[jimmyp50]

I have a Kimber classic in 300WSM that shoots reasonably well producing 1 inch to 1.5 inch groups with 180 grain bullets and 67 grains of RL19. It shoots well after the bore is fouled with 2-3 rounds but at least the first two fouling shots are off a few inches. The rifle is 3 years old and purchased new. After cleaning the barrel yesterday and examining the crown which I do from time to time on all my rifles with a 15X loop, the light entered the barrel such that I could look about a 1/2 inch down the bore. I noticed circular tool marks on top of the lands, AND in the grooves that extended into the bore as far as I could see. I do not own a chronograph, which is now on my short list of needed items. The marks are tool marks as they are very regularly spaced and are perpedicular to the bore such as a reamer would make. I am pondering replacing the barrel, but wonder if the tubbs final finish product would produce a smoother bore and possibly better accuracy/velocity? What is the consensus on the tubbs final finish product??

 

[William Iorg]

I don’t internet to discuss bolt action rifles very much but here are a few thoughts.
First, do not be too concerned about light tool marks in your barrel. I have seen similar marks in a number of rifles, some of which produced very fine accuracy. As an example we currently have a Remington Model 700 Classic in 222 Remington. The last 4” of the barrel display tooling marks which are clearly visible when looking through the barrel ---- the breech. This barrel will shoot just about anything we feed it inside 1 ¼” and some loads using premium bullets – Nosler Ballistic tips for example - will shoot ¾” five shot groups with selected loads. This barrel does foul a little but is easily cleaned.

I have several friends who shoot the 300WSM and they receive similar accuracy with the 180-grain bullets. Switching to lighter bullets has improved their group shooting considerably. If you have a need for the big 180’s I would try using a few different powders in the same burn rate area.
When my friends switched to the premium 150-grain bullets and the even lighter 125- and 130-grain bullets they began to shoot some very small groups using full power hunting loads. One Browning A-Bolt is a real shooter using the 125-grain bullets and these kill our little deer very well.
Everyone has an opinion and as they don’t cost much, here is mine: I would not polish the barrel or seriously consider replacing it until I had tried several different powders under the 180-grain bullets and I had given the lighter weight bullets a serious test.
. I would rather polish the bore with bullets than abrasives – if at all possible. You should find the accuracy life of your barrel to be quite good - I cannot get the rest of it in here but you get the idea!

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[MikeG]

I think the Tubbs product is more intended to work on the throat of a rifle, not down toward the muzzle. Were I to lap a rifle barrel, I would do it with lead bullets and abrasives, a.k.a. "firelapping" as discussed on this site. Opinion, you have a better chance of smoothing it all the way down, without washing out the throat, that way.

If you are already considering replacement, then firelapping is simple and very low cost. Again, personal preference, I would use lead bullets.

 

[pisgah]

I might try a bit of gentle bore polishing but frankly, as someone else has pointed out, in my limited exposure to rifles in this chambering that is about the level of accuracy I've seen. And it's plenty good for any practical application. Were this my rifle, I'd probably put it in the "ain't broke, don't fix" category.

 

[MontyF]

I'm going to put in a couple cents in this thread. I'm surprised you see circular reamer marks in the grooves since that machining operation isn't done with a reamer. Now I've seen rifles with what appears to be chatter marks from a reamer on the lands. One of the most apparent cases was on a Savage model 12 with a stainless barrel. Although the barrel looked like crap and easily fouled it still shot exceptional groups. I'd say lap the barrel. Even if you just keep it cleaned and shoot it enough, the fouling problem will be easier to deal with.

 

[MikeG]

Some of my Rugers appear to have reamer marks in the grooves. All I can guess is that the bore was first reamed, then the grooves formed by button rifling or hammer forging, and that the reamer marks didn't get ironed out.

Just a guess on my part.

 

[horseman 1]

I had a 44 mag pistol like that. It looked like they had sent a crew of elves down the barrel armed with hammers and chisels. I used some paper patched lead boolits and jewelers rouge when fire lapping. The paper will hold more compound. I could see the groups shrink with each cylinder full. It still isn't match grade, or at least I am not able to tell if it is, but the barrel looks slick and there is zero leading. It made a total piece of junk into a usuable pistol.

 

[MontyF]

Some of my Rugers appear to have reamer marks in the grooves. All I can guess is that the bore was first reamed, then the grooves formed by button rifling or hammer forging, and that the reamer marks didn't get ironed out.

Just a guess on my part.

You are right Mike. If there was reamer marks left in the barrel and it was hammer forged they could be still there after the rifling was formed.

On a button rifled barrel those reamer marks will be swedged out of the grooves. However if the button did chatter I suppose they could leave their own marks