I would start with production and learn how to break down a stage with less ammo. You'll learn to be more disciplined with your ammo vs starting off with 20+ rounds and putting 3 shots on a target to get 2 hits. And as Mcfoto mentioned, you'll learn to reload in production division.
I also started with a Glock 34. If you stick with the sport you'll end up with a bunch of different guns for different divisions. It's part of the fun.
USPSA shooters are generally friendly and accommodating people so you should be able to try a variety of fellow shooters' guns before purchasing anything.
Real world anecdote - years ago when I switched from Production division to Limited, I found myself doing more spraying & praying than calling my shots. I switched to revolver division for 6 months and learned to break down stages with only 6 rounds and became far more disciplined with my ammo since I had only 6 rounds vs 23.
Another issue that I've encountered is over-torqued stock screws. Cranking the stock screw too much causes the stock-to-receiver fit to change and has adversely affected one of my 10/22s.
Also, if the mags are new, I'll insert them into the receiver 50 - 100 times to knock the sharpness off of the mag screw ring and any other areas that cause resistance.
Looks like all MPX owners should check for this. In this sigtalk thread a shooter's gun arrived with a cracked bolt before he had a chance to shoot it: https://sigtalk.com/sig-sauer-rifles/255994-mpx-bolt-issues.html Sig sent him a new bolt. I'm not a member on that forum so I can't see the pictures.
You need to find out which brand works best in your 1911. I've tried Tripps, WIlson, CMC in my 9mm 1911. Hopefully you can try other shooter's mags before purchasing a bunch.
Not much difference in velocity according to these 10mm tests: http://www.ballisticsbytheinch.com/10mm.html
From 10 to 30 additional FPS with heavy bullets.
I have the McFadden but found it too finicky so I use the HKS version which is $5 and takes up no space.
https://www.amazon.com/HKS-22-B-Magazine-Speedloader-Challenger/dp/B000PW5GN4
"Smith & Wesson Brings Back the 10mm Model 610 Revolver"
1 page of info, no price, and 40 pages of commentary.
https://www.thetruthaboutguns.com/2019/03/daniel-zimmerman/smith-wesson-brings-back-the-10mm-model-610-revolver/
Left thumb into the slide causes that problem with my PM9 1911 with a light recoil spring. Test it by shooting strong hand only before making any hardware changes.
I also agree. I used their customer service twice, once for a spotting scope issue and once for a rifle scope issue and they were both handled quickly.
More commonly known as the "Czech Point" revo.
https://shop.reedsammo.com/Czech-Point-9mm-Revolver-CZPT9mm.htm
https://www.gunbroker.com/item/794831502
It's a 40 round mag for a Colt style AR9. That picture is from the image link in this thread: https://www.ar15.com/forums/ar-15/-/15-208951/
From back in 2004 when Sportsmanguide was selling them.
Unfortunately AZ is correct. I've used numerous Volquartsen kits and they've all resulted in triggers around 2 lbs. Find another "gunsmith" or a fellow shooter who's mechanically inclined.
Check out these videos just to get some general knowledge of the process. It's not rocket science.
https://volquartsen.com/howto/install_mk4_accurizing_kit
https://www.youtube.com/watch?v=YB9EmYwDyzg
https://www.youtube.com/watch?v=PMQlJCNEGso
There are multiple long standing issues with BX-25 mags which is why you don't see (many) people using them in steel matches. I don't even use mine for practice. Get six 10 round mags for matches. Change mags for each string and you'll never have to worry about round count.
Here's a fix for the most common BX-25 feed problem: https://www.youtube.com/watch?v=kSTumIx5tL0
Like bwikel mentions above, email or fax your form 5320 to NFAFax@atf.gov. The last 3 that emailed to the ATF for out of state matches all took one week for the email response.
The Hornady cleaner has worked well for me. Regardless of the solution, your eyes will tell you when it's time to filter or replace it. Dirty/cloudy solution with chunks of debris at the bottom.
RePete's coffer filter solution works well if you have the patience.