BJB

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.

I didn't know Blue Bullets made a 135 gr RN. I though they just made the TC in 135 gr.

Commercially produced ammo doesn't always use the same powder. They don't really care about velocity as much as they do pressure. So you can see variances in the same brand over time in different lots.

Put the barrel in the freezer for a while & then try again......and twist a little while pulling.

Remove the barrel. Ram a spent .223 case up there. Ram it in there pretty hard where it can grab the 9mm hull. Now you have something sticking out to grab a hold of. Remove the .223 case & the 9mm hull should come with it.

I think it's STV, instead of SVT. As stated above by @George16, it's Czech made ammo of good quality. The 124 is loaded to 124 NATO so it's hotter, but they do also produce a 115. They load to CIP specs so the ammo is short-throat friendly.

CZs run steel cased ammo just fine. BTW: Steel cased ammo is fine in USPSA provided the projectile jacket is non-magnetic. Some Tula and/or Wolf use a steel jacket, but some has "bi-metal". Check the projectile with a magnet before competing with it.

If 1.100" is what it takes for that barrel then that's fine. You're good-to-go. For a HP that's not even very short.

The Apex barrel is more accurate, particularly with heavier bullets, but mine had a very short leade so I bought a Clymer throat reamer and took care of that. You said your M&P was from 2009 so something you'll have to be aware of is sear flutter. The early sear springs were smaller and would weaken with use and miss the striker during reciprocation...... so you had a dead trigger. In 2011 or 2012 S&W finally went to a larger sear spring to fix this issue. Apex can help you out by upgrading your sear spring & housing on the older guns.

The SAAMI max of 1.169" is more for the dimensions of the magazine, not the leade of your barrel. You have found your new OAL and it's 1.12". If you load for a CZ, or Glock Gen 5, or Tanfoglio, etc......you'll find that your OAL requirement will likely be even shorter. 1.12" or 1.11" is a fairly common OAL for 124 JHP, not really short at all. You're good-to-go with that OAL.

Remove the offending barrel and plunk the offending rounds. It's likely just a shorter leade in this barrel and nothing wrong with the gun or chamber. Also, 1.148" is getting kinda long for a JHP in a non-Open gun.

Your G19 is a Gen 5. The Gen 5 have a short leade. Have to load short, which is no big deal, or ream the throat.