loads have met my every expectation. They are accurate, I do not use a blow tube any longer and I can literally shoot all day w/o losing accuracy from hardened or excessive BP fouling. During a test one time there was 80+ rounds fired from the H&R OM and 100+ from the H&R Carbine in one day w/o cleaning, blowing or anything else. At the end of the test I fired a 5 shot group from each at 100 yards and found they both still were as accurate as if clean. Speaking of cleaning; it is also so much easier w/o all the BP charcoal residue.

Ok, so what about my original TD target rifle? Well, that was super easy; I used the same load as for the M1873 405HB bullet and simply substituted the M1882 500 gr bullet cast of 16-1 form the Rapine 460500 mould. Those bullets drop exactly at 500 gr BTW and were sized at .4615 and also lubed with my beeswax/olive oil lube. This time I used standard R-P cases that were fire formed and NK sized. Primers were again WLRs (Other standard and magnum primers have been tested with little or discernable use with these duplex loads). The .4585 expander was used. Both the charges (4759 and 52 gr GC) were thrown with a Lyman 55 and no drop tube used). The compression die was used. Seating was adjusted so the front 1/3 of the driving band was engraved by the leade when the breach block was shut. The taper crimp die is used to just straighten out the case mouth bell. I fired 2 foulers and then 10 shots for record at 200 yards. The group was 2.9”, the velocity was 1200 fps with an SD of 4 and an ES of 14 fps. What could I say except ….sweet!

Next I’ll discuss some straight smokeless powder loads………to be continued…….

Larry Gibson

[oldfart1956]

Awesome Larry! Really enjoying the step by step approach and delighted to see the pressure readings included with the velocities. I probably worry too much about the pressure in this old gun but figger by the time I notice a problem I'd be launching parts like Elmer did. Audie....the Oldfart..

[Larry Gibson]

Been having real problems with my internet connectivity here (using old one from up north and nearest tower is way south in Parker). I posted Part IV but looks like it didn't make it and like an idot I didn't save it. Redoing it now and am about half done.......sorry for the delay. Part V is also done (and saved!) and will be posted with Part IV.

Larry Gibson

[Barnacle Brad]

Larry,
I am so glad to see you posting this material at this time! Your timing is impeccable!

I am getting ready to make up a batch of lead alloy. If I have not slugged my barrel am I better of to use a 20:1 or 16:1 alloy? This is for my 84 TD Rifle. I will be casting 459-405-HB (lee) and 459-500-3R.

Thanks in advance for you help. If the others are like me, there is no way to thank you enough...

Brad

[Larry Gibson]

Larry,
I am so glad to see you posting this material at this time! Your timing is impeccable!

I am getting ready to make up a batch of lead alloy. If I have not slugged my barrel am I better of to use a 20:1 or 16:1 alloy? This is for my 84 TD Rifle. I will be casting 459-405-HB (lee) and 459-500-3R.

Thanks in advance for you help. If the others are like me, there is no way to thank you enough...

Brad

If you're going to size .459 as per Wolf and depend on obturation/bumping up then use the 20/1 alloy.

However, if you're bullets are at or above groove diameter then go with the 16/1 alloy. That's if you are pushing upwords of service cartridge velocity; 1200 - 1350+ fps. If loading under 1200 fps the 20/1 alloy will be fine.

Larry Gibson