Big bore twist rate

[billd]

What twist rate would be best for a 66 caliber round ball?

Thanks
Bill

[blackbruin]

That .66 from Jason I grabbed last weekend was 1-66, be a while until I can let you know how it does.

[Old Ford2]

Large lead spheres need a slow twist to overcome inertia.
So .60 and bigger do well with 1:66 and even slower.
Once that big old ball gets spinning it is like a locomotive.
I have see .69 cal. bullets do amazingly well with a 1:104 twist.
A friend had this in his .69 Jaeger, and we had a hard time beating him at the range.
And we were shooting pea rifles compared to that monster .69.
Fred

[Robby]

If I remember correctly my .69 is 1 in 108". It is a very accurate and very consistent gun out to one hundred yards, and most probably further, but can't verify because a hundred is what I have.
Robby

[bigsmoke]

My .62 and my .69 that I have and the .66 and the .72 that I used to have were all 1:104.
The 8 bore and the 4 bores I used to have were all 1:144.
They all liked large amounts of powder but shot quite well.
The .62 likes 135 grains of Ffg for target shooting, and the .72 liked 160 grains of Ffg.
Agreed, that is a lot of powder to just poke a hole through a paper target, but that is what it likes.
On the other hand, at 100 yards, the .72 loaded with 200 grains of Ffg poked a hole clean through an 1,800 pound bison's neck.
John

[Daryl]

Considering my .69 with it's 66" twist starts really shooting well at 100yards out to 200 with 140gr. 2F, I'm not sure I would be "up" to shoot what a "104" twist might demand. Since I no longer have any of my 100yard targets in possession, I'll post this one - a 10 shot group which included 2 shots offhand, performed at 50 yards one day, testing different patches. I used the 12 ounce denim for this load, due to the 15 bore ball being used.
The gun does shoot well at 50yards with a mere 80gr. 2f, an easy shooting "plinking" load, and actually made some 2" groups at 100 with 'this' light load.



This one was shot with a 16 bore ball (.662") using 2, .017" denim patches, 6 ounce denim I think it was.



I honestly do not think I would go slower than about 80" or 85" twist, if wanting Forsyth-style rifling- shallow with very wide lands. For regular .012" deep rifling, I'd prefer a 66" to maybe a 70" twist.

[tddeangelo]

My 62 sports a 1:56 twist. I just got it a few months ago, and it's a hunting gun, not a target gun, so I have some experimenting to do yet. 120gr 2f under a 0.600 ball in 0.024 pillow ticking has been pretty consistently a 2.5" load at 50 yards and around 4" at 100 (off the bench). It's a Hoyt barrel, 46" long.

I have some 0.610 balls to mess with yet, but I got that kid settled quick, as the rifle arrived shortly before hunting season and I wanted to hunt with it.

Now that the season is over, I can play around a bit and see if I can dial it down any tighter.

[billd]

Thanks for all the info.

 Blackbruin, I ordered one from Jason, however it will be shorter and lighter than the man size barrel you bought.

Jason's recommendations are very similar to Daryl's for moderate powder loads.   My shoulder is too old for much more.

Thanks
Bill

[Dphariss]

What twist rate would be best for a 66 caliber round ball?

Thanks
Bill

I would not go slower than 80" and likely would go with 66-72. Those making very slow twist barrels and shooting ridiculously heavy powder charges have run off the rails.
140 gr of FF will give all the power one needs for anything that a 66 RB should be shot at.
Forsythe using a slightly larger ball "#15" about  .678+-, could drive a hardened ball though an Indian Elephant's head with 137 gr of  "Halls #2" (about like FFF Swiss I suspect since the European designation for FFF Swiss is #2 IIRC). This was from a rifle with barrels about 26" long. I doubt that the powder charges some people are recommending for "Fosythe" barrels are based on history or even effectiveness. Its more likely one of those phallic symbol things...
If I were to have another barrel made for a .662 ball I would want shallow grooves .008-.010"  that were at least 3X the lands and not fewer than 10 grooves.
One other thing that needs to be said. Forsythe was wrong in his idea that a slower twist gave higher velocity due to reduced friction. This was well known probably before he was born. Like all old books the "science" is often a little "off". Increased friction, resistance to initial projectile movement, produces HIGHER velocity with BP not lower. At one time rough reaming the bore of a shotgun for a few inches up from the breech was a way to increase shot penetration (velocity). What the slower twist does is allow more powder to be used. Given that many British/European rifles even of Forsythe's time (1850s-60s) have rifling of one turn in a barrel under 36", most indeed having twists suitable for very long bullets, its no wonder that stripping the patch was common with if the velocity was pushed much past 1000 FPS. While the fast twist was proven to be unnecessary by Baker around 1800 the practice persisted with some makers until the cartridge era and even beyond. This made many large bore English rifles unsuitable for large game and many hunters used SBs since Elephant and such were generally shot under 50 yards and often much closer. The fallacious idea that a fast twist was needed was the reason the belted ball with fitted rifling came into use. Sir Samuel Baker's  "Devil Stopper" was a 6 bore "two groove" rifle.

Dan

[bigsmoke]

Dpharis,
It would appear that you are possibly making a common mistake of confusing a dram with a drachm.
Assuming that you are looking at The Sporting Rifle and It's Projectiles where Forsythe is discussing recoil?  He says blah, blah, blah #15 spherical ball and 4 drachms Hall's #2 Rifle Powder.
So, a dram = 1/16 oz or 27.34 grains.  4 Drams = 109.36 grains
Alternately, a Drachm = 1/8 ounce or 60 grains.  4 drachms = 240 grains.
Huge difference.
Maybe Forsythe was advocating large powder charges in his rifles after all?
He called for 1:104 twist for longer ranges and 1:144 for shorter ranges (less than 150 yards).
Personally, I have had all my big bore rifles made with a 1:104 twist and found them pleasant to shoot, accurate, and amazingly flat shooting firearms.  Correction:  I did use 1:144 in my 8 and 4 bore rifles.  Anything from .62 to .72 was 104.
Also in the book, Forsythe mentions something about his 8 bore rifle and using 6 drachms powder in it.  Big boom!!!
In my .62, I use 135 grains Ffg GOEX and I find it is actually a more pleasant rifle to shoot than my .54 with 85 grains Ffg, 1:70 twist.  Go figure, both rifles weigh about the same.
John

[Dphariss]

Dpharis,
It would appear that you are possibly making a common mistake of confusing a dram with a drachm.
Assuming that you are looking at The Sporting Rifle and It's Projectiles where Forsythe is discussing recoil?  He says blah, blah, blah #15 spherical ball and 4 drachms Hall's #2 Rifle Powder.
So, a dram = 1/16 oz or 27.34 grains.  4 Drams = 109.36 grains
Alternately, a Drachm = 1/8 ounce or 60 grains.  4 drachms = 240 grains.
Huge difference.
Maybe Forsythe was advocating large powder charges in his rifles after all?
He called for 1:104 twist for longer ranges and 1:144 for shorter ranges (less than 150 yards).
Personally, I have had all my big bore rifles made with a 1:104 twist and found them pleasant to shoot, accurate, and amazingly flat shooting firearms.  Correction:  I did use 1:144 in my 8 and 4 bore rifles.  Anything from .62 to .72 was 104.
Also in the book, Forsythe mentions something about his 8 bore rifle and using 6 drachms powder in it.  Big boom!!!
In my .62, I use 135 grains Ffg GOEX and I find it is actually a more pleasant rifle to shoot than my .54 with 85 grains Ffg, 1:70 twist.  Go figure, both rifles weigh about the same.
John

Yeah I used to think that too. But I was wrong. Using his actual fired trajectories as a guide I recreated them with a ballisitics program. 1600 fps +-.   I chrono my 16 bore rifle with 140 gr of FF Swiss. 1600 fps. Do the same thing as see what you come up with.

Dan

[Dphariss]

Before I got a larger bore rifle I was also working on the idea that a 14 bore rifle would require the same ratio of powder to ball weight as a 50-54 caliber rifle would. Not knowing that the large bore rifles were far more efficient.
Thus a 16 bore would need something in the realm of 200 gr of powder to make 1600-1700 in a short barrel. This is not the case.
So the idea that Forsythe was using the 60 grain drachm  is not corrent. Nobody else in firearms at the time was doing this why would he?

Dan

[Dphariss]

And we have John Taylor in modern times (1930s) shooting 6 drams of powder in a 10 bore with hardened lead to kill African Elephant. The gun, a smooth bore, was engraved with the charge or perhaps it was cased and the case was marked. This tells us that Forsythe's "5 drams" was indeed drams SO FAR AS UTILITY, i.e. it would do want he wanted with that charge level. Which with a 15 ga ball would be about .29 of ball weight.  Taylor's charge in the 10 bore, assuming shooting an 11 ga ball he was using .26 of ball weight. Which is "ball park" in terms of powder charge/ball weight ratio.
Now Taylor states that the 10 bore was only suitable for heart/lung shots and he would not want to face a charge with it. But he did kill "13 good bulls" and several Rhino before his supply of modern ammunition arrived. He also stated he never lost an animal he shot with it. I suspect that, given the load it was regulated for that it was a short barreled smoothbore intended for use with ball. Then we go back to the American Revolution we have Hanger telling us that; first he never saw a Kentucky over 36 to the pound, and that he had one that he could shoot 1/2 ball weight of powder "without the slightest recoil". This falls into line with modern experience with 45-50 caliber rifles of today where 1/2 ball weight gives 65 to 90 grains for those ball sizes. Charges many shooter find to be close to perfect for accuracy and flat trajectory. When we go to calibers under 45 then the powder to ball weight ratio may go as high as .75 ball weight to obtain best accuracy as the lighter projectiles provide less inertia and are less efficient as a result. The reason for this as the balls diameter doubles, from .33 to .66 the weight of the .662 ball is 8 times that of the .331 ball. This increased inertia requires more pressure to move the ball and will produce a better burn of the powder as a result.

Dan

[Daryl]

I find 140gr. 2F (5.1drams), 29% of ball weight to be a good, accurate load in my 9 1/2 pound rifle & producing 1,500fps. There are few who agree, though.
1/.- aiming at 200yard target.


2/.- almost full recoil

[bigsmoke]

I believe I used to call that "Recoil Therapy".
Much less expensive than a visit to the chiropractor.

[Daryl]

Forsyth- chapter V
"******smooth bore, 9 lbs. weight, with 30-inch barrels, 14 gauge, loaded with spherical No.15 ball, and 4 drachms of powder, gives a moderate recoil.

Now, if Forsyth meant 4 drachms at 60gr. to the drachm, that would be 240gr. of powder. I can tell you from experience that he most certainly did not mean the Apothecary's weight of 60gr. to the drachm, but actually meant 27.3gr. to the Dram, as 109.2 t 110gr. does indeed give a moderate recoil. Look at the picture above of the recoil of a mere 5 drams + 4gr. - imagine 240gr., ie: 8.8drams!!!!!!!!!!!!

In an 8 pound SXS modern shotgun, my first shot of a 14 bore ball with 6 drams (191gr.) of 2F GOEX spun me around like a weathercock - ask Taylor- he was there. That shot also split the stock. I have also fired 240gr. from the rifle pictured above - it will lift you off the seat - moderate recoil it isn't.

Forsyth also talks about trajectories with certain powder charges in chapter 5.  These trajectories, and point blank ranges, correspond to drams  equivalent charges, not drachms.  His listed charges seem to match my zeros with those same powder charges very closely.

Also- when he refers to the issue 24 bore - military rifles, ie: the .577 Enfields, he also uses the drachm word, but the charges, ie: 2 1/2 drachms  match the dram charge actually used by the government- ie: 68gr.

As tot he elephant's head, Baker noted, "4 1/2 or even 5 drachms may be used in such a rifle without any very unpleasant recoil".  

5 drams would be 136gr. - note above what 5 drams + 4 gr. kicks like - 5 drachms would be 300gr. - YIKES - yes - I accidentally fired off one of those.

"without any very unpleasant recoil"  does not even remotely describe the recoil of that charge.

[bigsmoke]

This is all FWIW, of course.  Different strokes for different folks and all that.
In my old .69 caliber rifle, I regularly fired 200 grain charges and I did not feel that it had abusive recoil.  I have fired an entire trail walk a 250 grain charge and other than some steel silhouette targets getting bent up a little bit, no harm done.  Let's see, 250 grains = nearly 4 1/4 drachm.  It can be done and it's no big deal.  A complete waste of powder, but no big deal.
In my .72 caliber rifle, I did not feel that the recoil from 200 grains of Ffg was abusive, but I let another fellow shoot it one time and he said that it was the most brutal rifle he ever shot.
So, like everything, I think there are two different sides of the story.
Start light and go up in powder charge if you dare.
The big bores have definite sweet spots where accuracy is obtained without using a lot of powder.
In regards to Forsythe, Baker and all the other African and Indian big game hunters, these were guys who regularly shot and hunted nearly every day.  They probably killed more elephants in a year than we will ever see in our lifetime. This is what they did and they were used to doing it.  And don't forget, Baker was a really big guy as well.  What might be abusive to a 5'9" 170 pound American modern guy was no doubt a cake walk as far as he was concerned.
Me, I am 6' and about 235 pounds.  I absorb recoil pretty well.  Maybe other folks do not.
John

[heelerau]

Sir Samuel White Baker was an enormous man, all muscle, his two bore rifle used a charge of about 10 drams, and fired a half pound percussion shell. These Victorian era Englishmen  had iron nerve and would drop a charging elephant at a few yards. I believe this rifle wieghed in at about 20 lbs.  He himself was over 30 stone and all muscle, he found this rifles recoil to be brutal, but kill every thing he shot with it.
     I use drams, about 27grains equilivent in my rifle muskets and fowling pieces. I use grains in my longrifles.

[Daryl]

I'm 6' or more and 235 as well, John, but I do NOT like recoil any more- used to but it screwed up my shoulder cartilage.  I do enjoy shooting my little .69 - but only with the 140gr. charge or less powder. I am going to try some 4 to 5dram charges with Swiss 1 1/2 powder, just to observe the speds and recoil changes.

[bob in the woods]

I regularly shoot 120 gr powder in my .62, and 140 gr FFg in my 10 bore.  Based on the performance, I don't see any need for an increase in the charge. Even the trajectory is pretty good.  I did accidentally double charge the 10 bore ONCE !  Not something I care to do again 

[Vomitus]

 yep, when ya blow out that shoulder, you can always use the other one.

[billd]

Very interesting conversation.  I learned a lot.   Thanks,

[JBJ]

Leatherbelly, what do you do when both shoulders are blown (I'm there)? This getting old is for the birds! I now have to use a PAST recoil pad and it still takes a toll after a few shots from a big bore at full throttle. Wish I had had enough sense to use a PAST in years gone by. And ear protection! Too soon old and too late smart. Oh, well. Where's the aspirin?
J.B.

[Daryl]

JBT - a few years back, when my shoulder was at it's worse, I used a PAST shoulder pad under my 'period correct' shirt as I shot the .69 in 5 events. That was the best rendezvous I've had - 4 firsts in the ML events and placed middle of the pack in the BP ctg. offhand event with that ML rifle - the shooting was close, only to 250yards. I was quite happy with that placing.  I actually got 3 hits out of 5 shots at 250yards, the plate was quite large- about 2' IIRC.  Of all things, I screwed up on the 100yard range. LOL.
 
Just shows, the PAST works and there are several thicknesses available.