JoMiBru , it's cool
there seem to be two schools of thought

some guys shoot 1 round clean,shoot 1 clean , shoot 1 clean for around 5 rounds then they shoot 3 clean for about 15 , then shoot 10 and clean for 30 and in about 50 rounds they say the barrel is broken in

the other school is , shoot it and clean it shoot it clean it , 20-30 rounds , then 20-50 rounds and clean , repeat a few times.

the guys at my rifle club are of the shoot it some go home and clean it , and don't see a difference

I have been doing around 15-26 rounds and outing then clean somewhere around a hundred to 150 rounds I will expect it to be broken in I enjoy shooting a hole lot more than I do cleaning.

hoppes and a new boresnake makes pretty quick work of breaking in a barrel. I clean between first 5 shots then between 3 rd groups for about 30rds then in between 5 rd groups for 50 rds. all total 85 rds. By then you should be pretty well zeroed lol and barrel is broke in as its gonna get. I got my technique from my old squad leader back in the day. Ranger and sniper qualified. Owned plenty of his own rifles and shot quite a bit. Fine shot too. I will admit i only have done that whole thing once on one rifle that i bought new and was capable of shooting accurately enough to need a barrel break in. On my Ar's i usually do a few mag dumps to check function and break it all in, clean it all up, and work loads up. Shoots fine after that.

I don't entirely hold with the 3 tests your gun, 5 your shooting theory. If you can't make 5 good shots in a row, how can you be sure of 3. What if the "bad shot" is one of the first 3?

Here are a few things that help me when load testing:

Plan your trips to the range with the weather in mind. I look for days with winds below 5 mph.

Use an old fashioned egg timer to ensure you wait 3 min between shots.

If you are taking extra long to get a shot off, pull that cartridge and let it cool off.

Keep your rifle and ammo out of the direct sun.

Chronograph every shot and pay special attention to the reading for a flier. The reason for the flier may be at the reloading bench and not at the range.

Study your statistics with your group sizes to narrow down the optimum load. You can immediately discard loads with bad stats. The load that gives the best groups may not have the best stats but will be very close.

Those little paper plates for birthday cake at 400 yards. If you can do that every time coyotes and deer ain't safe.

I say the same also.Also I shoot alot of cast and gas check and lube I weight them and group them of +-.5 grs of each group and use the most of one for the main and the ones that are odd for different use. So it might be match or some thing like that for jacket that the weights are being close the same that will help some.As for how many ,for me is do a 5 to 10 shot group and then come back after the barrel cools and drop down ho many shots and let cool again and then try what the one shot is show. Because of when use for hunting you normal shot one shot not 5 normal.Clean how you feel will work for you.I use lube for my cast that I make myself and that is different then the use of jacket. Use what the gun tells you and go from there. This the advice I can give for what works for me.What do from the start with a gun is sight it in with factory rounds of my choice and then use that as my base to start.I do like what danny clifton stated and then I use the reloads to fine tune it and if I get the same or better so much the better.

Why stop. Its fun. I try to get my groups as small as I can with any rifle. The only premise is that it has to be a hunting bullet. Yes one does tend to end up with a bunch of left over components, but hey they may work well in a rifle I do not have ...yet

Possum Man , what Hoppes , #9 ? are you doing something to remove copper ?

when I clean after 15-30 rounds it is from the breech , with a rod and patches and solvent that will remove copper and I go till I have clean patches then 2 dry then an oil and 2 dry

EdP , I need to get a chronograph it's on the list but has to wait a while yet , I may be able to borrow one.

Danny Clifton , my 223 load that is right about where I stopped , had it consistent 10 round groups right about an inch at 100 , and took it to 2 and 3 and 4 and at 400 i had a 10 round group I could cover with a dollar bill and decided I was done.

but that load came very easy book starting shot that well right off.

I backed off on powder when primer hole got oblonged! Blew a few primers.
My old .223 would loose accracy if I went over 3200 fps, my t.20 shot 3 shot one hole groups at 4375 fps

I never get copper fouling, I applied molyfusion not long after having t.20 made, I get powder fouling, but never copper, barrel is more slippery with moly fusion, I lost 20fps after applying it

FYI for everyone that uses a bore snake. Talk with a gunsmith they hate them and will not recommend them. If that cord breaks you will buying a new barrel.

when im trying to chase a load i start in half grain increments find the best one and then go in .2 grain increments to find an even better group. I also try atlest two different powders. I have a 243 right now thats being a pain and i can't find a combo it really likes and maybe it wont get better but an inch is all it will do. Also i will try at least two different bullet makers to run, i really like barnes but they liked to be jumped alot so iwent with sierra match kings to compare.

Why would you need a new barrel??

Now the BS meter just went past the red and hit the pin

What I do is to start a load and look at the data and see what powders I have and test the ones I have on hand it can be 2 to 3 kind of powders and load 5 rounds each and then test them and see what one will group the best and then work on that one till I get what I am looking for.Also check for the primers for over pressure also.if i get up there.

Yukon and Scuba if the rope breaks on a bore snake and it becomes lodged in the barrel their is no way to get it out! its like a Chinese finger trap, no amount of pushing or pulling is going to work when their is nothing to push or pull.

Ok first, lets just calm down on the bore snake hating. Here is a 26" barrel with a flash hider/suppressor mount that adds another 2" to oal. there is no place the rope could break where you couldnt grab the snake part and just pull it back out.. ONLY exception being a barrel over 28" or the snake part breaking...which i have never seen. I have had the rope part come off but it was fraying well before and a simple visual inspection showed i needed a new snake.

and yes i have stuck a bore snake before. i stuck a worn out 30 cal in a .270 barrel. Everything went well until the doubled loop on the end tried to come through. I thought it would but i was wrong..and it was a pain to get out but it did come out without help of a pro and by god that old barrel was shiny clean lol. Cut the double loop off the end and it works fine for cleaning 270 stuff. The brushes had long since been worn from cleaning m240b barrels.

If your " gunsmith " cant get a snapped bore snake out of a barrel. he is probably a baker, plumber or elecchicken ...... whatever he is, he ain't no gun smith.
I have made a simple tool that screws onto a cleaning rod that gets those things out in no time and I aint rich yet. So it cant be all that difficult or I would have sold a bunch of those things.

Pete,
You said you have 67 rounds through it now. If you haven't already, and it is a new rifle, I'd suggest tightening all the screws and run another five rounds. Hate to say it but, horizontal stringing is usually human error. Also a good time to apply a coat of transmission fluid to the bore, let it soak overnight and then run patches down the bore until they come out clean. Then go see what you get for a group.
That rifle has some potential, with a couple nice groups already on a new barrel. If it's going to just be a deer rifle, it's already shooting better than about 90% of the people can shoot. If your looking for bugholes at 100 and quarters at 300, it's going to cost you a lot of money and a lot of practice to get there. You just have to put in the time and find the right recipe, and don't underestimate the "Buck Fever" affect. LOL I'm working on a Rem 700 SS .30-06 and a cast 195 gr. Fp at 2200 FPS now. Just need some time to wring it out.

PS: First shot fliers are common on clean wet bores. Something to remember opening weekend of deer season: