I am sorry but I have to call a little BS here. It is the length of the bullet along with the diameter that dictates the rate of twist. For example. A 22 caliber that shoots a 45 gr bullet might have a 1-12 twist. A 22 that shoots a 70 gr bullet will have a 1-9 twist. Also velocity has a minor role in it as well. There is more to it than just pure "the smaller the bore the faster the twist"
RON please re-read my post , you will notice i said projectile we are not just talking conical here but also round balls . i guess thats my falt , i wasnt clear when i said the above and differentiate between the two .
there is alot of things that are involved not just twist of rifling .
this might interest you .. you may also have already read this but im sure others here have not .
as a gunsmith myself , no where near the caliber of this fella by the way , but i totaly agree with this and have also found it what he is saying to be true
OK, Time to dispel a myth.
As a gun maker, and a former barrel maker (yes, I have done them myself many times)
I can tell you all with 100% certainty, that TWIST is by far the LEAST important thing to consider in the overall accuracy of a barrel for round balls
I have twisted them as fast as 1 in18" and gotten one hole groups at 50 yds with heavy charges. I have done the same thing with 1in 104".
The geometry of the rifling is WAY more important to accuracy than twist, and straightness and quality of the bore is paramount.
While twist is the least important thing to consider, it's not compleately un-important. But for strict accuracy, 1-48 is absolutely fine.
In Forsyth rifling, the idea is to spin the ball enough to keep some gyroscopic stability to it, and to keep the bore from fowling as much as we can. Forsyth rifling is about the best there is for that.
Now if it had the same geometry and had a twist of, let's say, 1-100", you would have to drive the ball forward faster to get a higher spin in revolutions per second. That means more powder. That means more power, and more recoil.
I recommend a 1-48 twist for a .62 for rifles that will be used for fun and targets more than for hunting.
I would use about 70 grains and maybe up to 90 gr. for your shooting, depending on what the rifle shot best. Shoot the load that shoot most accurately on deer and so forth, and I would go up to about 140 grains for buffalo. My own .62 rifle is twisted 1-56 and I shoot 140 gr in it. Also, for elk and buffalo shoot wheel weight balls. They penitrate MUCH better than pure lead. Don't water drop them. Just drop them on a pad and let them cool.
Now most barrels will shoot one load better than all others. In my gun, the difference between a 80 grain charge and a 140 grain charge is a 4" 25 yd group and a 1 hole 25 yd group. At 100 yds, my rifle will keep all the balls inside about 3" with the 140 grain charge, but won't keep them on a 16" square paper with an 80 grain charge.
However most barrels will not be as extreme in their load preference.
You just have to shoot it, and see for yourself.
The only thing that needs to be added (which is not widely known) is that the twist is the least important thing in rifling as far as strict accuracy goes. Geometry is far more important.
You see, once a ball is stable, it's stable, but the idea that you can 'twist it too fast for accuracy" is not correct. i have cut Forsyth style rifling in barrels as fast as 1-16 and they shoot one hole at 50 yds. The thing the slow twist will do better is LOAD easier once it's fouled.
The bigger the ball, the lest you have to twist it to make is stable because the larger the ball the larger the circumference, and the greater the rotational momentum will be.
ball in flight will loose over 60% of their velocity over the maximum effective range, but only about 10% of their rotational speed, so they don't "go unstable" like bullets will at extreme range. Or course a bullet has MUCH more range then a ball but it's not possible for a ball to "hit sideways" if you see my point.
Revolutions per second is what caused the "gyroscopic effect" of a ball in flight, and once it's enough, it's enough..........so the only 2 ways for the required R.P.S. to be reached is (A) how fast the barrel is rifled and (B) how fast the bullet is moving when it leaves a barrel. in VERY slow twists barres it's often necessary to move the ball at 1700 FPS or more to make them accurate, whereas if the barrel was twisted faster, you can use less powder and lower velocity, and still make is shoot very small groups, but at the cost or range.
So what you need to ask yourself is this:
What is the rifle going to be used for mostly.
Hunting? If so, get a .62 barrel rifled at about 1-66 or slower.
Target shooting? If so, get it rifled at about 1-40 to 1-48
You will find that wide grooved and narrow lands will load the easiest, and stay cleaner, with round bottom 1-1 rifling being in 2nd place.
Whitworth rifling should be avoided in ball barrels. It is quite accurate, but fowled very quickly, and loads
