View Full Version : 54cal boolit length for 1/48"

02-10-2007, 11:45 PM
Question, How long of a boolit will a 54 cal 1/48" twist stabalize at BP velocity.

02-11-2007, 02:19 AM
Here's this one, but it doesn't look at velocity. I think there is another one that does(if I can only remember where)

02-11-2007, 11:54 AM
I'm tempted to answer that one "by the book", but you know that answer and asked I'm sure to get an interesting discussion going. So, I'm going to give you one man's answer to your question, then discuss it more creatively.

I have never tried anything heavier in my .54's than a 435gr MaxiHunter, which I found out of two bbls with 1in48 to be not quite as accurate as a 430gr MaxiBall. The MaxiBall is a tad bit longer, but I couldn't say how much longer as I have no more MaxiHunters to measure (no mould), nor could I do any more than guess that their bearing surfaces are about the same length. The faster twist stabilizes rb's in both my barrels with no problem and shoots them accurately, too, which goes against conventional wisdom. The GM shoots much better groups than the T/C, but even the worst groups are still less than 4" 5shots @ 100yds, more than adequate for deer or moose around these parts. If you have anything heavier and are curious, I'd be willing to test them for you.

Sometimes you get lucky and end up with a barrel that seems to shoot anything you put through it well. (I suspect that I have lucked out there twice.) The more different m/l's I shoot and play with, the less it seems to make sense, but I have honestly come to believe that luck has almost as much to do with it as twist. The majority of barrels seem to have read the book and do perform noticeably better with the balls or slugs appropriate to their twist. But, maybe as many as one in five or one in six show no preference - either they shoot most everything reasonably well (a rare occurrence), or more commonly (with the cheap imports especially) they pattern like shotguns no matter what you stuff them with. I am at a loss for a logical explanation for this, but I cannot deny the evidence. It ought to be a science, but it's an art nevertheless. I've shot $50 cheapos that were absolute tack drivers, and others costing embarrassing amounts that might as well have been smoothbores. Often the problems can be diagnosed and corrected, but sometimes the problems are not obvious and would have me tearing my hair out were I not already bald.

The only 100% rule for me is that when you find a good one, hang onto it!

02-13-2007, 06:26 PM
Twist rate = 150 (or 180 at velocities over 2800 fps) times thediameter divided by the length divided by the diameter, all in inches.

For discussion purposes only! This is what I have for Greenhill's formula in my Excel worksheet for the calculation of projectile length vs. twist rate. I make NO representation as to the validity of the formula, or the accuracy of the results.

Uncle R.
02-28-2007, 02:59 PM
Gawd I hate 48" twists - neither fish nor fowl but a half-arsed compromise, at least in my admittedly limited experience.
I have TWO of them - in a .50 CVA Hawken and a .54 T/C Renegade. Both shoot round balls very well - but only with light loads. They're great for 50 yard plinking, but when hunting season rolls around and you want to tip the powder can a little higher the accuracy starts going downhill. By the time you get to a serious full-charge load they're shooting minute-of-paper-plate at 100 yards.
As for stabilizing conicals, they make round holes in the target (when they hit it) so I guess you could say they're stabilized - but those holes aren't very close together with anything I've tried yet and I've tried a lot of different stuff. Maxi-Balls, Buffalo bullets, Lee REAL bullets, those new-fangled Power Belt thingies - nothing's given usable hunting accuracy to date. The conicals exhibit the exact OPPOSITE behavior of round balls - the higher you tip the powder can the better they shoot - if you can call going from "all over the hillside" to 16" groups "better." I'm convinced that even the shortest conicals are way under-stabilized in a 48" twist.
I've seen my fellow club members shoot downright amazing groups at 200 yards with modern sabots and 28" twists. I've seen others shoot eye-popping groups at 100 yards with stompin' powder charges behind round balls and a 66" twist. For hunting, EITHER would be way preferable to what I've gotten from the 48s.
Uncle R.

02-28-2007, 07:53 PM
Does the TC scout have the 1 in 48 twist? I haven't fired the one I acquired recently as I am waiting for the cleaning jags and brushes to arrive before firing it. Dale

mr mom
02-28-2007, 10:02 PM
ive got the mold for the maxi hunter in .50 and .54... if you would like a few to try let me know....

03-01-2007, 08:37 PM
Uncle R:

Try the Buffalo Ball-et (310 grains) in your .54 Renegade using Pyrodex Select (loose) or black. You'll be pleased. I was with my own .54 Renegade. 2" 3 shot groups at 100 yards w/TC tang peep sight.

03-02-2007, 03:31 PM
I ran some #'s on Dans design site and even with very short nose all I can get is about .75" for length and about 380gn weight. This is with two lube grooves and three drive bands and keeping things as compressed as possible.
At this point if I changed anything the twist rate went down (faster). The 1/48" twist in 54 cal is basicly for an express loading with a light for cal boolit. I was going for the biggest boolit that would stabelize in the 1/48" twist most makers have standerdized. This twist seems like a poor comprimise in an atempt to handle both round and conicle but in my experiance when we comprimise we loose the best features of both. At any rate thats what we have to work with until the wizzards that make these decissions can get it right.
Anyway we now have a couple boolit designs under way, and a range of sizing diameters available from .540" to .544" in .001" jumps.
I hope to come up with a 54 cal barrel with a twist that will handle a boolit with a much higher SD. Something akin to shooting a 550gn in 45 cal, but I dont yet know what that will be. The only other thing I will need is somone to shoot it for me. After we get the buggs worked out of 54 cal we hope to start tooling up for 58 cal. Anyone know how I might get hold of Paul Bunion to do some test firing for me?

03-02-2007, 05:56 PM
I don't think you'll be needing this but I've got a .54 Maxi mold .950 long by 405 grns. available for you to try out. It's Eyetalian Palmetto brand. ANIB. No handls but I'm sure you've got something that'll fit.
Hope you're feeling better too!