With the 2R bullet, I have found it shoots much better with a gas check than bare. Notice they all are checked in the pic.
Also if you PC first, the gas check won't fit (Hornady gas check) on the bullet unless you flare the gas check before attempting to slit it on. (used a steel ball bearing and a hammer before I learned better)
Your mold could be different than mine (I have 3 two gang molds and recently upgraded to the 6 gang.
They all need the GC installed before PC )
Since flaring is a pita, it's 2 trips through the sizer. First installs gas check, PC bullet, and size to desired diameter. This is my present method.
I size to .310 for 300 blk and .312 for 7.62x39.
I have found the Lee sizing dies are undersized from the marking on the die. Measure a sized bullet diameter with a caliper to determine the true diameter.
I open up my sizing dies with a dowel wrapped with 400 grit wet/dry sandpaper turned with a drill to get the
diameter of the bullet to match what is stamped on the die.
Also get a Lyman M die ($20) to expand the neck. If you scrape the PC off, there goes accuracy and you may get some leading.
After seating a light crimp with a Lee FCD will take out the flare of the mouth.