Jim Watson
Member
barrel has a tighter chamber and a shorter leade
Tighter and shorter than what? The old barrel, the specifications? SAAMI blueprint dimensions are for the minimum chamber, all tolerances are plus.
I once saw a chart of chamber measurements, you are not always getting what the label says.
I have seen some true .223 chambers with a very short throat.
Or the handy Stony Point - now Hornady - gauge to measure the "jump" of the ogive to the lands.