It is no secret I have shot loads that have caused a considerable amount of debate in smokeless muzzle loading circles. To this date my name is less than mud at the Savage information center. I never started out wanting to cause an upheaval but then again I guess there was a time I was too stupid to avoid it. What caused all the debate? One word did: duplex.
Yes I?m responsible for duplex shooting in the 10ML and it is either a ?red badge of courage? or the ?scarlet letter? to carry for the rest of my days. That seems funny because I did not think of duplex nor am I anywhere near the first to use it successfully. If you have a Lyman book on reloading black powder cartridges you might notice that almost every BP case listed in the book has a 10% duplex load provided. Large bore target shooters have used the method longer than I can remember. And last but not least monstrous sized cases intended for African hunting have used a small amount of igniter powder since the beginning of smokeless shooting.
Despite the above facts it has been easy enough for critics to call all duplex shooting dangerous. To them and any one else with doubt I say: OK don?t shoot it and you?ll have no trouble. I?d also say the shooting of duplex has limited use even though it is perfectly safe. Yes I said perfectly safe! I think after more than 700 10ML shooters have reported shooting one hundred thousand plus shots without incident I can report it as safe.
I know what you?re thinking and it is the whole idea of this post: why? What reason is there for shooting a duplex in the first place? This is especially important when almost every cased round reloading manual says absolutely ?DON?T DUPLEX. The answer lies in the fact the 10ML (and the other examples quoted above) is not similar to a normal cased round. Also the bullets shot from a smokeless muzzleloader are not anywhere near normal for the caliber as would be shot from a case.
Since the bullet is a ?red herring? it requires special consideration. What is the normal weight bullet shot from a 50 caliber smokeless rifle? You can take my word on it, that bullet won?t weigh 262 grains (250 for the bullet 12 for the sabot). Load data for the 50 Alaskan lever gun will show bullets normally range in the 425 to 550 grain level. The heavier bullets can run 600 grains and the lightest weight you will ever see in a 50 caliber rifle (but not often) is 300 grains. So why does the most popular muzzle loading bullet weigh 262 grains?
Whatever the answer to the last question it can be stated a 250 grain bullet fired from a 50 caliber rifle raises problems that don?t occur with a heavier bullets or a smaller caliber bore. All you have to do to realize that is look at the powder suggestions for the factory loads. You will notice that all the loads suggest between 40 and 45 grains of powder for all weights of bullet. 45 grains is the top load because of the speed of the powder. None of the currently listed powders are actually RIFLE powder. One is a pistol powder (N110) and two (Imr-4759 and Xmr-5744) are reduced load rifle powders thus all are too fast burning to be used in normal rifle loads.
That should be no surprise as a very light weight bullet calls for a faster powder or a lot of a slower powder to make pressure. That is why you never see a 10ML load suggestion of 50 or 55 grains of powder. All powders are either too fast (the pressure would be excessive) or too slow (you need more powder for pressure) to work at these levels. So with a really light weight bullet and a large bore it is hard to match the powder level to a pressure that is useful for the conditions. That means a way to adjust the pressure of a given amount of powder with a given bullet weight would be very useful and that is exactly what duplex does.
Let?s look at two powders that can be shot smokeless and consider both their limitations. VV N110 is a very useful powder for a 250 grain bullet. It is easy to ignite and works up to a moderate speed at a good pressure for the entire system. The limitation is only 45 grains can be shot and stay below the best maximum pressure. H322 on the other can shoot a lot more powder than N110 and it too has good ignition qualities. However to get up to proper working pressure with the super light 250 grain bullet you have to use more than 80 grains of powder. Though this load will work at safe pressure you will find the recoil makes shooting it more than once an ill fated suggestion.
So it seems the two are totally incompatible with shooting say 60 grains of powder. N110 is too fast and H322 is too slow. But with duplex that seemingly improbable load level is a not a problem. We can speed up one powder and slow down the other by shooting both (not as a mix). If you load 20 grains of N110 and then simply put 40 grains of H322 on top it will shoot much like a powder designed for a 250 grain bullet and a 50 caliber rifle, because that is what it is.
Some will say: don?t you worry about the powders somehow mixing? My answer is no I don?t. You see I work my duplex loads so I?m always trying to increase the pressure of the slower powder rather than lower the pressure of the faster. These duplexes are loaded so they make the maximum pressure possible for such a load. Any mixture or shaking in together can only lessen the pressure it can never grow. So if the load is safe as a base it can only have less pressure (and be safer) with a disturbance.
I also know from many different trials and errors that once the bullet is seated properly it is almost impossible to have any load position movement that changes pressure or accuracy of the load. The claim can be backed up by the fact almost all duplex shooters report duplex is the most accurate load shot from their rifles. Again there should be no surprise. Rifles shoot with the best possible bullet speed and load pressure. The rifle itself picks what ?best? is but there is always a sweet spot for accuracy. With a duplex any load level can be adjusted to an almost infinite amount of possibilities.
In the above suggested load there is plenty of safe room to work with. The most accurate load might be 18/42 (18 grains of N110 under 42 grains of H322) or 21/39 but one thing for sure: there is always going to be an accurate position somewhere near the optimum pressure level without changing the base load level (there is always 60 grains total charge).
What I?m saying is a load is available at any charge level (50, 55, 60, 65, 70, etc.) any where between the two extremes of either N110 or H322 (45 to 85 grains) that has the same pressure as an ideal load of N110 or H322.
Some will note that the use for duplex is lessened by the development of loads that shoot single powders to speed with a 250 grain bullet. To that sentiment I agree. However there is still one problem. To reach the best pressure for consistency a powder like H-4198 or Reloader #7 will still have to shoot over 65 grains of powder. In many cases the bullet speed produced will be such recoil is more than just a concern. So shooting to an accurate level and an acceptable level of recoil may not both be possible. That?s no problem for duplex.
At this point I?d like to express a few ideas that should have come apparent in the discussion.
1. I never encouraged anyone to shoot duplex. People began to shoot it because they were friends of mind and they saw with their own eyes how well it worked. I still have no reason to convince you or anyone else to try it. If you don?t like it don?t shoot it and don?t suggest I told you to.
2. Duplex is for 250 grain (and lighter) bullets in a 50 caliber rifle. There is no real need for duplex with a 300 grain (or heavier) bullet or a smaller caliber rifle.
3. If you want to try it enlist the help of someone who has done it before and knows what he?s doing.
4. All the loads I suggest have been shot thousands of times and proven safe in several hundred rifles but they MUST be loaded correctly. In our suggested load as long as 20 grains of N110 and 40 grains of H322 are used it can?t be made hazardous. But with 40 or more grains of N110 and any amount of H322 all sorts of things (none good) could happen.
5. The idea began because shooting a 250 grain bullet is a very odd thing to do in a 50 caliber rifle.
6. Duplex can help achieve speed and accuracy while staying in an ideal pressure range
7. Shooting two powders at once cannot cause some type of magical explosion.
8. I only relate these things because I want to share what I know and learn. You have every reason to doubt me so ask others, look for examples, read up on the subject, and most of all think for yourself.
I have only shot duplex in the Savage model 10ML-II I make all the above statement as conerns that rifle only. I don't have any experience with other smokeless brands shooting duplex and cannot suggest a load or option for any other rifle.
Yes I?m responsible for duplex shooting in the 10ML and it is either a ?red badge of courage? or the ?scarlet letter? to carry for the rest of my days. That seems funny because I did not think of duplex nor am I anywhere near the first to use it successfully. If you have a Lyman book on reloading black powder cartridges you might notice that almost every BP case listed in the book has a 10% duplex load provided. Large bore target shooters have used the method longer than I can remember. And last but not least monstrous sized cases intended for African hunting have used a small amount of igniter powder since the beginning of smokeless shooting.
Despite the above facts it has been easy enough for critics to call all duplex shooting dangerous. To them and any one else with doubt I say: OK don?t shoot it and you?ll have no trouble. I?d also say the shooting of duplex has limited use even though it is perfectly safe. Yes I said perfectly safe! I think after more than 700 10ML shooters have reported shooting one hundred thousand plus shots without incident I can report it as safe.
I know what you?re thinking and it is the whole idea of this post: why? What reason is there for shooting a duplex in the first place? This is especially important when almost every cased round reloading manual says absolutely ?DON?T DUPLEX. The answer lies in the fact the 10ML (and the other examples quoted above) is not similar to a normal cased round. Also the bullets shot from a smokeless muzzleloader are not anywhere near normal for the caliber as would be shot from a case.
Since the bullet is a ?red herring? it requires special consideration. What is the normal weight bullet shot from a 50 caliber smokeless rifle? You can take my word on it, that bullet won?t weigh 262 grains (250 for the bullet 12 for the sabot). Load data for the 50 Alaskan lever gun will show bullets normally range in the 425 to 550 grain level. The heavier bullets can run 600 grains and the lightest weight you will ever see in a 50 caliber rifle (but not often) is 300 grains. So why does the most popular muzzle loading bullet weigh 262 grains?
Whatever the answer to the last question it can be stated a 250 grain bullet fired from a 50 caliber rifle raises problems that don?t occur with a heavier bullets or a smaller caliber bore. All you have to do to realize that is look at the powder suggestions for the factory loads. You will notice that all the loads suggest between 40 and 45 grains of powder for all weights of bullet. 45 grains is the top load because of the speed of the powder. None of the currently listed powders are actually RIFLE powder. One is a pistol powder (N110) and two (Imr-4759 and Xmr-5744) are reduced load rifle powders thus all are too fast burning to be used in normal rifle loads.
That should be no surprise as a very light weight bullet calls for a faster powder or a lot of a slower powder to make pressure. That is why you never see a 10ML load suggestion of 50 or 55 grains of powder. All powders are either too fast (the pressure would be excessive) or too slow (you need more powder for pressure) to work at these levels. So with a really light weight bullet and a large bore it is hard to match the powder level to a pressure that is useful for the conditions. That means a way to adjust the pressure of a given amount of powder with a given bullet weight would be very useful and that is exactly what duplex does.
Let?s look at two powders that can be shot smokeless and consider both their limitations. VV N110 is a very useful powder for a 250 grain bullet. It is easy to ignite and works up to a moderate speed at a good pressure for the entire system. The limitation is only 45 grains can be shot and stay below the best maximum pressure. H322 on the other can shoot a lot more powder than N110 and it too has good ignition qualities. However to get up to proper working pressure with the super light 250 grain bullet you have to use more than 80 grains of powder. Though this load will work at safe pressure you will find the recoil makes shooting it more than once an ill fated suggestion.
So it seems the two are totally incompatible with shooting say 60 grains of powder. N110 is too fast and H322 is too slow. But with duplex that seemingly improbable load level is a not a problem. We can speed up one powder and slow down the other by shooting both (not as a mix). If you load 20 grains of N110 and then simply put 40 grains of H322 on top it will shoot much like a powder designed for a 250 grain bullet and a 50 caliber rifle, because that is what it is.
Some will say: don?t you worry about the powders somehow mixing? My answer is no I don?t. You see I work my duplex loads so I?m always trying to increase the pressure of the slower powder rather than lower the pressure of the faster. These duplexes are loaded so they make the maximum pressure possible for such a load. Any mixture or shaking in together can only lessen the pressure it can never grow. So if the load is safe as a base it can only have less pressure (and be safer) with a disturbance.
I also know from many different trials and errors that once the bullet is seated properly it is almost impossible to have any load position movement that changes pressure or accuracy of the load. The claim can be backed up by the fact almost all duplex shooters report duplex is the most accurate load shot from their rifles. Again there should be no surprise. Rifles shoot with the best possible bullet speed and load pressure. The rifle itself picks what ?best? is but there is always a sweet spot for accuracy. With a duplex any load level can be adjusted to an almost infinite amount of possibilities.
In the above suggested load there is plenty of safe room to work with. The most accurate load might be 18/42 (18 grains of N110 under 42 grains of H322) or 21/39 but one thing for sure: there is always going to be an accurate position somewhere near the optimum pressure level without changing the base load level (there is always 60 grains total charge).
What I?m saying is a load is available at any charge level (50, 55, 60, 65, 70, etc.) any where between the two extremes of either N110 or H322 (45 to 85 grains) that has the same pressure as an ideal load of N110 or H322.
Some will note that the use for duplex is lessened by the development of loads that shoot single powders to speed with a 250 grain bullet. To that sentiment I agree. However there is still one problem. To reach the best pressure for consistency a powder like H-4198 or Reloader #7 will still have to shoot over 65 grains of powder. In many cases the bullet speed produced will be such recoil is more than just a concern. So shooting to an accurate level and an acceptable level of recoil may not both be possible. That?s no problem for duplex.
At this point I?d like to express a few ideas that should have come apparent in the discussion.
1. I never encouraged anyone to shoot duplex. People began to shoot it because they were friends of mind and they saw with their own eyes how well it worked. I still have no reason to convince you or anyone else to try it. If you don?t like it don?t shoot it and don?t suggest I told you to.
2. Duplex is for 250 grain (and lighter) bullets in a 50 caliber rifle. There is no real need for duplex with a 300 grain (or heavier) bullet or a smaller caliber rifle.
3. If you want to try it enlist the help of someone who has done it before and knows what he?s doing.
4. All the loads I suggest have been shot thousands of times and proven safe in several hundred rifles but they MUST be loaded correctly. In our suggested load as long as 20 grains of N110 and 40 grains of H322 are used it can?t be made hazardous. But with 40 or more grains of N110 and any amount of H322 all sorts of things (none good) could happen.
5. The idea began because shooting a 250 grain bullet is a very odd thing to do in a 50 caliber rifle.
6. Duplex can help achieve speed and accuracy while staying in an ideal pressure range
7. Shooting two powders at once cannot cause some type of magical explosion.
8. I only relate these things because I want to share what I know and learn. You have every reason to doubt me so ask others, look for examples, read up on the subject, and most of all think for yourself.
I have only shot duplex in the Savage model 10ML-II I make all the above statement as conerns that rifle only. I don't have any experience with other smokeless brands shooting duplex and cannot suggest a load or option for any other rifle.
I have shot duplex from nearly the beginning. Additionally, I have found that duplex improves the accuracy I can get in nearly every smokeless MLer I shoot regardless of bullet wt or caliber. I happen to believe that even the 300g bullet's accuracy, or at least efficiency, is also helped with duplex - just not as much as lighter bullets. The lighter the bullet, the more duplex helps. The 45 cal with 200SSTs and 195 DCs certainly benefits from duplex. Even the rather inefficient, extremely popular, 14/61 duplex is more accurate that any other 250SST load in the 10/ML2, at least for many of us. 75gs of powder for 2630'/sec isn't very efficient. RB's later direction of 20/40 is certainly a needed direction for this bullet wt/velocity. 
