Tikka 243 Bolt hard to close 25% of the time?

[WEATHERBY460]

I have a tikka 243 that with factory ammo, the bolt is hard to close about 5 out of 20 rounds when using factory nosler and winchester ammo. When i close the bolt, then push the bolt down to lock it, is when the most resistance happens. I am noticing a slight mark on the back of the case, possibly caused by the ejector pin. This mark shows up even before i fire the round. I did have the front base screw sticking down in the receiver so I shortened that, but that did not help. Any ideas?

 

[ShtrRdy]

If you cycle the bolt many times is it always smooth and no hang-ups?

 

[westcliffe01]

So closing the bolt with no round chambered is perfectly OK and you only get the resistance with a factory round ?

You could consider getting or borrowing a "GO" headspace gauge and seeing if the bolt will close on it. If not, then you have confirmed that something is wrong.

You could start by removing the bolt from the action and confirming that you can push your ejector pin flush with the surface of the bolt. If it will not go flush, there is something dimensionally wrong with the ejector pin/bolt and it will need to be fixed by the factory. With some negotiation perhaps you could arrange just to return the bolt instead of the entire rifle which is a lot more expensive both ways... If the ejector pin is not the problem then your chamber was cut too shallow. Thats a more major fix than the ejector...

You could also clean the bolt and action with some solvent to get any oil off and then apply blue to the back of the bolt logs and then repeat the bolt closing exercise 1 time on a cartridge and then remove the bolt to confirm you are getting contact on all 3 lugs. If not, either the machining of the bolt lugs or the action could be off and thats likely to require the factory to replace your rifle with one that is properly in spec.

 

[WEATHERBY460]

Using a hornady head space comparator (the tool that attaches to a caliper jaw), the gun will chamber rounds at1.626" just fine. 1.628" and the bolt closes very hard, but will close. 1.630", the bolt wont close at all.

Is it the ammo, or do I have a tight chamber?

 

[ShtrRdy]

Looking at the SAAMI chamber drawing it shows a 1.630" minimum from breach face to shoulder datum. Sounds like it might be a short chamber.

Do you reload?

 

[westcliffe01]

I dont know how Hornady's comparitor is made, but I have attached an image of the case dimensions which give a dimension of 1.56" to the start of the shoulder. Trust in a proper go gauge. Then if it gets sent back to the factory the results will match.