Loss of precision

[Cloudhopper]

I've had a Sako 85 for the last 13 years and it's always reliably shot groups the size of your thumb nail. Fired about 2000-2500 rounds of 308. Late last year I went to the range and re-zeroed it with a new moderator and some non-lead ammo and it performed as expected. First half of this year I put about 40 or 50 rounds through it without any noticeable issues and left it in the cabinet for a couple of months unused.

Prior to a trip to Scotland the other week, I patched the barrel to remove storage lubricant and noticed the presence of rust. When I did the shooting test it performed way below par. I cleaned it when I got home and when I pushed the patch through it felt like the barrel was full of sand and the patches were showing rust. I used a bristle brush and thoroughly cleaned it until it was bright and shiny and checked the action screws and scope mounts. There's nothing visibly wrong with the bore, the throat is slightly dull sure but its seen 2500 rounds and this dullness doesn't extend for more than a couple inches up the bore. The crown and last couple of inches of the bore appear perfect.

Went back to the range yesterday and it wasn't good. Groups two or three times the size I'm used to with many flyers. Cleaned the rifle when I got home and put thought some KG12 copper remover which seemed to work and I plan to go back to the range next week for another go but not too hopeful. I'll take another scope with me but I don't think it's the issue here. There's a shoot with the club this weekend out to 600m, I can't trust my rifle to shoot a 4" group at 200m so I'll give this a miss.

Has anyone had this experience and what should I expect now? If I put 30 or 40 rounds through it is it likely the barrel will settle down? Is this sudden loss of precision normal and does it indicate that a new barrel is required?
CH

 

[8x57]

I think you need to identify the problem through a process of elimination as you've introduced a number of possible variables in addition to the possibilities of scope failure and bedding issues. I'm told it's possible to re-fit the action in the stock incorrectly with the 85 giving results similar to what you have reported, though I've never had any such issues with mine to date (rifle of similar age).
If it were my rifle I would remove the new moderator and revert back to your old ammunition or ammunition of known quality and shoot a few groups. If these were good I would then re-fit the moderator and shoot a few more groups before trying the new non lead ammunition again.

 

[bullet chucker]

My Tikka showed a loss of poi at the range, I noticed straight away' I could not believe not seeing the strike where I aimed? When I patched it at home it was very difficult to get the cleaning rod through the barrel,with perseverance I managed to clean it but did feel' a 'dirty' tight area I had not noticed before,persistent push through with the rod and then with a Bore Snake it seems the barrel is clean. Yesterday at Bisley I booked a lane to try my pride and joy only to find the first shot was low and left to point of aim (damn) My follow up shot was on the money, now to run a patch through, (I had cleaning rod with me) then fire again to see what the out come would be, the indication was a minor' scope adjustment to be as before and now confident again.
I would give yours a serious cleaning regime then shoot and see.

BC.

 

[User00040]

I've had a Sako 85 for the last 13 years and it's always reliably shot groups the size of your thumb nail. Fired about 2000-2500 rounds of 308. Late last year I went to the range and re-zeroed it with a new moderator and some non-lead ammo and it performed as expected. First half of this year I put about 40 or 50 rounds through it without any noticeable issues and left it in the cabinet for a couple of months unused.

Prior to a trip to Scotland the other week, I patched the barrel to remove storage lubricant and noticed the presence of rust. When I did the shooting test it performed way below par. I cleaned it when I got home and when I pushed the patch through it felt like the barrel was full of sand and the patches were showing rust. I used a bristle brush and thoroughly cleaned it until it was bright and shiny and checked the action screws and scope mounts. There's nothing visibly wrong with the bore, the throat is slightly dull sure but its seen 2500 rounds and this dullness doesn't extend for more than a couple inches up the bore. The crown and last couple of inches of the bore appear perfect.

Went back to the range yesterday and it wasn't good. Groups two or three times the size I'm used to with many flyers. Cleaned the rifle when I got home and put thought some KG12 copper remover which seemed to work and I plan to go back to the range next week for another go but not too hopeful. I'll take another scope with me but I don't think it's the issue here. There's a shoot with the club this weekend out to 600m, I can't trust my rifle to shoot a 4" group at 200m so I'll give this a miss.

Has anyone had this experience and what should I expect now? If I put 30 or 40 rounds through it is it likely the barrel will settle down? Is this sudden loss of precision normal and does it indicate that a new barrel is required?
CH

Did you store it with the moderator left on the rifle after shooting?

If so, RIP barrel

 

[Cloudhopper]

Did you store it with the moderator left on the rifle after shooting?

If so, RIP barrel

No. Always stored with a well oiled barrel, no moderator. No change in storage conditions.
CH

 

[finnbear270]

Oil is hygroscopic, I store all mine dry & bright patched, in a well regulated atmosphere.

 

[Muir]

I've had a Sako 85 for the last 13 years and it's always reliably shot groups the size of your thumb nail. Fired about 2000-2500 rounds of 308. Late last year I went to the range and re-zeroed it with a new moderator and some non-lead ammo and it performed as expected. First half of this year I put about 40 or 50 rounds through it without any noticeable issues and left it in the cabinet for a couple of months unused.

Prior to a trip to Scotland the other week, I patched the barrel to remove storage lubricant and noticed the presence of rust. When I did the shooting test it performed way below par. I cleaned it when I got home and when I pushed the patch through it felt like the barrel was full of sand and the patches were showing rust. I used a bristle brush and thoroughly cleaned it until it was bright and shiny and checked the action screws and scope mounts. There's nothing visibly wrong with the bore, the throat is slightly dull sure but its seen 2500 rounds and this dullness doesn't extend for more than a couple inches up the bore. The crown and last couple of inches of the bore appear perfect.

Went back to the range yesterday and it wasn't good. Groups two or three times the size I'm used to with many flyers. Cleaned the rifle when I got home and put thought some KG12 copper remover which seemed to work and I plan to go back to the range next week for another go but not too hopeful. I'll take another scope with me but I don't think it's the issue here. There's a shoot with the club this weekend out to 600m, I can't trust my rifle to shoot a 4" group at 200m so I'll give this a miss.

Has anyone had this experience and what should I expect now? If I put 30 or 40 rounds through it is it likely the barrel will settle down? Is this sudden loss of precision normal and does it indicate that a new barrel is required?
CH

You've already written it off so you will never shoot a good group with it. Your confidence is shot.

I agree with those who say you have changed too many things at once. Go back to what worked. Then change one variable at a time. A little rust will not cause a rifle's accuracy to go to hell. It may well be that the throat is worn but that can be compensated for with a change in loading technique. When you've exhausted all options, then write it off. JMHO ~Muir

 

[308rws]

Does it group without the moderator?

 

[User00026]

It shot well one day, a few months later not, only one thing has changed, time…that means IF nothing else has changed (no knocks on the way home 4 months earlier, you didn’t clean it thoroughly before putting away 4 months earlier, your ammo has not changed), THEN, only TIME has changed, which means the barrel has been impacted by storage.

Clean the living hell out of it, even with some serious grit (see Nathan Forster), then put rounds through it and see if it tightens up again.

When you shoot it next, if still not good, take the mod off and see what happens, if still bad, try with factory ammo you’ve used before and that worked.

Also think about if YOU are doing something different, ie, installed bipod and shoot it off a hard surface etc

 

[Cloudhopper]

Does it group without the moderator?

Not tried it.
It was fine when I first tried it with the new moderator and then with the new factory ammo back in December.
CH

 

[Cloudhopper]

It shot well one day, a few months later not, only one thing has changed, time…that means IF nothing else has changed (no knocks on the way home 4 months earlier, you didn’t clean it thoroughly before putting away 4 months earlier, your ammo has not changed), THEN, only TIME has changed, which means the barrel has been impacted by storage.

Clean the living hell out of it, even with some serious grit (see Nathan Forster), then put rounds through it and see if it tightens up again.

When you shoot it next, if still not good, take the mod off and see what happens, if still bad, try with factory ammo you’ve used before and that worked.

Also think about if YOU are doing something different, ie, installed bipod and shoot it off a hard surface etc

That's what I plan to do, clean the sh1t out of it and shoot it.
Nothing has changed since last December, my shooting style, surface, bipod, storage location and conditions, cleaning regime, etc, all the same. The only difference I'm aware of is the rather sudden onset of rust. I'm wondering if there's anything corrosive about the latest ammo (Barnes VOR-TX 130grTTSX?).
CH

 

[User00026]

It’ll likely be copper build up, buy a good copper remover.

 

[8x57]

You said that you checked the mounts but if it is fitted with optilocks did you check the screws that connect the rings to the mounts?

 

[User00026]

You said that you checked the mounts but if it is fitted with optilocks did you check the screws that connect the rings to the mounts?

Very good point, my fathers tikka M65 lost accuracy and it was the screws connecting the bases to the rings that had loosened. You can only check that by removing the mounts and tightening from underneath. A horrible design really as you will only ever know the issue when it arises

 

[Cloudhopper]

You said that you checked the mounts but if it is fitted with optilocks did you check the screws that connect the rings to the mounts?

This is the second scope I've had on this rifle. The first scope I mounted with Optilock rings and bases and got caught out by loose screws between the rings and mounts. For the second scope that I'm using now I've mounted it with Optilock ring mounts, so no separate bases and a neater solution.
CH

 

[finnbear270]

Clean it out on soak for a few days, repeated brush scrubbing & patching, with fresh applications of copper remover, recently I have found Bore Tech Eliminator to be a good option, I chain a bolt free rifle to a steel fixture while on soak.

 

[Ttocs]

I’ve a Tikka T3x stainless in .204R I’ve had for about 5 years and roughly 1k rounds. Even with my NV attached I can usually shoot a group the size if my little finger nail at 100 yards. After a visit to the range last year, I decided to clean my rifle having been guilted into it by others at the range; I should say my normal cleaning routine for this rifle is to wipe down the outside after use, my other rifles get a pull through with a bore snake.
Any way, I thuroughly cleaned it with carbon eliminator then Wipe Out until it was spotless - popped out to fire a few rounds through it an it was all over the place ie 3 to 4 inches one way then 6 inches out in the other direction. 20 rounds later and I was getting 2” groups - I was gutted. It’s now had 50 rounds through it since the clean and the groups have come down to <1” - hopefully it’ll continue to improve with time.
That’s the last time I’ll clean that rifle.
My deduction - all rifles are different and some don’t like to be cleaned

5 shot group from my 204R (as was) on 1cm graph paper

 

[Cloudhopper]

So, thoroughly cleaned the barrel before the next trip to the range and thought for the sake of completeness I should check and tighten everything, including the screws that hold the recoil lug retaining plate to the forend (Sako 85). This necessitated removing the barrel and action from the stock and upon doing so found a fairly large piece of oil soaked kitchen towel jammed between the barrel channel and underside of the barrel. Put everything back together and the rifle shot perfectly, as before.
CH