Rifle Break In?

[cking]

unless you have a bore scope you are all just guessing what is happening. Most good barrels are lapped by manufacturer, but that is before they are chambered. The chamber throat where chamber meets the rifling is where reamer marks are problem and they are at 90' to bore. They cut copper and then plate out somewhere down barrel when gas expands enough and cools. So the shoot then clean makes sense until the copper plating drops off. For new barrel clean it and shoot it a couple of times and then clean and see where the problem spot is. That will tell you a lot about the barrel. With AR it is nice because you can point barrel up at the sky and look right down the bore. Feel on bore brush will tell you also. I would not fire lap a bore unless it is giving me accuracy problems.

[Mick]

unless you have a bore scope you are all just guessing what is happening. Most good barrels are lapped by manufacturer, but that is before they are chambered. The chamber throat where chamber meets the rifling is where reamer marks are problem and they are at 90' to bore. They cut copper and then plate out somewhere down barrel when gas expands enough and cools. So the shoot then clean makes sense until the copper plating drops off. For new barrel clean it and shoot it a couple of times and then clean and see where the problem spot is. That will tell you a lot about the barrel. With AR it is nice because you can point barrel up at the sky and look right down the bore. Feel on bore brush will tell you also. I would not fire lap a bore unless it is giving me accuracy problems.

I think we we're all fire lapping a virgin bore...

If you waited to fire lap until it was giving you problems, wouldn't that be too late?

At least according to what we believe so far...

[cking]

By fire lapping I mean the grit on the bullet. Tubbs fire lapping routine. The fire clean routine exposes the sharp edges to plasma and keeps the crud from building up infront of sharp edge.

Last month precision shooting had rig a guy came up with that allows you to lap in line with bore the throat area. he takes a fired casing drills out primer area to allow cleaning rod through. then takes and reams the neck out so bullet easily passes. then he drills out and taps a bullet from base, then puts the case over the rod, screws on the bullet, put JB on bullet and works the bullet in and out from casing into the throat area to polish the transition area. But this is from same guy who slugs his barrel blanks to select only barrels that taper to muzzle.