.

I would suggest that you contact the former Chiappa factory's US advisor & pre-eminate Model 1892/92 US gunsmith, Steve Young, to get the skinny on them.

Steve's Gunz | "The Rossi 92 Specialist"


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In the event that anyone else is curious, I'll respond...

Yes, I own a Chiappa 1892 in 44 Magnum; it's a special version with a full length buttstock but a 12" barrel. That's completely legal here in Canada, without any restriction.

The quality of these guns is very high - fit and finish is good, materials excellent, no blemishes or tool marks, with one exception. The muzzle crown was rough, so I remedied that in ten minutes with a brass tool and valve grinding paste.

The ladder sight on the rifle is quite good, but my eyes are middle aged, and far from able to focus for best results, so I installed a Marbles tang peep from Brownells. Because the Chiappa is a clone of the Winchester 92, this sight is very easy to install. A tang peep on this short barrelled carbine increases the sight radius to the same as a 20" barrelled rifle with open sights. That is why I was willing to pay a premium for the Chiappa over the Rossi - the Italian gun is a faithful copy of the original, no stupid safeties or non-standard things like off-size sight dovetails. And, as you said, it has a fast 1:16 twist, which is why I preferred it over the Marlin 1894, which has a 1:38 barrel.

This little carbine is a hoot to shoot - it's just over 30" in length, and with a full magazine (six shots, not five as the specs say), it weighs just over five pounds. With full house loads (240 gr. Truncated Cone bullets and 24.0 gr. of W296), it's snappy, but not unpleasant to shoot, and it gets only about 100 fps less velocity than a 16" barrelled rifle. It's accurate, too...it'll group into about an inch @ 25 yards.

Photo is with the tang peep installed, but before the ladder rear was replaced with a dovetail filler.

 

1-20 for 44mag and 1-16 for .45 colt. Oh really? In my opinion those rates are way to fast and need to be around 1-30. Which is what I'm told Rossi was using. Most everyone uses 1-16 for the Colt. The .44 mag hops around various twists from 1-20 1-30 to 1-38 depending on who is driving. Makes no sense to me. My Uberti .45 COlt is 1-16 with is too fast but deal with it by shooting them slower and using the heaviest bullet I can get.

 

Just curious, but what is it about the quicker twist that you don't like? Does it affect the bullet in some way that is detrimental to the bullet or accuracy? Seems to me being able to shoot a wider range of bullet weights would be advantageous. What is the down side? Like I said, just curious & not taking sides.

 

Correct me if I'm wrong, but didn't the Marlin 1894 (44 Mag) change from a 1-38 Micro-Groove to a 1-20 Ballard type barrel around 1998 or so? I see post here sometimes, like shawnbo's, that only say the Marlin is a 1-38.

 

I did considerable reading since yesterday when I posted that and I find that there are two strings of thought about twist rates. There is the "there is no such thing as overstabilization" group that claim that more is always better and the "too much twist will cause the bullet to fly like the space shuttle landing when it's drop's" which causes accuracy problems. After reading a bit it appears that the only effect over spinning has is that it amplifies the out of balance of the bullet at times and in only very severe cases. After believing that too fast a twist has negative effects on accuracy for a lifetime, trying to convince me it doesn't is like convincing me aliens are landing in my front yard and not to worry about it. I'm more confused than ever. Here's one article I read that explains the effect very well. Excuse me while I chase the aliens out of my front yard before the dog bites them.

https://anarchangel.blogspot.com/2007/01/stabilization-mythology.html

 

IMHO, once again, WAAAAAAAAAAAAAY too much is made of twist rate in big bores.

https://anarchangel.blogspot.com/2007/01/stabilization-mythology.html

Very little of this article is relevant here. We're not talking about high velocity .22's where a few grains here and a couple inches of twist there make significant differences. Two or three inches of twist rate make a significant difference in the .223 but go completely unnoticed in a .44 or .45. Double the twist rate and you have something to talk about. Going from a 55gr to a 75gr bullet doesn't sound like much but in a .223, those 20grs are very significant. In a .44 or .45, in the context of stability, it ain't much at all. Context is important and everything is relative.

 

It really just depends on what you are doing. If you are deer hunting, and the bullets don't come apart leaving the muzzle; no big deal.

It IS a big deal if bullets are too fragile, and it CAN be a big deal when shooting some specialty, long range matches (eg. 1,000 yards and so forth).

But for most of us, no problem.....

 

It's like we are to believe if the bullets aren't exploding when they leave the barrel we're OK. I find that hard to believe, Oh wait a minute one of the aliens is knocking at my door. I'll be back after I find out what he wants.........

 

The 1:38 twist Marlin used on the 1894 works great for the typical 44 Mag loads of a 240 gr. bullet at rifle velocity (1700+ fps), otherwise they (and Browning in their 1892) wouldn't have used it. If you want to go with heavy bullets (300+ grs.), a faster twist is better. All the 44 Magnum handgun manufacturers use(d) 1:18 to 1:24 twist rates, because a 240 grain magnum load won't stabilize optimally at handgun velocities @ 1:38, and heavy bullets wouldn't stabilize at all.

Any given .429" bullet that is fine at 1:38 spin is NOT going to come apart at the same velocity in a 1:20 barrel, especially a bullet that doesn't have to negotiate a cylinder/barrel gap, at the velocity parameters of the 44 Magnum. If I'm shooting a 1892 repro with a 12" barrel, which I am, I want the faster twist.

 

" If I'm shooting a 1892 repro with a 12" barrel, which I am, I want the faster twist."

Why would barrel length have any effect on what twist rate.?

 

It doesn't - it affects attainable velocity, which does.

 

Chiappa is the parent company of Armi Sport, and Armi Sport makes great lever guns. Their Model 92 is a much more faithful copy of a Winchester Model 92, right down to the little details.

They are well made with great finish on both the metal and the wood, and they are however, in my experience, not quite as accurate as a Rossi 92 with cast bullet loads (see below for some discussion on that). But on the plus side, unlike a Rossi they are very slick functioning right out of the box and they are not over sprung like the Rossi Model 92.

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With regard to barrel twist, if you use a traditional twist rate formula and plug in a traditional .45 Colt lead bullet velocity of 1000 fps and a 255 gr cast bullet length of around .635", you get a ideal twist rate of about 1 in 36".

That seems slow, except the .45 caliber bullet has a large diameter and that large diameter brings with it more gyroscopic effect as the bullet spins, so it doesn't need (nor do you really want) as much spin.

Thus 1 in 36 to 1 in 38 rates made sense back in the day and they still make sense now with cast bullets in the 255 gr weight range at traditional non gas checked cast bullet velocities.

If you plug in a more modern bullet like the 250 gr FTX and a velocity of 1700 fps and it's longer bullet length of .660", you get an even slower ideal twist rate of about 1 in 44" due to the higher velocity.

If you go with a 300 gr FTX and punch it out at carbine velocities around 1500 fps, the extra length and reduced velocity puts the ideal twist rate at about 1 in 34" - where the traditional 1 in 30 something twist rates still work well.

However, if you use a 350 gr bullet with a length around .995" and push it at 1000 fps, the ideal twist rate now increases to about 1 in 22.

Thus, the faster twist rates in the 1 in 20 and 1 in 16 range makes sense, but only with long heavy 325-350 grain bullets at slow to moderate velocities. With everything else you're spinning the bullet faster than necessary. That's not a problem if the bullet is very high quality and the center of gravity and the center of form are both on the longitudinal axis of the bullet.

If they are not, (due to imperfect mold fill, an inclusion or void in the bullet, etc) the bullet will rotate around the center of form in the barrel, but will then have to transition to rotating around it's center of gravity once it leaves the barrel. This will result in yaw and the increased wind pressure on one side of the bullet will cause precession 90 degrees farter round the rotation. Excess spin will increase the precession, with adverse effects on accuracy.

That is why I suspect I get less accuracy with my Armi Sport Model 92 than with my Rossi 92s with cast bullets.

 

Craig C -

Try to be a little more diplomatic in your responses. Thank you.

 

I was being diplomatic.

 

While its possible to spin a bullet too slow it is also possible to spin it too fast. There is no such thing as "over stabilization" but spinning a cast bullet that has some imperfections causes the bullet to be unstable from being out of balance but not over stabilized. There is a difference. In a perfect world where bullets are perfectly balanced and round and perfectly centered in the bore when fired they will shoot just as good with a fast twist as with a slower twist. But the perfect world only exists in our minds. As you speed up the bullet you also risk stripping it past the initial rifling in the throat where it goes from 0 RPM to many thousands of RPM in a few milliseconds. I like to stabilise it enough but not so much I have to worry about stripping or wobbling. Winchester did many tests back when they created the 44-40 and determined that 1-38 was sufficient to stabilise the 200 grain lead bullet at 1300 or so FPS. I think that's too slow but upping that to 1-30 was a good compromise. I think they use 1-28 now in their japanese made 73's which is probably about perfect.

 

Twist rates are a funny thing. The first thing that people don't realize is, they aren't the exact same thing in every barrel coming off the line. Maybe hammer forged are? Button rifling can have 'fast' and 'slow' spots in the barrel.

I have 3 .25 cal barrels in different cartridges, and a 4th waiting on an action. Of the 3, one is exactly 1-10," one is 1-10.1" or so, and the other is closer to 1-10 3/8" Despite that, all three will shoot 120gr. bullets reasonably well. So it can be done.

I've known people who had .25 cal barrels that wouldn't shoot bullets over 100 grains well, but none of them measured the actual twist rate, before the gun or barrel went on down the road. So we really don't know if they were just a victim of the slower side of the manufacturing tolerance on the rifling, or it came off the line with the rifling machine set wrong.

My .444, with the s-l-o-w 1-38" twist, runs out of stability between 325 and 335grains, with the Beartooth 325gr. bullet. Initial groups were 'crappy' but on the paper at 100 yards. Closer inspection finally revealed that a few of the bullet holes were slightly oblong. Turning 0.050" off the nose of the bullet, tightened up groups dramatically.

On the other hand, Marshall shoots those same bullets in his Marlin .444, also with the slow twist rate, and doesn't have problems. I'd guess his "1-38" twist is a smidge faster than my "1-38" twist.

Point being, when you are at the edge of stability, it doesn't take much to cause problems.

 

This ain't rocket science. There is no magic here. If it was too fast for the rifles, it would be too fast for the pistols. It ain't. Sure, the slower twists may be fine for bullets up to a certain weight but are closer to the edge of stability. Heavier bullets are over the edge and they tumble. If a 240gr is fine but a 300gr is teetering, you know you're way too close to the edge. The issue here has nothing to do with standard weight bullets in standard loads. Those work either way. The issue here is getting a fast enough twist to use the fullest potential of the cartridge with bullets up to 350-360gr. A 1-38" twist simply doesn't work for bullets much over 300gr unless you get into .444Marlin velocities. A 1-20" twist works for ALL bullet weights, proven fact.

What Winchester determined 140yrs ago with a lightweight 200gr bullet out of the .44-40 is irrelevant. What we need today is a fast twist barrel that will stabilize the same heavy bullets we use in our revolvers, which also works perfectly fine with lighter bullets. We finally have it, don't whine about it now.

EDIT: Using the Berger stability calculator, we see that a .430" 240gr at 1200fps in a 1-38" twist is marginally stable. Move up to a 300gr and you're even less stable, bordering on "unstable". That's fine for standard loads but anything much heavier is going to be unstable without more velocity.

 

One other thing, to Craig's point -

Stability in the air is one thing, stability in a denser medium (ie. the critter) is another. If it is marginally stable in air, it may not stay nose-forward, in the critter. With expanding bullets this is a whole 'nother can of worms, but generally speaking, the expanding bullets get shorter, quickly, and tend to keep going in the same direction.

With non-expanding (hard cast), you want the bullet to stay nose-forward, and not tumble. So, some 'extra' twist rate is good.

My .444 will never know the difference, if a heavy bullet tumbles in a 90 lb. whitetail. But on a bigger critter it might matter.

 

I think we all need to remember the great Colonel Greenhill and his twist rate formula. The classic formula is: T' = 150 / L' twist = 150 divided by the length of the bullet in calibers. The complete formula is available in several location around the net.
Example.. Measure the length of your bullet and divide it by the diameter. Divide 150 by that number and you have the minimum twist rate.
I saw a website that does all that for you: Barrel Twist Calculator

 

Mike makes a good point. While I have nothing to support it, it stands to reason that if a bullet is marginally stable in the air it very well may not penetrate straight once it reaches the target.

I don't know where the Greenhill formula applies but it doesn't apply here. It errs well on the slow side.

The Berger calculator uses the Miller formula and seems to be more accurate.

 

Groo here
You all have been hitting the edges but not on target..
The twist rate is not important,,, it is the RPM!!!!!!!!!!!!!!!!
A given length of bullet needs a given RPM to be stable.
A 1/16in twist would be fine in a pistol with a short barrel as long as a specific RPM [caused by FPS]
can be gotten.
In a rifle the same RPM can be gotten at a much slower twist rate because the FPS his higher.[due to the much longer barrel]
Take a 44 at a 1/18 inch barrel twist at 900fps [240gr bullet 44 spec ] the rpm is 32000.
Take the same load in a rifle [1700fps 44 mag] and the rpm is 68000.
Change the rifle to a 1/32 twist and the RPM is 32000
The bullet will shoot fine in both .
So the key is to get the RPM's into the correct range.

 

Groo, that is not entirely correct. Speed does matter.... to an extent. For a bullet that is marginal in stability due to twist rate, SOMETIMES increasing the speed helps. Sometimes. There is a theoretical advantage to increasing the speed, but as a practical matter, the increased drag on the bullet can somewhat cancel that out. So, it depends. You can play around with things like the JBM stability calculator and see that speed is a small part of it. There's also a further can of worms regarding bullets shape, and how it handles the trans-sonic zone (transition from super-sonic to sub-sonic).

 

I think you're missing his point here. the faster you drive the bullet down the barrel, the higher the rpms will be once it leaves the barrel. A heavier bullet due to it being slower needs a faster twist to obtain the desired rpm to stabilize it. He hit it spot on with that. All that aside, I've never had accuracy problems with any of my 44 mag rifles and carbines with heavy bullets (290-350 gr) due to the twist rate. My oldest is a B92, all the rest are Rossis made in the past twenty years.

 

I am not missing the 'point' - the 'point' is not entirely correct. RPM is heavily influenced by velocity. But stability is not. RPM and stability are not the same thing. Example from the JBM stability calculator:

A 220gr. .308 bullet 1.5 inches long, at a velocity of 3,000 fps has a stability factor of 1.265 in a 1-12" twist barrel, which should be fine for most purposes.

A 220gr. .308 bullet 1.5 inches long, at a velocity of 1,500 fps has a stability factor of 1.004 in a 1-12" twist barrel, which is predicted to be BARELY stable with a stability factor of 1.004 - at exactly half the RPM. The RPM drops by a half, the stability by about 20%. They are not proportional. Twist has a far greater influence, than RPM.

 

RPM affects the stability. They're not the same thing, but one affects the other. That was his point.

 

Hey guys been awhile....read this post start to finish wow good learnings...I’ve got a win94 in 444...1/38 twist Ruger 96 44mag 1/20 a smith 629 6” with 1/20 i try to use only btb in my win444 it seems to be good with 250-290 lfn at about 2000-2250 tops...accy is ok i need more trigger time the ruger likes heavy bullets but have to use wfn to cycle or use 44spcl brass...my dillema is should I slow my 444 to maybe 1800 to see if accy gets better or go same speed with and save heavies for my nef444 1/20 twist... I fire lapped it but not the others...yet!! I reallt am quite reluctant to lapp the smith it loves cast and im nice to it...the win is tuff to shoot my brass are .060 shorter than normal to use lfn btb’s...again I need more time to get it right...marshalls advice on fire lapped nakes alot of sense to help in accommodating either twists in 44 cals...but to a point???? Again it seems more trigger time is needed to explore hope i made sense in my query...thanks guys...oh yea I’m fixing to go for a taylor/chiappa Alaskan in 45lc...$$$$ you think it’s worth playing with ??since I reload I should be able to find a good shooter load this would be my first 45lc...or I go with the Winchester short carbine 20” a lil cheaper but not a takedown??’....thanks again

 

See https://arxiv.org/pdf/1309.5039. A very comprehensive paper on stability

 

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Years ago, some gun writer was sitting around trying to think of something half way intelligent to write about. Similar to those who started the Boxer Rebellion years ago. so he hit upon the idea of twist rates, and published his article. From that the argument has grown to what it is today, which is mostly just BS.