P Taylor

https://www.cdnnsports.com/smith-wesson-m-p40-m2-0-fde-slide.html

CDNN has new 5 inch .40 slides for 50 bucks , I recently purchased 2 of them. One of those and barrel and you have one in .40

....one other thing....if running the Chen SI magwell some base pads will take a bite out of your palm on the forward part of the magwell where it curves in.

The McCormick Power Mags I have do not drop free when empty, the follower moves forward when fired until empty and drags on the frame. The mags are reliable but do not drop free. Wilsons have worked well but maybe need more frequent spring and follower changes. Ed Browns have worked fine as have my Tripp mags. One thing to watch is if you run a mag well some mags will not seat if the base mage is wider than the mag. I have a few like this and I think they are Meg-Gar and the Brownell 8 rd mags but do not remember off hand for sure.

I have read on slides it is a way to mark which machine the parts come from for QA tracking if there is a problem. No idea if it is the same on barrels.

The 357sig barrel is the most accurate set up I have for a M&P. I would put more time into the round if there was more industry support behind it. I have a 40 to 9 Apex barrel shoots well , have considered cutting it for a 357sig chamber.

I have KKM barrels in .40 and 357sig , do not know how they compare to other brands but they did improve accuracy over the stock barrel 40 barrel.

....and I think it was Sarco that bought out the PARA inventory. Last time I looked the inventory was getting low but some things still available.

Check the breechface cut , some makers use a .40 cut for 9mm , Super 38 and .40 caliber. If it has the .40 breech face it is just barrel , mags and springs to go to 40 or 9mm.

I carry a 5 inch steel frame 1911 but I am taller/bigger than most people , 6'4" and 230lbs. Good holster and belt is needed for any carry but maybe a little more important with the heavier pistols.

I have wondered the same myself , the size of a 2011 grip could be reduced by using a magazine that was designed for a 9mm pistol or a .40 pistol. New trigger would also be needed to match the width. Years ago there was a smith out in I think Ca. that modified a single stack 1911 to use Smith M39 mags. Just a matter of time and money , no idea if it would pay for itself.

Watchmen

I added a 1050 to my bench about 2 years ago. If doing again I would get 2 more 550s to put with the one I already had instead. If I knew I could get 550s I would probably sell the 1050 and do just that but with current events not sure I want to chance it.

It is the striker spring holding the slide a bit, on my M&Ps if I give the slide a push forward with my thumb after resetting the sear the slide does not move when the striker falls. I am not a competitive shooter and use heavy .40s for carry. The heavier recoil spring for the 200gr 40s also helps to seat the slide so I would guess if you are using a lighter recoil spring with 9mm the problem is worse.