BJB

Get an account on "Practiscore". Search for the clubs local to you that run USPSA or Practical Pistol. Contact information will be listed for the match director. Contact the MD & tell'em you're new & want to shoot and the MD will have all kinds of information for you. For the clubs that set-up the day prior, folks will often shoot a little after the stages are set-up. That will be your chance to be introduced to the sport before the actual match.

If you're looking for a mid-130 power factor then you'll likely need 3.8 to 4.0 gr of N320 with a 125 gr coated depending on your barrel length. A little compression at 4.0 gr is no big deal with N320 at these 9mm minor velocities you're looking for.

For coated bullets using Sport Pistol I load as follows @ 1.12": 125 gr = 4.0 gr SP 135 gr = 3.7 gr SP 147 gr = 3.4 gr SP These will all give you mid-130s power factor via a 4.5" barrel. If you load a plated 135 gr bullet with 3.3 gr SP if will likely be a little weaker than you want.

Try a new battery.

That scrape is in front of the driving band so leading shouldn't be coming from that scrape. It's likely coming from elsewhere, like gas cutting, etc.

I have not used CCI magnum pistol primers but I have used thousands & thousands of Winchester & Federal magnum small pistol primers. Neither one of those gave any appreciable increase in velocity over the standard small pistol primers.

With Blue Bullets that isn't a big deal.....but 0.356" are slightly better for me. FYI: Blue Bullets will sell you 9mm sized 0.356" upon request. Look under "special order profile". Also: Their RN profile has a big fat ogive and you may have to load short. Their TC profile allows you to load a little longer and they were more accurate for me.

Set your crimp to around 0.378" and you'll never have to touch it again no matter what bullet shape or coating/jacket you use. In taper crimp, the crimp doesn't hold the bullet, it simply removes the bell you put in there.

No.

cost & accuracy.

Your single action pistol with the 21 lb hammer spring should light them off every time. Where CCI primers can cause some issue is in double action guns that have the main spring lowered a lot. CCI is usually fine even then, most of the time, if you have an extended firing pin and reduced firing pin spring.

Fired in a stepped chamber. Likely either a Walther or H&K. There's nothing wrong with that brass. Reload it normally.

Yes, I noticed seeing SP becoming more smokey back in the winter when I got into a new jug.......and more carbon in the gun too.

Compare them in your gun/guns and find out. That's the only way to know. For me there was a slight difference. Shooting 10-shot groups at 25 yds, the 0.355 bullets would mostly have a nice 2" or so group with 1 or 2 shots being a little further out making it a 3" or 3.5" group, when most were in the 2" group. The 0.356 bullets kept everything in a nice 2" group for me, no little flyers.