NEW Tikka CTR groups and stiff bolt?

[upstate1985]

Put 60 rounds through my new Tikka CTR SS in .308 today. Three different boxes, three different loads. Below are two groups, with the smaller being my best of the day, and the larger with my worst. The larger group was with some random off the shelf BTHP, which the rifle did not love, but we still got a couple decent groups out of it.

Question: I am coming from hunting rifles, and this is my first rifle of this type. The bolt seems a bit stiff when pushing it down to lock it into battery. It was not so stiff that it was alarming, but I am curious if others have had this experience? The bolt stiffness was not ammo specific, but did seem worse with the above mention group the rifle did not like.

 

[blisters]

Is there resistance when closing the bolt on an empty action?
Check the action screws: Back them off a turn or so and then cycle the action again and see if it makes a difference. If so you can shorten the screw. If you torque the screws too hard the rear one will come into contact with the bolt (depending on stock and bottom metal).

 

[pineoak]

Make sure it's .308 and not 7.62x51, not the same.

Doubt that's the issues, but just in case.

new guns can require some break in, the stock Tikka arm is a bit short too

 

[Jmccracken1214]

Make sure it's .308 and not 7.62x51, not the same.

Doubt that's the issues, but just in case.

new guns can require some break in, the stock Tikka arm is a bit short too

Why would x51 cause a stiff bolt?

It’s at a lower pressure than 308 ammo.

 

[pineoak]

You are correct about the pressure, but most bolt guns usually have tighter chambers than the semi automatics that would normally shoot the mil spec stuff

There is often greater variation in size/length of both brass and bullets and generally speaking isn't as well suited for a 308 match chamber

There is also an issue of the brass expanding differently after firing

As blisters has asked above, are you experiencing the same bolt close experience on an empty chamber?

Or is it for specific rounds?

Other people might disagree, but I would never recommend shooting 762 out of a 308 chamber

Yes, 762 is a lower pressure.

Leave the mil spec stuff to the semis.

 

[BLKWLFK9]

It could honestly be the bolt shroud spring. I had that issue on my current tikka. It would be a heavy close at random times.

 

[upstate1985]

OK, great feedback. Here is a few answers...

1. With an empty chamber there is no resistance, nice, smooth, and easy.
2. I tried a couple different boxes at the house. I must have gotten it backwards, its the premium hunting stuff that is stiff, not the cheap BTHP.
3. It is the stainless model, which comes with a black bolt. I am seeing a little wear on the bolt, which is to be expeced, but makes me wonder if it will just loosen up over time.
4. Rifle is marked .308 and so is the ammo.
5. It is NOT stiff on an empty case. Not sure if this data point is worth anything.
6. Busted out the calipers and this is where it gets weird. The ammo that is tight is both shorter in OA and more narrow on the neck?
7. Got out a black marker, marked up the ammo, and took a look at where I am getting contact on the bullets. No results.
8. I have some GMM on the way.

 

[upstate1985]

Well after playing around with it and marking up a couple cases, it seems to be tight and making contact on the shoulder of the case. Is this normal, should I contact a smith?

 

[918v]

Sako and Tikka 308s are headspaced on the tight side. Both my TRGs have zero clearance with fgmm and Lapua factory brass, it’s not an issue.

 

[HousePlant]

My Tikka 270 deer rifle's bolt is a we bit "tight" to close, but it's also a wee bit "tight" to open and that means it doesn't open when I'm charging through brush getting to my deer sniping spots like my CZ 308 will. Accurate to 500 yards with Nosler BT 130 gr. No complaints.

Every Tikka I've used has been a little "tighter" to open and close the bolt but loosens up over about 200 rounds.

 

[Oldmauser]

The action is tight by design. I had ctr in 308 and this did not disturb me much. Moreover, if you want to tighten your groups, get a brake. Ctr in 308 was no fun to shoot for me withouta brake.