Gents:

I came across something today I understand but don't really get: cylindrical vs. non-cylindrical action. I think I understand the obvious, but what makes one more desirable than the other and why would one choose one over the other?

Thanks!

Jeff

quote:

Originally posted by jsl3170:
Gents:

I came across something today I understand but don't really get: cylindrical vs. non-cylindrical action. I think I understand the obvious, but what makes one more desirable than the other and why would one choose one over the other?

Thanks!

Jeff

A round item is easier to setup and true than a square one?

You need only look a"round" to see that "round" rules. Breasts are round. Need I say anything more?

In Harold R.Vaughn's book, "Rifle Accuracy Facts", he addresses this very question. Basically, he contends that an action which is abolutely symetrical, both inside and out, will produce greater accuracy than one which is not.

I do not know that I 100% believe everything Mr.Vaughn says in his book, but I AM sure he knows more about it than I do. He was the supervisor of the Aeroballistics Division of the Aerodynamics Department of the Sandia National Laboratories in New Mexico (where my son also worked), until his retirement in 1986. He is considered the "father" of the ballistics/flight mechanics technology for nuclear ordnance used by the Sandia National Labs, so he just might know what he is talking about, ya think?

(He also is the first person to come up with a numerical solution to predict fluid motion inside spin-stabilized, liquid-filled artillery shells, and is also one of the fathers of the guidance systems used in current "smart" projectiles [bombs, shells, missiles, re-entry vehicles, etc.]).

Oh, and his hobbies include "precision shooting" and hunting. His biggest elk once held the #13 spot in the record books, and he has a grand slam on sheep. His home workshop has a Clausing lathe, a good vertical mill and so on...he is really into this stuff.

quote:

Originally posted by Alberta Canuck:
I do not know that I 100% believe everything Mr.Vaughn says in his book, but I AM sure he knows more about it than I do. He was the supervisor of the Aeroballistics Division of the Aerodynamics Department of the Sandia National Laboratories in New Mexico (where my son also worked), until his retirement in 1986. He is considered the "father" of the ballistics/flight mechanics technology for nuclear ordnance used by the Sandia National Labs, so he just might know what he is talking about, ya think?

(He also is the first person to come up with a numerical solution to predict fluid motion inside spin-stabilized, liquid-filled artillery shells, and is also one of the fathers of the guidance systems used in current "smart" projectiles [bombs, shells, missiles, re-entry vehicles, etc.]).

And to think, my only experiences are with breasts...

quote:

Originally posted by Westpac:


And to think, my only experiences are with breasts...

Ah So! You and Mr.Vaughn obviously have different priorities in your hobbies. None-the-less, you both appear to have arrived at the same conclusions (on preferable action shape).

Based on the routes you used to arive at those independent conclusions, I must think I would prefer your brail map to his cogitative one...

Best wishes, M......

AC

Well, here is where it came from: I was perusing the Hill Country rifles web page and noticed their announcement regarding a working relationship with Waffenfabrik Hein. Apparently, Hein has produced an action for them and I noticed it mentioned it was a cylindrical design. I had spoken with Hein last fall and he made a point of telling me he favored a flat bottomed design so I was curious as to why one may be favored over another.

Am I correct in my assumption that M70s, Dakotas, GMAs, Empires and other Mauser-type desings are flat bottomed? And this is because?

quote:

Originally posted by jsl3170:
Am I correct in my assumption that M70s, Dakotas, GMAs, Empires and other Mauser-type desings are flat bottomed? And this is because?

Yes, because they are flat of the bottom. They have a flat seat, or, bedding surface as opposed to one that is round.

quote:

Originally posted by jsl3170:

Am I correct in my assumption that M70s, Dakotas, GMAs, Empires and other Mauser-type desings are flat bottomed? And this is because?

I am not sure there is any definitive answer to your new question. No-one I know was inside the heads of the brothers Mauser at the time.

If I had to guess, I would suspect it came from the history of gun-making. I.e., in the late 1800's, most guns were machined from forgings. Forgings were probably easier to make rectangular than true round, with the machinery of the late 1800s. Also, much of the items made in those days were partly made and almost entirely fitted together, by hand. It is much easier to file a surface flat in fitting than to file it round to a precise dimension. Ditto with stocking. I always found it easier to make a precise flat inletting cut in wood than a round one.

Then too, in those days although a surprising amount was known about harmonics, suprisingly few folks viewed barreled actions as a functioning tuning fork. So, they didn't really worry as much about vibration in the action itself or in its joints with anything else. That probably also explains why they used a thread design in the receiver and on the barrel which really bears rather undependably at the time of firing, giving a relatively loose joint. (Also may explain why they torqued their barrels into the receivers so tightly.

As for later actions, well, there's an awful lot of copying going on over the last century or so, as opposed to totally independent, well thought out, original design ideas....

How's that for a lengthy "who knows" ?

I suppose the general direction I am heading in is to wonder whether we should avoid these cylindrical actions? The aforementioned makers continue to mfg flat-bottomed actions for a specific reason I guess. Beyond histrionics, is there another reason?

quote:

They have a flat seat

same deal in mainland china.

Round actions are easier to make, just machine
a round bar. And they are accurate like
Savage guns.Flat bottoms seat down good,
especially if the recoil lug is at extreme
front of action. Locked on lugs used on round
actions being more forward more get more stock
mass to hold recoil forces. Both have different
virtues. Ed

If you are asking why many of the semi-custom, higher-priced actions are still flat bottomed, ask yourself this question too, "Are shooters conservatives or liberals?"

To many folks, rifles which look absolutely Traditional are the only ones they think look like "real guns". They like the looks of all the extra milling cuts, even though they add cost but not necessarily greater functionality.

Many people don't like round actions for the same reasons they don't like cast receivers, composite stocks, high tech plastic trigger-guards, etc.

So, they are paying mainly for appearances, although they find many other ways to rationalize their preferences. I like the old style stuff better too, but I know it is costing me, both in money and accuracy. I finally am old enough to just say, "Well, I like it and I have the bucks to buy it, so I'm gonna."

If you're gonna try to sell high buck rifles, that's a good way to go. A niche market still not completely filled.

I don't like that pesky sandwich style recoil lug. It looks cheesy above the wood line. And the fact you can't just use a 24" crescent wrench to remove the barrel. The only reason manufactures are making them is they are cheaper to produce. The whole reason for the design of the rem700/etc. wasn't accuracy. IMHO the reason people think the round actions are more accurate is it takes so much more work to accurately bed a flat action than half ass bed a piece of round stock. Even in the testing lab. The half ass bedded piece of round stock seems to shoot reasonably well.

To answer your question "what makes one more desirable than the other and why would one choose one over the other?", you would need to look at the two major organizations who utilize each of the two actions for their purpose, the ACGG, and the NBRSA.

A lot of money is spent trying to prove that each design is equally suitable across the board, but when you take a good hard look at the two venues, you will find more "flat bottomed" receivers at an ACGG event, and more "cylindrical" receivers at an NBRSA event.

How about the width of the feed area being generally wider on the flat bottoms? A-Square makes mention of this with their boomers.

quote:

Originally posted by Westpac:

A lot of money is spent trying to prove that each design is equally suitable across the board, but when you take a good hard look at the two venues, you will find more "flat bottomed" receivers at an ACGG event, and more "cylindrical" receivers at an NBRSA event.

Certainly correct, M.

Likewise, it is quite possible to find very high priced custom actions of both configurations in those venues, so I hardly think it is the fact that round actions cost less to make which is the ruling determinant. They surely don't necessarily cost less to buy.

It certainly seems to be easier to make round actions shoot tiny groups. As was noted above, even a half-assed bedded one will usually shoot fairly decently for all uses except BR. There have been even Remington Rolling Block actions modified for successful bench rest shooting (though only one, really, that I know of), so yes, it IS possible to make a flat bottomed action shoot well enough to compete with (if you can do it with a Rolling block, doing it with an otherwise modern action with a flat bottom should be a piece of cake)...the Stolle Panda is a good example of that, as are the "sleeved" Remingtons which used to be commonly used in BR.

At the same time, it is possible to make a round action which will accept any size of sporting cartridge in its magazine. Just takes a bigger diameter piece of "tubing" to start with, though one could flatten the top and sides, and leave the bottom round if they really wanted to.

The one thing which would be pretty hard to find in the current market would be a round action with a controlled round feed/extractor, for a DG rifle.

Anyway, the longer I live, the more sure I am that gunners are pretty well ruled by the traditions (and sometimes fads) of their particular branch of the sport, not the superiority of ANY particular action for all purposes.

Best wishes all,

AC

Alberta Canuck,

The point of my post; go to Hill Country Rifles and see their announcement concerning their association with Hein. They are round action rifles for DG.

quote:

Originally posted by jsl3170:
Alberta Canuck,

The point of my post; go to Hill Country Rifles and see their announcement concerning their association with Hein. They are round action rifles for DG.

Thanks, I will do that in just a few minutes, for my own education. Of course, thhat makes even less the superiority of either one over the other.

BTW, before I go, are their new round actions by H controlled round feed?...or just push-feed with something like an M-16 extractor but chambered for DG cartridges?

It looks to be the same as the Dakota 97 action. A Md 70-type round action, CRF, with a washer recoil lug...which is similar to what Kimber offers.

From what I understand, Dakota went with a round tube on the 97 to reduce costs versus the 76. It makes it lighter as well as can be seen by Rem 700 vs Win Md 70.

Vaughn is no longer with us. His book is the most intellegent gun book I have ever read.
A cylindrical action is easier to make, but
it is more symetrical in it's flexing.
Vaughn pointed out that "barrel whip" was in a large part caused by the receiver flexing under recoil.
Good Luck!

Rifles Inc. lightweight 700rem rigs seem to group accurately and thats even after they have trimmed the receiver down in dia. to resemble an large ring M98.
My weatherby varmintmasters .224mag&22/250, the old ones with the short cylindrical repeater action,&rather small in dia,were phenominally accurate.
[edited to add] and when you look at them,apart from the left sidewall there aint much holding them together,,after the top port&magazine feed port is machined out, the right rail is rather slim and flimsy, they seem to defy the claimed principle of receiver "harmonics" as a major contributor to fine accuracy.

quote:

but what makes one more desirable than the other and why would one choose one over the other?

If I was designing a rifle for thrift it would be a cylindrical action. Lathe work is always more efficient than milling as the time in the cut is greater for lathes. Accuracy has been proven as well.....they are very accurate.

However, if I was designing an action for hi-dollar and high end customers then the action would look much more like a M-70 with flat bottoms. Properly done these can also be extremely accurate but they have greater acceptability among gun fanciers.

In fact.....the actual differences between the two are cost of production.....the cylindrical actions simply cost less to produce unless one goes to investment casting.

quote:

Originally posted by Alberta Canuck:
Anyway, the longer I live, the more sure I am that gunners are pretty well ruled by the traditions (and sometimes fads) of their particular branch of the sport, not the superiority of ANY particular action for all purposes.

Best wishes all,

AC

I think that sums it up, teeth to tail.

quote:

Originally posted by hawkins:
Vaughn is no longer with us. His book is the most intellegent gun book I have ever read.
A cylindrical action is easier to make, but
it is more symetrical in it's flexing.
Vaughn pointed out that "barrel whip" was in a large part caused by the receiver flexing under recoil.
Good Luck!

Yes, the causes of barrel vibrations are some of the many things Vaughn analysed using the best of modern instruments, and his very competent brain. He also tested those analyses in very mundane rifles to see how well the theories developed fitted the facts of existing hunting rifles. He showed dramatically how reducing the asymetry of an action in the short distance between the breech end of the barrel and the back of the locking lug recesses dramatically reduced barrel whip in a
Remington M721 barreled action, for instance.

I believe he proved pretty well that a symetrical action provided "easier" accuracy in other respects as well. And, of course, most round actions are more symetrical from the get-go than most forged, other-than-round, actions.

I am very sorry to hear that Mr.Vaughn has passed away. I thought he was probably the best bridge between fantasy and fact in rifle building that I ever encountered.

To anyone who is actually interested in why and how rifles shoot best, I think they owe themselves a copy of his book...it was published in hardback by Precision Shooting, Contacting them might engender a paperback second edition if enough folks rattled Dave Brennan's cage about it. He's an astute businessman as well as a deeply interested shooter himself, so he might just leap at the opportunity if he saw the market was there.

BTW, for those who have been following the urination contests in the threads dealing with how to determine pressures and/or build loads with chronographs here at AR, Vaughn's second chapter deals with exactly those considerations, with all of crusher, piezo, and strain gauges.

Vaughn's book also gave the first rational description of the cause of wind drift (why it is a function of velocity loss). No Alice the wind isn't "blowing against the side of the bullet".
I can't recomend this book too highly.
A few years back I called Vaughn to thank him for writing it. A nice guy, he sounded not too well even then.
Good luck!

BTW, Mr.Vaughn did reach a pretty straight forward conclusion about the relationship of "barrel (muzzle) whip" and the resulting accuracy problems, relative to (caused by) receiver design. To quote from the bottom of page 82,

"in view of the (test) results already obtained, the flat bottom receiver appears to be a poor design." "

That should create an interesting firestorm of flames...



Anyway, he has a LOT of other interesting info in the book...a major one being a scientific explanation of why very slightly increasing or decreasing powder charges may cause dramatic improvements in reducing vertical stringing and producing smaller group sizes; Why stiffer (for the same weight) fluted barrels HARM easy attainment of superior accuracy; And "why" a rifle shot with no contact other than the finger on the trigger will usually shoot more accurately than a tightly held rifle (under circumstances where that is a practical choice).


Am I gonna explain all the above? No. You guys GOTTA get the book and read it. I don't sell it, or even know where you can buy a copy, but I do think it is a "MUST" for anyone really serious about rifle accuracy based on sound science.

P.S: I am NOT saying everyone should agree with what he says, just that they need to read how he reached those conclusions, then with an understanding of the problems, make up their own theories, tests, approaches, conclusions.

Some nice person on the internet sent me a copy of the Vaughn book.
I would seem ungrateful if I said anything bad about that book.



Bart Bobbit is the famous competitor at Camp Perry.

quote:

2. Bart Bobbitt Apr 15 1993

I don't recommend the M700 action for a long range rifle using a magnum
cartridge. They have a history of shooting loose from their bedding due
to the round receiver; this takes about 200 to 300 rounds. And the M700
recoil lug has been known to bend with magnum cartridges. Instead, I
think a Winchester M70 action is much better; their track record is
about perfect and they are a much more reliable action.

Looking through the book [that I paid for with my own money], "Bolt Action Rifles" by De Haas, there are over 100 actions shown, and half are flat bottomed and half are round bottomed.

There may be a reason for the diversity, as seen by Stiller, that builds both:



Stiller Precision builds the Viper, a Panda-style flat-bottomed aluminum action with steel bolt and steel insert for the barrel.
Stiller's less-expensive line of Predator actions are a drop in replacement for the Remington 700.

quote:

Originally posted by Alberta Canuck:
... Harold R.Vaughn's book, "Rifle Accuracy Facts"...

For anybody interested, Amazon lists a few of these books. - about $35.

See this: Amazon Link

- mike

From a practical day to day experience level, not scientific, the occasions you see a flat bottom action rifle used at a long range prone match, w/ sling, not bench, is rare indeed. Certainly there are some, but by far and away the majority of the actions observed are a Remington 700 or a clone thereof. Cost of mfg. believe was primary reason for introduction, but the big plus was that they perform very well and adding a Tubbs lug will help as well to prevent flexing w/ long heavy barrels. Would not want to venture a guess what a modern forged/milled Rem. Model 30 would cost today! A whole lot of work and excess weight/material and yet not as likely to produce an accurate match grade rifle. The fellow that designed/engineered the 700 series of actions for Remington was way underpaid.

The Stiller Viper and Kelby's Panda are both flat bottomed and are among the best BR receivers built.
Probably more records set with the Panda than any other receiver. Bear in mind, many more of them have been sold than all other custom receivers combines. The BAT round action is probably considered the best at this time by most competitors. Ultimately I don't think that the shape in itself make it more accurate.
Butch

Hi,Butch-

I pretty much agree that ultimately either shape can be made to shoot very well indeed. (Among others I personally have/use a Panda and a Teddy). But I think Vaughn's point was that the round actions are easier to make shoot really well...they don't require the same amount of care and tuning to make them shoot at their best competitively.

I suspect it is also true that the great majority of shooters, even competing benchresters, can't shoot well enough to make the differences any great concern for them. (I'll be quick to say that goes for me, too.)

Among those who have enough skill they can tell the differences, it is probably also true they can shoot well enough that they could win with either one, so it still is no earth-shaking concern for them either.

I will agree with you, AC.
Butch