Ammo to break in new rifle


Mar 6, 2016
I have hunted all my life but just now getting into long range shooting. I have never properly broken in a new rifle. I will be reloading ammo for this rifle (300 win mag) and was just wanting some advice on load sizes I should do the break in with or if I should just go buy a box and do the break in with that?

Thanks in advance!
Kind of up to you. Nothing wrong with buying a couple boxes of factory ammo for barrel break-in. I'd pick ammo that has the brass you'd want to use. If you're wanting high end brass, then you might be better off just loading your own.

The last rifle I did barrel break-in on, I used the bullets and powder I was hoping would work out. I ended up shooting a full box of virgin Nosler brass (50ct), but you don't need that many to break in a barrel. I was also able to baseline my velocity and sight in my scope.

Then, after that I had 50 pieces of once fired brass for accuracy development. and I already had some ground work done since I was using the bullets and powder that I wanted. It just maximizes your time at the range, and the money you spend on ammo.
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I did similar with a 270 Win. Worked on pressure/load range while breaking in the barrel (no data was out for the 165gr Matrix, other than what I found on here and other sites).
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