yodogsandman
Well-Known Member
No, just showing that duplexing has been published in a major cast bullet load book.
I've edited Post#18 to exclude any charge info. My bad!
How Do You Safely Duplex Load With Slow For Cartridge Powders?
- Thread starter yodogsandman
- Start date
No, just showing that duplexing has been published in a major cast bullet load book.
I've edited Post#18 to exclude any charge info. My bad!
Josh
Well-Known Member
Yes, you duplex it just like smokeless powders, it is an acceptable load for one of the black powder competitions (not sure which one, will have to look) it reduces the fouling left in the bores.
fiver
Well-Known Member
well if someone can't figure out that this is about as advanced as finding your own load data for HV cast rifle loads they won't know what to do with the info anyway.
and if they try without using their brains they will lose an eye.
a duplex load is nothing more than increasing the initial ignition pressure to get the main powder charge burning in it's happy zone sooner so more of it is used before the bullet exits the barrel.
you use enough of the kicker charge to accomplish the job but not more than necessary.
18 grs of red-dot is probably too much, 20grs of 4227 is probably about right depending on what and how much your trying to ignite.
however the 18grs of red-dot is probably producing a much lower peak pressure when the actual powder is being fully ignited.
that's where the problem lies.
lower peak ignition and higher residual burn pressure of the main charge.
the case shape and main powder amount/speed has to be taken into account.
and if they try without using their brains they will lose an eye.
a duplex load is nothing more than increasing the initial ignition pressure to get the main powder charge burning in it's happy zone sooner so more of it is used before the bullet exits the barrel.
you use enough of the kicker charge to accomplish the job but not more than necessary.
18 grs of red-dot is probably too much, 20grs of 4227 is probably about right depending on what and how much your trying to ignite.
however the 18grs of red-dot is probably producing a much lower peak pressure when the actual powder is being fully ignited.
that's where the problem lies.
lower peak ignition and higher residual burn pressure of the main charge.
the case shape and main powder amount/speed has to be taken into account.
The only other qualifier is to ensure that the original load was at the 100 % fill level of the case with minimal compression. Do not attempt to load and shoot cases of duplexed powder that have any rattle room, ie, less than 100 % full capacity. I have worked up a couple of loads I will use until I run out of cheap WC860/872 if I live long enough to shoot what I have. I trust it more than I would using a filler but that is just me and my opinions. As Al said, do not buy a powder with the sole intent to work up a duplex load. No one on this sight should have a problem with having to clean their guns after shooting them, duplexing just gives you the extra burn and with some loads that shows up in group size. I will say I have never shot a duplexed load I could not better with faster powders.
Ian
Notorious member
"[snip] The way to use it is add about two or three grains of booster on top of the primer and subtract the same volume from a 100% load of the slow-for-cartridge powder. This all assumes that the grains of the booster and main charge are compatible shapes and sizes so they won't intermix much. Go shooting. Make observations and compare them to those of the 100% un-boostered load. If it seems prudent, add another grain of booster and repeat. [snip]"
I wrote about the whole deal being about 100% load density, yet the point got missed by a couple of people. That pretty much makes a point by itself.
Duplexing smokeless powder to good effect for certain applications is extremely useful, but those who have the desire to go there can and have pretty much figured out why they need to in the first place and how to do it safely and effectively all on their own. I hate to sound "elitist", but perhaps it should stay that way. Said another way, "If you're smart enough to be fooling around with it in the first place, you're smart enough to figure out how". A person needs to develop their own understanding in their own terms, in their own head, and no way better than working it out in their own way rather than taking someone else's explanation or instructions and attempting to duplicate those without full understanding.
I wrote about the whole deal being about 100% load density, yet the point got missed by a couple of people. That pretty much makes a point by itself.
Duplexing smokeless powder to good effect for certain applications is extremely useful, but those who have the desire to go there can and have pretty much figured out why they need to in the first place and how to do it safely and effectively all on their own. I hate to sound "elitist", but perhaps it should stay that way. Said another way, "If you're smart enough to be fooling around with it in the first place, you're smart enough to figure out how". A person needs to develop their own understanding in their own terms, in their own head, and no way better than working it out in their own way rather than taking someone else's explanation or instructions and attempting to duplicate those without full understanding.
9
9.3X62AL
Guest
I have only seen printed load data using duplex and triplex loads in one place--an old 3rd Edition of "Cartridge of the World" by Frank Barnes, printed c. 1968. In it was data for the 454 Casull that used this method in the days before WW-296 and H-110 were commercially available, around 1964.
My text was sterilized of useful info on my caliber, fuels, and procedures intentionally.
My text was sterilized of useful info on my caliber, fuels, and procedures intentionally.
I disagree.
It is well above the knowledge level needed to work up a single powder load. To duplex or worse triplex a load you must know the effect one powder will have on the other powder(s) burn rate and pressure curve. Since there is no way for a home reloader to determine that effect the danger of such experimentation is obvious.
It is well known the Dick Casull used triplex loads in the development of the 454 Casull. That is well published but not the loads and what was never published about his experiments was how many firearms were lost before coming up with the final loads and finally developing his own revolver to handle such pressures.
.
smokeywolf
Well-Known Member
I've endevored to teach my wife and kids to apply the simple concept of risk vs reward when making decisions on how or if something should be done or tried.
I have duplexed smokeless as a booster under black, but follow a method and formula established and recorded well over half century ago and practiced even longer. Probably would not have tried it then, but had an entry in Dad's ledger showing the recipe.
Duplexing smokeless with smokeless is a completely different ballgame. Without the hardware and instrumentation to safely test, measure and record results, I don't see reward outweighing risk in duplexing smokeless.
Risk vs reward.
I have duplexed smokeless as a booster under black, but follow a method and formula established and recorded well over half century ago and practiced even longer. Probably would not have tried it then, but had an entry in Dad's ledger showing the recipe.
Duplexing smokeless with smokeless is a completely different ballgame. Without the hardware and instrumentation to safely test, measure and record results, I don't see reward outweighing risk in duplexing smokeless.
Risk vs reward.
9
9.3X62AL
Guest
The rationle for duplexing has to some extent "self-correctred". For me, it was the chance to use inexpensive fuels that were easy to get for an economical return. As time went on, some of these glacier-slow 50 BMG and 20mm/30mm cannon powders were the only milsurp--and at time the only powders of any type--to be commercially available. Gotta look at this hobby activity from a costs/benefits perspective from time to time. Sure--that $3/lb charcoal-slow fuel was cheap, and in a few limited venues it does decent work. But I didn't like the brass burn-throughs I spoke of above. Given the gentle pressures and sedate, consistent velocities the loads produced, these occurrences were real anomalies in a straight-wall case. No mas.
F
freebullet
Guest
So yall think 30gr of tg under 50gr of 7383 gonna work in the bmg?
9
9.3X62AL
Guest
7383 was squirrely stuff. It made great garden fertilizer.
yodogsandman
Well-Known Member
Things would be different if we could get surplus 4895, W844, W846 or W852 at a decent price again.
9
9.3X62AL
Guest
True that!
Maven
Well-Known Member
I've got to disagree with you Al re 7383. If you don't use max. loads, heavily compressed loads, or max., compressed loads in hot weather, it's quite tractable. In fact, I loaded 50 rounds of 7.62 x 39mm + NOE 163r. CB with it this afternoon: 22.7gr. + mag. primers -> ~1,608 fps, with normal ejection from my SKS, and little unburned powder left behind. In my .30-06, using jacketed bullets, it approximates IMR 4350, but is a tad slower in my .243Win., also with jacketed bullets. It also has produced outstanding accuracy in all 3 guns, which is really saying something considering the short sight radius and heavy trigger pull of the SKS. Garden fertilizer? No, not yet, but it was quite a bargain at $7/lb. years ago and I'm still very pleased with it. Would I purchase it again? Not likely, as milsurp propellants are no longer inexpensive, and sometimes rival canister powders in price, e.g., WC 820 v. AA #9.
9
9.3X62AL
Guest
A lot of shooters say what you posted, Maven--guys like you whose skills I respect highly. But a significant number of other men whose work I think highly of had weird and unpredictable excursions of pressure and velocity while using it. Too scary for my tastes.
Josh
Well-Known Member
If you would like, I can PM you my full load workup using 7383 (lot 48000) in my 30-06. It may give you some insight as to how 7383 performs.