MISSALOT

He stuck it to the base of the cartridge to lengthen it progressively.

I have a Tikka m55 in 22-250 fitted with a nearly new 24" Walther heavy barrel (1:14 twist). It shoots 1/2 to 3/4 inch groups at 100m. all day long with factory loaded Winchester 55gr sp, which chrono at 3,765fps for a whopping 1,730fpe. V-Max 50gr home loads group within 1/2 inch. Privi are also very accurate. I recently bought a block of Hornady V-Max 55gr factory ammo. To say the least the results were scary! Shots were all over the place on target, spread out randomly over 8 inches. Bolt was tight on extraction and primers were flattened, clear signs of excess pressure. The dealer was very fair, took back what was left and fully refunded me. He took one of the rounds and chambered it progressively with increasing layers of insulating tape. With three layers the round was a tight fit. His conclusion: a non-standard chamber. I didn't think to check the COAL but I suspect the bullets were seating tight in the rifling, which would cause a pressure spike - or am I spouting nonsense? I can't understand why no other round gives this problem. Any suggestions?

What is the barrel length? Nice stock. Are there any marks not shown in the pictures?