I have a Sako 75 in .243, which is eight years old and owned from new. It fires 100 to 150 rounds per year so has fired no more than 1,500 absolute max. It shoots very well with home loaded ammunition, loaded to sensible limits. It has never fired hot loads. It is cleaned properly etc.
When I bought the rifle, I measured the overall length to the origin of the rifling, using a RCBS precision micrometre. The reading was +135 so after the usual working up and trying different settings, I settled on +125 bullet depth seating, thus giving ten thousands of an inch clearance.
Yesterday, for some unknown reason, I decided to measure the rifle again. I found that the measurement to the origin of the rifling is now +140, so 5 thou' longer than when new.
QIs this normal wear and tear ?
Q As there is no deterioration in accuracy, would you leave the bullet depth setting as it is or try setting it out another 5 thou' ?
As its not broken, I am tempted to leave well alone. What do you think ?