Rate of Twist and conicals

[Oldnamvet]

It is pretty much established that a PRB will shoot well even with a faster rate of twist if the load has been fine tuned for that particular rifle. But how about conicals? Can you shoot them adequately from a round ball barrel if the right load is used? Where is the point at which there is just not enough twist to stabilize the conical? I am talking about using it at moderate ranges - up to 50 yards - for better penetration of things like wild hogs. I realize that it will depend on powder, exactly the correct rate of twist as well as the particular conical being used. Just looking for general experiences of those who have tried it.

 

[Tumblernotch]

I don't know about solid conicals, but the Minie bullet has worked quite well in a 1 in 72 twist since the 1850's.

 

[CoyoteJoe]

There really is more to it than just twist rate, barrels for conicals generally have shallow grooves, only .003"-.005" deep. The bare lead bullet will not slug up enough to fill deeper grooves without blow-by. A barrel for patched balls will generally have grooves .010"-.015" deep. It is the patch which fills those deep grooves, a conical can not do so. There is nothing wrong with trying conicals in your round ball barrel, some claim to have gotten acceptable accuracy with them, but I certainly would recommend a wad under the bullet to help reduce gas cutting caused by blow-by in the grooves. You also may well have a mess of leading to clean out after shooting conicals.

 

[Blizzard of '93]

have you tryed any Lee REAL slugs? they do well in my .50. with 70gr 3F is stout load. I'm hopeing to go after hogs with mine useing that slug. at about 50 yds.

 

[nw_hunter]

Good question! I hunted for many years with a shotgun (Imp. cylinder) using slugs.Made a good 50 yrd. gun, and that's a smooth bore!I would think a slow twist roundball barrel would shoot a decent group out to 50 or so yards with a conical of some type.Perhaps someone on the forum can give us a range report on trying conicals in a roundball barrel? :hmm:

 

[paulvallandigham]

As long as you use a OP wad, or filler between the powder charge and the slug, you should be able to work up a load with any conical that will give you " Minute of deer " accuracy out well past 50 yards. It depends as much on velocity as the ROT and bore diameter as to how well stabilized a conical will be in the air. The ROT provides Rotational spin, while the powder charge provides the velocity to push the bullet through the air. Old records indicate that trials were held where rifling was as slows as 1:120 inches, and even slower for some of the .75 caliber bullets, and balls. I have not seen data on how accurate these tests barrel shot, but the fact that someone took the time to make up a barrel with that slow a ROT rifling, indicates they thought there was some merit. Without knowing the powder charges used, the weight and length of the bullets used, it would now be impossible to duplicate those events.

About the slowest ROT you find in american made rifle barrel is a 1:72. Conicals can be made to shoot well even out of this slow rate of twist, if they are short enough bullets. Some long, heavy bullets also seem to shoot okay with slow ROT, but these are usually fired in cartridge guns, with shallow grooves. Competition shooters tend to use fast ROT barrels with these large bullets for best long range accuracy. Its not uncommon to find these heavy, long bullets, " Key-holing " the targets at close range, and then stabilizing when they get out beyond 100 yards. :hmm:

 

[Little Wattsy]

As long as you use a OP wad, or filler between the powder charge and the slug, you should be able to work up a load with any conical that will give you " Minute of deer " accuracy out well past 50 yards. It depends as much on velocity as the ROT and bore diameter as to how well stabilized a conical will be in the air. The ROT provides Rotational spin, while the powder charge provides the velocity to push the bullet through the air. Old records indicate that trials were held where rifling was as slows as 1:120 inches, and even slower for some of the .75 caliber bullets, and balls. I have not seen data on how accurate these tests barrel shot, but the fact that someone took the time to make up a barrel with that slow a ROT rifling, indicates they thought there was some merit. Without knowing the powder charges used, the weight and length of the bullets used, it would now be impossible to duplicate those events.

About the slowest ROT you find in american made rifle barrel is a 1:72. Conicals can be made to shoot well even out of this slow rate of twist, if they are short enough bullets. Some long, heavy bullets also seem to shoot okay with slow ROT, but these are usually fired in cartridge guns, with shallow grooves. Competition shooters tend to use fast ROT barrels with these large bullets for best long range accuracy. Its not uncommon to find these heavy, long bullets, " Key-holing " the targets at close range, and then stabilizing when they get out beyond 100 yards. :hmm:

I will have to utter (RESPECTFULY) :bull: here. Once an object starts to "key-hole" it would defy the laws of physics to have it self stabalize into a nice tight spiral...As energy MUST spread out and we must WORK at containg it.
Picture a soft ball and a foot ball. SHOULD be thrown two DIFFERANT ways for BEST effect. HOWEVER you CAN throw the soft ball BOTH ways ie: like you should OR like you would throw the football and at shorter ranges BOTH would be resonably effective. Try and throw the foot ball like a soft ball however and it will key-hole and be a disaster dang quickly.
Length of object/bullet will have impact also....The longer the conical the faster the twist rate will NEED to be (to a point) to stabalize it. NOTE: My conical of choice (in a 26" green Mt 1 in 28 twist barrel) is the Hornady Great Plains 460 Gr. Its almost a full 1" long and states on the box "Not for twist rates under a 1 in 32". Groups FAR better for me then the shorter 385 Gr HGP's
ALLLLLL of that being said there is NO HARM in trying anything and IF it workd by golly go to it! I would probably recomend the NEED :wink: for additional guns to accomidate various bullets and loads :grin:

 

[brpc]

What is the caliber and/make of your rifle?

I recently tested some Hornady Pa. conicals in a 50 cal Lyman GPR ball twist barrel. They shot great!

With 90 grs. of 777 they would all touch at 50 yds. With 100 grs. 777 they would open up to 2.5 inches at 50 yds. The conical weights 240 grs and is very short. Apparently what is required for a slow twist barrel.

I believe that Hornady makes them in 50 cal only.

Jim

 

[Little Wattsy]

What is the caliber and/make of your rifle?

I recently tested some Hornady Pa. conicals in a 50 cal Lyman GPR ball twist barrel. They shot great!

With 90 grs. of 777 they would all touch at 50 yds. With 100 grs. 777 they would open up to 2.5 inches at 50 yds. The conical weights 240 grs and is very short. Apparently what is required for a slow twist barrel.

I believe that Hornady makes them in 50 cal only.

Jim

Been tryin to find some of those locally, wanna try them too. Thought it might be a nice game load, a little hevier then a PRB and yet a lot less expensive then most conicals.... :hmm:

 

[renovato]

I've had some fair success with the short Buffalo Ballet in slow twist barrels. I always use a wad under it though, but they seem to shoot pretty straight with a stout charge. On the other hand, being in Texas, I've put a heckuva lotta balls through hogs. Unless you're using a relatively small bore like a .45, I don't think you really need a conical for them. I know a .54 PRB flattens them like Thor's Hammer. I don't shoot any that are over about 250 lbs though so I can't say how effective it'd be on "hogzilla".

 

[Semisane]

Here's the one and only target I shot with 300 grain Lee REALs out of my 1 in 60" twist .54 caliber Great Plains flintlock. I think they did pretty well considering I used 95 grains of FFFg. A lighter charge (or better shooter :redface: ) would likely tighten up the group.

 

[paulvallandigham]

The real benefit of using heavy conicals, vs. RB is that you don't have to use as much powder to get the kind of penetration needed to kill game with the former. Definitely, reduct that powder charge. 80 grains should be tops for that bullet. You can go down to 55 grains easily and still get good performance at the typical whitetail deer ranges.

 

[Oldnamvet]

At the present I am rifleless as I sell things to finance some flintlocks. My .54 renegade with a GM ball shooter barrel was a gift to my son-in-law to keep him from buying an in-...... more modern rendition of a bp rifle. So I am currently helping him and he was wanting to try conicals. I had only shot PRB in it so wondered where we could start with the best chance of success. I think I have a handle on it now. Thanks to all who answered. Hogs up here run up to several hundred pounds. They got out from various places and have been breeding and tearing up some farms. DNR says have at them any time you want. I saw one last deer season that a guy shot that went over 400lbs. I just wanted to be sure if he popped a hog with the .54, it would have the potential to put it down with a good hit.

 

[paulvallandigham]

The .230 grain Round ball out of that .54 will take care of any deer. Do some penetration testing with the load you intend to use for hunting to see. That will put your mind at rest.

There are FLAT based conicals available , with molds available from Lyman and Lee Precision, as well as others. YOu can also buy the T/C Maxi-ball which weighs 400 GRAINS!!!YIPES!, which is over-kill for any deer, IMHO.

May I suggest that you buy 25-50 of the conicals from a supplier like Track of the Wolf, FIRST, and try them out in the gun before you invest in a mold, or even make a final decision that this is what you need to hunt deer? :hmm:

 

[slowpokebr549]

My .54 has a 1:48 twist. It likes the shorter of the TC maxi's. I forget the weight, I think it is 385 gr. It takes a pretty good amount of powder to get mine to group,that and an overpowder wad.My fifty is a 1:66 and it does a decent job with conicals provided that they arent too long and I don't try to overpower them.It loved ballets from Buffaloe, but I can't find them anymore.All that being said, I flattened a big sow with a roundball a couple of years ago.Just don't shoot em in the gristle plate, especially boars.Oh yeah, have easy to climb tree nearby or a slow buddy with you.

 

[paulvallandigham]

Try the Lee Precision R.E.A.L. slug as a substitute for that Ballette. With that Slow ROT, you need to stay with the shorter conicals. :thumbsup:

 

[slowpokebr549]

I haven't found any REALs around here.I would like to find some for my Old Army though. My fifty is so accurate with prb that I am slightly ashamed to put anything else down it.A fifty eight solved any need I had for more power.

 

[paulvallandigham]

YOu can either buy a $20.00 mold from Lee to cast your own, or buy them from suppliers. Check the " Links" section on the index page, under Member resources. Track of the Wolf has them, but so do most other suppliers.