Hello 22Shooter:
On the barrel wear problem . . .
A bore guide protects the rifling just ahead of the chamber. When you push a cleaning rod down the barrel it will bend in the middle. It just is not stiff enough not to bend: So, as the rod is pushed down the bore, the high point of the bend rubs agains the bore. If you will check a well used barrel with a bore scope you may find healthy lands and groves at both ends and land wear in the middle of the bore. Using good tight patches will increase the wear. It is generally accepted that a good CF match grade barrel is DONE in 1500 shots. By done, I mean it ain't gon'a shot like it did when it was new.
A few years ago BR shooters were asking the question: Which does the least damage? Bare steel rods or covered with plastic (like the Parker-Hale). The plastic rod cover can imbed dirt in the covering and "lap" the barrel. Is a bare steel rod better? Seems they both can damage a bore.
In a rimfire barrel, a good cleaning will scrub out all the lubricating wax. To get good accuracy back, more shots are needed than the few used to warm the barrel. I talked with Butch Hongisto about a need for a "light" cleaning that may be needed. He said if the accuracy goes south during a match, and you don't have the usual 300 rounds through the barrel since the last cleaning, you may have a piece of lead stuck on the barrel wall. When he suspects that, he will run a loose patch through the barrel (during the match). On that advice I have used a "loose" patch on the end of a Patch Worm during a match. Sometimes it helped, and I don't believe one loose patch could remove much of the lead.
At for warm-up shots: You will find the number needed will depend on each individual rifle. Something like the rifle that "likes" one lot of ammo and hates another.
Have fun at the range.
Joe Haller (Mr. Frosty)