260 remington. went bad.

[Wildboarem]

Look to your scope as others said. 4064 is like most other powders and can exhibit sensitivity to temp change. Federal still uses a similar powder in the FGMM stuff for .308. Velocity difference can be as much as 1 fps per 1 degree. So that could be a 30-40fps shift. If your on the edge of a node that could easily push you out. You mentioned you had h4350. That is by far the most popular powder for the .260 with bullets over 120 gr. maybe a powder switch is in your future. Hope you find the issue.

[LongRange]

Ok im going to be the bad guy here and tell you.....it is either your scope or you!!!....a 30 to 40fps spread WILL NOT cause the problems your having....a carbon ring(which ive never heard of)is NOT going to cause the problem.....CHECK YOUR SCOPE LIKE I TOLD YOU!!!!!! If you scope is tracking true then the problem is you!!

[tom338]

Am going to check the scope out. I don't think its me. I have the same scope on a 338. So while the barrel is cooling off on the 260 I am shooting the 338. shooting way better groups with the 338 than the 260. Off to the deer stand this morning. Then hopefully have this issue resolved before my trip out west. Thanks for all the advice will post on what happens to the 260.

[JCalhoun]

I'll second what longrange said.

When you are certain and for sure there is nothing wrong with the the rifle always check the scope. Swap it with a spare if you have one or run a box test.

After the scope is confirmed as good the last possibility is the shooter and his technique. How stable and consistent is the position? Breathing and trigger control? Follow through? Flinching? Eye relief? Grip?

[Code4]

Try a different scope. That one is entry level and may have gone 'west'.

[varmint72]

First check the crown and make sure there is no damage.if that is ok then some bore polishing compound in the barrel.

[jonbearman]

You use Iosso bore paste or JB Bore taste. You use a brush one size bigger and saturate the brush and turn it around and around like 20 times and then clean it out(the paste) All paste turns black when used, you are looking for a dark brown color. If you knew someone with a bore scope it would tell you immediately if the hard carbon ring in the neck area of the chamber is there. Carbon rings are always an accuracy killer.

[barrel-nut]

For hard carbon deposits, Wipe-out Carb-out works well, as does GM(as in General Motors') Top Engine Cleaner, if you can find it. But I don't think this is necessarily your problem. Can't hurt to do it, though.

Did you get to try swapping scopes yet?

[LongRange]

For hard carbon deposits, Wipe-out Carb-out works well, as does GM(as in General Motors') Top Engine Cleaner, if you can find it. But I don't think this is necessarily your problem. Can't hurt to do it, though.

Did you get to try swapping scopes yet?

man i loved the GM TEC 2 patches 5mins and one more patch and carbon gone!! im using slip 2000 carbon killer now and its pretty good stuff.

[tom338]

Well it's NOT the scope, and it's not me. For some reason this barrel just won't shoot the loads it started out shooting so good. It does however like some different loads that it did not shoot well at all before. Now if it will just repeat the load again. Will find out when the wind goes down again. Did not clean the barrel from the last 40 test rounds thru. And put another 60 test rounds thru when I found another bullet to group good. Still no clue as to why the groups fell apart and won't group from the first found bullets, does not make any sense

[LongRange]

I thought for sure it was the scope. My factory 300wm barrel was like this...id work up a good load and the next time id shoot it wasnt so good. As long as the barrel was clean it shot well after about 50 rounds it would start to drop off and 75 to 100 rounds nothing would shoot...I got tired of that real quick and rebarreled it.

[foxx]

Well it's NOT the scope, and it's not me. For some reason this barrel just won't shoot the loads it started out shooting so good. It does however like some different loads that it did not shoot well at all before. Now if it will just repeat the load again. Will find out when the wind goes down again. Did not clean the barrel from the last 40 test rounds thru. And put another 60 test rounds thru when I found another bullet to group good. Still no clue as to why the groups fell apart and won't group from the first found bullets, does not make any sense

Temp / weather swings?

[chukarmandoo]

If any of the above recommendations don't solve the problem, free to shoot us an email at contact@criterionbarrels.com. We'd be more than happy to help troubleshoot the problem and get that rifle back to performing like it was.

Soooooo! I think this is the answer. Or you could just keep @#$%^&* around with it!

[tom338]

I have been in contact with them. They wanted info and I sent it to them today. Sooooooo…while @#$%^&* around with it, I found a load it will shoot so I can take it on a hunt next week. If it repeats what it shot the other day which was a 0.30 3 shot group at 100 yards. Maybe with a little tweaking that group will shrink.

[olddav]

tom338
did you use the same powder?
did you need to increase or decrease charge?
did you use the same bullet?

[tom338]

IMR 4064 out of the same jug. This barrel just likes it better than anything else I have tried in it, h4381sc, h380,w760, h4350,h4320,rl19,rl17,rl22.
Before groups fell apart this barrel shot 130 and 140 grain Nosler accubonds. Both would shoot 0.350 groups. The 130 liked 37.0 grains and the 140's 36.0 grains of 4064. When the groups opened up I tried more and less powder, different seating depths--lots of things, different primers. No good. Now the barrel likes ( am going to try again today) 120 grain Barnes TTSX over 37.5 grains of 4064. Seated 0.40 off. Tried 0.50 off and 0.60 off, 40 was the best with 0.30 group at 100 yards. Before this barrel would not group Barnes any better than 0.925. I kept track of all the different things I tried. Barrel also hates BR primers, or at least the CCI's. Likes WLR primers best.

[olddav]

Now that's interesting!
I would assume something changed in the manufacturing process of the bullets, but I'm just guessing.
I will have to save this for future reverence!

[barrel-nut]

You say you're getting .3" groups, with the old loads and the new, which is excellent performance by most any standards. Just out of curiosity, on the groups that "fell apart", to what extent are we talking? .5? 1"? 1 1/2"? That's just strange.
Eta: I mean you were getting .3" groups with the old loads.

[tom338]

When I say the groups fell apart they went from 0.350 at 100 yards to 1.25. That was using 130 grain accubond bullets and 37.0 grains of 4064. Thats what it does right now. Can't even get a 1 inch group any more.

Now with Barnes 120grain TTSX am shooting 0.300 @ 100 yards. Did it again today. That load this summer and up until a week ago would shoot 0.850 at best. With the Noslers shooting so much better I never tried to tweak the Barnes until now.

[BillPa]

When I say the groups fell apart they went from 0.350 at 100 yards to 1.25. That was using 130 grain accubond bullets and 37.0 grains of 4064. Thats what it does right now. Can't even get a 1 inch group any more.

Now with Barnes 120grain TTSX am shooting 0.300 @ 100 yards.

A few weeks ago I decided my 260 was going to be my backup goat scare'n gun. Ran to the local clip joint and picked up a box of 120 NBTs, what I used the last time two years ago. Loaded some teeth, to the range ....1-1/2" - 2" shotgun patterns. Hummmm...re-read my scribbling (notes) then tried an old load, 120 Nosler Solid Base, H4350....1/2"-5/8". More Hummmm The NBTs shot a tad better two years ago so sump'm changed.

Pulled the box of NBTs, about half measured .570" ogive to heel, the rest anywhere from .582"-.586". To make matters worse, I used a split neck case to soft seat both, the seating depths of the .570"s were within .001" every time, the rest were all over the map. I sorted then loaded 10 of the .570"s, 1/2" groups. So now I have maybe 15-20 good bullets and about the same number fishing sinkers.

Don't ever believe they don't mix bullets made on different machines-dies!.

Bill