Beretta PX4: Converting from 9mm to .40 Questions & Help

[Redcoat3340]

I have a very slick 9mm Beretta PX4 Compact (Langdon slicked it up).

I want to go to .40 and understand all I need to do it is put on .40 slide, barrel, recoil spring and use 40 mags.

I have all the necessary pieces but they are for a FULL SIZE PX4, not the compact like I have.

The mags stick out a bit (but that's not a problem) and the slide fits on the frame.

There is also a gap (as expected) between the end of the frame and the front of the barrel.

My problem: the slide won't rack. Feels like something is "stuck," and it looks like the end of the recoil spring -- which has a "big" round "button" on the end surrounding the spring while the 9mm recoil spring does not have one is getting in the way.

My question: Will the full size .40 slide, etc. work on the compact frame? Is it me doing something wrong or are the two assemblies simply not compatible?
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[5-SHOTS]

That "round button" works as a some sort of recoil buffer in the Px4 full size frame.
The Compact model has a plastic sleeve in the locking block/recoil spring assembly to fill the gap between the front of the slide and the dust cover.
The only idea I have is to try to remove the plastic sleeve from the locking block or buy a locking block for the full size model. If you already have the full size locking block but the full size slide still doesn't rack in the compact frame, I suggest to make a front adapter to use the compact recoil spring in the full size slide and the full size locking block.

 

[5-SHOTS]

Locking blocks are different anyway.

Compact:

Full Size:


Compact:

Full size:

 

[worker]

I suspect you need a completed slide + barrel for that PX4 compact.
I have never seen berretta selling these however...