Does powder placement affect velocity? We test three loads two with mixed powders and one with the black powder loaded first, followed by the smokeless powder.
Sorry folks, I neglected to mention that there was no noticeable difference in fouling between all of these loads. They all burned exceptionally clean.
Your latest duplex 303 is very interesting, great job!! You neglected to say how clean the upside down load was. This is my only thing that is of interest for myself other than the consistency. Thanks Willard. Another great video. Ted
Ya.. do note the primer results, perhaps this will do better with lighter bullets (150 grn.) [paper patched in 30-40 Kraig out of a Winchester 1894 Carbine (note that .303 Brit can be resized to 30 Government)]..
I have payed with duplex loads for years, A gunsmith by the name of Rocky Gibbs got me interested in. He used all kinds of techniques with a lot of different powders and other things, but they were al smokeless powder loads. He used a charge of rifle powder on top of a charge of pistol powder and vice versa. His explanation for the faster FPS of the pistol powder on top was that the rifle powder had moved the pistol powder down the barrel before it ignited and gave the projectile a powerful boot because it couldn't over come the pressure of the rifle powder and therefore the pistol powder exploded on top of the rifle charge and boosted the pressure rapidly near the end of the barrel. I tried many of his loads and one thing I will say, the crack of the rifle is way different.
The reverse duplex load is the way I would load it. It made no sense to me to put the faster burning powder in first. Just something I sensed rather than having empirical data to explain. It is in my mind that the pressures are maintained further down the barrel and therefore higher speeds are out of the barrel.
Like an artillery shells powder train - a line of blackpowder ignites the main NC-powder charge in a flash. Pressure spike and flat primers go together as I would have predicted - nice. Once again, great on the video.
The upside down load for a bottle neck cartridge and its increase in velocity is very cool.... but given Jakes hypothesis on why this is evident for the 303 would suggest straight wall cases would not benefit from an upside down load and the increase in velocity. Sounds like more testing is required to prove the benefits are also realized in straight wall cases...
The best way I can explain why the "upside down" duplex load works better is that the final "kick" from the smokeless happens when the bullet has momentum at the end of barrel travel, rather than at the start when the projectile is at rest. Think of the previous duplex load as putting your foot to the floor on a gas pedal and then letting off. The upside sown is like rolling forward with 50% throttle then flooring it for a bit. My question is what if you put just enough smokeless on the bottom (just enough to cover the primer hole so that ignites first getting the black powder to temp to burn clean), blackpowder, then the remaining smokeless on top. I think this might even the momentum down the barrel and give even faster results.
Another outstanding video that didn't suck! That, and I just don't want to have to make my own damn video... Thank you for going where most of us have feared to tread. The mixing and upside down stacking have both been "off limits", for alleged "safety" reasons, for as long as I have been loading duplex loads. I never dared even try, for lack of any published results, advice, or any sort of encouragement. I'm not sure you realize just how relatively "ground breaking" your efforts are on this front. Very, very interesting results. I think the mixing of the powders was the most vehemently recommended against, with everyone convinced they were going to blow up their guns. To see your results, and just how inconsequential mixing the powders proved to be, pretty much puts all of that unsupported, untested "advice" to rest. Thanks for that. Surprising, too, are the results from doing it "backwards". That kinda forces us to rethink a lot of what we thought we "knew" about all of this. Ah, the vagaries of internal ballistics... So, I have to wonder (keeping in mind your theory regarding the placement just below the bottleneck), how a straight walled case would react to an "upside down" load? I do know that bottlenecks and straight black powder don't seem to get along very well, with what I have found to be significantly increased fouling in the throat area in cartridges like the .44-77 and .44-90. I actually gave up on both because of those fouling issues, following the lead of the Sharps rifle company when they phased them out in favor of straight walled cases. There has to be some weird dynamic with that bottleneck, as evidenced by that fouling (in straight black loads) and your discoveries regarding velocities. Once again, the vagaries of internal ballistics...
I wonder if people using duplex loads was less about performance and more about how cleanly it made the cartridge burn. Less fouling might mean more accuracy for long strings of fire. Also the early smokeless powders would me much less stable than what we have now. Things like cordite and Poudre B burned really hot and fast if i'm not mistaken. Something that would be interesting to try would be flash paper instead of smokeless powder. It is basically straight nitrocellulose. It might emulate the early smokeless powders better.
If the smokeless on top shoots well that seems to produce very nice results. Definitely a load to work up on though given the pressure signs. Really cool to see a load that can replicate the original velocities without compression shenanigans. Fascinating to see how position of each charge affects the outcome.
To me it seems like the art of finding the perfect powder load is about getting the projectile to slowly build velocity all the way to the end of the barrel by gradually increasing the pressure. If the powder is all exhausted significantly before the exit you can lose speed and accuracy and if the powder is not completely burned before exit you have significant muzzle flash and unburned powder fouling. This has to be balanced and limited by the amount of pressure the barrel and cartridge are capable of containing. I think these results are down to the black powder first arrangement allowing all the powder to burn by igniting the slower powder first and the faster powder second. You may be around the limits of what you can do with this in the 303 but it makes me wonder about something like 45/70 and other big slow black powder cartridges and adding a little topper dose of smokeless to boost their velocity. The reaction happens so fast inside the barrel that from our perception it's instantaneous but clearly the timing is more important than I would have assumed or the mixed loads would give the same type of results.
Your speculation about finding the perfect powder load isn't far off. It's why there are different burn rates of smokeless powder, so you can cater where that maximum pressure spike occurs to your particular barrel. Handgun powders burn fast so that they've generated all of their pressure in a stumpy barrel. Magnum rifle powders burn slow because there's a lot of powder and they want to make sure that it doesn't just spike the pressure and blow up the barrel. (The consequences of using too fast a powder in a large rifle cartridge are amply demonstrated by Kentucky Ballistics' infamous accident with a .50BMG rifle)
This makes sense🤔 from a combustion/deflagration view of the 2 propellants. The black powder will decompose faster than the smokeless, initially however, the carbon/sulfides generated could be flash-coating the smokeless powder and creating a delay, when the smokeless is on the bottom because the burning front follows the propellant and the "exhaust" is in the back before it's in the front. This also meant the smokeless on top was combusted, uncoated by residue from the black powder because it was defligrated by the flame front directly. I love your videos ❤ The experiments, within reason😂, are fascinating. It took me a bit to puzzle this one out but based on similar studies, this is a reasonable possibility. Mega cool That coffee grounds powder was no Espresso tho😂🤣😅👍🍉
Just a guess. Black powder works off of an explosion. Smokeless powder is a propellant. Meaning when it's burning it's the expanding gasses that propel the bullet. So with the smokeless on the bottom it's pushing the black powder out into an uncompressed state causing a loss of detonation. Like a fire cracker that's not been rolled up tightly. Very interesting results.
Great Result! Totally unexpected. Keep up the good work! I wonder what the result will be with a reverse duplex-BP load...coarse-slow-rifle-BP to start with fine-fast-pistol-BP on top? Maybe worth one more test with the 303? ;-)
A very interesting video indeed. I would not have guessed that the 'upside down' charging would have made that much difference. Try it in a pistol load to see what it does there.
I could tell right away the upside-down load was faster because of the sound. I think the reason it is faster is sort of like a reburner on a wood stove, burning the extra gases that would normally go out the barrel.
Larger ratio of black powder vs nitrocellulose for the reversed duplex loads would be interesting to see. As well as nitrocellulose with and without added nitroglycerine. Something burning around the speed of unique/2400/universal at 1/4ered loads so the pressure spike around the neck of the cartridge isn't too intense.
This also makes me curious if you could achieve any benefit from doping a smokeless powder load with a small base of black powder or is it limited to cartridges which were originally black powder?
If I am not incorrect black powder does not completely burn. If I assume correctly the black powder gave the basic oomph and the smokeless bund itself plus the residual black powder. and as I am typing this your explanation does sound most plausible . THANK YOU
Oh, it all makes sense, once I've seen the results! Obviously, I'd never guess it'd be like that beforehand... ;-) Anyway, it seems that smokeless being ignited late, once the pressure is already elevated by the burning black, that would make it burn faster. That'd create a higher pressure spike and flatten those primers. Reminder to myself: Don't *ever* mess with duplex loads!
I remember reading about experiments by the ODGs where they duplexed and triplexed powders, AND mixed them Seems there is an application for all of them IIRC, the duplex/triplex loads had fast nitro powder farthest away from the primer, so as to burn only once in the barrel this helped accelerate the bullet once it was already moving by the slower powders I wonder how the BE would act not mixed, but put in last also, I wonder about $$, using a cheap surplus 50BMG powder, melt it in acetone, dry it, and grind it fine. this would remove any deterrent coating, and make it much faster, add this on top of slow/black powder
You are using a SMLE. When the British use black powder in the Lee Medford or Enfield 303 rifles the had long barrels. Could that be the reason for higher volicidy?
I have a TC Black Mt Magnum with musket caps for ignition. I don't have any black power only Pirodex and Blackhorn 209. I was hoping to try a duplex load of Pirodex to Ingnite the Blackhorn 209 so I can get a cleaner burning. The gun is rated for a 150g charge so it can handle a pressure well if I play around with a 10g primer of Pirodex to get the Blackhorn to fire. IS this worth a try or should I give up on the idea of ever using Blackhorn in a sidelock.
@Everythingblackpowder Not sure where to ask this question. How do you sight with your Kibler rifles? I have seen other RU-vidrs grind the front sight until it was almost gone. I have just completed a SMR and will be building my Colonial rifle next.
I’ve heard a lot of people say they had to file their front sight down to a nub but I didn’t have that issue at all. I had to hit mine with 10 or 15 swipes with a file but that was all.
theory time black powder builds pressure in the chamber the 5744 bumps the pressure hard towards end of burn vs lil pressure bump at the start of burn with a slow build of pressure over the rest of the burn a 10% bump at the top end vs a 10% bump at nothing (10% arbitrary number for effect actually closer to 0.5% @ 15% smokeless)
Great video. Have you ever loaded/shot the 50-95? I have a load of IMR 4198, 35 grains and CCI 200 primer under a 450 gr Barnes FP. Having trouble finding components lately.
Would it be safe to try a duplex load in a muzzle loader or would pressures be too high? Wonder if you could get a super clean bore with a touch of smokeless and the toilet paper bp.
would love to know if this can be used in Cap and ball revolvers or in early black powder pistols like the S&W no.3 .44 Russian or the old webleys in .455 to cut down on BP fouling
I have a few questions for anyone knowledgeable in such, would it possible for a .38 special to be a good candidate for a duplex load since it has a higher pressure potential than 3f can possibly generated? Also would it be possible to load a .38 special with say 21.5gr. of 4f powder since it is so fast burning in a short barrel like a pistol? And if 4f is feasible would it then be good with a duplex loading? Perhaps 4f and 3f duplex loading to enhance the burning capabilities?
I could never get my duplexed loads to work reliably. I used IMR SR4759 and when the full charge would ignite I would get amazing velocity and super clean burns. However 1-10 wouldn’t fully ignite. My duplexed 45 Colt would get 1,800 fps out of a 24” barrel (when fully ignited). When I had a failure to ignite it would be 600fps and that’s practically a squib. Gave up after that.
Wow, that’s interesting! I haven’t had that problem with any duplex load I’ve experimented with but I’ve never used 4759. So far I’ve used R7, A5744, Bullseye and Red dot.
@@Everythingblackpowder It’s an older now discontinued powder that approximated BP pressure maximums at a smokeless pressure curve. I wish I could remember the charge sizes but it was 6 years ago and the video never got uploaded. Duplex loads still fascinate me though. Ever since I read about Roosevelts duplexed 45/75 for big game.
@@Everythingblackpowder Thanks man. I’m glad to see guys like yourself carrying the torch, and even better than I did! I have done a livestream with @MadrasArsenal and I think those may continue semi-regular. These days though, the majority of my time goes to my kids. God bless!
Looks like you have max’d out the 303 britt using the duplex “upside down”… mission accomplished?! Did you notice if all loads (mixed etc) were as clean? You metioned the extra pressure may have come from the bottleneck area in the round with the reversed duplx, will you be doing the same testing with the .45 colt? I just had to ask…another great video Jake! I learn in all your vids, thank you sir!!
IMO, Stacking the smokeless powder on top of the black powder means it's the last to ignite. We are talking nano seconds here but my hypothesis is still viable. I'm guessing here, but perhaps that higher pressure at the end of the ignition may account for the extra velocity. Mixing on the other hand, dilutes the smokeless powder and affects the pressure created.
Great video! Could you tell any difference in accuracy with the different loads? I have very limited experience with black powder let alone duplex loads so I am very curious. Phil
Very interesting . Now i want to see what something like that does in an old Marlin 30-30 . May leave that to the professionals and not try that myself , but still want to see that .
You should proceed to do so with caution and logic as your associates. You will find it interesting. Remember it is a smaller case than the .303 British. In other words, consider trying lighter bullets, but long enough to cycle through the action (the carrier). Lyman No. 2 for casting alloy. 115ish (32-20 WCF) sized down, or 125ish, up to 150 gr. (flat nosed). I like Lee Precision bullet sizing dies best. Want better expansion? Try a softer lead alloy and paper jacketing to protect the soft lead bullet from stripping rifling or leading. Reference this, THE PAPER JACKET, By Paul Matthews, Wolf Publishing Company. In addition, scrap any idea of modern petrochemical based smokeless powder bullet lube. It will create a big mess and nothing more. Go with bees wax mixed with natural animal lards & tallows. I am currently experimenting with gee (clarified butter) and bees wax. Gee is available in stores that sell real food (high quality). Crisco sucks… as do all of the other plant based oils/grease.
So, I have an H&R 1871 Buffalo Rifle in 45/70. I plan to load BP loads. However your experiment here has me thinking a duplex powder charge would possibly improve performance. What do you think?
Cant stop here with the .303 You still have to run some heavy cast bullet loads. Like a 215 or 220 grain. Straigt bp and duplex. Im thinking a 220 grainer should get 1600fps. And would make a super brush cartrige.
Hmmmm. I wonder about the practicality of the upside down load. Would the smokeless on top settle during shipping and handling? If so…how would that translate into performance? This experiment was more fun than a barrel of monkeys, IMO. Keep up the good work fellas.
Hey, just wanted you to know that I am sorry, I accidentally kinda copied your name not knowing it was already taken, my name is very similar to yours. Sorry again.
The way I understand it smokeless powder burns faster as the pressure rises. The black powder gives your initial spike in pressure, then the smokeless powder ignites and stretches your pressure spike out further after your pressure is already up.
You and several others have an answer that makes the most sense. Smokeless on the bottom has to make its own pressure but if on top, it gets to ride the wave of pressure from the bp charge.
I used to have a few older reloading books from the late 60s and the early 70s that listed some black powder duplex loads, and the whole purpose wasn't to get more velocity but to get cleaner shots. Some of the early black powder enthusiasts had lost the knowledge of the early black powder loads. The main loss was a proper lubricant for black powder, and after a few shots, all accuracy was lost without cleaning the barrel. But duplex loads allowed more shots between cleaning the barrel. Some of Mike Venturino's articles talked about this issue. In his early days, his experience with the Sharp's rifle and accuracy problems he had.
I know artillery uses BP but is it duplexes with smokeless for real? Does it depend on the gun size? I remember watching them 155 Paladins firing and lot of visible flash and smoke and THUNDER
@gb123-ej8wh The 16 inch cannons on old battleships used duplex loads. Same thing. Small ignition charge of BP with an absolute metric shit ton of smokeless on top.
I have heard that as well but I figured that was more of a reliance sort of thing more than a velocity thing. Black powder has a "liquid" phase when it burns that allows it to retain intense burning heat for a comparatively very long time when stood side by side with smokeless powders. (Which is why it burns faster in open air as it can hold the heat of the reaction closer to itself and other unreacted black powder particles) I figure it's that extended duration of intense heat that guarantees that the smokeless powder will go off more reliably even in less than ideal situations where quality may have been potentially compromised.
I’d say your results when measured with modern chronograph equipment are well within margin of error when compared against 1890’s-1950’s vintage speed measuring accuracy.
The reversed duplex load actually makes a lot of sense as to why it would produce higher velocity, as it is basically a military duplex load. Meaning that the slower burning powder had more time to build up pressure as it burns, before it hits the faster burning powder to introduce a power spike. In a sense it would be like burn normal gasoline to obtain your take off power to get up to speed, before you introduced nitro s-oxide. Putting the smokeless at the beginning, is like using nitro s-oxide to take off all you would do is spin your wheels before you caught traction resulting in being at your power curve sooner then later.
Artillery shells have been loaded like this since WW1 or earlier. Initially it was because the smokeless powder wasn't that great yet - but then they discovered that even with good powder this just works better
Remember the 303 black powder cartridge was fired in the Lee Medford and Long Lee Enfield not the SMLE No.1 MK lll. Both the Lee Metford and the Long Lee Enfield had a longer barrel.
Yes I was completely destroyed in a few forms asking about this subject. You talked about how people act when the subject is brought up in your first video on the subject. I have to say I’m so happy that forums are being more and more irrelevant.
Old very known use of. RED DOT powder. 1=5. (1 grain red dot = 5 grains blackpowder) for use in target rifles of 45-70 40-60 38-55 ect. Mixed. Generally. One shot glass reddot to a pound of black powder , the duplex of smokeless near the primer was called a "kicker" of a burn rate powder. Of 4227 or so behind a very very slow smokeless or black powder. Now mixed smokeless is the original "duplex". The theory is the higher nitro content has extra oxygen to help with the burn . It just so happens 13gr reddot equals 65gr black in velocity ,( pressure not withstanding) , green dot and unique also works , many high nitro powders ( fast work well ) Bullseye the highest nitro content
Wonder what mass fraction the BP solids form when they're propelled down the barrel. It's going to be a small number, but (and this is a serious "what if" speculation)... could SP-BP and mixed be suffering from having to accelerate the bullet *and* the residues, where BP-SP mostly propels the projectile, since the solids are mostly behind that charge? If you only had access to a high speed camera and some quartz tubes...
Good show thanks for the good info. Are you still gonna do a video of how you make the Black powder using charcoal. I'l be looking forward to your next videos of course but I sure enjoyed watching and learned a lot from the 303 experiments you did. Later. God Bless. NW ga.
So here is my best (very unprofessional yet lengthy) guess as to why the upside down load was achieving higher velocity: black powder burns far more gradually and steadily than smokeless and is more like a push than a punch. When you mix in smokeless evenly you get slight bursts or spikes of energy in the burn's timeline. Those spikes in energy or pressure may deplete or be relieved as the bullet moves down the barrel providing more and more volume for those little pressure spikes to be relieved (perhaps creating a "speed up and slow down" effect as the bullet travels down the barrel"?). However, when you load the smokeless powder on top in an upside down configuration the steadier burn of the black powder builds up as it would with a straight black powder load and finishes off with a crescendo of all the smokeless going off at the end rather than spread throughout the burn in smaller bursts. Like a running start before punting the football. Or... perhaps something to that effect. Like I said, I am no expert, but I figure that may make some sense.
Try the faster burning powder on the top this time. Thats gotta give a little more. And i think it works that way because the black powder gets it movong then the smokeless gives ot that little extra nudge
