The pre-64 Winchester Model 70 was chambered for a while in 250-3000 Savage, the barrels of which were manufactured with a relatively slow 1-in-14 twist.
Going much further back in time, the Winchester Model 86 chambered in 45-70 Govt was made with a 1-in-20 barrel to stabilize 400 grain and heavier bullets. But Winchester made Model 86s chambered for the 45-90 Express with a much slower rate of twist, 1-in-32, because the cartridge was to be loaded with shorter and lighter 300 grain bullets.
It was once received wisdom that bullets could be spun too fast- overstabilized- by too great a rate of twist for the bullet’s length, to the detriment of accuracy.
I believe there was a corollary theory that excessive rates of twist retarded muzzle velocity and unnecessarily increased breech pressure. This also supported Winchester’s decision on twist rates for its light Express cartridges. (A decision later adopted by Weatherby in the late Forties, e.g the 1-in-12 twist for the early 270 and 7mm Weatherby Magnum rifles.)
The “Goldilocks” rate of twist theory affected the competition between the 244 Remington and the 243 Winchester designs in 1955.
Does anyone have actual experience with an overstabilized bullet?
I’m not one to believe post Civil War engineers at WRA were acting out of ignorance or inexperience.
I’ve read bullets were once less internally consistent, that their mass was more unevenly distributed, such that the minimum rotational velocity necessary to stabilize them in flight was best.
War stories?
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
Bill,
It’s mind boggling to me to even try to comprehend a lot of this, but I do understand, and I can appreciate it. It also reminds me if the 1-36 twist rate of the first model 1873’s, in my feeble mind. Powder, bullet weights, etc………….all add to where we are with this.
Anthony
Interesting question indeed, that I never saw written about or even discussed! But I have thought a lot about in my mind, and two things you mentioned I kinda already formed my own opinion, but my experiences are limited to 30-30, 30-06, 270, and 22 Rinfires, theirs being long accepted twist rates that seem perfect for needed bullet weights. My only pondering being, ” Maybe Winchester should’ve used a faster rate in the 270WCF? But it seems to be fine until bullet weights exceed 150gr, and I’d never need or want anything bigger than a 150gr, but, the rifle could be very beneficial as a big game killer in say Alaska or Africa with 160-180gr bullets? But I think for the 270’s intended use, 110-150gr they got it right, and a faster twist would and could work against the main design of a 130gr.
But will a faster rate increase pressure? IDK, once an object is set in motion, either forward or spinning, maybe it doesn’t effect it as much as we think? One good comparison I can think of in near or almost the same bullets is 30wcf vs 32Spl. From what I’ve seen, the 30wcf is usually more accurate down range with near equal bullet lengths at the same velocities. But those comparisons to me are limited!
And look at the fouling of a barrel of the long range black powder shooters, in a fast twist rate barrel! This to me seems like maybe it could increase pressure also? There’s some remarkably accurate cartridges shooting long heavy bullets with a really slow twist! But I’m sure there’s a perfect twist rate for every weight&length bullet that’s “just like Baby Bears Soup, just right!” thus better accuracy!
But in my mind, I gotta think a too fast twist would work to slow a bullet down to fast at longer rangers? This just seems to me has got to be true! Again IDK, but I’d bet it would! But it sounds like over stabilized?
Gentlemen: I didn’t make my question as clear as should have been done.
1. Going back to the 45-90 Express, an original offering in the Winchester 1866, I think we can safely assume Mr. Bennett considered the 86 to be an extremely important product at the time of its introduction. WRA paid a big ($40,000 in cash and goods) price for Browning’s action design and Winchester’s best gun designers and senior mechanics, particularly Mason, labored to make the rest of the gun approach perfection.
If the barrels of the original 1886 were rifled differently as between the 45-70-400 and 45-90-300, the former with a twist rate of 1-in-20 and the latter at 1-in-32, it is hard for me to believe that was done on just on the say-so of outsiders. President Bennett was a graduate of the Sheffield Scientific School, now called Yale University’s School of Engineering, then as now not exactly chopped liver. Mr. Bennett was well known for having an experimental turn of mind and a taste for ballistics. He was the leading spirit and hands-on involved in creating the 44 WCF.
My point is, if the new 1886 rifle when chambered in 45-90-300 would shoot factory ammunition at its best if barreled with a 1-in-32 twist, instead of a 1-in-20 twist, that was almost certainly an empirically demonstrated fact, because it was done on Bennett’s watch.
2. Going forward to the Twenty-First Century, Winchester Guns, heir to the Winchester Repeating Arms gunmaking assets, contracts with Kabushi kikaisha Miroku [Miroku Corporation] to recreate the Model 1886 in both 45-90 and 45-70 chamberings. Of practical necessity to utilize high-precision machining techniques and equipment, the new guns are rendered in metric rather than SAE, but the metric dimensions of both caliber rifles’ chambers and bores convert exactly to the original Winchester inch designs.
Except the new 1886 45-90 barrel is rifled with a 1-in-20 twist. While a cynic might sneer that this was done just to save money – why maintain two different barrel inventories — I disagree.
Neither FN Herstal nor its subsidiary Browning Arms d/b/a Winchester Guns sell guns that don’t shoot accurately, and the guns they sell are priced accordingly. Some things are too clear to be argued. By all accounts so far, modern 300 grain .458 bullets can be made to shoot quite accurately in a 1-in-20 Miroku-made barrel.
So can modern 139 grain .284 bullets in a 1-in-10 barrel. And even modern 110 grain .308 bullets in a 1-in-10 barrel.
So, what changed? The homogeneity of modern jacketed bullet cores and a lack of voids in modern lead alloy bullets?
Is overstabilization no longer relevant? Was it more myth than fact?
PS. I’m aware of the ROT/Stability engines available on the Web and have happily spent hours playing with them. But the algorithms and formulae they employ are based on modern projectiles. I don’t think they can provide complete answers.
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
Zeb, You are now into the intrinsics that keep some from sleeping well at night! I for one can’t tell you much, especially that you don’t already suspect or know. But I do have some anecdotal info that may help. I have seen definitely “overstabilized” bullets. A fellow in WY was shooting prairie dogs with a .22-250 IMP, and using about 40 grain cup and core bullets at excess of 4,000 fps. They blew up as they were fired, printing two or three dust puffs somewhere near the prairie dogs. Would a homogeneous bullet do that? I suspect not. Add to that my shooting a 1 in 8 twist .223 using a 60 grain cup and core bullet, I had no problems nor did I have inaccuracies. I have gone as high as 72 grain cup and core bullets and shoot very accurately, tho the 69 gr. Sierra Match bullet may be the best for accuracy in my rifle. Lightest is a 50 gr, and it does well. Lastly is the bench rest crowd and my bench rest rifle. In 6mm, it uses a 1 in 13 twist and is limited on the top end as to length of bullet to about 70 to 75 grains for a cup and core bullet. I doubt a homogeneous bullet would stabilize at those weights. I was told by the builder the idea was to get a twist rate that allowed the highest velocity and minimally stabilized the average bullet length for 100 yard shooting. Some of my thoughts–bullets are different and ‘better’ than they used to be. And there is plenty of say so and old wives’ tales out there. Under radial spinning is more damaging to accuracy usually than over radial spinning/stabilization. Slow twist rates can be helped by higher velocities. Plus I am sure I’ve missed some other points. My personal thought anymore is to not think of these things as they need to be tested and adapted as circumstance requires. Tim
As Tim described, there are many instances of modern projectiles “exploding”/ coming apart due to velocity and spin. In addition to metallurgy, profile shape has changed. I’m not a student of old ammunition but when the profile (shape and length) of the factory bullet changed, then so did its ballistic coefficient (BC). Mr. Bennet would have realized the change in BC might require a better suited twist rate and experimented to find the most suitable for the ammunition of the period.
Technically, the glass is always full; half liquid, half air....
WACA #10293
Thank you, Tim and Ron. To sum up my understanding of what you’ve said;
1. There is a radial velocity beyond which some cup-and-core bullets will come apart in flight, from internal stresses created by being spun too rapidly.
2. There is a question whether a homogenous bullet would do so but you think it unlikely.
3. Too slow a twist is more damaging to accuracy than too fast a twist, within a certain range of radial velocities the upper and lower limits of which depend on the physical characteristics of the bullet.
That would seem to leave hanging the question whether you have observed or experienced a decrease in accuracy from a bullet when its radial velocity increases past a certain point but before it fails to reach the target (or makes more than one hole) because it has self-destructed. That, to me, would be a proven case of inaccuracy caused by overstabilization
I’m guessing cranky old Texas German antebellum scheutzenfest competitors would have opinions! If you plied them with enough lager.
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
Bill,
Later this Spring I will be testing the theory on shooting light bullets in a faster twist. Specifically, I loaded (20) rounds of 222 Rem Mag using a 35-gr Hornady V-Max bullet with 25-grains of IMR 4198.
I am going to shoot this load in my Remington Model 700 BDL Heavy Varmint that has a 24-inch barrel with a 1:14 twist (designed for 55-grain factory loads). Doing the math, the 35-gr bullet is just 64% of the standard bullet weight, and the load I chose should be somewhere in the 3,900 – 4,000 fps range. I believe that this will be a test of precisely what you are asking about.
WACA Historian & Board of Director Member #6571L
rwsem said
As Tim described, there are many instances of modern projectiles “exploding”/ coming apart due to velocity and spin.
I’ve never had this happen. But was curious to know if anyone has done this or had it happen. Was there any visual signs of it happening while in flight.
It got me to thinking of how very hot loads can cause a bullet to smoke. Which I’ve seen before.
WACA #8783 - Checkout my Reloading Tool Survey!
https://winchestercollector.org/forum/winchester-research-surveys/winchester-reloading-tool-survey/
Bert H. said
Bill,Later this Spring I will be testing the theory on shooting light bullets in a faster twist. Specifically, I loaded (20) rounds of 222 Rem Mag using a 35-gr Hornady V-Max bullet with 25-grains of IMR 4198.
I am going to shoot this load in my Remington Model 700 BDL Heavy Varmint that has a 24-inch barrel with a 1:14 twist (designed for 55-grain factory loads). Doing the math, the 35-gr bullet is just 64% of the standard bullet weight, and the load I chose should be somewhere in the 3,900 – 4,000 fps range. I believe that this will be a test of precisely what you are asking about.
Bert, yes, that should give us some useful answers and I look forward to your results.
One caveat, if those 35 grain bullets are what you showed me at Cody.
They have a long polymer tip, materially increasing their length.
How does the OAL of the tipped 35 grain bullet compare to the OAL of a “normal” 55 grain .224 spitzer that we know shoots accurately in 1-in-14 at .222 Mag velocities?
My understanding is it’s length rather than weight that matters. If so, maybe a stubby 40 grain 224 Hornet bullet would give a starker comparison.
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
Bill,
They are indeed the bullets I showed you at the Cody show (I had loaded up a 50-round batch of them for my K-Hornet).
The OAL of the 35-gr V-Max bullet is significantly shorter at just .517″ whereas the OAL of the 55-gr SP 222 Rem bullet is .708″.
Just for fun, I measured a 45-gr HP Remington Hornet bullet (that I load in my standard Hornet), and they are .518″, nearly identical to the Hornady 35-gr V-Max bullets. My Model 43 22 Hornet absolutely loves the 45-gr HP bullets.
Bert
WACA Historian & Board of Director Member #6571L
Bert H. said
Bill,They are indeed the bullets I showed you at the Cody show (I had loaded up a 50-round batch of them for my K-Hornet).
The OAL of the 35-gr V-Max bullet is significantly shorter at just .517″ whereas the OAL of the 55-gr SP 222 Rem bullet is .708″.
Just for fun, I measured a 45-gr HP Remington Hornet bullet (that I load in my standard Hornet), and they are .518″, nearly identical to the Hornady 35-gr V-Max bullets. My Model 43 22 Hornet absolutely loves the 45-gr HP bullets.
Bert
Excellent! Now we’ve got a solid baseline for the experiment. All you need is a windless day and a set of control groups of the “standard” 55 grain bullet, from the same rifle at the same range session. Should you use the same primer and powder, albeit in different quantities?
I’ve never owned a .220 Swift but Winchester was said to get velocities over 4.000 fs with 40 grain bullets from a 26″ barrel and not all of them exploded in flight. Hard on barrels, I understand.
If you can prove up an accurate >4k load with the Hornady 35 grain bullet from a .222 Magnum and its much more modest quantity of cooler-burning powder, that would be a real coup. I think it would also tend to disprove there is a maximum radial velocity for best accuracy.
If, however, the groups open up with the shorter bullet, but tighten up with reduced quantities of powder and velocity, that should tend to prove the opposite, the only other variable being a possible loss of accuracy caused by a change in the particular barrel’s oscillation frequency with a maximum powder charge.
All this assumes a rock steady shooter who ate a solid breakfast and is not still metabolizing alcohol from the night before.
Your fellow Members are counting on you.
Bill
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
Bill,
My pet load for the Triple-Deuce Mag is 27.5 grains of IMR 4064 under a 50-gr Sierra Blitz SP or a 50-gr Nosler HP. It produces 3,405 fps out of the 24-inch barrel. That load is above the currently published maximum, but when my grandfather developed the accuracy load for his Remington Model 722 Triple-Deuce back in the early 1950s, he consistently shot “one-hole” 5-shot groups with it. I can consistently shoot 1/2 MOA groups with my Model 700 Heavy Varmint. No signs of pressure, easy extraction, and with just neck sizing, I get at least (15) load cycles out on each case. I have one batch of old REM-UMC brass that has (21) reload cycles, and a couple of batches of Herter’s brass with (20) load cycles.
I just recently scored this full case of NOS 222 Rem Mag ammo in an auction… it brings my total supply to (60) boxes (1,200 rounds) of factory new 222 Rem Mag ammo. I have another 1,300 rounds of reloads.
WACA Historian & Board of Director Member #6571L
Bill,
As far as the .220 Swift is concerned, my 1948 model 70 in that caliber, as a shooter with a Hart Heavy Barrel, and an ultra varmint Unertl scope, is simply a tack driver. (Already in Louis model 70, survey, for collector clarification, purposes). I have no idea whatever happened to the original barrel. Maybe it was worn out, like you say. Bought from a late friend, years ago who needed the money. He loved the model 70, and the .220 swift caliber, as he would shoot wood chucks,(groundhogs), here in Ohio, and at our Pa farm/hunt property, as I’ve seen him take some extremely long distance shots, with amazing results. Never had the need for anything other than factory loads, as did my old friend, who also was a re loader, and a few years older than me. I don’t remember him ever loading anything up for the .220 Swift, as no ammo came with the gun when I bought it years ago. That’s not to say he didn’t work up any loads for it, as he liked to dabble in that area, ans we never had issues with poor performance of the ammo we used. I was always told by him and my late brother in law, who introduced me to this gentleman that the loads we we’re using we’re @4,000 fps, or there about. At least that was the conversation several years ago, and we had several woodchucks stacked up from long distance shots, over a few years, back in the day. We had such great results with the ammo we we’re using, as mostly Winchester ammo as I recall, and possibly among others. I relish the great memories, as I still have the rifle and will hand it down to my Sons!
Anthony
I think we couldn’t ask for a better test bed. Although I’m a diehard fan of the original Model 70, I remember admiring a Remington 700 HV BDL at Mcbride’s not long after it was introduced and wishing I could bail it out. Even though I was not a varmint hunter, in the strictest sense of the term.
The 222 Magnum has always seemed to me to be a practical ideal smallbore design; not too much and not too little. But it got swamped between the company’s other two designs (or adoptions), the .223 and the .22-250. All three cartridges reflect the tastes of Remington’s engineering staff of the time. The late Mike Walker was a dedicated varmint hunter.
- Bill
WACA # 65205; life member, NRA; member, TGCA; member, TSRA; amateur preservationist
"I have seen wicked men and fools, a great many of both, and I believe they both get paid in the end, but the fools first." -- David Balfour, narrator and protagonist of the novel, Kidnapped, by Robert Louis Stevenson.
I can see you guys are detail guys. My apologies for the long post.
I have two rifles in .25-20 that have different twist rates. One is a Model 1892 with a factory-original barrel and a 1:14 rate of twist. The other is a Model 1973 that was converted from .32-20 using a Marlin .25-36 barrel. The twist rate on that rifle is 1:8.
The .25-36 was Marlin’s answer to Winchester’s .25-35. Like the .25-35, it used a long, 117-grain bullet, which is the reason for the fast rate of twist.
My standard .25-20 small-game load uses a plain-base 85-grain bullet cast from wheel weight metal and powered by 7.0 grains of IMR 4227. The muzzle velocity is 1,356 f.p.s.
The Greenhill formula is the standard method for calculating rate of twist, given that particular bullet’s diameter, length, specific gravity and velocity. For my 85-grain load, the Greenhill rate calculates the optimal rate to be 1:15. For my 65-grain load, the Greenhill result is 1:16.
Both of these rifles are equipped with Lyman tang rear sights and windage-adjustable blade front sights. Both barrels are 24 inches long with six lands and grooves. Both bores rate as very good. Both are shiny and bright, with strong rifling, no visible wear and no visible pitting. These guns are good shooters.
I have tested both side-by-side at our local range under identical conditions. Both shoot groups that are similar in size, regardless of load. The usual 5-shot group for both rifles is 3.0 inches at 100 yards. I get the same result with both loads.
It was never my intention to mount a .25-36 barrel on my Model ’73. I asked my gunsmith to sleeve the old, worn-out .32-20 barrel but he happened to have a Marlin .25-36 barrel on hand. I asked him about the rate of twist. “Don’t worry, he said.” “It’s OK to spin a bullet too fast, just don’t spin it too slow.” Turns out, he was right.
For those of you who want to try this at home, the link below will take you to a website with the Greenhill formula. It’s an excellent website. All you have to do is fill-in the variables for your bullet and it will do the calculation for you.
https://www.vcalc.com/wiki/AndrewBudd/Greenhill+Formula+for+Optimal+Rifling+Twist+Rate
To use the formula, one of the variables you will need to know is the specific gravity of your bullet material. For lead, the SG is 11.35, tin is 7.31, antimony is 6.69 and copper is 8.89. For my calculation, I assumed wheel weight metal to be 95% lead and 5% antimony. For jacketed lead-core bullets, the website suggests using 10.9.
It’s very easy to determine the rate of twist on your rifle. All it takes is a cleaning rod, a tight patch and a measuring tape. Put a mark on the rod, install the patch, push the patch down the barrel until the rod has made one full turn and measure the distance.
Good luck. Pete.
Zebulon said
The 222 Magnum has always seemed to me to be a practical ideal smallbore design; not too much and not too little. But it got swamped between the company’s other two designs (or adoptions), the .223 and the .22-250. All three cartridges reflect the tastes of Remington’s engineering staff of the time. The late Mike Walker was a dedicated varmint hunter.
It was my grandfather’s and my father’s favorite varmint cartridge going back to 1950. Neither one of them ever saw the need for a 220 Swift or a 22-250. A 50-gr pill moving out @ 3400+ fps was enough to exterminate all varmints and coyotes out to 350-yds. I used that load to shoot a Prairie Dog at a measured distance of 417-yds (using a bit of Kentucky windage). I suspect that the 35-gr V-Max load will be sufficient out to 400-yds if the wind is not blowing. Shooting varmints @ 100 – 150 yards with a Triple-Deuce Mag is boring child’s play, and it is why I am a bigger fan of the 22 Hornet/K-Hornet cartridge for that distance.
Bert
WACA Historian & Board of Director Member #6571L
Zebulon said
I’m guessing cranky old Texas German antebellum scheutzenfest competitors would have opinions! If you plied them with enough lager.
I happen to know a three generation schuetzen Family from the Hill Country. The youngest one works with me and when I asked about it, he said, “No way a German is going to push the limits like that. Powder costs money and we’re tight”.
Technically, the glass is always full; half liquid, half air....
WACA #10293
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