When I had a C&R license about 6 years ago, thru the internet, bought a decently sporterized Arisaka type 38 action rifle that was suppose to be a .257 Roberts from a Pawnshop in Prescott, Arizona. I'd phoned the Pawnshop, inquiring whose barrel was on it. Pawnshop called owner of rifle they were selling it for, who was a very elderly man that had the rifle made for his wife to hunt with a very long time ago by a gunsmith in Prescott back then. So answer was it had an A&M barrel on it. A&M ?, research showed their was a gunsmith shop in Prescott back in the late 70s owned by a Atkinson and Marquette. They had quite a reputation for quality custom work back then and one of them made their own barrels. The barrel guy would later go to work for a couple of major rifle manufacturers running the barrel making, after he'd had a falling out the the other gunsmith.
Well, the rifle turned out to have the original 6.5 cal military barrel and it'd been rechambered to .257R, so it was a 6.5x257R. No problem for me to reload as I already reloaded for both the 6.5x55 Swede and 257 Roberts.....between my die sets, I could reload 6.5x257R ammo. Condition of the Arisaka's bore was nothing to brag about, lands looked decent, but rifling had its typical look of minor frosting/pitting, you'd find in a military barrel.
LOL, at best, the rifle would shoot a 3 1/2 - 4" 100yd group....absolutely never had a cloverleaf, it threw bullets all over the target. After a 100 or so rounds downrange, I happen to read an article about some new bore coating product with teflon in it. Short while later, came home from an auto parts store with a crankcase STP like product that had teflon in it. I'd gone to the store to buy some wiper blades and happen to see the STP like product with teflon and remembered the article I'd read. Hmmmmm, what the heck, bought a bottle of it.
Loaded up some 6.5x257R ammo and went to range. I'd swab a glob of the product in the muzzle of bore, run a patch down the bore to evenly spread it and remove any excess. Then I'd fire a round and swab some more of it down the bore between each shot. By the fourth or so round, I noticed my groups tightening on the target. Darn if I didn't shoot a clover leaf, something I'd not been able to even get close to doing before. Forget, how many swabs of the teplon product I did, at least eight, but ended up shooting slightly less than a one inch group with the rifle before I ran out of the 20 rounds I'd reloaded.
Went home and proceeded to clean the Arisaka's bore. Discovered my patches sure as heck went down the bore a lot smoother and the bore had a white-ish appearance....guess the teplon was burned into the bore.
P.S., doing what I did with the teflon STP stuff in my Arisaka's bore is NOT something I'd recommend to anyone. But, the type 38 arisaka action has quite a reputation for strength and I'd used some pretty mild powder charges in my reloads for my experiment.
Then there is the early 1950's era, SAKO rifle I found in a Cabela's used rifle rack that had been labeled as being a custom mauser. It was the first rifle SAKO made to sell in the U.S. SAKO used FN commercial mauser actions to build them. SAKO only made them for a few years before making their own action. However, FN asked SAKO to continue making the FN action rifles for Browning to sell under their label.
Paid $360 plus TAX for my SAKO. Outward appearance of rifle showed it'd been well used, like it'd been someones truck gun. However, bore of rifle, bolt face and etc., was fantastic. Had appearance of seldom being fired. When I got home, I did some internet research to make sure I did have what I suspected was an early SAKO. Found a few on them listed for sale, lowest price of them was around $900, highest was $1400. Their pics confirmed I had a SAKO. Hot dang! I took care of the external problems on metal and stock and then spent a few sessions at range with my 30-06 SAKO. Sadly, about 1 1/2" to 1 3/4" group was best it would shoot. Now the rifle is one of my safe queens that I occasionally take to range. Generally someone there will stop at my shooting bench to find out what the heck rifle I'm shooting and I have the pleasure to recount my story about finding it.