Help w Rifle Inaccuracy

[2-Stix]

My 308 and 7rm tikka like federal with barnes tsx, some barnes with ttsx and some nosler. 308 likes 165 vs 150. 7rm likes 160 vs 150. I ran about 3-5 boxes to land on one for each caliber. And right now I lost some confidence in my 308 after missing a buck last season. I burned up some boxes this week and chased my zero some like an idiot. 2.5 in groups, a few .75...I think I was heating up the barrel as I was rushing more shots and wandering around in my groups. I have shot in the past with most groups .75-1.25. I am going to head back out and hope it was rushing and an over heated barrel...that could be it...and getting a few factory loads to run. I have shot sub .5" groups with both rifles.

 

[MCS]

I've seen a couple tikkas that just won't shoot good. My friends 7mm shot ok at best and got flyers. He tried multiple different hand loads and factory ammo it just wouldn't shoot. He had the action trued and rebarreled it after waisting a ton of money and time on it. My Dad's tikka shot a 3" group on a good day no matter what ammo you put in it. He also waisted a ton of time and ammo trying to make it shoot. He sold it and purchased a savage 116.

 

[ResearchinStuff]

My 308 and 7rm tikka like federal with barnes tsx, some barnes with ttsx and some nosler. 308 likes 165 vs 150. 7rm likes 160 vs 150. I ran about 3-5 boxes to land on one for each caliber. And right now I lost some confidence in my 308 after missing a buck last season. I burned up some boxes this week and chased my zero some like an idiot. 2.5 in groups, a few .75...I think I was heating up the barrel as I was rushing more shots and wandering around in my groups. I have shot in the past with most groups .75-1.25. I am going to head back out and hope it was rushing and an over heated barrel...that could be it...and getting a few factory loads to run. I have shot sub .5" groups with both rifles.

What scope and mounting system on your 308? And how many shots per group? You may have been playing in the small sample size noise hornady observed with their testing....

 

[2-Stix]

What scope and mounting system on your 308? And how many shots per group? You may have been playing in the small sample size noise hornady observed with their testing....
View attachment 529034

Thats interesting. All my groups were 3 shot. Talley lows with a Leupold vx3 3.5x10x40.

Groups as following .... 1.35", 2, .875, 1.75, 2.5, 2.5....a set at 200 was 1.5. and I got so frustrated I quit logging them. In the past I was going between my 308 and 7rm. I think I heated up the barrel. I plan to go back thursday and try again. My shots were also faster turn around. The barrel was warn, not what I would consider hot. But I was turning my 3 shots around pretty quick. Under probably 2-4min groups.

 

[AkRyan]

If all else fails try removing the brake! Tension can also effect barrel harmonics.

 

[ResearchinStuff]

Thats interesting. All my groups were 3 shot. Talley lows with a Leupold vx3 3.5x10x40.

Groups as following .... 1.35", 2, .875, 1.75, 2.5, 2.5....a set at 200 was 1.5. and I got so frustrated I quit logging them. In the past I was going between my 308 and 7rm. I think I heated up the barrel. I plan to go back thursday and try again. My shots were also faster turn around. The barrel was warn, not what I would consider hot. But I was turning my 3 shots around pretty quick. Under probably 2-4min groups.

Your average group was 1 83". Using hornadys observed variation, anything within 0.55-3.11" is expected on a 3 shot group, and all of yours are within that. No reason to think something is wrong or changed. You're only a few rounds short of seeing your rifles true cone if you overlay all the groups and make a composite.

Small sample sizes for groups lead to a lot of frustration and unmet expectations for shooters. Give this a listen before you further frustrate yourself

 

[2-Stix]

First...thank you for your info..its comforting. This was really good to listen to. I listen to the follow up also on Ep 52 also. I had much better groups in the past. And my groups this round were about 3" away from where they were last time on the target also, windage mostly. Here is my groups the last 2 times out when I was figuring out what I wanted to use on my CDS load. My 7rm is a Tikka Veil 24" with a factory break, with Talley lows and VX5HD 3-15x44. The podcast informs this data I logged to be true generally. Good stuff...thanks. I do still think I heated up the barrel. I will hit the range one more time...5 mins between shots to cool and go what what every happens.

I was thinking shoot 3 shots groups from .5-1.25 and no more than 2 and I would be very happy.

What would you recommend for shot groups? My zero is at 200. I was thinking maybe a better way I should do a 10 shot at 100, then 10 shot at 200 then make my adjustments to the scope. Do this for my 308 and 7rm. Do the same down the road with my 6.5 I am building for my sons first hunt in a few years.

 

[wind gypsy]

Any barrel that needs 5 minutes between shots in March might as well get scrapped. If that really is the issue the barrel is faulty. You should be able to get it too hot to touch without things really opening up.

 

[2-Stix]

Its a pencil barrel and it's 70+ degrees here in March. 105 in the summer. I can reflect back that the more I pushed my barrel the more the groups opened up. I think it does have an impact.

 

[ResearchinStuff]

530106[/ATTACH]

Barring noticeable wind (~10mph for your gun), the 3" shift at 200 is indicative that your scope has lost zero/ internally failed. I know 3" off trip to trip is normal with a Leupold (lived that for 20 years), but with a solid system (swfa/nightforce scope, sportsmatch/nightforce/arc rings) that nonsense doesn't happen. You can learn more about scope reliability here: https://rokslide.com/forums/forums/rifle-scope-field-evaluations.133/

The recommendation from hornady is to get 20 shots on paper, however you want to shot them, then use the center of that 20 shot group to set your zero. Zeroing at 100 will reduce your shooter and windage error on that 20 shot group, allowing a more precise zero. You can then dial up for whatever range you want and confirm there.

 

[ResearchinStuff]

@2-Stix also, have you done the basic tikka stock work to improve consistency? Aggressive free float the barrel, install pillars, epoxy bed the action/recoil lug, torque the action screws to 65 in-lbs (don't do without pillars installed)?

 

[2-Stix]

That 3" shift I saw was my first cold bore shot after 2 hunts last year, and it was at 100. I just read an article about cold bore shift. My first hunt was a very heavy brushy hands and knees pack out followed by a missed buck hence the working to check zero and get some confidence back. After that cold bore it got better. I am a newer hunter that hunts with family that has hunted for 60 years. But they are very old school. Running loose compared to what we are discussing here. The run $200 vortex scopes on cheap Savages. They kill everything in site, but at 50-250 yards.

And yes Hornady did recommend a 20 even better 30 group. I guess like the guy said, I am trying to cheat the process and get it done faster. I was looking at going 10 at 100 then out to 200 and hope to be done.

 

[2-Stix]

@2-Stix also, have you done the basic tikka stock work to improve consistency? Aggressive free float the barrel, install pillars, epoxy bed the action/recoil lug, torque the action screws to 65 in-lbs (don't do without pillars installed)?

I just read up on some of that. I have added the MT bottom metal and torque to 50 in the trigger screw and 40 on the front. I plan to aggressively free float the 3 rifles this weekend and put off going back out to the range. I have not installed pillars or epoxy work. I added the MT recoil lug and action screws.

Thanks for all this prodding...its good and getting me educated.

 

[ResearchinStuff]

That 3" shift I saw was my first cold bore shot after 2 hunts last year, and it was at 100.

unless there was a 20 mph wind pushing in that direction, I would characterize that performance as "losing zero due to normal field use."

 

[2-Stix]

unless there was a 20 mph wind pushing in that direction, I would characterize that performance as "losing zero due to normal field use."

I might have a hard pill to swallow with my Leupolds. I been reading that link of scopes. Thanks for that.

I will make some adjustments to my free float, head back out, run at least a 10 shot group. Dial out to 200, a few at 400 and come back to 100 and see what's up. I killed game from 75-225 so far. I would cut myself off at 400 at this point.

 

[wind gypsy]

Its a pencil barrel and it's 70+ degrees here in March. 105 in the summer. I can reflect back that the more I pushed my barrel the more the groups opened up. I think it does have an impact.

I can’t tell you at which point a barrel is too hot to count on but if you can stand to hold it in your bare hand it shouldn’t be throwing shots. I’m not saying no barrels do, just that such a barrel is unacceptable IMO as many of them do not act that way.

 

[2-Stix]

I can’t tell you at which point a barrel is too hot to count on but if you can stand to hold it in your bare hand it shouldn’t be throwing shots. I’m not saying no barrels do, just that such a barrel is unacceptable IMO as many of them do not act that way.

I have read the stainless hammer forged barrels have this issue. The material expands and can throw rounds. It could be a factor I was fighting, it could not be. I do know the 2 days I had last year a the range I was working on 2 rifles for grouping for my CDS dials and I was shooting 3, then moving to the other rifle. I didn't do that this time. Could or could not be some of it.

 

[ResearchinStuff]

I can't find the specifics on the steels used by Tikka, but in many cases stainless barrels are 416, while chrome moly are 4140. 416 stainless has a lower thermal expansion rate than does 4140. So, a 416 stainless barrel should be more stable in its behavior as it gets hotter, than an otherwise identical chrome moly 4140 barrel.

Stainless Steel - Grade 416 (UNS S41600)

416 is the most machinable grade of stainless steel. It is a low cost grade and can be used unhardened, hardened and highly tempered states. Hardness is optimised at the expense of other properties and corrosion resistance is lower than for austenitic grades. Applications include valves, gears etc.

www.azom.com

AISI 4140 Alloy Steel (UNS G41400)

Alloy steels are designated by AISI four-digit numbers. They comprise different kinds of steels having composition exceeding the limitations of B, C, Mn, Mo, Ni, Si, Cr, and Va set for carbon steels.

www.azom.com

 

[Formidilosus]

I have read the stainless hammer forged barrels have this issue. The material expands and can throw rounds.

No. Stop reading wherever you read that from. The steel doesn’t walk. Sako/Tikka barrels will group inside their cone nearly until they start to glow. Mirage off a barrel can cause group issues. However it will be generally vertical.

 

[2-Stix]

A bull barrel doesn't hold true in a longer string of shots they a thin contour?