A funny story about barrel runout.

[NZ_Fclass]

Similar...I have a 223 Tikka, that has always shot well. I bought it from a young guy at the club that had a young family and lost his job. It has an aftermarket barrel/stock. Honestly, I just played with it at the club on calm days, at 400500 yds. I would normally clean the target. I also use it for the 300m shoot - we have an F-Class 300m in NZ.

So- I go to the club expecting a 300 yd - to find that its an 800 yd shoot. (must get new glasses). Ho Hum - wind up the scope and miss the target by a considerable amount. Maybe I turned the windage accidentally?

I changed the scope - a fairly new Sightron and zeroed it back at 100. Shot a sub 1/2MoA. The following week was a 300m at another range. I had to move about 4 MoA left. Dropped it off at the gunsmith.

Turns out that the 20 MoA rail - from a well-known manufacturer was the issue - the screw holes were off the centreline. BTW - he took the barrel off and clocked it - the bore is less than .002 off.

Incidentally - the scope that I changed to - and still have on there - is a Vixen Artes 5-30. New one to me - but seems really good. 34mm tube.

 

[Alex Wheeler]

I mentioned the shape of the curve because it was unusual. At least it was unusual that it was so easy to see. I wouldnt say the all bores wander in a helix. Its more random than that in my opinion. Im in my 10th year of gunsmithing full time and this is a first so I doubt its going to be something that most guys will come across. But its an extreme example and just one of those experiences you put in the memory bank.

 

[DGP4]

I remember seeing an old picture of a German gun manufacturer where the workers used a jig mounted to the roof to straighten out the barrels. They would look through the bore and make small adjustments bending the barrel in the jig until the barrel was straight.

 

[Acyr]

Video of barrel straightening