Maximum loads in 1:48 twist with patched round ball.

[flynth]

Hi,

I'm currently reading "The sporting rifle and its projectiles" written by James Forsyth in 1860-s and he talks at length how people choose smoothbores over rifles (given the same caliber) because manufacturers make rifling with twists too fast to shoot PRB with heavy hunting load accurately at distances around 60-70m. As an example of twist he considers too fast he gives 1:42 in a 13 bore (.71 cal) rifle. He talks how when loaded with 48 grains (1 and 3/4ths of a dram) of powder it was accurate, but with even a little more it would strip the patch. That sounds to me like an extraordinary claim.

Perhaps the powders they used back then were measured by volume and they were much denser than what we have now. He talks elsewhere about a great rifle with a twist rate of 1:104,. 69 cal (14 bore) which he loaded with 137 grains (5 drams) getting muzzle velocity of 1600ft (calculated from ball drop he gives). With a modern powder I get same speed from a. 58 cal with a ball almost half his weight with 120 grains. So we can probably assume they had powders from a third to double the energy of ours.

Still, even if we take that doubling into account his claim is that using today's powder one should expect to not be able to use more than 90 grains in a. 71cal with a 1:42 twist before PRB would strip the rifling and be "no more accurate than a smoothbore". He also claims tight fitting balls and patches that have to be "hammered in" the barrels don't improve this.

I'm reluctant to dismiss authors experience of many months of shooting in India, and at the same time it sounds wrong.

I would very much like to find out what is the maximum radial acceleration a patched round ball combo can take before slipping. Modern mechanics tells us the tighter the ball-patch interface is the higher the friction and the higher the force it can impart on the ball before slippage.

Personally I haven't observed any deterioration in accuracy that can't be explained by my handling of the recoil with my. 58 cal even with 150 grains. It would be very interesting to find out what other people observed. If you found what your rifles maximum accurate PRB load is please reply with the caliber, twist rate, barrel length, ball size, patch thickness, lube type, load and powder type. Also muzzle velocity if known.

If I have few answers(ideally from people with different caliber rifles) I'll try to find out if one can calculate when this slippage will occur based on caliber, velocity, patch thickness and twist. I think having an equation like this would be very useful to many people.

[charlie b]

The twist and load will depend on caliber. Larger dia ball is more mass, so takes more effort to spin up.

Typically round ball twist rates are very slow, 1:60 kind of thing for 50cal. It does not take much movement to stabilize a ball so slower is the key for higher power loads.

If you do have a faster twist then yes you are limited to the load you can use. I have fired patched ball loads from my .50 cal Lyman Great Plains Hunter with 1:32 twist. It seems to like low charges and shorter ranges (30gn powder, 50yds). When I tried 80gn of powder the groups opened up quite a bit (paper plate size at 100yd). Never got to 100gn.

So, yes, his comments about a 1:42 twist being too fast for a .71 at higher charge weights would seem correct.

[Outpost75]

I have a T/C .45 cal. with 1:48" twist, but for heavy loads I don't shoot patched balls, but load an oversized ball bare, using a mallet and short starter to engrave it and get it into the muzzle. Once engraved you can ram it down easily enough. I load a .457" ball cast 1:30 tin-lead, with an Ox Yoke Originals lubricated wad under the ball with 80 grains of Goex 3Fg. Accurate and powerful.

Spit patch between shots.

[rodwha]

I have a T/C .45 cal. with 1:48" twist, but for heavy loads I don't shoot patched balls, but load an oversized ball bare, using a mallet and short starter to engrave it and get it into the muzzle. Once engraved you can ram it down easily enough. I load a .457" ball cast 1:30 tin-lead, with an Ox Yoke Originals lubricated wad under the ball with 80 grains of Goex 3Fg. Accurate and powerful.

Spit patch between shots.

Very interesting. I’ve read of using an oversized ball without a patch but have never come across anyone who did it.

Do you notice an accuracy difference between patched and bare?

[Outpost75]

Very interesting. I’ve read of using an oversized ball without a patch but have never come across anyone who did it.

Do you notice an accuracy difference between patched and bare?

Bare ball with lubricated wad underneath and then spit-patched between shots was more accurate. Under 2 inches at 50 yards with iron sights. Got the idea from an old Gun Digest article by Ed Harris which had LOTS of data, as is his usual custom. Convinced me!

[bigted]

Outpost, do you experience leading with your bare ball? Wonder how pure lead would do loaded thusely.

[Outpost75]

Outpost, do you experience leading with your bare ball? Wonder how pure lead would do loaded thusely.

No leading using Ox Yoke Originals lubricated wad under ball. I did not use pure lead but only 1:30 which I already had for BP cartridge loading in .44-40 and .45 Colt. The slight tin addition is needed in order to achieve the required groove diameter ball. Using pure lead I would have needed to buy a larger mold, because pure lead casts about 0.003" smaller in diameter.

[KCSO]

The maximum load is the one that groups best! If 75 grains of FFG will shoot clear through a bison what more do you need? If hunting Grizzly in the alders go to a 58 or a 62.

[bigted]

I think I have a .457 or .458 ball mold, have to look and try this out.

Can you start the bare ball with the short leg on a short starter with your palm or does it require a hammer to start into the rifling?

[Outpost75]

I think I have a .457 or .458 ball mold, have to look and try this out.

Can you start the bare ball with the short leg on a short starter with your palm or does it require a hammer to start into the rifling?

I use the short leg AND a rawhide hammer. Then once engraved it can be driven down with long starter using the palm and finally with both hands having a firm grip on a fiberglass Wonder Rod.

I do the same thing in the .50 cal. using a .509" ball with 100 grains and in the .54 with a .545 ball and 120 grains, a manly load...

[hpdrifter]

I used to have a TC Hawken; 1:48 with shallow rifling, which I think needs to be part of the equation.

If I loaded more than 80 grains(volume--really 78 is what I decided on) the groups opened up. No science there, just observation.

[Outpost75]

I used to have a TC Hawken; 1:48 with shallow rifling, which I think needs to be part of the equation.

If I loaded more than 80 grains(volume--really 78 is what I decided on) the groups opened up. No science there, just observation.

So is mine. Bare groove diameter bullets are better!

[rodwha]

Bare ball with lubricated wad underneath and then spit-patched between shots was more accurate. Under 2 inches at 50 yards with iron sights. Got the idea from an old Gun Digest article by Ed Harris which had LOTS of data, as is his usual custom. Convinced me!

Does the ball have to be land diameter or does obturation fill minor gaps? Seems a custom ball mold would be needed as Lyman states the lands are ~.520”.

Have you tried shorter for caliber bullets like the Lee REAL or Hornady PA Conical? I’m curious how accuracy and range compares to a bare ball.

[flynth]

I used to have a TC Hawken; 1:48 with shallow rifling, which I think needs to be part of the equation.

If I loaded more than 80 grains(volume--really 78 is what I decided on) the groups opened up. No science there, just observation.

What ball size and patch thickness did you use? Also what kind of patch lube and do you know the bore diameter of the rifle?

Regarding my answer to the question I went to the range today and I took my 12 gauge side by side smoothbore with me to have a comparison. Shooting a .715 pure lead round ball from the cylinder bore the ball without a patch was basically finger tight in first 2 inches of the bore and it fell in by itself the rest of the way. I used a thick cork wad under the ball and a thin paper card on top. With 90 gr of powder I got 1050fps and about 8 inch group at 50m.

With a rifled 58 cal double using 575 ball both barrels shot well with a thin patch (0.008 inch) and 70 grains. When I increased to 90 grains I had to use a thicker patch (0.01 inch) in the right barrel to maintain the same accuracy. At 120 grains I had to use the thicker patch in both barrels. I didn't find a load that would strip the thicker patch. The rifle has 1:48 twist. Interestingly with a ball 5 thou smaller it shoots no better than a smoothbore with all loads I tested (70 to 120)..

[indian joe]

I am shooting a 1/48 twist 45 cal flinter (the last several years) well past my shooting prime but that rifle good enough to get me a few wins still.
Its a cheap belgian barrel with shallow rifling, and shoots fine with 55 grains FFFg goex with a ticking patch - 65 grains is enough to upset it and 70 is a total waste of time - have had a couple of 45 CVA barrels (66twist) that would handle about any powder load you fed them and still accurate - the CVA rifling is a little deeper than this Belgian barrel but not by much and rifling depth would be part of the theory here - I dont like deep rifled barrels no matter the twist - have found deep rifling more problematical to load for and the idea of having it (deep) to give the fouling someplace to lodge - just seems dumb to me. If you are shooting a load that clogs things up you only gonna get a few more shots - learn to handle the fouling!!!

A mallet is a tool to be used in the workshop for bashing things - has no place in the loading of a muzzle loader in my scheme of things - bare ball loading might work in some peculiar ciscumstances but the patched round ball was a major advancement in rifle shooting 300years ago - why smash a bare ball down with a hammer when a hollow based minie will get it done so much easier???
just opinions - we all got em!

[DIRT Farmer]

The round ball bench rest shooters have been through all of this and if you want to learn go sit with them with a note book. I knew a very sucessful one in the medal count, his 50 ran a 505 patched ball started thrugh the false muzzle with a starter designed just for it.He loaded 150 grains of Dupont fffg which he had several 25lb kegs of from the same lot just for this rifle. His twist rate for shooting out to 400 yards was 1 turn in 14 feet, and yes that is what I ment to write. If you want to shoot match call the barrel maker, depending on the bore the maker will tell you the best rate of twist for his barrel and the load range for the bullet or ball you intend to shoot. And yes the old CVA round ball barrels with 1/66 shot good.

[Outpost75]

Does the ball have to be land diameter or does obturation fill minor gaps? Seems a custom ball mold would be needed as Lyman states the lands are ~.520”.

Have you tried shorter for caliber bullets like the Lee REAL or Hornady PA Conical? I’m curious how accuracy and range compares to a bare ball.

My bare balls are GROOVE, not land diameter. Yes, custom mold. Old Walt Melander NEI, no longer in business. Smaller balls require patching. R.E.A.L. OK, but less accurate.

[indian joe]

The round ball bench rest shooters have been through all of this and if you want to learn go sit with them with a note book. I knew a very sucessful one in the medal count, his 50 ran a 505 patched ball started thrugh the false muzzle with a starter designed just for it.He loaded 150 grains of Dupont fffg which he had several 25lb kegs of from the same lot just for this rifle. His twist rate for shooting out to 400 yards was 1 turn in 14 feet, and yes that is what I ment to write. If you want to shoot match call the barrel maker, depending on the bore the maker will tell you the best rate of twist for his barrel and the load range for the bullet or ball you intend to shoot. And yes the old CVA round ball barrels with 1/66 shot good.

Curious -- how good do these RB bench guns shoot for all the extra trouble ? I had a CVA 50 cal pennsylvania flinter twenty years ago I always reckoned might have done MOA if someone other than me hadda benched it with a decent scope aboard - I did a couple of ten shot just on two inches at 100yards (unsupported sitting position, open barrel sights) - that was the limit of my eyesight and ability to hold on my best day then (can remember it - cant repeat it )

[pietro]

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T/C used mostly 1:48' twist barrels, and their loading manual show their maximum suggested PRB load for different bore sizes with a MAXIMUM label.










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[DIRT Farmer]

The round ball bench guns shoot like bench rest guns should. I was watching a quater match one day, the target was x centerwith the x ring 1/2 inch. the shooter lost the bet because he left part of the line on the x ring. Most have bases to shoot open sights, peep sights and scopes. 40 pounds and up and they regulary shoot out to 200 yards with round ball. Even I could shoot round balls off the target frame.