I was reading on this site and others that some people just clean for carbon and don't bother with the copper.

Does it really make that big of a difference? And how often do you actually clean?

My bro said he cleans his 7mm mag after 18-20rds. That seems kind of excessive.

I normally don't touch the barrel unless accuracy drops off...when it does drop I completely clean the barrel of both carbon and copper, than have to refoul the barrel to bring the accuracy back...

I think a lot of the confusion comes when people mix in all kinds of rifles. There are plenty of people who never clean the barrels on their AR's. If I remember right a couple of the big name trainers basically advocated the same. With a precision rifle that you are expecting a much higher level of accuracy you will most likely have to address copper at some point.

In my opinion this is the advice everyone should follow

I have never used a copper solvent.  After a weekend of shooting, I soak my bore in a "bland" (non-reactive) solvent for about 5 minutes and then run a dry boresnake thru my barrel twice.  I then mop the chamber with a dry mop.  Next I brush and wipe down the bolt with an oil cloth and then lightly lube the lugs, replace the bolt, function check and call it good.

For me, "a weekend of shooting" can be as little as 20 rounds or as much as 150 but typically it is ~50 rounds.

YMMV.

Hoppe's #9 patches at 250 rounds. Hoppe's #9, brush, and JB paste at 500. I try to stay between needing to foul and too fouled.

Coppers a lot easier to address than carbon.

Maybe once or twice in the life of my average match rifle barrel. In no case before 400-500 rounds but these are not factory barrels. They're all lapped custom aftermarket stuff.

Yes, cleaning copper out certainly matters.  In precision rifles, I clean thoroughly, including copper, but seldom.  I monitor and enter how many rounds of which type of ammo were fired in that rifle's log book.  When a rifle is thoroughly cleaned, that too gets entered into the log book.  I have best results (accuracy) when I foul the rifles with around 10-20 rounds before I really begin to compete, or test loads for accuracy.  Usually, in my precision rifles, accuracy begins to fall off around 200 rounds or so.  I'll first try a light cleaning with only Hoppe's, and shoot.  If accuracy returns, I continue, if not, I will do a more thorough cleaning.

With rifles like AR15 that are used for practical rifle matches, or 3 gun shooting, I do not consider them to be precision rifles, so they are cleaned less often.  I clean those rifles to get out carbon, unburned powder, re-lubricate, and inspect them.  Copper is only cleaned out of the bore if I notice a significant decrease in accuracy, or at around the 400-700 round count.  Less than 400-700 rounds and the rifles are cleaned with something like Hoppe's, and not cleaned to remove copper (something like Sweet's 7.62).

Whenever I clean to remove copper, I am very meticulous about removing any of the copper solvent, and insuring that none of the solvent is left anywhere in the rifle.  That kind of requires the I re-clean with Hoppe's to remove the Sweet's, then re-lubricate the rifle, and insure that the bore and chamber are free of all solvents and oil.  The final touch is running patches with rubbing alcohol through the bore and chamber to insure that there is no solvent or oil of any kind left in the chamber and bore, then using dry patches to insure all the alcohol is removed.   Final process is to re-lubricate any parts requiring lubrication.  Bores are not lubricated unless they are going into long term storage, in which case I put a little tag onto the trigger guard noting when the bore was oiled.

Having oil in the bore raises pressures, hence reducing accuracy as well as safety.  Having oil in the chamber increases bolt thrust as the cartridge cases cannot grip the chamber walls adequately.

I realize this sounds like lots of work, but it really does help keep my rifle's working well, and makes it less likely that I will blow my rifle and/or my self up.

I clean most of my precision rifles every 100-200 rounds, but do it to avoid issues with carbon much more than I do with copper.

Generally speaking, good quality barrels don't really have a lot of problems with copper, until you get a lot of rounds on them.

Fortunately, copper is super easy to take care of with a good copper-oriented bore cleaner, it'll just melt right out.

As far as cleaning every 20-30 rounds, that's crazy unless you're in the BR game and actually know what you're doing.  For a hunting rifle, it basically means you're constantly putting excess rifles down the tube just to foul it back out again.

Here's waht works for me every 100-200 rounds.
BoreTech C4 - Carbon cleaner
Bronze Brush 20-30 strokes
More BoreTech C4
BoreTech Copper Cleaner
Finish out with a patch of Kroil or Lockeeze to neutralize the boretech stuff.

Run some JB every ~300-400 rounds.

Borescope shows me that process keeps all my tubes at their best.

So something like a factory Savage barrel (tight bore/groove with lots of tooling marks) is going to grab and hold copper, to the point that it may build up pressure and cause uber-high velocities and poor accuracy.  You have to stay on top of that with frequent deep soaks of Wipeout or the like.

Precision rifles with quality lapped barrels, the name of the game is mostly going to be carbon.  Copper fouling may be a "thing" within the first 100 rounds due to fresh cut throats wearing in and smoothing corners off.  In the process they'll cut and vaporize some copper off of jackets that will deposit in a very thin layer down the bore and can be seen near the muzzle.  After that point in the barrel's life, I would clean carbon as necessary (6.5 PRC, 7mm SAUM, 6.5-284, probably clean every 100 rounds.  Baby 6mm's probably good for 300-500+.  Not all cartridges/powders are the same), but don't worry about copper.  I especially leave copper alone as a barrel is getting towards the end of its life.

at around 200 rounds through my HMR PRO, im not touching the barrel until it starts opening up.

If you pay attention to how it is grouping, cleaning every 200-400 rounds is fine IMO.

I have two benchrest shooter friends .  One cleans his gun after every shoot so 5-20 rounds. One every 400 rounds.

What makes you happy?

Bench rest shooters clean every 20 rounds or so. I’m not saying this is the way but they do it for a reason.

If you’re shooting no more than that between cleanings at BR matches, it works.

You can have a rifle go completely out of tune if it’s doped and zeroed on a completely clean barrel over the course of a long match.

Every 100 rounds I clean out the copper.