Troubleshooting

[fwm]

Working up a load for a Tikka CTR in 6.5 Creedmoor and I’m getting 2 distinct grouping in a group. At various powder charges I get 3 shots touching then a gap with 2 shots touching. My best groups are about .75 moa but I’m hoping for better. I’ve checked action screws and scope mount. It is possible it’s me but I don’t get this with other rifles I’m shooting on the same range trip. Any ideas to check? I do have another scope I can try if need be. Shooting 130gr Hornady ELD match ( I couldn’t find 140gr) over H4350. I should add I’m getting very little vertical the dispersion is horizontal on the best loads.

 

[Toolman]

Rule out your scope and rings, after that I would bed it.

 

[chrismc]

If it were me, I would play with seating depth. Took my 2-1 groups away on more than one occasion

 

[josh.s]

Shooting 130gr Hornady ELD match ( I couldn’t find 140gr) over H4350.

It's quite difficult to source ELD-Ms right now, but my CTR likes 147 gr ELD-M over 40.3 gr H4350. Had OK results with the 140s and haven't tried 130s.

 

[fwm]

Yes 130gr was all I could find in anything 264 at the moment. I'll try my other scope to rule that out. When I changed seating depth groups opened up. Right now I'm 2.850" OAL.

 

[Lead hammer]

Is your barrel getting hot?

 

[maynard]

Bedding would be the first thing. The scope is likely good as there isn't a huge shift in your groups.

 

[Dwayne Cyr]

Does your scope have a parallax adjustment and is it adjusted properly?

 

[chrismc]

you played with seat depths? Like lots? I would do 20-40-60-80-100-120 and see. It may surprise you!!!

 

[fwm]

Thanks for all the suggestions I have some things to try now.

 

[fwm]

Finally able to get to the range again. I’ve installed a different scope to start with. That made no difference as I expected. I fired loads with varying seating depth. Up to 40 thou difference didn’t seem to help the 2-3group or group size which I found odd. I've heard Tikkas have very long throats so maybe that's a factor. My next step was different primers. My standard primer has been CCI LR. CCI BR made nicer round groups with slightly tighter avg. my last attempt was loads using Varget rather than H4350. That was the ticket. I still need a bit of development but my best was 4 in 1 hole with one slightly apart. Overall group less than 1/2”.

 

[MartyK2500]

2 years ago I had the exact same problem and went through a lengthy thread to try and correct it.
Turns out my necks we're too tight.
It's a long shot but may be worth investigating into given how little effort it takes to verify this.
I see you have solved your problem, I also had better results at the time with varget vs H4350 as velocity would help alleviate the problem, but if necks are too tight and you correct this, all loads will be accurate again.

Can a bullet freely drop into a fired neck?
Does the outer neck dia expand at least 3 thous before and after firing?

 

[Buckmastr]

Confirm that your hold is consistent. Too much cheek pressure can effect the point of impact. Watch the front sling stud when shooting off a front bag. Dry fire a few times and watch how the reticle reacts.

 

[fwm]

2 years ago I had the exact same problem and went through a lengthy thread to try and correct it.
Turns out my necks we're too tight.
It's a long shot but may be worth investigating into given how little effort it takes to verify this.
I see you have solved your problem, I also had better results at the time with varget vs H4350 as velocity would help alleviate the problem, but if necks are too tight and you correct this, all loads will be accurate again.

Can a bullet freely drop into a fired neck?
Does the outer neck dia expand at least 3 thous before and after firing?

Just checked some of the fired cases and a bullet easily slides in maybe even a bit of wiggle room