How many shots?

Your barrel should tell you. When accuracy falls off, it's time to clean. It might be 25 rounds, or 250+ rounds. It can vary by individual barrel and ammo.

This guy is spot on, but you don't want your rifle telling you at an inopportune time that it needs a cleaning. That can be humbling and embarrassing. And just because it went 400 rds last time, that it will make it again!
 
Keep shooting until you see a change in accuracy, then you'll know.

I've gone 650 rounds on a Bartlien and only cleaned it because I no longer could stand the suspense. Now I go every 250 "just because" I don't want the moment is starts to open up happen at the wrong time.
 
Every gun is different and has its own preferences. I've always just shot until accuracy becomes unacceptable. In my case1 MOA or greater is unacceptable so take that in to consideration. I had a virgin new Bartlien .308 that I ran to 2000+ rounds with zero cleaning it before it reach the 1 MOA mark, decided to clean it up (carbon/ copper) Took about 50 rounds to come back from 2 MOA to 1/3 MOA. With the same POI

I’ve cleaned a few times since then ( at 4000+) and haven’t had issues like that first time CCB/CB/FB are all the same now. Just have to watch out for any solvent left in the bore after cleaning, if it’s not dried out the first shot is a squirrelly.
 
I clean after every range trip, but I also put a good deal downrange. I suppose I clean, on average, every 100-200rds. I've heard from (at least one quality barrel maker, forget which) say you should clean after every trip. One thing is certain: I don't notice accuracy improve with excessive fouling.

Corrosion and shit can happen easier if you put it away dirty too; moisture can collect in barrels, particularly larger bores, and then you get rust spots (depending on material). IME anyway.
 
No I did not do any barrel break in accept pulling the trigger. I can't say that's what everyone needs to do but it worked for me. I also shoot this gun on a weekly basis often daliy if can so I'm not overly worried about it corrosion building up. If it gets pissed own or if I was going to let it sit for awhile I'd do the responsible thing and clean her up proper but generally if I know I'm going to be out later I just wipe it down.

Now ARs on the other hand...I don't know why but if I start cleaning just a little bit I can't stop myself.
 
I don't do barrel break in, per se, but I will clean after every range session for the first 200 or so...just because.

Remember the whole "clean your guns each and every time you shoot them" is a carry over from the old days of potentially corrosive primers. But I don't live where it's high humidity and that's a factor as well.
 
My barrels on my .308 gas guns with decoppered barrel takes about 20-40 rounds to show consistency. I shoot it with brass in carbon out until I see zero shifts... Some of my guns have thousands of rounds with only mpro7 ran through em.

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I clean after every range trip. 60 or so rounds. Probably over doing it it seems. While on the subject, I've been using Hoppes #9 and brass brushes forever, however I've seen some guys recommend nylon. Any thoughts?
 
I really like Wipe Out foamy bore cleaner. One of my shooting buddies is one of the best competitive shooters in the country and he turned me on to it.

I foam up the bore, let it sit overnight, 3 dry patches. If the patches are still dirty, I'll foam it up again and run patches when I come home in the evening. Maybe one more time overnight. 3 times is the max I've needed.

On occasion I've run some more aggressive solvent through afterward, and have found no traces of anything.

2nd string of cleaner is the Hoppes copper solvent - not as aggressive as others, I use a patch and maybe a nylon brush. Again, I do it over a couple of days, running clean patches, and more solvent until I see clean patches.

Last, I have the more aggressive stuff, like Montana Extreme or Butches - I use that for more stubborn barrels. Same deal, patches and nylon brush.

I've used the super aggressive stuff, like Barns and 7.62, but after reading the directions, they scare me and I have not used them for years.