I'm interested in converting a M&P40 compact to 9mm for range/plinking and versatility. I'm not seeing any makers for a conversion barrel for the 4" size and I know the stock barrels have extra play in them and will get an actual conversion barrel. I don't believe that the conversion barrels have a taper like the M&P barrels. Does anyone know if the full size 4.25" 40 to 9 conversion barrel will fit in a compact frame?

I would recommend that you check with KKM Precision. Welcome to the forum from North Carolina.

There is a thread where a member used the 4.25 conversion barrel and had a gunsmith cut it down to 4"

I have a 40 M&P Compact(version 1). Happened to see Midway advertised a 9mm S&W barrel for $68 and jumped on it. Of course then I had to beat the woods for mags and ultimately got a 12 and 17 rounder which emulates the way I carry it in 40, that is, with a 10 in the gun and 15 rounder backup. That barrel WORKS! It amazed me how accurate it is and has no problem with ejection in my 40 slide. Would consider making the switch down to 9 if and when ammo becomes more readily available...I reload 40 but am not planning on reloading 9. Of course with recent events I don`t think ammo is going to be readily available any time soon (if ever). Good Luck, John

Whether or not it fits, the barrel lug geometry could well be different.

Welcome to the Forum

Just because something is not on a Company's website does not necessarily mean that they do not make it or have it in stock.

Call the company and talk to a real person. If they tell you is it not on their site, ask if they will make you one

You might have to wait for their next run of barrels, but most all of the major manufacturers are very happy to take your money and are willing to help

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"Acta non verba"