loads, barrel length and velocity

we have had several discussions involving differences in powder charges or other load data for given calibers, e.g., the recent one on whether or not a 70 gr charge was enough for a .50 for hunting. It occurred to me that in many cases we were comparing apples and oranges. For example, roundball has made it clear that he prefers 90gr load for his .50 (and I stated that 70gr was enough for me). The differences here, I believe, lie mostly in the choice of firearms--we were leaving out important variables in our discussion. Roundball (and I don't really want to personalize this, just for example)shoots a .50 T/C Hawken which has a 28" barrel (if stock) and I shoot a custom .50 with a 44" barrel. All other things equal, the longer barrel requires less powder than a short one to reach a given velocity (and all things equal, same velocity equals same energy/'killing power'). A quick look at my old Lyman BP Handbook tables shows that a .50 with a 28" bbl and 90 gr fffg Goex generates about 1800 fps (with a different brand powder only 1686 fps). I achieve that velocity with about 75 gr fffg Goex. For the .54 the results are also dramatic: in a 28" bbl it takes 100 gr fffg to reach 1600 fps, but it takes only 80 gr fffg to exceed that velocity in a 43" bbl. Most of the old timers shot longrifles with barrels in excess of 36". most over 40". Another factor is rifling twist. Other factors are gun dependent, or patch/lube dependent, but I think these are less important than the above. Old Walter Cline, a founder of the NMLRA, tested many ML rifles and declared that 1400 fps was the most accurate velocity in most rifles. For a .50 with a 43" bbl this equates to under a 50 gr charge (the tables don't go low enough). I am not sure, but think that many he tested probably had 1:48 twists. Yet many target shooters use very large charges (high velocities) in their custom rifles to get the best accuracy. In any event, roundball and I are using similar hunting loads as far as performance goes, even though he loads 90 gr and I load 70 gr--other variables are at work.

 

[roundball]

Interesting...and FWIW, actually most of mine are 32" x 1:66" TC round ball barrels, but your point would still make sense overall...and all I do is just use TC's load data that they publish for use in their own TC rifles.
:front:

 

Ahh, I kinda thought you had aftermarket bbls...the tables book indicates that with a 1:66 32" .50 BBL your 90 gr load approaches 1900 fps. To achieve that I would have to load a bit over 80 grs (my .54 load). As it is you have about a 165 fps advantage over my 70 gr load. At 100 yds this equates to a difference in ft/lbs of energy of 56 ft/lbs (464 vs 408). In the case of a well placed shot, probably not significant, but real. Another thing that the Lyman tables show is that the law of diminishing returns applies: you don't get a linear relationship between increased charge and velocity. There is a cut-off point for each caliber where further increase in load is not efficient. For a .50 with a 32" bbl that cutoff is about 100 grs (90 gr for a 43" bbl). All this begs the question of what is needed as 'killing power'. And many variables apply here as well. The old .45/70 and modern .44 Mag both outperform our .45 and .50 roundball rifles in downrange energy. I have been a .22 shooter for over 50 years and I am still impressed by what that little 40 gr pill at under 1200 fps will do. Imagine what a 178 gr pill at 1800 fps can do!!!

 

[Stumpkiller]

I shoot a .45 ACP quite often. That 230 gr bullet is the same weight as a .54 round ball, and not a lot more efficient. At 750 fps or so out at 25 yards I'm pretty sure I don't want to try and catch one. So, how far down range does a .54 ball started out at, say, 1,600 fps have to be to still be loping along at 750 fps?

 

The tables show the ball still moving out at 750fps at nearly 200 yds! (.535 ball started at 1600fps). And to get that velocity with a 43" bbl you need only 80 grs fffg!

I shoot a .45 ACP quite often. That 230 gr bullet is the same weight as a .54 round ball, and not a lot more efficient. At 750 fps or so out at 25 yards I'm pretty sure I don't want to try and catch one. So, how far down range does a .54 ball started out at, say, 1,600 fps have to be to still be loping along at 750 fps?

 

[roundball]

The tables show the ball still moving out at 750fps at nearly 200 yds! (.535 ball started at 1600fps). And to get that velocity with a 43" bbl you need only 80 grs fffg!

And plenty of energy to punch into a deer's heart at 100-125yds...just gotta put it in there...shot a buck that stopped broadside on a loggers road at 70yds...530 ball went through him like he was butter...would have surely killed him at twice that distance

 

just to follow this line with .50 data: my 70 gr fffg load in my 44" bbl generates 1700-1800 fps at the muzzle, and at 75 yds the ball is still going as fast as .22 muzzle velocities and retains about 500 ft/lbs energy. The ball from my .50 rifle smacks the deer or target at 75 yds at just under 1200 fps with a ball 4.5 times heavier than a .22 slug. Roundball's 90 gr load in his 32" bbl, generates almost 1900fps at the muzzle and at 75 yds is going at bit over 1200 fps for 600+/- ft/lbs of energy. Both of these are killing loads if shot is placed well and the deciding factor for me is accuracy of the load IN MY RIFLE. It may take 100 grs in some rifles to attain the accuracy, or 60 gr in others. The fellow who built my rifle uses 60 gr fffg in his identical .50 to get max accuracy IN HIS RIFLE...your results may vary.

 

[roundball]

And after hunting season when the range is deserted in January, I want to set up a chronograph and run actual tests on my loads/my rifles...embarrassed to say that I bought a chronograph over a year ago and haven't used it yet.

It will be particularly interesting to see if Oxyoke's claims are true that bore buttons markedly increase velocity...run tests with and without the buttons.

ie: TC's manual lists my load at 2135fps/mv out of a standard barrel (without wads)

 

Here are some more stats that I thought interesting--you can do all sorts of things with these numbers: Let's assume that we desire about 500 ft/lbs of energy at 75 yds (I'll keep all the following with a 32" bbl for simplicity). If we have a .45 (.495 ball)we will need to start it at 2100 fps. For a .50 (.495 ball) we need 1700 fps MV. For a .54 (.535 ball) we need a MV of only 1400 fps! This is of course because of increased ball weight, velocity isn't the only factor. Now the interesting part, the loads to achieve this 500 ft/lbs at 75 yds are very close for all three calibers: 70 grs fffg for the .54, 75 gr for the .50 and 80 gr for the .45. Note the reverse order of load sizes to achieve the result: smaller caliber, larger load--kinda counter to what most of us do....

 

[roundball]

Here are some more stats that I thought interesting--you can do all sorts of things with these numbers: Let's assume that we desire about 500 ft/lbs of energy at 75 yds (I'll keep all the following with a 32" bbl for simplicity). If we have a .45 (.495 ball)we will need to start it at 2100 fps. For a .50 (.495 ball) we need 1700 fps MV. For a .54 (.535 ball) we need a MV of only 1400 fps! This is of course because of increased ball weight, velocity isn't the only factor. Now the interesting part, the loads to achieve this 500 ft/lbs at 75 yds are very close for all three calibers: 70 grs fffg for the .54, 75 gr for the .50 and 80 gr for the .45. Note the reverse order of load sizes to achieve the result: smaller caliber, larger load--kinda counter to what most of us do....

Yes, and in the case of my .45cal, strictly using TC's load data as a source, I reduce their .45cal RB max load of 110grns 2F by 18%, resulting in my 90grn charge of 3F that I use in it.

And in the same vein, I use the same 90grn Goex 3F powder charge for round balls in the .50/.54 calibers.

I use a mid range charge of 100grns 2F with the heavier .58cal ball, just because it has such a high "whompability factor" to begin with.

 

eace: well, we agree on the .58 load, I also used 100 grs ffg in my .58 (a custom Hawken I made myself in 1982 with a heavy 36" Green River barrel and modelled after a Taos museum piece). That sucker was a heavy rifle but "whomped'm" on the other end! Someone out in Colorado I think has that rifle now, as I traded it at the Rocky Mt Rondy back in about 1989 for a beautiful flintlock longrifle. Should have a nice aged patina on it now....

 

[Stumpkiller]

Well then this is a beautiful system. With open, iron sights and a patched round ball a deer hunting muzzleloader is self regulating in calibers of .50 on up.

I can't SEE near as far as my .54 ball will carry lethally with the 82 grain charge I'm using in a 44" 1:66" barrel, and I need a rest to get past 70 or 80 yards and keep the sights in a deer's vitals in any case.

Ain't that just elegant? ::

 

[Runner]

That is the reality. Last day of season last year, a big doe walked by 100 yards out. I never even lifted the gun. A couple of years before that a nice buck was feeding in the oats about 80 yards out. I could not get into position in the stand to get the kind of stable sight picture I require to shoot at a deer. I finally sat back and let him walk. In that case a long oak limb was involved in the decision. The reality is that I don't need a load that dumps 600 fpe at over 100 yards, cause I am never going to shoot that far at a living animal. I can keep them all on a paper plate at 100 most of the time on the targets. I regularly shoot steel plates at that range. I did not go to a muzzleloader for long range hunting. 70 grains of 3f Goex or Grafs is plenty for me.