Upon grant of my FAC in April, I purchased my first rimfire. A lovely Sako Quad in .17 HMR with Lightsteam 4.5-14x44 and SAK moderator. The gun shop advised the rifle wasn't very old and had fired less than a few hundred rounds. Quite a bargain at £650 I thought. Although only managing an average group size of 1-1.5 inches at 100m, it's proven quite devastating on the rabbit population on my permission. Hearing of others consistently realising sub 1-inch, I just put the larger group sizes down to being out of practice.
I then added a semi-customised Ruger 10/22 in August but could only manage groups of 2-3 inches at 50m. Very long story short, after cleaning excessively, trying different scopes, with and without moderator and different makes of ammo (>300 rounds in total), I gave up and sent it back. The experience rather put off second hand rifles and I was just counting my blessing that at least the Quad had worked out well.
This was at least, until the last week. Two-weeks ago after a deep clean, I put in my first 5-round cloverleaf with the Quad at 50 metres. Needless to say I was delighted, the old eye appearing to have returned after 6-months and ~700 rounds of practice. Having only fired ~30-rounds, I cleaned the bolt and action, but left the barrel. Stepping up to 100 metres this week I was expecting sub 1-inch, but was sadly disappointed, still realising 1.5-inches. However, things just didn't feel quite right. Marksmanship principles were applied just as consistently as at 50-metres and rounds would appear to just 'jump' from point of aim. Not far, but far enough to make up the 1.5 inch group size and just not feel right. The spring the bolt rides over never having sat right from purchase and now almost completely broken off, I took it into my local gun shop today to enquire about a repair. They kindly rang the importers (GMK?) who looked up the serial number. It was first purchased in April 2005. They then ran a brush through the barrel to enable a better view of the bore, which revealed very worn rifling. That rather explained why even just ~30-rounds gave sufficient coating to reduce the effects of what's left of the rifling. Clearly the rifle was not a few months old and the barrel pretty much shot out.
There are clearly honest types out there, including the chap who sold me the 10/22 who took it back without question. However, lesson well and truly learned and the "two from two" negative experiences has left me resolved never to buy second hand again.