.45-70 Duplex loads?

[hc18flyer]

I recently found 3.5 # of Goex 1 1/2 X black powder. I would like to try some duplex loads in our Browning high wall. I have both 4227 and 4759 powders. I have the Lee 405 grain pb mold, and could cast some in 20 to 1 or 25 to 1 alloy? I have been ready old posts on duplex loads and have the Lyman Cast bullet handbook. hc

[BLAHUT]

Try magnum primers first and see ????

[M-Tecs]

As a kicker I've only used 4759. It really helps with fouling control.

https://castboolits.gunloads.com/showthread.php?137201-Black-powder-duplex-loads

https://castboolits.gunloads.com/showthread.php?276757-Need-SR4759-replacement-for-45-70-duplex-loads

https://forum.castbulletassoc.org/thread/duplex-45-70-loads/

[Nobade]

I'd use the 4759. That bullet doesn't carry much lube so you'll pretty much need to duplex to get it to work with BP. Don't go above 10% with the smokeless and use minimal compression unlike straight black loads.

[indian joe]

I tried both and came up best with the 4227 (by a decent margin of accuracy) 7 grains ----4227 is very close to equal density to black powder where 4759 is much more bulky (my 4759 was really old so maybe that made a difference but I would not go past 4227 for duplex - also using it in a 38/40 model 92)
Rifle is Chiappa 1886
Over the chrono I got single digit Extreme Spread with this load

[freakonaleash]

I have used 4227, 5744, and 4759. Always less than 10%. Usually between 4 to 7grs depending on the cartridge.

[NSB]

I respect those that like to shoot black powder and be traditional. That being said, if you’re going to add smokeless into the mix, why not just use smokeless and skip the black?

[hc18flyer]

I respect those that like to shoot black powder and be traditional. That being said, if you’re going to add smokeless into the mix, why not just use smokeless and skip the black?

Because I like blackpowder and I have 3.5 # of 1 1/2 F. Does me no good on the shelf? I have read that a duplex load can help clean up some of the fouling? Should be fun shooting and use some of it up. hc18flyer

PS- It will be fun to watch my Grandson and nephew's reaction when they fire one for the first time!

[ascast]

What Nobade and Indian joe said. Start low and increase unt fouling is gone, or 10%. I have shot a little over 10% to get clean n a trapdoor with no ill effect. Not sure why 10% s considered the top end. have fun.

[Gray Fox]

In other words, what your saying is for a load of 65 grains of BP, use up to 6.5 grains of the smokeless and deduct that amount from the BP charge, is that the correct relationship? GF

[Chill Wills]

What Nobade and Indian joe said. Start low and increase unt fouling is gone, or 10%. I have shot a little over 10% to get clean n a trapdoor with no ill effect. Not sure why 10% s considered the top end. have fun.

The American NRA - in their rules of competition for BPTR state 10% maximum. Not as a safety issue but as a ceiling, so you do not bring a smokeless load to a BP match. In Canada, their ruling body allows 20% for the same reasons. The older Lyman cast bullet handbook lists Duplex loads for the 45-70 Govt.

[Gray Fox]

OK, here's a question that may draw some flack, can Pyrodex be duplex loaded? I ask because I was gifted a 12# case of Pyrodex cartridge grade that was sitting in a powder bunker under controlled conditions. GF

[steveu]

I have used both 4759 and 4227 in my Trapdoor and my 50-90, both worked well.

[indian joe]

In other words, what your saying is for a load of 65 grains of BP, use up to 6.5 grains of the smokeless and deduct that amount from the BP charge, is that the correct relationship? GF

That works for me --10% is adequate to clean up the BP charge ---more ? would be for a different reason (cheating in a competition maybe????)
I make my BP (2bucks /pound)and buy the smokeless so no incentive for using extra.
With a 10% duplex load behind a 335 grain boolit I get a whisker over 1500 FPS velocity
I like it for the '86

[Castaway]

BLAHUT, I don’t understand your post. He asked about duplex loads and you asked a question about magnum primers. Are you suggesting to use magnum primers with duplex loads? If so, why the question? Please clarify

[indian joe]

I'd use the 4759. That bullet doesn't carry much lube so you'll pretty much need to duplex to get it to work with BP. Don't go above 10% with the smokeless and use minimal compression unlike straight black loads.

I've not changed my compression at all with the 4227 but it does kinda make sense for 4759 seeing that stuff is a tubular (hollow) grain structure

[Larry Gibson]

If wanting to maintain the same pressure and velocity levels with duplex loads you must reduce the amount of BP an appropriate amount to compensate for the pressure/velocity of the smokeless powder. For my replicant m1873 45-70 Government loads I use(d) 7 gr of 4759 under 54 gr of GOEX Cartridge. That maintain the same psi (measured) and velocity as a standard 70 gr load of just GOEX Cartridge. It also blew out most all the fouling out of my long original TD rifle letting me shoot 100+ cartridges w/o wiping, blowing or cleaning. Accuracy remained excellent from the first to the last rounds fired.

[hc18flyer]

Thanks to all for their replies! I understand I need to reduce the black powder charge. It will be my first experience with bp cartridge, so I have some homework to do. And I will have to get lube and vegetable wads(for lack of a better term). Thanks, hc18flyer

[freakonaleash]

If this is your first experience with BPCR I'd recommend you stick with straight black powder.

[Froogal]

OK, here's a question that may draw some flack, can Pyrodex be duplex loaded? I ask because I was gifted a 12# case of Pyrodex cartridge grade that was sitting in a powder bunker under controlled conditions. GF

I recently loaded about 100 .45 Colt cartridges using .3cc of 4227 and 1.9cc of Pyrodex (3F). 200 grain RNFP. Shot 50 of those yesterday through a Cimarron SAA with 4 3/4" barrel. Recoil was a bit more than anticipated but otherwise worked very well. Accuracy was as good as I am.

[BLAHUT]

BLAHUT, I don’t understand your post. He asked about duplex loads and you asked a question about magnum primers. Are you suggesting to use magnum primers with duplex loads? If so, why the question? Please clarify

No duplex loads just a magnum primer in place of duplex load ?

[barnetmill]

No duplex loads just a magnum primer in place of duplex load ?

So just changing the primer to magnum makes the fouling go away?
It is my understanding the original mercury fulminate priming had different detonation characteristics from what is used today. So maybe a change in priming makes a different.

[M-Tecs]

So just changing the primer to magnum makes the fouling go away?
It is my understanding the original mercury fulminate priming had different detonation characteristics from what is used today. So maybe a change in priming makes a different.

Magnum primers tend to make the fouling harder and drier. Mild primers tend to produce the easiest fouling to deal with. It's common for the serious competitors to use paper shims and pistol primers to reduce fouling and get better SD's.

The only thing I have ever found that significantly reduces fouling is a smokeless kicker charge.

[indian joe]

If wanting to maintain the same pressure and velocity levels with duplex loads you must reduce the amount of BP an appropriate amount to compensate for the pressure/velocity of the smokeless powder. For my replicant m1873 45-70 Government loads I use(d) 7 gr of 4759 under 54 gr of GOEX Cartridge. That maintain the same psi (measured) and velocity as a standard 70 gr load of just GOEX Cartridge. It also blew out most all the fouling out of my long original TD rifle letting me shoot 100+ cartridges w/o wiping, blowing or cleaning. Accuracy remained excellent from the first to the last rounds fired.

makes sense to me - I have not handled 4759 for ages but guessing because of its extra bulk you would likely lose three or four grains total capacity - that brings us to 65 gr - reduce the compression some so we dont crush the smokeless grains - yep it makes sense

couple of points I am curious about with duplex loading
1) I assumed that substituting some smokeless for black would get us a velocity increase - I believe somewhere 50 - 80FPS in my 45/70 where we lose 7 grains of black in favour of 7 grains of 4227 ----however I have not done the side by side test to confirm this

following on from that I also assumed an increase in operating pressure

2) somebody hereabouts (think it might have been "savvy jack " aka Brian Austin) posted some pressure test numbers showing for 44/40 ( I think) a decrease in pressure with duplex along with an increase of velocity ---has anybody seen this????

with the potential pressure increase in mind I have only ran duplex in my '92 and '86 actions -- I have a brass ('66) gun I would not do it in and also a Uberti 76 that only ever gets straight black

[Milky Duck]

STOP...... you dont replace 7grns of BP with 7grns of smokeless...... you replace your 7grns of BP ,being 1/10th of the total charge weight with 1/10th or less of a smokeless powder charge or you will be increasing the power of the load..well thats the way I understand it to work anyway. Ive done it and it appears to be a LOT cleaner afterwards.

[indian joe]

STOP...... you dont replace 7grns of BP with 7grns of smokeless...... you replace your 7grns of BP ,being 1/10th of the total charge weight with 1/10th or less of a smokeless powder charge or you will be increasing the power of the load..well thats the way I understand it to work anyway. Ive done it and it appears to be a LOT cleaner afterwards.

where did we get lost here ????

1) we talkin about 45/70 charges ----yes?
2) 70grains of black is full charge------? tis at my place so yes?
3) put 7 grains of 4227 in first
4) add 63 grains of blackpowder
5) dont shake ---dont stir ---dont even knock a case over and retrieve it --- just quietly add your overpowder wad and compress to the required depth
6) add a boolit and finish the assembly

so we lose 7 grains of blackpowder from the load and replace it with 7 grains of 4227

this grain for grain works because the bulk density of 4227 is near as dang it to the density of blackpowder

would require some small adjustment for SR4759 as it is a hollow tube grain structure specifically to increase its volume (lower density)

everything I have read on this says use a medium burn rate smokeless (4227 -- SR4759) UP TO a maximum of 10% of the blackpowder charge weight and reduce the blackpowder charge accordingly ---never seen anything that says use ten percent of a normal smokeless charge then top up with black (that might work ok, but would be a lesser smokeless charge)

Stay away from fast burning pistol powders (red dot and co) for this excercise !!!!!!

I think we are kind of chasing each other around the berry bush here :bigsmyl2:

ps yes if you use the full 10%smokeless - proly increases velocity some
Pressure too we would think but I did see some numbers posted that said the opposite ----dont know where that was and it dont matter enough for me to dig it out

[Chill Wills]

2) somebody hereabouts (think it might have been "savvy jack " aka Brian Austin) posted some pressure test numbers showing for 44/40 ( I think) a decrease in pressure with duplex along with an increase of velocity ---has anybody seen this????


One of the older Lyman loading manuals has pressure tested load data for duplex and if I remember right, it shows a very favorable example of this for the 45-70 Govt. I am curious now too and I will try to dig out the old Lyman loading book later today. Duplex may not mean higher pressure automatically. I haven't assembled any duplex loads an many years so I can't remember.

[Chill Wills]

Lee Shaver, the gunsmith did a test that was published, maybe 20years ago, where he made three groups of Duplex loads. 1-smokeless on the bottom of the powder column. 2-smokeless added on the top of the powder column. And 3- the two powders, smokeless and the BP were mixed together before being placed in the case. The outcome? He found no difference in velocity or performance. I think that was an old Singleshot Exchange write-up. Take it for what it is worth....

[Larry Gibson]

I don't use a duplex load to increase velocity or performance. I use the duplex load simply because it shoots "clean" by greatly reducing the amount of BP residue left in the bore. I have had 100+ rounds shot through my TDs in a day without needing any sort of wiping, cleaning or blowing to maintain accuracy throughout the shooting.

I have chronographed and pressure tested [Oehler M43] my TD duplex 45-70 load [405 HB, 7 gr 4759, 54 gr GOEX Cartridge] and a standard 45-70 load [405 HB over 70 gr GOEX cartridge] in a 24" barrel test rifle. Also tested some original REM-UMC cartridges [no year on the headstamp] which had a 405 swaged bullet over 70 gr of what appeared to be 3 fg sized BP.

The last test I ran was in 2019.

The duplex load ran 1285 fps at 20,400 psi.
The standard service 45-70 load ran 1244 fps at 19,100 psi.
The REM-UMC ran 1233 fps at 22,000 psi.

[Milky Duck]

where did we get lost here ????

1) we talkin about 45/70 charges ----yes?
2) 70grains of black is full charge------? tis at my place so yes?
3) put 7 grains of 4227 in first
4) add 63 grains of blackpowder
5) dont shake ---dont stir ---dont even knock a case over and retrieve it --- just quietly add your overpowder wad and compress to the required depth
6) add a boolit and finish the assembly

so we lose 7 grains of blackpowder from the load and replace it with 7 grains of 4227

this grain for grain works because the bulk density of 4227 is near as dang it to the density of blackpowder

would require some small adjustment for SR4759 as it is a hollow tube grain structure specifically to increase its volume (lower density)

everything I have read on this says use a medium burn rate smokeless (4227 -- SR4759) UP TO a maximum of 10% of the blackpowder charge weight and reduce the blackpowder charge accordingly ---never seen anything that says use ten percent of a normal smokeless charge then top up with black (that might work ok, but would be a lesser smokeless charge)

Stay away from fast burning pistol powders (red dot and co) for this excercise !!!!!!

I think we are kind of chasing each other around the berry bush here :bigsmyl2:

ps yes if you use the full 10%smokeless - proly increases velocity some
Pressure too we would think but I did see some numbers posted that said the opposite ----dont know where that was and it dont matter enough for me to dig it out

because 7grns of smokeless is **** ton more POWERFUL than 7gns of black
its like putting petrol in a diesel motor or vice versa.

I measure charges on a beam scale not by volume....

[deces]

Smokeless & Black in one case, this sounds fun. Following.

[M-Tecs]

Duplex loading has been around a very long time. It first started with different grades of BP followed by semi-smokeless under BP than later still true smokeless under BP. Ideal and others made duplex powder measures. Same for the big-name target gunsmiths back in the day. When done properly duplexing has very long and distinguished history.

https://www.pbase.com/halp/schuetzen_measures

https://www.reloadingtool.com/ideal-no-6-powder-measures

[barnetmill]

Duplex loading has been around a very long time. It first started with different grades of BP followed by semi-smokeless under BP than later still true smokeless under BP. Ideal and others made duplex powder measures. Same for the big-name target gunsmiths back in the day. When done properly duplexing has very long and distinguished history.

https://www.pbase.com/halp/schuetzen_measures

https://www.reloadingtool.com/ideal-no-6-powder-measures

Can duplexing powder charges be done in a flint or cap lock muzzle loader?

[M-Tecs]

Can duplexing powder charges be done in a flint or cap lock muzzle loader?

Some use BP under Blackhorn 209 in sidelocks. I have been planning to use BP/Blackhorn 209 in my ROA for a hunting load but I have not gotten around to any serious testing yet. On flinters and cap lock I would think flash hole location might be an issue.

https://castboolits.gunloads.com/showthread.php?177703-blackhorn-209-in-a-side-lock

[indian joe]

because 7grns of smokeless is **** ton more POWERFUL than 7gns of black
its like putting petrol in a diesel motor or vice versa.

If you read my earlier posts? - I did write --I use these loads in my 86 and 92 actions - have a brass (66) that I would not do it and also run my 1876 on straight black - in the 86 maybe gain 50 to 80FPS with a 335 grain boolit ---proly about what you would get by switching up from FFG to FFFg black

I measure charges on a beam scale not by volume....

Anytime I tell ya grains it is weight not guesstimate

[indian joe]

Can duplexing powder charges be done in a flint or cap lock muzzle loader?

why? get your patch lube right in a muzzle loader - only time you need to clean it is when you done shooting for the day, clean it, put it back in the safe

[deces]

Is there a general starting ratio of BP & smokeless to start off at?

[barnetmill]

why? get your patch lube right in a muzzle loader - only time you need to clean it is when you done shooting for the day, clean it, put it back in the safe

My old side caplock TC rifle was used when purchased about 35 years ago and is meant to use long cylindrical 54 cal slugs. Does not shoot patched round balls accurately. I am guessing because of the twist.
I was asking because I was interested to see what the answers might be.

Actually right now I have no black powder and have found no percussion caps locally.

[missionary5155]

For fouling issues we use the next faster BP. Such as going to 3F where 2F was not burning clean enough.
If desiring to stay at the same 2F velocity Less 3F will be needed.
All we have ever used is Goex. Good to read it is getting back up in the supply line.

[freakonaleash]

Can duplexing powder charges be done in a flint or cap lock muzzle loader?

NO! You'll blow your fool head off.

[freakonaleash]

Is there a general starting ratio of BP & smokeless to start off at?

Yes. Read all of the above information , it's all there.

[freakonaleash]

Smokeless & Black in one case, this sounds fun. Following.

Has been done since 1900. Mostly in extremely competitive schuetzen matches. Done for fouling control, no other reason. Still done yet today.

[barnetmill]

NO! You'll blow your fool head off.

Can you offer examples or what have you actually seen? Why would my head be a fool head? Does asking a valid question make one a fool?
What pressures can a typical cap lock barrel contain prior to it letting go?

[indian joe]

My old side caplock TC rifle was used when purchased about 35 years ago and is meant to use long cylindrical 54 cal slugs. Does not shoot patched round balls accurately. I am guessing because of the twist.
I was asking because I was interested to see what the answers might be.

Actually right now I have no black powder and have found no percussion caps locally.

ahhhh ok got ya
I havent done it (would not) dont know anybody that has done, nor heard of it--if you decide to try it I suggest be careful - dont do the 10% thing

[marvelshooter]

I have wanted to try duplex loads for a while and after following this thread and reading what else I could find I gave it a go. I load a paper patched boolit over a lightly compressed load of 2F for a .38-55 rolling block. Yes I know 3F would be better but 2F is what I have. Anyway I loaded 4 grains of 2400 in first and then the 2F as usual. No reduction for the 2400. I assembled just 10 rounds mostly to check for excess pressure and experienced none. There didn't seem to be a lot of fouling but it was only 10 shots. I will be experimenting further.

[M-Tecs]

Can you offer examples or what have you actually seen? Why would my head be a fool head? Does asking a valid question make one a fool?
What pressures can a typical cap lock barrel contain prior to it letting go?

The primary issue with both flinters and caplocks is that the ignition system is not up to the higher pressures of some of the smokeless powders. Second is the materials used in barrel construction tend to have significantly less hoop strength than steels used in most smokeless guns.

In the early days of semi-smokeless and smokeless they sold "bulk" powder to be used as a one-to-one volume black powder replacement.

Blackhorn 209 is claimed to be a smokeless powder with a little smoke added.

[barnetmill]

ahhhh ok got ya
I havent done it (would not) dont know anybody that has done, nor heard of it--if you decide to try it I suggest be careful - dont do the 10% thing

I have seen it done a few years ago by Iraqveteran8888. They kept going with straight smokeless powder loads until they blew it up, but those loads that caused failure would have likely blown up a modern cartridge gun if one could have gotten that amount of powder into the gun. They did not use a pressure transducer. I have no idea at what pressure the barrel will fail at for modern steels and that question of also for the older BP cartridge guns.
They kept warning not to use smokeless and duh eventually the gun blew up.
Just for my own information I will look up that old youtube to see what charge made that side cap lock gun fail.

[barnetmill]

The primary issue with both flinters and caplocks is that the ignition system is not up to the higher pressures of some of the smokeless powders. Second is the materials used in barrel construction tend to have significantly less hoop strength than steels used in most smokeless guns.

In the early days of semi-smokeless and smokeless they sold "bulk" powder to be used as a one-to-one volume black powder replacement.

Blackhorn 209 is claimed to be a smokeless powder with a little smoke added.

Are the steels used today for muzzleloading guns inferior to what is used in modern cartridge guns. I have not been able find any specs for this and for modern barrels I have no idea what hoop strength might be. Both flinters and caplocks have a hole going to the outside and I can see safety problems. But are duplex loads used of 10% or less of smokeless/black powder so high pressure that the lock or barrel will fail?
Look someone puts in an 80 grain load by bulk of 2400 in a 54 cal cap lock gun and it is likely coming apart, but so would your magnum Weatherby. Basically I will not be trying such by myself, but would like to see someone investigate it.

[indian joe]

Are the steels used today for muzzleloading guns inferior to what is used in modern cartridge guns. I have not been able find any specs for this and for modern barrels I have no idea what hoop strength might be. Both flinters and caplocks have a hole going to the outside and I can see safety problems. But are duplex loads used of 10% or less of smokeless/black powder so high pressure that the lock or barrel will fail?
Look someone puts in an 80 grain load by bulk of 2400 in a 54 cal cap lock gun and it is likely coming apart, but so would your magnum Weatherby. Basically I will not be trying such by myself, but would like to see someone investigate it.

my previous posts should tell that I am not a "fraidy cat" or negative to duplex loading in its appropriate place
however I reckon there are a swag of more practical, more effective, much safer, ways to handle a fouling problem in muzzleloaders than fooling around with duplex smokeless/blackpowder loads.................round ball guns are the easiest ...I have a target on my wall shot at the Canberra range years ago 100yards, sitting position with a CVA flinter, 42" barrel, the first five in a group 2"x2" ..the second five in a ragged conjoined hole that went a tad under 1"x1" ....I could see those days and I was shooting pretty good and (often) - the load was so simple 70 grains of Goex 5FA - 490 ball - damp moosemilk ticking patch. just load em and shoot em no foolin about.
for the long boolit still plenty options, decent lube , card wad on the powder + damp felt wad, none of em any more complicated than loading two different powders .............................

[M-Tecs]

Are the steels used today for muzzleloading guns inferior to what is used in modern cartridge guns. I have not been able find any specs for this and for modern barrels I have no idea what hoop strength might be. Both flinters and caplocks have a hole going to the outside and I can see safety problems. But are duplex loads used of 10% or less of smokeless/black powder so high pressure that the lock or barrel will fail?
Look someone puts in an 80 grain load by bulk of 2400 in a 54 cal cap lock gun and it is likely coming apart, but so would your magnum Weatherby. Basically I will not be trying such by myself, but would like to see someone investigate it.

Most modern cartridge gun barrels today are 4130, 4140, 4150 or 4340 chrome molybdenum alloy ordinance grade steel if blued. Most of the SS barrels are 416 or 416-R ordinance grade stainless steel. Lothar Walther made the barrels for Black Star. Claim was it was a different alloy but I never could find out what it was.

At one time the majority of modern muzzle loading barrel producers use 12L14. Not sure if that is still true today. I do know 1137MOD steel is popular today.

12L14 is a leaded free machining steel that does NOT provided very high hoop stress strength. Hoop strength is the measure of a pressure vessel to withstand the internal pressures. This first came to be a big deal when steam engines switched for low pressure to high pressure designs.

One other issue with using non-ordinance grade steel for barrels is slag inclusions and or sulfur content.

Unless specifically designed for smokeless it generally is not a good idea to use smokeless in a muzzleloader. There are SOME smokeless powders that have a pressure curve similar to BP and they have successfully been used in BP muzzleloaders. That was far more common in the 60's and 70's pre-Pyrodex.

The issue is smokeless powders in muzzleloaders tend to not be very tolerant of mistakes like leaving a ramrod in the bore or a double charge.

BP as an ignition aid under Blackhorn 209 works well and appears to be safe.

[barnetmill]

Most modern cartridge gun barrels today are 4130, 4140, 4150 or 4340 chrome molybdenum alloy ordinance grade steel if blued. Most of the SS barrels are 416 or 416-R ordinance grade stainless steel. Lothar Walther made the barrels for Black Star. Claim was it was a different alloy but I never could find out what it was.

At one time the majority of modern muzzle loading barrel producers use 12L14. Not sure if that is still true today. I do know 1137MOD steel is popular today.

12L14 is a leaded free machining steel that does NOT provided very high hoop stress strength. Hoop strength is the measure of a pressure vessel to withstand the internal pressures. This first came to be a big deal when steam engines switched for low pressure to high pressure designs.

One other issue with using non-ordinance grade steel for barrels is slag inclusions and or sulfur content.

Unless specifically designed for smokeless it generally is not a good idea to use smokeless in a muzzleloader. There are SOME smokeless powders that have a pressure curve similar to BP and they have successfully been used in BP muzzleloaders. That was far more common in the 60's and 70's pre-Pyrodex.

The issue is smokeless powders tend to not be very tolerant of mistakes like leaving a ramrod in the bore or a double charge.

BP as an ignition aid under Blackhorn 209 works well and appears to be safe.

Very good answer backed with some specific data.

Black powder is an interesting mixture. One can load a gun to the muzzle with black powder and a ball and the barrel would not explode. I have not seen anyone try that with any kind of smokeless powder yet.

[freakonaleash]

If you load a muzzleloader clear to the muzzle with black powder it will blow . The weight of the powder it self would be the culprit. Muzzle loading barrels are made from 12L14. Soft stuff that was never intended for firearms, but it works fine for the low pressures rational loads of lack powder creates. 1130 is used by green mountain for their muzzle loading barrels. Kibler uses green mountain blanks. Hoyt, Burton and Rice use 12L14. Getz did too. Ed Rayle uses some sort of modern barrel steel that is so hard it's difficult to file.

[freakonaleash]

Can you offer examples or what have you actually seen? Why would my head be a fool head? Does asking a valid question make one a fool?
What pressures can a typical cap lock barrel contain prior to it letting go?
I suggest you do it and report back.

[barnetmill]

I suggest you do it and report back.

Your suggestion is not offered in a friendly way and to be courteous as we are supposed to be here I will offer no counter suggestions. The point is there are all sorts of urban legends and half truths on the net and I am just trying to get find out the truth. You made a statement and I asked for evidence. You could of answered honestly that you knew of none.
But many urban legends do have at least some truth associated with them. There are plenty of people that blow things up and video it. I have only seen one with a side lock muzzle loader and it seemed that within in reason that it was safe.
As they say, do not do this at home.

The h 209 powder seems interesting.

[Ajohns]

This maybe a dumb question, but I'll throw it out since this a duplex thread.
Could one use a few grains of 4227 over black in the loading of a Burnside catridge? Or a Maynard?
Both use an enclosed case, but a flash hole in the rear.

Just curious if anyone has, or if it would benefit less fouling.

[Larry Gibson]

The main idea for the duplex cartridge is for the small smokeless charge to blow the charcoal residue out of the barrel. When developing the load, you can actually see [by looking in the bore from the breach end] how much of the charcoal residue has been blown out. Refer you to Spence Wolf's book on replicating 45-70 M1873 loads for the "how to".

[indian joe]

If you load a muzzleloader clear to the muzzle with black powder it will blow . The weight of the powder it self would be the culprit. Muzzle loading barrels are made from 12L14. Soft stuff that was never intended for firearms, but it works fine for the low pressures rational loads of lack powder creates. 1130 is used by green mountain for their muzzle loading barrels. Kibler uses green mountain blanks. Hoyt, Burton and Rice use 12L14. Getz did too. Ed Rayle uses some sort of modern barrel steel that is so hard it's difficult to file.

not arguing yes or nohere but offer a story
I have three post hole guns different lengths designed for blasting grade blackpowder (about quarter inch gravel size grains) the powder chamber in the longest one is about 15 - 18 inches x 1 inch (it is a glutton for powder!!!!!) there is a nipple at the top end of the powder chamber and most of a foot of solid shaft above the nipple - these are designed to be filled to the end with powder - you cap it with a half handful of dirt to stop the charge from falling out then proceed to whale on it with a 12 pound sledgehammer till its right down in the ground where you want the hole - driving one of these into hard ground can take a while - I normally use the shortest gun but this particular day it was broken (stress fractured from all the hammering) only had one hole to make so took out the big long gun, but being cheap and almost out of blasting powder I elected to half fill the chamber then fill the remainder of the charge chamber with dirt (BIG mistake) then belted it down into an old roadway near the shed. I had used this dirt cannon plenty of times but this day with the half charge and plenty of constriction to hold it in that thing blew the nipple clean out of the metal body just shredded fibres of steel where it used to be - the nipple was airborne long enough for me to figure something wasnt right, walk over to the site puzzle a little then clunk!, tinkle tinkle plop - it landed on the shed roof, rolled off and landed where I had been standing --- have no idea of the pressure involved but an engineer bloke I showed it too guessed in excess of 100.000psi.
All that to say I would feel safer (I think there would be less pressure) with the barrel full of powder and the ball at the end compared to a half full barrel -----whatever ----not about to make a utube video to investigate the theory

[freakonaleash]

Friendly way? If you won't listen to me you're free to do what ever you like. I personally don't care and assume no responsibility for your actions. You're a big boy, go against My recommendations if you think you know more about it than I do. How can I be more courteous than telling you to do what ever you think is right.