I know the barrel on a Beretta 92 does not rotate when cycling. Does the locking block move during cycling? Or does the sliding wedge and pin just allow installation and removal of barrel?
I know the barrel on a Beretta 92 does not rotate when cycling. Does the locking block move during cycling? Or does the sliding wedge and pin just allow installation and removal of barrel?
Yes, it moves. When "up"' it's engaged with the slide. As the slide and barrel recoil together, the block pivots down, disengaging the slide from the barrel.
We may lose and we may win, but we will never be here again.......
Ok, the recoil rearward forces the pin "in" allowing the block to tilt down unlocking the block from slide. This allows the slide to move rearward, ejecting spent case and clambering new round as recoil spring returns slide to battery. I guess at the end of that process the locking block raises up re-engaging the lock between the the slide and locking block. That tilting up and down happens extremely fast and never malfunctions. What actually pushes the block up at the end? I mean the pin is not being pushed until recoil of next shot but the absence of the pin being pushed doesn't tilt up the block?
So I watched an Army video about M9 operation. It shows the barrel moving rearward a distance equal to the pin insertion distance. I don't think I realized the barrel actually moved axially? If it does move rearward, I assume the forward movement at the end of cycle operation is when the locking block is forced up into the slide lock position. I guess there is contact with the bottom of the block to force it up as the barrel moves forward when slide contacts it as recoil spring extends fully. I did not know the barrel moved back and forth? Maybe 1/8" to3/16"?
Last edited by Rmiked; 03-27-2017 at 08:10 PM.
I believe the takedown lever pushes up against the front of the locking block when the slide and barrel return to battery.
Last edited by ReverendMeat; 03-27-2017 at 08:14 PM.
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Yea, I just took mine apart and examined it. There is a flat ledge that goes across frame at takedown lever that the forward sloped edge of locking block collides with and pushes it up on last 1/4" of forward barrel travel. If you look at barrel from side while you pull slide back you can see rearward barrel movement comparing barrel with guide rod (which does not move). I can't believe I have had pistol for 8 weeks and didn't know barrel moved rearward. It's so subtle I didn't see it.
It's a very neat design and you will also notice it allows for better feeding (notice that the feedramp isn't as steep as other designs.) You'll notice the mag is practically inline with the bore. I believe this quirk really helps it in feeding reliability.
It is a wonderful design that feeds super reliably and exhibits a nice soft recoil impulse. The only fly in the ointment it the relatively small lugs that engage the slide. They fatigue and break off at roughly 15k rounds. I have a spare block kit in my parts inventory for my M9A3. I will replace it at 15k. Sometimes they break sooner...but not so big a deal. I think the entire kit was 35 dollars and it includes a new recoil spring.
You should replace the recoil spring about every 5K rounds too.
Make sure both sides of the locking block engage the slide by inspecting the wear. It's not common to have only one side engage but if you do have that condition you can expect early locking block failure. Also the newest blocks should have much better durability than the originals. I think they're on gen 3 now. I had an M9 that had tens of thousands of rounds on one locking block and it had no visible cracking.
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