I travel between forums and I happen to come across a thread that a poster questions that most rifles you can just shoot and shoot and shoot, as long as you clean and lube while others say shoot one round clean barrel and repeat for x number of rounds. I know that you have to do the initial cleaning to get rid of the manufacturer gunk. Ammo can make or break your shooting experience so I ask did you guys break in? and what is your ammo of choice that worked well since the start?

My usual break in of new rifle barrels is to clean after every shot for 20 rounds and then clean after each 5 shot string for 60 rounds. After that I shoot 2 fouling shots and then 5 or 6 rounds and clean. This has produced and maintained excellent accuracy for me for more than 40 years. But if your reference is for AR type rifles, well then just shoot them until empty, reload and repeat.

Is it a S&W M&P AR-15?

Here's what Bushmaster has to say about breaking in a chrome lined barrel:

"After firing a couple hundred rounds, the chrome lining will "polish out" from its light, flat gray, factory-new look to a brightly reflective, polished appearance. During this break-in period, excessive cleaning with solvent or brush should be avoided as that will only prolong the time (and number of rounds) it takes to achieve the final "bullet polishing" of the barrel."

I have other rifles which I fired one, cleaned and repeated five times. Then I fired three and cleaned, then five and cleaned, and finally ten and cleaned.

After that I stopped "breaking in" and clean only when accuracy drops.

Sorry forgot to mention that I am talking about AR's specifically M&P15

Unless you are a benchrest competitor shooting a barrel with some maker-specified break in requirements, I say run a patch through it and shoot it! I have never seen any empirical evidence that following some elaborate break in procedure adds one whit to barrel life or accuracy.

have to ask what is a patch? I know of the hard brush that you stick down the barrel (seen my father clean his handguns) idk about those on an AR application, sorry for the questions I just like to be through and ready when i buy my AR