Does anyone have experience with a rotary action semi-auto (like the Beretta Px4 Storm)

drobs said:

Beretta PX4 - the answer to the question no one asked.

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Unless the question was -

Can you get me a Beretta that is lighter than an M9/92FS, and has a barrel lockup design that is strong enough for high round counts with .40 S&W ammo (with 14 round mags too), and could you also offer it in .45 Auto?

The Beretta M9/92FS is a great gun, but it is big, and putting .40 S&W in those guns was an afterthought that never really was that great. The 90 Series was never offered in .45 Auto.

I have several of the STOEGER 8000 9m.m. and STOEGER 8040 pistols and a BERETTA 8000D pistols. I think they are not bad for recoil. I bought the 8040 because my agency was still using .40 S&W ammo and I wanted an inexpensive gun shooting the same ammo. I was very impressed with it overall. I have shot some hot .40 S&W and the biggest problem was not the recoil, but the blast and noise.

HOWEVER, I also bought a STOEGER 8045 and it is much more snappy when shooting. The recoils is less of a problem than the muzzle rise. I will shoot it some more and report back.

Jim

JTQ said:

I don't consider this a big deal.

The SIG P320 uses a different mag than the P226 (heck, isn't there variety even among the P228 and P229, and even within the P229 family), the HK P30 uses a different mag than the USP. I don't know how many polymer pistols FN has marketed in the last 20 years, but do any of them use the same mags?

The M9/92 mags are certainly available, but the PX4 mags are arguably a better mag.

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Magazines apparently have a higher margin than guns. At one point I was organizing magazines and found four from different makers that seemed to use the same magazine tube, but with different locking notches. Changing magazines ever so slightly in new models guarantees makers multiple future magazine sales.

gc70 said:

Magazines apparently have a higher margin than guns. At one point I was organizing magazines and found four from different makers that seemed to use the same magazine tube, but with different locking notches. Changing magazines ever so slightly in new models guarantees makers multiple future magazine sales.

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I've seen comments from Ernest Langdon that while the Beretta 92 mags are fine, they are 1970's technology. The PX4 magazines are an improved magazine. Beretta didn't want to be tied to old technology by trying to make the PX4 work with an old mag design.

I think there would be some logic to using the PX4 mag with the APX, since the PX4 would have been only about 10-15 years old when the APX was introduced, but the 92 mag design was probably 30 years old when the PX4 was introduced. It was time for a new mag.

gc70 said:

Changing magazines ever so slightly in new models guarantees makers multiple future magazine sales.

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Feel free to point the finger at FN. They've had a bunch of guns over the past couple of decades and I'm not sure anything is shared between these very similar firearms.

In the Beretta line-up, the M9/92, PX4, and the APX are all very different guns.

JTQ said:

I've seen comments from Ernest Langdon that while the Beretta 92 mags are fine, they are 1970's technology. The PX4 magazines are an improved magazine. Beretta didn't want to be tied to old technology by trying to make the PX4 work with an old mag design.

I think there would be some logic to using the PX4 mag with the APX, since the PX4 would have been only about 10-15 years old when the APX was introduced, but the 92 mag design was probably 30 years old when the PX4 was introduced. It was time for a new mag.

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Here is Langdon's video about 92 and PX4 magazines. In short, magazines in guns built around the .40S&W round were usually optimized for the fatter round's stack width. The .40 magazines are wider and 9mm versions of the magazines have grooves on the side to reduce the 9mm stack width.

I think the original 96 magazines had a capacity limit of 11 rounds of .40 S&W while the PX4 gave 14 rounds of the same caliber. These are both in non-extended tube length mags.

C0untZer0 said:

It seems like there is a market for full-sized softer-shooting pistols, like the 380 ACP, and the rotary barrel supposedly dissipates recoil away from the shooter’s hand and greatly reduces muzzle jump. The design also allows a lower bore-axis.

I don't know why they're not more popular and I think a full-sized 380 ACP utilizing a rotary action, with a low-bore axis would be well recieved,

I think Savage had a rotary action 380 ACP at one time, but I could be wrong...

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The old savage 380 had a rotating lug, but the barrel did not travel backwards and so was a retarded blowback.

Searle's design consisted of a separate breechblock that contained a spring-loaded striker with a prominent cocking lever that was inserted into the rear of the pistol's slide where it was held in place by a tongue-and-groove system. The barrel had a lug on top of the chamber that mated with a helical groove on the inside of the slide and another on the bottom that fitted into a slot in the frame. At the instant of firing, the barrel and breechblock/slide unit were locked together, but as the slide started rearward, it bore against the top lug. As the bottom lug prevented the barrel from moving to the rear to any degree, the helical groove in the slide rotated the barrel to the right approximately 5 degrees where the lug entered a straight groove in the slide and allowed the breechblock to recoil fully, extracting the spent cartridge case.

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"the helical groove in the slide rotated the barrel to the right approximately 5 degrees"

Part of the Searle concept was that the rifling twist, rotating the bullet to the right, would generate a countertorque to the left and delay the barrel's turn by enough to matter.

C0untZer0 said:

I wonder if the 380 ACP cartridge has enough energy to operate a rotary action reliably.

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Probably. It has enough energy to operate a long recoil action in the Frommer Stop, which seems a lot of work for a small cartridge.

A handloader could reduce 9mm P and get softer springs to see how low you could go if you had a Beretta or Grand Power to tinker with.

WestKentucky writes:

I’m especially thinking of the Grendel p10 and it’s not so distant cousin the Keltec P3AT.

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Yes, that Grendel is rude, particularly without its optional grip-extender in place. It differed from its Kel-Tec descendant, though, in being a blowback-operated gun, which certainly didn't help. I've never shot the P3-AT, but the Taurus TCP I own isn't nearly as rough as the P10.

Incidentally, the new LCP-MAX does a fine job mitigating perceived recoil quite a bit over the TCP (I have no experience with the earlier incarnations of the LCP.)

When I see a bit more ammunition coming around, I'll try the Mauser M2 .45 pistol I've been sitting on for like two years now. The closest I can put it up against is one of two 1911 pistols I own. It's a bit chunkier on grip and girth, though, for having the same magazine capacity.

Jim Watson said:

"the helical groove in the slide rotated the barrel to the right approximately 5 degrees"

Part of the Searle concept was that the rifling twist, rotating the bullet to the right, would generate a countertorque to the left and delay the barrel's turn by enough to matter.



Probably. It has enough energy to operate a long recoil action in the Frommer Stop, which seems a lot of work for a small cartridge.

A handloader could reduce 9mm P and get softer springs to see how low you could go if you had a Beretta or Grand Power to tinker with.

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The .32 frommer stop will work with standard .32 acp loads in my experience. So it is no surprise that a .380 can operate the .380 ones two. But ideally there was the equivalent of plus loadings for those pistols.

I bought my wife a Beretta Cougar 8045 about a decade ago.

It's the softest shooting .45 ACP that I have shot, but the only other .45s that I've shot are a Glock 21 and a couple of 1911s.

If it had a double stack magazine it probably would have had more success in the market.

"but the barrel did not travel backwards and so was a retarded blowback."
I think part of the reason some have labeled the Savage a RB is because someone in Germany made spark photography images which proved that the slide was opening before the bullet left the barrel. It is a unique concept that no one else ever even tried and it's possible the geometries involved could have been tweaked to get it to work.
I'm surprised that no one mentioned my favorite rotating barrel pistol, the CZ 24 in .380 (The later CZ 27 was .32 blowback). Mine functions perfectly and it's unique also in several ways, I think Hugo Schmeisser worked on the prototype stages. I admit to loving the history of gun design almost as much as shooting them.

Ahh! The Boberg is another one I think!

HisSoldier said:

"but the barrel did not travel backwards and so was a retarded blowback."
I think part of the reason some have labeled the Savage a RB is because someone in Germany made spark photography images which proved that the slide was opening before the bullet left the barrel. It is a unique concept that no one else ever even tried and it's possible the geometries involved could have been tweaked to get it to work.
I'm surprised that no one mentioned my favorite rotating barrel pistol, the CZ 24 in .380 (The later CZ 27 was .32 blowback). Mine functions perfectly and it's unique also in several ways, I think Hugo Schmeisser worked on the prototype stages. I admit to loving the history of gun design almost as much as shooting them.

Ahh! The Boberg is another one I think!

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Retarded/delayed rotary angled lugs: Such has been tried through history. The most recent is the CMMG delayed/retarded blowback of the Banshee series of pistol caliber guns.

What's Radial Delayed Blowback
CMMG designed the radial delayed blowback system used by the Mk17 Banshee to overcome the faults with traditional blowback designs. The radial delayed blowback system utilizes a proprietary bolt and chamber. The bolt lugs are angular and lock into the proprietary chamber. These angular bolt lugs lock into the chamber and do not unlock until pressure levels have dropped.

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But the principle here is old, going back IIRC to 1890's and Ferdinand Ritter von Mannlicher (January 30, 1848 – January 20, 1904)

Mannlicher designed two semi-automatic rifles both called Model 93, one based on his turn-bolt rifle and the other based on his straight-pull rifle. The rifles had a recoil spring housing behind the bolt and the bolt locking lugs were angled, so the bolt started turning on firing, essentially a hesitation lock or delayed blowback much like the later Thompson Autorifle utilising the Blish lock. In this system there was no recoiling barrel nor gas piston as with other rifle-caliber autoloading designs, so the mechanism was simple, but ejection of fired cartridge casings was so fierce as to be hazardous to bystanders.

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10mm Banshee pistol

I saw a CMMG at the range demo day and thought it looked promising.
I don't know how you would get that system into a real pistol, though.

I am a fan. I have both a 9mm PX4 and a CX4 that uses PX4 mags. They both have been 100% reliable with zero hiccups. They're fun to shoot and accurate and make a good HD setup.

Jim Watson said:

I saw a CMMG at the range demo day and thought it looked promising.
I don't know how you would get that system into a real pistol, though.

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That system is used for AR pistol caliber arms because one can not readily use a recoiling barrel gas pressure is often not adequate for operation. The slanted lugs seem to be only a minor modification of the system and there is still a lot of mass in the BCG along with buffer wts and ample spring in the buffer tube.

I understand how it works.
Olympic Arms and an outfit in Huntsville made locked breech pistol caliber AR-oids.
Both are defunct which may say something about the idea.

"Retarded/delayed rotary angled lugs: Such has been tried through history."

My reference was to utilizing the inertia of the bullet to retard barrel rotation which (In principle) slows opening, not merely rotating barrels. Do you know of any other designs that used bullet rotational inertia to slow breech opening?

I can't think of any other than the Savages.
Randy Lee did make use of rifling torque in his Apex/Barsto barrels for the rather infamously erratic S&W Plastic M&P. Not in lockup but by biasing the barrel into a consistent position while still in battery.

C0untZer0 said:

I wonder if the 380 ACP cartridge has enough energy to operate a rotary action reliably.

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This is a misplaced concern, I think. Consider two independent lines of reasoning.

First, Glock 42 exists, and the characteristics of rotating barrel lock-up are not that different from a tilting barrel. Yes, it wastes more energy in the friction, but otherwise it's not different enough from preventing a rotating barrel .380 from existing.

Second, the amount of energy harvested into the action is the integral of the force over the distance. So, you can vary it greatly by changing the rate of the groove and the mass of the moving parts. Well to be honest I haven't done the calculations, but common sense suggests that sky is the limit. I'm pretty sure you can harvest way more than from any delayed blowback simply because the distance can be made huge in comparison to what a moving case can sustain.

C0untZer0 said:

Does the barrel have to rotate in a specific direction?

One of the criticisms I've heard about rotary action is that it takes more time to do follow up shots. I'm not sure if that is because it takes longer to get the sights back on target or because it takes longer for the gun to go back into battery?

But if it is because it takes longer to get the sights back on target maybe the gun is rotating the wrong way. I think most rotary action handguns rotate clockwise, which is rotating AWAY from the support hand of a right handed shooter. Maybe if the gun rotated into the support hand of a right handed shooter it would be easier to get the sights back on target more quickly?

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Some time ago I saw a video, which I can no longer find, where the firing time of three or four pistols was measured, including a Beretta Px4 Storm. The Px4 was the one with the longest firing time. But I think this is completely irrelevant to any shooter in the world. No shooter in the world can be faster than the firing time of a pistol (just think of a full auto Glock to understand what I mean).

Regarding the direction of rotation of the barrel I can say that in delayed blowback pistols such as the MAB PA15, the direction of rotation of the bullet is opposite to the direction of rotation of the barrel to delay the opening of the slide by a fraction of a second but, I repeat , it is not a locked breech action.

As for the Px4, the barrel rotates counterclockwise but I don't know the direction of rotation of the bullet.

As for the Grand Power Q100, the barrel rotates clockwise and the bullet also rotates clockwise. Despite this, I assure you that the Grand Power is the most stable pistol I have ever fired with. It absolutely does not suffer from rotations either on one side or the other typical instead of the pistols with the Browning system which tend to rotate counterclockwise in the hand.