i have a hawkeye borescope and have noticed

[savage308]

i have a borescope and have noticed something unusual . there are small lines that cut across the rifiling as though the bullets are somehow spinning
faster than the twist of the rifle. i am sure this isnt happening so what could cause this?

[Rangeball]

Machining marks from the original bore before the rifling was added?

[Tallwalker]

Bores are gundrilled, reamed, and sometimes honed before rifling. What you are seeing are marks from the reaming operation. Some barrels are "bore broached" before having the rifling broached too. This sometimes leaves marks, but they are in the direction of bullet travel. Honing is an expensive operation, and is usually skipped except for some shotgun barrels, or higher quality button rifled barrels.

[FredWT]

Those machine marks can be lapped out. Usually they cause a lot of coppering or leading, sometimes they don't. I bought one of those Hawkeyes for my shop when I was still in the service. I have seen some nasty stuff and I have seen some beautiful barrels. Sometimes ignorance is bliss.

[savage308]

these are not the usual lines that are 90 degrees from the bore that i see in all of my h&r barrels and i have 14 in differeny calibers,
these follow the rifeling but seem to somehow be faster twist if that could be possible? it may be that im cleaning it wrong becouse i noticed this after a copper cleaning with JB bore paste then finishing with kroil oil.

[peternap]

Multi purpose gain twist ...just kidding.

They're machine marks. Fire lap it.

[tykempster]

I wouldn't clean with JB...you're eating metal.

[trotterlg]

You are probably seeing marks left as the turning reamer was extracted from the barrel.  Larry