Just got my 6.5 grendel upper in there was no break in procedure mentioned in the manual. Is it acutually necessary to break it in or not? Will it have any effect on accuracy or barrel life either way?

Absolutely not. Seems like most of the evidence for breaking in a barrel is anecdotal (well, so is all of the evidence against doing it), but I can't think of a legitimate reason to go through the break-in procedure. Cleaning your barrel in between shots isn't going to magically improve accuracy. Shooting it, however, will do more to smooth out any roughness left by the manufacturing process.

If you really want to keep your barrel's performance, don't shoot it to the point where you could cook an egg on it regularly.

there is a lot of argument both ways.
some gun manufactures say yes

Also depends on the material used.
Stainless usually settles in faster but has shorter life due to softer material.
Chrome plated bore may not change much at all.
Some of the harder steel treated barrels may take a lot of shots to break in.

I say all that to say this:
I've done it both ways and a few variations.
Usually follow the manufacturers instructions if available.
If they don't provide breakin instructions, I shoot it.

I hunt pigs...most shoot MOP (Minute Of Pig) after a little while and all of them usually settle in pretty close after some shots...

No

NO!

Depends on what you wish from the weapon, type, bbl, ect. I've
used a 100 rd program designed by one of the Texas bbl. co's and
had good luck with it, though time consuming and somewhat costly.
I think if you use your cleaning rod and the bbl is very slick when new, about 20 rounds of shooting and cleaning will pretty much sweeten your weapon..I've shot rifles that shot out of the box..but breaking in the bbl facilitates cleaning usually..My TRG
seems to have been lapped when I got it, but it's a little more expensive rifle than my Rem. or Savage, or Win..Don

No.

If the manual doesn't mention it, then there is no need.

Some manufacturer recommend breaking in the barrel in a certain way. Even then it's a debatable subject.

Break-in, no.

Fouling, yes. I bumped a thread that shows how a fouled barrel shoots.

I've also been tasked with load development for a friend's 7 Rem Mag Thompson Encore/ bullberry barrel. He brought me a virgin barreled rifle, scope only set for eye relief and his components. I leveled, bore sighted, and sighted in with 175 gr. SMK and the lowest powder charge the books called for, simply for zeroing, fouling the barrel, and fire forming brass.

Bore solvent, dry patch twice.

Shot one, 7 MOA low, 1/2 MOA right. I adjusted.
Shot two, elevation good, windage good.
Shot three, elevation good, 1/4 MOA right. I did not adjust.
Shot four, elevation good, 1/2 MOA right. I adjusted.
Shot five, elevation good, 1/4 MOA right.

Ran a dry patch down it, just to remove machining fluid and powder residue.

Next day,

Shot 6 1/2 MOA right. I adjusted.

Shots 7, 8, 9, 10 printed 1/2 MOA and the variance was windage which could very well have been the guy driving the rifle.

I won't start load development until the barrel has, at least, 20 rounds on it to get it fouled. I just don't think it will show you what it's capable of until it's fouled.

NO. Barrel break in is a myth. It's 6#'s of horse crap in a 4# bag.

NO ONE can PROVE what takes place in a barrel during break in, that will not happen as the round count go's up.

Read from the folks that get real serious about groups.

"How to break in a barrel"

http://www.6mmbr.com/GailMcMbreakin.html

Doesnt hurt anything, but no I dont buy into it.
Cant prove my belief, just dont believe it makes a difference.

I've done it both ways. When younger I didn't but now I do. I dunno if it helps or not. Keeps me at the range longer though.

I had one that the mfr said to clean after each shot up to 25. then shoot 10 rounds and clean. Repeat until you reach 100. Took awhile but I did it anyway.

I believe in it, and I think everyone should clean between rounds for at least the first 5 shots of any rifle. The main reason for doing this is to make sure you are not leaving any barrel debris left by those first intial shots in the barrel causing damage on subsequent shots.

Believe it or not most barrles if you run a scope down them brand new will have quite a bit of material in them that will not be there after the first 5 or 10 shots as the barrel is smoothed out.

Now for most people this doesn't mater one bit as they only care about getting a rifle good enough to hunt with and never put more than 20 rounds down them a year and most people less than that. However, for those who do alot of shooting and want their barrels to be the best they can be at least some minimal break in precuations should be followed. While copper is not going to damage your barrel, shooting a copper bullet and picking up steel bits and dragging them though the barrel will.

Personally I am pretty up tight about it and use at least a 40 round break in on all new rifles.

1. Clean with patch and bruch between each of the first 5 shots.
2. Clean with Patch and Brush after the next 3 sets of 5 shots.
3. Claan with patch and Brush after the nest two groups of 10 shots.

For me this does several things.
1. I am certain I have removed any defects or bits fro the factory machining process.
2. To me it seems the rifles are easier to clean and do not foul as rapidly as in an un-broke in barrel.
3. I always use Remington Coreloks for this process and it generates my first batch of once shot brass for reloading purposes.
4. I have shot the gun enough by that point to know how it is going to shoot and have it sighted in to a base level before developing loads for it.

Like I said for most people this is not even a reality, but I am pretty serious about it and when I scope my barrels versus someone elses I can tell a difference.

And yes, I clean the barrel thouroughly before ven firing the first shot out of it.

I think it is a good idea to use a mop and some JB bore cleaning compound on a new rifle. I consider it to be like lapping compound. I put it on a "mop" and work it back and forth through the bore for maybe 10-20 strokes. Then I run clean patches till they run out clean. After that I dry snake it three or four times when ever I feel like it. I've never found that dry snaking it hurts the accuracy any, and it will remove carbon deposits...

Agree with Chuck McDonald. My Brother was a barrel maker for the precision shooting crowd. He did a lot of things to finish a barrel that the factories don't. He often let me look down new barrels with his bore microscope to see the metal "junk" in those new barrels after polishing.

BTW, the article out of 6BR is admittedly a dissenting point of view.

However, I do agree that improper use of cleaning rods can damage a barrel.

Yeah...

Ive read lots of both side of the defense. In my view polygonal barrels are just a vs of a worn in barrel. Everything you want and need to happen in a rifle cut barrel. The polygonal does to begin with.

Smooth lands, tight seal. However, why break in a barrel. When it's going to break in anyway the more you shoot it? Why waste the rounds, cleaning supplies,barrel life?

The difference of a 4moa barrel before break in and after isn't going to make it more accurate. Just a hair easier to clean.

Grasshopper, after thinking about it, I'm not sure what "breaking in a barrel" REALLY means. If it is cleaning out all the junk by heating and then swabbing, I guess it makes sense to do it as part of the initial cleaning and smoothing process.

I've known some of the precision shooting crowd that spend way more $ than I would on a gun and scope. $10K or more isn't out of the question for them. They break in a new barrel and also clean about every 10 rounds during a match. And, they don't get a fouling shot at the next round.

To a guy like me, it probably wouldn't matter a whole lot. I'm getting old and can no longer shoot like I used to anyway.

It sounds like you are trying to dodge the duty..If you wish the
better performance, and easier cleaning for the life of the bbl. it is required.. If you just want to shoot the crap out of it and
run some patches thru it once or twice a yr. plan on a new bbl in
about 2 or 3 yrs.. Seriously, If you look on most of the bbl mfg's websites they have rec. breakin procedures..Now if you paid
for a hand lapped bbl. you will not do much..There is a 100 round
procedure that I used to follow for guys that I broke in the bbls. It is time conuming and costly especially in the summer..but I've never had a bbl that wasn't easier to clean, and
much easier to reload for and shoot than say a normal factory rifle..This execise is for the person who wants ultimate performance from their weapon..not someone who just plays occasionally at the range. The first 10 to 20 rounds of it will
probably take you a 1/2 day..Don

I am a converter, I don't toil and trouble, scrub and bubble my barrels anymore!

I will clean it very well in the chamber and inside the barrel before the first shot is fired, due to the machining process of building the gun. Like stated, I want all the small particals out of the rifle. I shoot/clean for about 4-5 shots. After this, I shoot it like normal. The first few patches are VERY dirty on 1 round fired, and they come out cleaner on the next rounds fired.

On my competition 260 Rem, I cleaned it at the house when it was brand new. I forgot the cleaning rod, and shot it with no barrel break in. It was a less than 1/4 moa gun for about 2600 rounds. It had shot some 1" at 500 and 1 3/8" groups at 600 yards. And it was done with no barrel brake in. I have also seen several rifles shoot similar with a proper break in.

LOL...

Does chrome lined barrels "need" to be broke in? How many rounds does it take on a hard chrome bore?

What about stainless? Stainless is softer then it's carbon steel counter part. Whats the low down on those?

I see it all like this. Some folks wax their car, some don't.

Not all precision shooters break in barrels. Last gun I had built was done by a guy that is well respected in the Texas BR cicuit, he recommends cleaning before shooting the first round then just cleaning every 20.