rodwha
11-01-2020, 05:13 PM
I have two percussion black powder revolvers that I’ve made a few designs for. What I ended up finding out is that they both seem to have a powder charge they do well with no matter what projectile I use, be it a round ball, my 170, or my 195 grn bullet. I have a new powder measure so I’ll need further testing to find tune my modifications, but will be filling the excess chamber room of these with more lead. From the last measurements I took configuring for their prior powder charges I estimated this bullet to be .497” long and likely 210-230 grns with a .375” meplat. This is the design so far:
https://i.postimg.cc/pXvwt5pm/D276-FFBA-EA5-C-4506-B33-C-02422-D14-F36-E.jpg (https://postimg.cc/MXsP7T0w)
I use energetic powders and have noted similar loads as mine so I estimate a muzzle velocity from my Remington New Model Army 950 FPS +/- and the ROA around 1025-1050. But I have a wild hair in my nether regions that I’d like a muzzleloader barrel to use these as either full bore conicals or paper patched. I’m thinking a nice carbine of 24-28” using peep sights, and pushed by 40-60 grns of powder, the upper level there being about on par with standard .44 Mag performance from a handgun. Sort of like a Jack-of-all-trades I “understand “ a lot of the things that go into bullet designs, but don’t necessarily know the finer details or maybe even old wives tales versus field results. So please bear with me and give me some feedback.
I’ll begin with the lead. As is I’ve only ever cast my projectiles, including my rifle balls/REALs, with pure lead. But I’ve had fill issues, along with having moved to a city that doesn’t sell scrap lead it appears, that have made me contemplate RotoMetals 2% tin when I get lower on lead. I know that for my revolvers and full bore conicals I need softer lead. But I also know that as the velocity goes way up you need the lead harder to keep it from stripping the riflings. So at what velocity does pure lead and 2% tin fail?
Having just read a portion of a sticky on meplats I’m contemplating mine. At .375” I’m at about 83%. At revolver velocities I’m all good, but being fairly light and short for caliber I’m wondering how it would likely behave on medium game. I’m still at a loss for how wide meplat bullets behave coming down from being super sonic. I estimated this being a problem at around 1150 FPS and estimating rifle velocities it looked like effective range would be rather short, ranging from as little as 50 yds and barely getting to 100. And maybe using this bullet from a rifle would only be used with lighter loads to keep the velocity issue in check. And of course I could always just use a better bullet, either commercial or another design (I’m considering modifying that 45-245C for my Ruger, and have a 285 grn version that I no longer had a use for as bears weren’t going to be on the menu after all.
http://accuratemolds.com/bullet_detail.php?bullet=45-285C-D.png
Looking at published loads this lighter bullet would likely start around 1300 FPS on up to about 1600 FPS.
This wobble I’ve read about, does this matter if it happens well before it’s down range? I assume my BC would be rather low (used .150). If I were to start this bullet at say 1200 FPS and it hits this wobble soon after, would it have stabilized by the time it’s 75 yds down range hitting a doe?
I recall reading old stuff on making wide meplat bullets back when I was designing my original bullets. It stated something like them finding ~78% meplat was the maximum one would want as beyond this they found the bullet tended to yaw a bit and not track straight upon impact. I’m wondering if this might have been the “wobble” and not meplat.
Since I’d like for this design to work in a carbine as well I’m wondering how meplat and BC relate when the OAL stays the same.
I must admit that since even my NMA is getting standard .45 ACP performance (~375 ft/lbs) I’ve considered cutting the powder charge a smidge just to elongate my bullet. But accuracy being such an important aspect, and my offhand shooting could use some tightening, I don’t know that I’d want to sacrifice any of it. :D
https://i.postimg.cc/pXvwt5pm/D276-FFBA-EA5-C-4506-B33-C-02422-D14-F36-E.jpg (https://postimg.cc/MXsP7T0w)
I use energetic powders and have noted similar loads as mine so I estimate a muzzle velocity from my Remington New Model Army 950 FPS +/- and the ROA around 1025-1050. But I have a wild hair in my nether regions that I’d like a muzzleloader barrel to use these as either full bore conicals or paper patched. I’m thinking a nice carbine of 24-28” using peep sights, and pushed by 40-60 grns of powder, the upper level there being about on par with standard .44 Mag performance from a handgun. Sort of like a Jack-of-all-trades I “understand “ a lot of the things that go into bullet designs, but don’t necessarily know the finer details or maybe even old wives tales versus field results. So please bear with me and give me some feedback.
I’ll begin with the lead. As is I’ve only ever cast my projectiles, including my rifle balls/REALs, with pure lead. But I’ve had fill issues, along with having moved to a city that doesn’t sell scrap lead it appears, that have made me contemplate RotoMetals 2% tin when I get lower on lead. I know that for my revolvers and full bore conicals I need softer lead. But I also know that as the velocity goes way up you need the lead harder to keep it from stripping the riflings. So at what velocity does pure lead and 2% tin fail?
Having just read a portion of a sticky on meplats I’m contemplating mine. At .375” I’m at about 83%. At revolver velocities I’m all good, but being fairly light and short for caliber I’m wondering how it would likely behave on medium game. I’m still at a loss for how wide meplat bullets behave coming down from being super sonic. I estimated this being a problem at around 1150 FPS and estimating rifle velocities it looked like effective range would be rather short, ranging from as little as 50 yds and barely getting to 100. And maybe using this bullet from a rifle would only be used with lighter loads to keep the velocity issue in check. And of course I could always just use a better bullet, either commercial or another design (I’m considering modifying that 45-245C for my Ruger, and have a 285 grn version that I no longer had a use for as bears weren’t going to be on the menu after all.
http://accuratemolds.com/bullet_detail.php?bullet=45-285C-D.png
Looking at published loads this lighter bullet would likely start around 1300 FPS on up to about 1600 FPS.
This wobble I’ve read about, does this matter if it happens well before it’s down range? I assume my BC would be rather low (used .150). If I were to start this bullet at say 1200 FPS and it hits this wobble soon after, would it have stabilized by the time it’s 75 yds down range hitting a doe?
I recall reading old stuff on making wide meplat bullets back when I was designing my original bullets. It stated something like them finding ~78% meplat was the maximum one would want as beyond this they found the bullet tended to yaw a bit and not track straight upon impact. I’m wondering if this might have been the “wobble” and not meplat.
Since I’d like for this design to work in a carbine as well I’m wondering how meplat and BC relate when the OAL stays the same.
I must admit that since even my NMA is getting standard .45 ACP performance (~375 ft/lbs) I’ve considered cutting the powder charge a smidge just to elongate my bullet. But accuracy being such an important aspect, and my offhand shooting could use some tightening, I don’t know that I’d want to sacrifice any of it. :D