Sprky222 said:
I guess my question is...Do you feel this combination of components will work well in a 4 5/8" as well as a 20" barrel? Also, after reading Barnes reloading data it lists the 20.0 gr loading as a starting load with 22 grains as a max load.
As 44 AMP said, it depends on the twist rate and also on the bullet. Your Super Blackhawk and Big Boy both have 20" twists, I believe, and the Barnes is a solid bullet, so you don't need to worry about excessive spin distorting them. It can affect accuracy adversely if a bullet has any flaw in the uniformity of its mass distribution, but I don't think you'll have an issue with that. Indeed, you should be able to shoot hard-cast bullets just fine in both guns, especially if they have gas checks.
If your concern is how the powder burns in different barrel lengths, forget about it. Figure that by the time the bullet has moved about an inch in the rifle barrel and about 2 inches of the revolver barrel, it will have passed its pressure peak and will be burning remaining powder. That ongoing burn will produce some muzzle flash and blast in the shorter revolver barrel that the longer rifle barrel covers up much better, but other than velocity, that's usually about it for the differences. The same powder that produces maximum velocity in your revolver will also produce maximum velocity in the Henry, though the revolver maximum will be lower, of course.
Revolvers can sometimes retard the burning of slower powders, with their cylinder throats being the equivalent of a long freebore that bleeds bypass gas out of the barrel/cylinder gap. That bleed-off gets bigger as the bullet base clears the cylinder face, exposing powder gases to the gap. That puts a momentary hiccup in the powder burn and its pressure curve. In snub nose designs, this can lead irregular combustion and a correspondingly large velocity variation, but I don't recall seeing the issue in revolver barrels of three inches and longer.
Hodgdon, unlike Barnes, has access to data powder for the products it makes. Barnes, like all the bullet makers who publish data, will have bought their test powder off the shelf and will have no way of knowing whether the lot they bought is average or is on the upper or lower side of the burn rate tolerance that Hodgdon maintains. Also, there are two different handgun Velocity & Pressure barrel designs for 44 Magnum in the SAAMI standard. One has a 0.008" vent to mimic a revolver barrel/cylinder gap, followed by 4" of barrel, while the other is an 8.275" barrel with no vent that mimics a single-shot pistol. Barnes mentions an 8" barrel, and we don't know what it was. Since that's not a SAAMI standard length, it suggests development in a commercial chamber and barrel, which would lower pressure a bit, and combined with having a slower burn rate lot of powder, it could combine to account for the 11% maximun load difference. We'd have to talk to them to find out about the test conditions. SAAMI standard V&P barrels have a chamber and headspace that is within 0.0005" of minimum to provide worst-case pressure. Hodgdon used the 8.275" V&P barrel for pressure testing, as it tends to maximize pressure without the vent (gives worst-case pressure).
Since you want to load for the Henry, which is closer to the barrel design used by Hodgdon (closed breech and no vent), and since Hodgdon can control burn rate they use for testing, I would follow Hodgdon's loads, and if you want to work up to the Barnes loads in your revolver, let that be a separate issue. Keep in mind that none of the published charge differences would cause pressures to reach proof load level, so using the lower Hodgdon limit is not a matter of avoiding a gun blow-up, but more that hotter loads wear forcing cones and throats and other such things faster than cooler ones do. You can work up as you choose, of course, but I like to make things last, myself. If you only shoot it a few times a year, you may conclude what to do differently.
