Beretta 92 locking block operation?

[SSGN_Doc]

The locking block also keeps the slide and barrel and slide locked together for the moment of highest pressure inside the barrel, so the high pressures to not break through the thinner walls of the cartridge case. Part of the differences in a locked breach vs. blowback operating system.

Remove the lugs and the barrel can move forward as the slide moves rearward too soon, and hot gas is going to find the weakest point to escape. That would be the cartridge case walls forward of the cartridge case head. Nobody wants that.

[Maca]

Quick question, is this wear on the right side only (not bilateral), normal during break in? You can feel it with your fingernail.

For context, this gun has had 175 rounds through it.

[Rmiked]

My initial reaction is that is a machining mark and not a wear mark. My guess is that mark was there when you bought the pistol. And you are just now noticing it. I would be interested in thoughts of those with more 92 experience than me however.

[Joe in PNG]

I suspect it to be a proof mark of some sort.

If you look at the photo on the Brownells page, you can see the exact same mark.

[Maca]

I suspect it to be a proof mark of some sort.

If you look at the photo on the Brownells page, you can see the exact same mark.

Thanks a great find! Thank you.

[TiroFijo]

Well, kind of, but not really, maybe a little bit.

The locking block is the mechanism that holds the slide forward and locked up. When the gun fires, the barrel wants to move forward, with the direction of the bullet. The brass case expands to fill the chamber and keep "most" if not all of the gases moving behind the bullet toward the muzzle. The locking block ''ears" hold the barrel into the slide keeping it from moving forward. It is being pulled forward by the barrel and pushed up by the frame and the disassembly lever.

As soon as the bullet exits the barrel, the pressure pulling the barrel forward drops, but the remaining pressure in the barrel is pushing the barrel rearward suddenly. The barrel and the slide move rearward together for a short distance as the locking block is pushed down by the locking block plunger, which is hitting the frame right below the chamber, and as it comes off of the disassembly lever and frame, allowing it to move downward away from the barrel. The "ears" of the locking block disengage from the slide allowing the barrel to fully un-lock from the slide.

There are more details, but that is the basics of how the locking-block work.

As with any other pistol that is recoil operated with a locked breech, the barrel+slide start moving rearwards as soon as the bullet starts moving forward. The barrel+slide recoil a small distance (normally in the order of 0.1") at the moment of bullet exit, and the jet effect of the expanding gases leaving the bore behind the bullet give it a little boost.

Easy to see in any slow motion video detailing the moment of bullet exit.

[Evil_Ed]

As with any other pistol that is recoil operated with a locked breech, the barrel+slide start moving rearwards as soon as the bullet starts moving forward. The barrel+slide recoil a small distance (normally in the order of 0.1") at the moment of bullet exit, and the jet effect of the expanding gases leaving the bore behind the bullet give it a little boost.

Easy to see in any slow motion video detailing the moment of bullet exit.

There was a great slow-motion video compilation on Youtube from...I think it was Kurzzeit? One of their compilations; they took an IPSC 1911 (probably 2011 tbh)-pattern gun with a full length dust cover, and then put graph markings lined up on both the slide and frame. When they fired it, you could clearly see the markings start to move/mis-align before the bullet left the bore. I would expect that if a similar thing were done with a Beretta, you'd see the same thing...the barrel/slide start to move back before the bullet left the bore.

[TiroFijo]

There was a great slow-motion video compilation on Youtube from...I think it was Kurzzeit? One of their compilations; they took an IPSC 1911 (probably 2011 tbh)-pattern gun with a full length dust cover, and then put graph markings lined up on both the slide and frame. When they fired it, you could clearly see the markings start to move/mis-align before the bullet left the bore. I would expect that if a similar thing were done with a Beretta, you'd see the same thing...the barrel/slide start to move back before the bullet left the bore.

Twenty years ago slow motion videos detailing everything were hard to get, they were expensive and manufaturers treated them like inside information.

I wrote to Werner Mehl ten years ago asking for that close up, and predicting the amount of slide movement, and he kindly obliged...

https://www.1911forum.com/threads/1911-dynamics-2.3141/

Sadly it is no longer on his site or YouTube

There is also footage of a cutaway 1911 made by Virgil Tripp showing the same thing, he made it after some email exchanges with me, even engraved the front of the frame to measure the movement.

[Evil_Ed]

Twenty years ago slow motion videos detailing everything were hard to get, they were expensive and manufaturers treated them like inside information.

I wrote to Werner Mehl ten years ago asking for that close up, and predicting the amount of slide movement, and he kindly obliged...

https://www.1911forum.com/threads/1911-dynamics-2.3141/

Sadly it is no longer on his site or YouTube

There is also footage of a cutaway 1911 made by Virgil Tripp showing the same thing, he made it after some email exchanges with me, even engraved the front of the frame to measure the movement.

So we have you to thank for those videos! Awesome! I remember when they hit youtube way back when, and they were super illustrative of how things actually work in a Browning-type locked handgun. It really opened my eyes up as to the physics and timing behind things.

[TiroFijo]

So we have you to thank for those videos! Awesome! I remember when they hit youtube way back when, and they were super illustrative of how things actually work in a Browning-type locked handgun. It really opened my eyes up as to the physics and timing behind things.

How it all originated...

https://www.1911forum.com/threads/1911-dynamics.2977/

It is amazing what an exchange of ideas between people who live on the other side of the world and do not know each other but share a common interest/hobby can lead to, the magic of internet forums and email.