"but azuru is saying that it is all down to barrel treating , lapping and god knows what else that cost's an arm and a leg"
Holly, accuracy is impossible to have if we don't have consistency...In the other forum I went a little farther by doing a little analysis on external variables and Twist Rate of a barrel.
Consistency in velocity will not help if the pellet does not have an appropriate Gyroscopic stabilization (Twist rate of a barrel) and in that thread this fact is explained in detail.
We can have a smooth barrel having ZERO fps. variances shot to shot and this barrel will NEVER group at 50 meters...It may at 5-8 meters but not at long distances.
What I discuss in that thread adds to consistency and of course accuracy, but there are many other things to consider for attaining consistency shot after shot...Stock-action fit & bedding, action barrel fit and squareness, torque on screws & barrel, bore smoothness, choke, etc...
Not that a not well torqued or squared gun will not shot, but is a fact that it will be more consistent if torqued right, bedded right, squared right, with a good barrel action fit, etc....
Everything done right and to specs helps for consistency and accuracy and at the end It adds up.
The barrel work and other I suggest in that other forum do not cost an arm and a leg, anyone can do it but is is advisable to fully understand what you are doing and the theory behind it...It is not the same to LAP a barrel than to POLISH a barrel.
I slug all of my barrels (air and powder) and POLISH the barrels until the slug goes from breech to exiting the crown smoothly with no TIGHT or LOOSE spots...If a barrel has tight spots you can fix it, if your barrel has tight and then loose spots, it will be almost impossible and you will need to then LAP the tighter parts to match the loose spots...BETTER TO GET A NEW BARREL or understand that that particular barrel will not be a killer barrel...
We all need to understand that a high Twist ratio barrel will tend to be better at longer distances and where wind is present...Low TR ratios are very good at 10 M and similar indoor environments. A less invasive barrel (less twist rate) is better for accuracy under certain conditions (Shot distances - no wind). A more invasive barrel is in theory less accurate at shorter distances where there is no wind but will be more accurate at longer distances.
My BR barrels will be outperformed by thousands of an inch at 10 meters but these same BR barrels will outperform those exceptional 10 M barrels at 50 meters by .250" or more!
This is personal but I rather have a Benchrest barrel (for FT shooting) that shots .25 of an inch edge to edge groups at 50 M and let's say .100" ctc at 10 M than a 10 M outstanding barrel that shoots .001 ctc at 10 M and .750" or worse at 50 meters.
Producing consistency for shooting .500 ctc. groups at 50 meters requires very little effort, but from there on the effort goes exponential...It takes a great effort and many little changes to increase accuracy/consistency to .125 consistent edge to edge groups at 50 M but it is possible...What we need is a rifle that will shoot where it is aimed so if we make a little mistake, the error doesn't add up to the error (lack of accuracy) of the gun. In other words, LET'S INCREASE THE SWEET SPOT of the accuracy!