Stan, I've made most of mine as a "dished/step" crown, and have had them of nearly every type. I've got to confess to liking them (regardless of general type) "lapped" - just enough to [lightly] bevel the groove: this type of crown has held up extremely well for me - though, I confess to scarcely ever cleaning. This past weekend, I shot the entire GRAND AGG (100/200), including the "warm-up" matches without cleaning! The Kostyshyn barrel, which, at the beginning of the day, had just over 3000 rounds through it, shot me a nifty 498-22X ; not enough to best the HOT shooting "SWEET BABY JAMES" (Lederer), but the crown sure isn't worn out either ! ;) This barrel features one of my square [deeply] cut (faced) crowns, out to about 0.050" past the groove, then with a 29 Deg. "dish", leaving a "nice" flat on the "outside" end of the barrel crown. I know people who freshen their square and un-lapped crowns every couple of GRAND AGGs, and swear by it. Following re-crowning, I have yet to observe a restoration of precision, this, I assume, indicates that the various crowns, if undamaged, all hold up well to shooting and moderate cleaning. RG