@AyJay - mate, I can feel your pain reading this - don't know why people don't read the question.
Things to look for with a 2nd hand rifle.
1. Always best if you can physically have a look and get hands on the rifle in question - photos and even videos will only show so much.
2. Don't rush when you're looking it over.
3. Muzzle - check the muzzle, particularly the crown - is in good condition with no signs of corrosion, nicks to the crown etc. If the rifle is displayed with moderator on the rifle, do remove the moderator and inspect the threads for corrosion, damage etc.
4. General condition - does it look like it's been slung in the back of a pig farmer's pick up or like it has been a fairweather only rifle? This is not always conclusive as to overall condition, but can give you a good idea about how the owner has cared for it (or not).
5. Bolt - is there pitting/cutting (look for a small circle around the firing pin hole) on the face of the bolt? Does it close properly and not display any gritty or crunchy feeling? Is there accumulated grease/dirt in the firing pin area? Worth dry firing it as well (take a Snap Cap with you as some owners won't want dry firing on an empty chamber) and get a feel for the trigger pull weight and lock time (if it seems slow and you've noticed excessive grease/dirt in the bolt firing pin space it could just need a clean). Check the extractor claw and ejector are not damaged (your Snap Cap round will help here as well).
6. Magazines - Snap Caps help again as you can run a few rounds through the mags and see how it feeds. Check the lips, springs etc all work and there aren't any cracks.
7. Stock - and obvious cracks, splits etc. A couple of chips here and there on a synthetic stock shouldn't put you off, but I can appreciate it may. Check around the receiver screws for signs of obvious over tightening (could be cracked receiver mount or a crack running from the receiver mount on the stock). Butt pad loose or excessively worn (but seller says it has only had 50 rounds through it, honest guv...)
8. Scope mounts - does it have a picatinny rail or mount, or does it have a dove tail? Has it been glued on? Or badly mounted? Check for rust under rail or claws/dovetail.
9. Chamber/rifling - onvious enough, but worth a good look. Rough chamber, carbon ring, missing riffling, frosted rifling, pitting etc all need to be considered.
That's about it I think, but bottom line is, if there is something niggling you, you need to decide if it is something you can replace (and afford to replace) or if it is a no go and walk away.
