you must be referring to polygonal rifling, what you have stated is true, except there are many different firearms with polygonal rifling that should not have lead ran through them, some HK's, glocks, Jericho 941 ( also known as baby eagle, Uzi eagle ) are just a few of the more common ones you should not use lead in. The polygonal rifling has very, very small lands and grooves ( speculated to be in the 0.001 range ) and its also 9 sided, hence the term "poly" the leading is difficult to spot and makes it easy for a bullet to become stuck in the grooves due to unseen leading.The shape of the rifling (poly something) in a Glock is designed for jacketed bullets, lead bullets will leave severe lead fouling and catastrophic failure. There are after market barrels with conventional rifling if someone is determined to shoot lead bullets.
Favorite Loads - 22-250 - Savage bull barrel varmint rifle-
36 Gr Barnes Varmint grenade - IMR8203XBR Powder - 38.3 gr - once fired brass - Remington large rifle primer Ogives measured with hornady tools - set at 2.027which is 0.036 off the lands - this is close to the maximum length to keep the bullet seated in the case- 0.500" 5 shot groups - Chronograph velocity 4,378 f/s - wonderful for prairie dogs and coyotes out to 250 yds
Wyoming deer and antelope load -
65 Gr Sierra SPBT-IMR 8203 XBR Powder- 32.5 gr - 0.56" 5 shot groups - Chronograph velocity 3,429 f/s- Ogive set at 2.114 which is 0.010 off the lands- Have used this on antelope to 350 yds and on deer to 250 yds for the last 3 years
Source manual is the HOGDON Annual Manual - very good load resource for $10
Don't know why H322 doesn't seem to get much love but... 26gr under a .224 40gr Sierra Blitzking Poly tipped with a 2.250 COAL in a 18" R5 Wylde will get sub moa at 150 all day. Has a nice 'punch' to it.