At the end of my noose

[Hunterjones]

I have seen many rifles that a good copper removal made a significant difference in accuracy on but none ever as "magical" as that particular rifle

 

[SouthLoganCountyShooter]

Did you try putting it back in the cracked original stock?

Also, something mechanical is happening here.

A Teslong bore scope is cheap. It would eliminate possibilities of an obstruction like rust.

BTW.....my original thought was scope and/or base+rings.....maybe the crown is damaged.

I'm going to put it back in the cracked stock and see how it does. That was my next thoughts.

 

[SouthLoganCountyShooter]

I would try tightening the action screws.

35 in pounds isn't very much. Try 45. If it is pillar bedded, keep going up until you get to 65.

All mine are at 65 with pillars.

35 is what wby told me with wood stock. No pillars. I'm going g to grind out the bedding rebed it and try 45.

 

[SouthLoganCountyShooter]

4 things already mentioned I'll emphasise. Make sure recoil lug is clear on bottom. Check crown. Try MORE torque on front action screw.
With those 3 said, the FIRST thing I'd try is an ABSOLUTE bore cleaning. Like use a whatever copper cleaner you can get your hands on and clean until patches show absolutely no fouling in barrel at all.
I bought a used Ruger #1 in 300 Wby about 15 years ago. Gun had no marks on it and seller said gun shot "fine". Well I don't know how truthful he was being because when I went over things prior to first range trip, he scope mounting screws were just hand tight at best. I replaced that scope with a proven scope of mine at the time. The bore looked clean but I went ahead and ran a few wet and dry swabs of whatever bore cleaner I had on the shelf then thru the bore, they looked clean, so I took a box of factory Wby 165 TSX ammo to the range w/me and proceeded. Got rifle zeroed and shot 3 groups at 100 yards that averaged about 3.5". I was disgusted. Scratched my head for a bit then thought but couldn't hurt to use copper cleaner in bore. Used a combo of Hoopes and Barnes CR10 and patches actually came out VERY blue at first and I cleaned until they were white. Next 3 groups averaged 5/8" and all I did was clean copper from bore. Rifle ended up shooting several hand loads as accurately or more than that factory stuff.
It was a MAJOR eye opener for me. It was truly like magic happened right in front of my eyes.

I got a new bottle of cr10 today. I'm going to strip and rebed action and clean the crap out of the bore.

 

[BillLarson]

Please let us no when you find out what it was....

 

[GSP814]

A buddy bought a Mark V in 338, it threw a a pretty good buckshot pattern. He tried everything and nothing helped. His stock also cracked. Good luck.

 

[Bret GRAVELINE Graveline]

I'm inclined to think its the bedding, glass bedding rifle is not a automatic fix, many times all that happens is one just epoxyed the problem into the gun, best way to check this is to shot a group with the rear guard screw removed, if the rifle is properly bedded no harm will come to the rifle, if a rifle is properly bedded, it does not need to be more than good and tight, let alone 65 inch pounds, pillars or not, one can check bedding with either a deflection or dail indicator with a magnetic base that will clamp to a barrel, or better if one has a mill and machine vise, but not everyone has access to one.

 

[SouthLoganCountyShooter]

A buddy bought a Mark V in 338, it threw a a pretty good buckshot pattern. He tried everything and nothing helped. His stock also cracked. Good luck.

Yeah I think there design sucks. Just milling out rear sections behind recoil lug. Dropping in a peace of al thread and epoxy in. Just don't work with heavy recoiling magnum. I'm going to mill it out do a full cross bolt. Maybe even pillars. After I figure it out.

 

[Calvin45]

try new ammo..... new cases/bullets..

He already said he did that…

 

[Calvin45]

100 percent it's gotta be an issue with the stock I think. I mean if it shot well enough with the old stock and all that's changed is putting it in a new one….if it was an issue with the crown it'd shoot crappy with anything you fed it, not better with some than others. I find it very very unlikely that your barrel magically sprung an ailment, so no I do not think it's time to rebarrel.

This has something to do with the fit of the action into the stock or the barrel harmonics, again as they're affected by this stock. I'd be shocked if it isn't that….

 

[338 dude]

I would try tightening the action screws.

35 in pounds isn't very much. Try 45. If it is pillar bedded, keep going up until you get to 65.

All mine are at 65 with pillars.

From this site

 

[Ol' Red]

Following this one. I have a Vanguard in .338 Win Mag that shoots OK. Just under 1 MOA. I tried some Nosler factory 250 grain Accubonds and it puts the first two rounds in the same hole. Third shot is 3/4" away. Three tries on a cold bore were identical. I was going to remove the stock and check it out but have not had time yet. It is the Vanguard II stock.

 

[Hunterjones]

With all that's been covered here I have also had a couple of mid priced factory rifles I've bought new over the years that shot pretty well with minimum rounds down the tube that suddenly lost accuracy in a big way and there was NOTHING that a very seasoned gunsmith or I tried that could bring the accuracy back. Cleaning, crowning, bedding, scope changing….Nothing. I've owned approximately 200 centerfire rifles over about the last 35 years or so and I've just had to give up on a couple of them. I was somewhat of a "horse trader" for many years so lots of guns would come and go. I owned a precision machining company for about 35 years and know mechanical things as well….
Sometimes some things make absolutely Zero sense, you never figure them out and unless you enjoy frustration and punishment there are times you just need to throw them on Gunbroker and start over.

 

[Hunterjones]

I also remember a story that a Cabela's Gun Library manager told me about a guy who bought a gun that shot well at first and he brought it back because accuracy was waning only for them to discover that barrel was beginning to come loose at action…….