Ok here's one I've never seen or read about.

Back in '72 I bought new Sako Vixen .222mag at the gunclub in Weisbaden and sent it home. When I got to the gun, I cleaned it and pushing the first patch thru a brand new bore.

It had hollows in the bore. No sign at all of bulging on the outside. It lasted just over 6000 rnds of 55gr, 25gr 4895 loads.

We just scoped it a month ago and it looks perfect. Still has the hollows in four places. It shot less than dime sized groups from day one until the accuracy went to hell.

I contacted ? the importer but, they never replied as the gun didn't come thru them. After it started scattering shots I had it rebarreled and it went to .230" ten shot groups with the same load and sorting bullets. Best I found were 30 & 40gr V'max. The 30's scattered all over the hillside beyond 200yds. So I stopped using those and stick with 40's and 55gr for prairie dogs.

Thanks guys, just wondering what you feel caused these hollows. IF anyone is close enough you can sure stop by and push a patch thru it yourself.

George

If they were there from day one on a new rifle, then it was due to the barrel manufacturing process; I am not sure how SAKO makes barrels, but it was due to the drilling and reaming process, or hammer forging process. Or, less likely, hard and soft spots in the steel, which is very hard on reamers and rifling tooling.
One question for you is, (which is too late now), was the bore over size, or the grooves, oversize. Doesn't matter anyway.
A good example of why it is good to test fire the barrel, no matter what it looks like; it might just perform well.

That used to be pretty common and can be caused by a lot of things. Sakos are hammer forged so the likely cause was a hard spot in the barrel. When they turned it down the harder portion simply sprang back up as the outside hoop strength was removed.
Or, the hammers got to far ahead of the cylinder when they made the barrel. Remington had the same problem in their hammer forged stainless barrels for a while. Some times its only a few loose spots, some times the barrel actually looks wavy all the way down. Like bulges, these barrels with loose spots will sometimes shoot just fine. Other times, not so much. We really don't have any idea why some barrels shoot well. We simply have a few tried and true methods that we know will generally make most barrels shoot better, on average. But, there are always exceptions to the rules.

Ripples in a hammer forged barrel:

Gunsmith Rod Henrickson ripples2 by Rod Henrickson, on Flickr

hammer forging rings by Rod Henrickson, on Flickr

Thank you for your thoughts an experiences. I had no clue and we couldn't see any difference's with a bore scope looking for it.

Knowing what it was like I set a rod and tight patch up for my buddy with the scope ahead of time so he'd know I wasn't bsing him. he sure had a funny look on his face the first time the patch turned loose. Much like he hadn't believed me.

We scoped half dozen or more barrels. I have an old original 1917 Enfield I've shot the hell out of since 1958 myself. Back in '73 I had it rechambered to .300Win/m, might have 7-800 of those thru it but, mostly '06 for p/dogs. I've done about everything that can be done to it short of blowing it up.
The bore is very badly alligatored all the way to the muzzle. I've ordered a new barrel for it now just because of what I've seen in that one knowing in such shape it can't last forever.

Last I shot it to check zero it was making just less than an inch groups with 5 200gr GK's and my hunting loads. As long as it shoots, that's all I care really, but, I would like all my guns to be in good condition. Never know what the next guy might want to do with them.

Thanks again,
George

This is an interesting thread. I once had a Winchester model 70 .375 that had exactly that same thing. about 4 inches from the muzzle there was a spot where a tight patch or brush would just jump through for about an inch before it contacted again.

I am not a bench rest shooter but the rifle shot selected bullets into 2 to 2 1/2 inch groups very consistently. I had always assumed that the previous owner had shot it with a bore obstruction but I suppose it just came from the factory like that. I took it to Africa and it worked like a charm.

The ring in the barrel always bothered me though and so in a minor financial panic is sold it. Wish I had it back

I built a .38-72 BPCR rifle with a Mcgowen barrel that has a loose spot a few inches in front of the chamber. It is very accurate, it is my wife's and she has shot 12 inch 10 shot groups at 600 yards with it using cast bullets. But, it leads like crazy, starting at that spot. Doesn't make the accuracy fall off appreciably, but is sure annoying. I'd rebarrel it if it wasn't so accurate.....

Just on a related side note:


I have known a few gun plumbers and hobbyists who have worried themselves to the point of doing something about those loose spots and have lapped the barrel to try to close them up. I must confess I have even done it myself a few times, just to see, or at a customers request. In most all of the cases that I have been privy to, or involved in, the guns shot poorer after lapping. I think most of those loose spots (if they can be felt with a patch and rod) are generally pretty severe. I'm estimating .001 to .003 inch and that is a lot of material to remove. To give optimum performance most bore diameters are generally held to .0005 or better and in most cases and taking .0005 or .0015 inch per side off is just asking for problems.

I will no longer lap to correct this problem. Even if the customer is really - REALLY - R E A L L Y insistent. It's not that I have a problem with taking money for nothing. I do that all the time correcting trivial cosmetic stuff that deer won't see from the road. I guess it comes down to that do-no-harm thing that doctors are supposed to adhere too, but seldom do.

Yes the stress on your wallet and mind may not be worth it . However Out of curiosity I wonder if the newer "powder metal " method of making tool steels as we see in knife steels would be more consistent .These are seen in things like Crucibles CPM S35VN. Though they are not always perfect 100 % either.
And the deer don't act perfectly 100 % either !

mete:

I ran into that kind of deal once or more most likely.
The one time I know what happened because of it. A buddy and I went to the range just before he shipped to S/Korea for a few years. He had a Llama Comanche .38. He'd fired it and was dumping the empties when he dropped it on the hammer and it broke off. Steel will not break like that in the summer heat.

Strange thing later. I got the gun for $100 less because he'd just broke it. A few yrs later I let a guy take it to try out before buying it. He got run off the road and then kicked in the head and died from it. After the killers trial I contacted the Sheriff's dept. about the gun as I had the ser#. The under sheriff met me and held the gun behind a box out of sight: "describe it" I gave the ser#, "not good enough" Among other things I recalled was chip off the butt stock. Then told him: "what you really want to know about is that broken hammer I filed down to clean off the sharp edges". "here's your gun sir".

I went from there to the gunsmith and he happened to have a S&W steel hammer and put it in. Then I went to visit Dad and one of his friends was there. I told about the gun and hassle with the law etc. This guy asked if I had it, showed it to him and sold it for $75 more than I had in it. I never fired it after the hammer was put in. Hell of a deal.

Another gun part I had break was the L lever extractor in a NEF rifle, cintered metal is a sorry way to make things. About as good as cast iron imo.

George