[LFW]

The rotation locking system as used in the Beretta Cougar and the Mauser M2 seems like a great idea. It's simple, barrel remains in the straight axis, not much movement. Unlike the P38 falling block system of lock-up, the rotation system allows placement of the recoil spring under the barrel so the slide and receiver stay slim. I've never even fired a pistol with this sytem so know nothing about it. Anyone care to pontificate either pro or con on it?--Leigh

[PCRCCW]

Ive shot one cougar and it was a nice gun. I didnt know much about the barrel lockup at the time but thought it sounded cool.

The Beretta literature makes it sound like anything JMB designed would become outdated 20 years ago...but the rotational lockup really didnt catch on.

The biggest difference theoretically anyway, is recoil tends to come straight back at you instead of alot of muzzle rise. But I really couldnt tell a hell of alot of difference in the 45 I shot.

YMMV...Shoot well

[Mike Irwin]

Rotational locking is a LOT older than the Beretta.

Far as I know, the first gun to use it was either the Steyr Hahn...

I THINK it was the Steyr Hahn, but it may have been a Roth...

In any event, it's been around since the before WW I.

[SelfProclaimedExpert]

Unlike the P38 falling block system of lock-up, the rotation system allows placement of the recoil spring under the barrel so the slide and receiver stay slim.

This is a bit off. The Beretta 92 uses the P38 system. Its spring is underneath the barrel, but the slide is big because of the locking block width. The P38 spring system is, if anything, better.

It's funny you bring up slide width. The Cougar slide doesn't strike me as particularly skinny. There has to be room for those barrel lugs to rotate in.

While I'd agree that straight line feeding might be better, I doubt there is any accuracy advantage. Rotating barrels are held in battery by the two lugs at the chamber end of the barrel. There is no support or centering of the muzzle end (it doesn't touch the slide). While a very accurate gun of this type could be built, it hasn't yet. Beretta 8000 owners report less accuracy than with their 92s.

The locking block system may be more accurate, but it is not very durable. The rotation system is tougher, as evidensed by the .45 loading (no one has ever made a P38/92 type pistol in caliber larger than .40).

Regular old Browning lock-up is easier to get good accuracy from and is the slimmest recoil system, since the locking occurs above and below the bore. It is no more complex and is likely easier to machine. For a recoil system, dropping the barrel, rather than rotating it, is hard to beat.

[Navy joe]

As Mike said, it started life in the Roth-Steyr Repetierpistole M.07 designed by Karel Krnka of Roth's employee. Roth made ammo for Steyr and the rest of the Austrian realm. Apparently Steyr later copied the M.07 in several respects including lock-up with it's Pistole Modell 1911 :D Which was released commercially and known as the Steyr-Hahn. The next year after army trials the same pistol was adopted as the M.12. Hahn being German for Hammer as in Steyr with hammer to differentiate it from the striker fired M.07. Also using this system were the Obregon, Colt All-American, and Cougar as mentioned.

No, I'm no wealth of knowledge, about three days ago I found an old SGN under the couch along with some cat toys, road maps, stripper clips and a baseball. I perused the SGN and it had some excellent articles including one on the M.12. I have no idea why I trashed it, I rescued it for this post and will return the rag to my firearms reference stack.

Yours truly,
-Eagerly awaiting my Glock-Hahn. :evil:

[mete]

Rotating barrel designs are older than that - Schwarzlose 1895, also Savage (poor design) , CZ 1924 and others. Rotation was anywhere from 5- 90 degrees. But the success of a gun cannot be attributed to just one feature but rather the entire gun from cost of manufacturing to reliability. The rotating barrel design has been around over 100 years there's nothing wrong with it . Success of the Cougar and M2 remain to be seen.

[Jim K]

Actually, the rotating barrel was a Browning concept; he worked on that idea before coming up with the dropping barrel and link system. I have not checked the dates, but that was probably before Roth came up with the same idea.

The first major pistol to use it was, as others have said, the Roth Steyr. It was also used in the Steyr Hahn, the CZ Model 28, and some others, notably the justifiably ill-fated Colt 2000, which was a POS. The Savage pistols were not truly locked breech; the rotating barrel served to slow slide opening but there is no true lock.

Probably the best application for a large pistol was the Obregon, which is .45 caliber and resembles the Model 1911. It eliminates a lot of the problem areas of the Browning design, like the link, barrel vertical movement, barrel springing, feed ramp alignment, etc.

Jim

[SelfProclaimedExpert]

The Savage and later Mab PA-15 were delay systems. The barrel didn't recoil, it rotates in place.

[Cthulhu]

While a very accurate gun of this type could be built, it hasn't yet. Beretta 8000 owners report less accuracy than with their 92s.

Has anyone else noticed this? I found the 8000 series in 9mm and .40 to be about as accurate as their 92/96 counterparts while the shocker was the 8045, which was stunningly accurate despite its short sight radius. Perhaps there are other factors at play on that one, but I shoot the .45 Cougar better than any stock 92/96 pistol. Its short chunky configuration almost makes the slide mounted safety tolerable. Offer one with a frame mounted safety ala the original 92 and I'd probably have to buy one.

While the accuracy benefits of rotary barrels might be subject to debate, I've noticed that the design has increased most peoples' problems with reassembling the gun after fieldstripping. Working in a gunshop and watching guns get torn down on a daily basis, Beretta Cougars seem to be a problem for many users, though not as bad as Ruger autos.

[SelfProclaimedExpert]

Just remembered something else: Lubrication is something of a big deal with this design. I can't remember any 8000 reports right off, but more than a couple M2s locked up tight as the oil ran dry during range sessions.

Again, could be a solveable problem. But there is a lot of bearing surface involved in this system.

[LFW]

Thanks for sharing all of your knowledge on this subject. As I suspected, the design isn't as good as it seemed at first glance. How is it for reliability, better or worse than the Browning tilt barrel?--Leigh

[SelfProclaimedExpert]

As I kind of alluded to, I think straight barrel actions feed better in general, all other factors being equal. They don't have to contend with feed ramps or breechface and extractor friction.

But there is the matter of lubrication and dirt tolerance with the twisting barrel.

[Cthulhu]

The lubrication needs might differ from a browning style or P38 wedge block design, however the Beretta manual doesn't specify any extra lubrication requirements. The range guns at my shop see many rounds between cleanings and they are lubricated to a minimum to keep down on fouling from built-up powder. The range Cougars are treated the same way and have not shown themselves to be less reliable than the other designs when subjected to accumulated dirt and fouling. Actually the guns that require the most frequent cleaning (and repair in this first case) are the Desert Eagles, followed by the Ruger/Browning/S&W .22 autos, and the S&W revolvers.

I wouldn't be surprised by any major malfunctions attributed to the Sig/Mauser M2. It is not the engineering gem that the advertisements purport it too be. The only positives are the low price due to the fact that it is rather unpopular and the fact that the .40 S&W versions are relatively easy to convert to 10mm.