RBinAR said:
Rangeball said:
RB, I'm confused. Once the bullet is seated, shouldn't it react to the charge just like a breach loader as it's slammed down the barrel?
Did I misunderstand? I thought you were shooting without sabots? What are you doing to avoid the problem you posted above?
Question 1 Yes and no! A breech loader works completely differently from a muzzleloader as far as forcing the bullet into the rifling. The bullet does not touch any part of the rifling when it's in the firing position. The first small amount the bullet moves in a chamber is often called the "freebore" it's freebore because it's free of rifling.
As the bullet moves toward the rifling the freebore starts to cone shape toward the final shape of the rifling and the bullet is force shaped to fit exactly the size of the barrel. The effect is to use the bullet as a complete gas seal for the expanding powder charge. Thus very little or any of the gas from ignition can get past the sides of the bullet and all the gas acts to push the bullet down the barrel while the rifling spins the bullet for stability.
Question 2 In a muzzleloader there is no forcing cone there is no freebore there is only rifling from one end of the barrel to the other. That would seem to say you can't shoot jacketed bullets from a muzzleloader because you can't get a uniform gas seal. But there is a way it's not the same as a breech loader but it will work if conditions are right .
With the above in consideration, let's jump to another topic. But really, its not another topic. Have you noticed that the Bad Bull uses H-4350 while we sabot shooters shooting the same caliber and wt bullets use much faster powders? And we shoot slower. Likewise have you noticed that we use a lesser load for bullet wt and caliber than you'd expect from looking in a loading manual for equavilent bores/bullets? 6 years ago I asked Toby Bridges why he was using such fast powders for the 10-ML as opposed to slower powders. His answer was, "Because they work". So we shoot the moderately fast powders, get 35,000psi and above on some loads(5744 45gs/300SST and a # of others, especially with the loads published 5-6 years ago). If we shot 90+ gs of H-322 with 250g bullet we could get well above 2500'/sec with relatively low pressure(well below 35000psi) but with significant recoil and extreme temp sensitivity. If we upped the fast pistol powder loads, pressures rose to too hi a level. Intermediate powders (IMR-4198,VV-120,etc) gave faster velocities w/o higher pressures but often have some temp sensitivity and much more recoil. What is different with smokeless MLers and cartridge rifles other than the obvious loading end? - 2 things, no cartridge neck tension and, much more significant, no land engraving of the bullet. Significant presssure increase occurs overcoming these resistances that allows the slower powders to rise to acceptable working pressure. How can we use these slower powder, gain velocity, not raise pressure, and incidentally get increased accuracy and getting significantly smaller pressure and velocitity std deviations? Here's how: raise the pressure of the slower powder by using a small amount of a faster powder that initially gets to pressure with the resistance of the bullet, its bore friction with the sabot, and the wt of the bullet/propellant. IOWs the faster powder substitutes for the neck tension resistance and the much greater bullet/land engraving. The resistance of a saboted bullet to initial movement is much less than the resistance a bullet has of neck tension and engraving the lands, much less! This isn't rocket science(something RB actually is involved in) but the approach is novel, effective, extremely consistent, generates very safe pressures(his duplex loads have lower pressures than the book loads - a whole lot less than some book loads), and have been more accurate and consistent than ANY single powder load for the vast majority or possibly all of us who utilize duplex loading. I shoot a 250 SST @ 2630'/sec @ MOA or better with less pressure than a 43g VV-110 load. So do a bunch of other ML-2 shooters. The "arguments" against duplex, so far, just haven't been convincing. They largely have centered around 1) its dangerous, and 2) you shouldn't mix powders in cartridges. Huh? I have extreme trouble understanding #1 and the second is apples and oranges. Well designed and pressure tested duplex(layering, not mixing, of 2 powders) is extremely safe IMO, until shown otherwise. Its different, novel, and like anything new, meets resistance. So did multigrade oils, smokeless powders in cartridge guns, compound bows, automobiles, airplanes, etc. I use all these, including duplex. RB may want to correct, edit, add to some of the above.
Steve White
