Do 9mm top assemblies inter change between gen 2 and gen 3 9mm Smiths? I see a few used gen 2 slides and barrels for sale and wonder will they drop onto my gen 3 alum frame....and vice versa? I'm not talking DAO but normal DA/SA guns. And what about .40? Does a gen 2 .40 top end fit and function (with the correct magazine) on a gen 3 9mm frame?

Thanks for any guidance as I dream up crazy ideas for expanding the usefulness of my 915 S&W.

do a search in this forum for 'frankenguns'. you should find your answer(s) in one of the many threads/posts.

While I have never tried any 2nd-3rd gen Frankenguns, my understanding is that a 2nd gen slide may work on your 915, and it may not work due to some of the design changes. In general, I try to keep any slide swaps within the same 'revisions' of the 3rd Gen family, and while the 915 is an earlier model, it already has the wider barrel hood revision and may not be compatible with earlier 2nd gen slides/barrels. Someone with actual experience with this (like JohnHL, I believe) may be along soon for a more definitive answer.

Any 3-digit .40 models you are considering (411, 410) are actually 3rd Gen Value Line models, but only the 411 would be compatible (in theory) with your 915, as they were produced at the same time. The 410 lacks the front rail indents. I do not think any .40 cal would work with your 915 in reality though, since the .40 mags have a bump on the front that would keep them from being inserted into your 9mm guns.

A shorter 3.5" barrel slide (3913/6904) or a different 4" slide (5904/5906) with the wide barrel hood would be possible matches for your 915, if that was something you were looking for.

It has also been my experience that a 5906 slide will not go on to a 4006 frame as they engineered a very small difference in the frame area near the slide stop hole that prevents the 9mm slide on a .40 cal frame.

I'm not trying to be cryptic about specifics of the difference, I just didn't try or inspect any further beyond noticing that it appeared specifically designed to prevent the swap, much like the magazine dimple mentioned in the post above mine.

Without knowing more, it seems as if S&W purposely made these changes to prevent caliber swaps.

I have not attempted to put a .40cal top end on a 9mm frame but my guess is that it won't work without specific modification.

After re-reading your original post, I will also add:

I have had some success with same caliber 2nd Gen top ends placed on 3rd Gen frames however, in my experience it was only install, I never attempted live fire functioning, it was just for kicks while playing in front of the gun safe.

Also to one other detail, there was never a .40cal 2nd Gen made, the 3rd Gen Model 4006 was the first ever S&W .40cal pistol on the market... and actually... gulp, Glock swindled & plotted & schemed to get the first ".40 Smith & Wesson" chambered pistol for public sale with the Glock 22 which hit the market before the 4006 actually did. A kick in the face to S&W with the round actually named ".40 Smith & Wesson"

Excluding TSW models, 2nd and 3rd gen 9mm top ends will usually swap with no problems.

Again, excluding TSW models, .40s&w slides are too wide at the front rails to fit on a 9mm frame of any generation.

John

OK...thanks. Good to know.

With the introduction of the TSW guns ..... some/most slides had the heavier 'box rails" first introduced on the PC guns.

That said ..... I've got a 59xx slide and barrel and a 915 slide and barrel that will fit on a 6904............

IMO unless you are or have a gunsmith do it................. I'd avoid mixing generations...... probably some form of incest involved..