Just to put my perspective on things I have only been able to go to the expense of having one shotgun regulated. It was my Purdey Bar in wood and the only reason that I considered having this done was the barrels where not in the best of condition at the start of its restoration some 50 years ago. Both top and bottom ribs had to be removed plus a replacement forend securing loop had to be fitted. It was a no brainer to have it done the point of impact for the two barrels was to be tested and adjusted if necessary, but more importantly was the pellet density in a 30inch circle at forty yards, seeing that both barrels were of true cylinder. The outcome came between 119 and 128 pellets in the circle so you could assume you should expect results somewhere between the two given figures. Though more importantly was the fact that the gun would only be consistent with the cartridges that where used at the time, with a recommendation that the same cartridges should whenever possible in the future. I was billed for 100 cartridges and when the gun was returned after restoration two boxes of unused cartridges accompanied the gun, I somehow never wanted to use them so they will accompany the gun together with the documentation to its next owner.
As the gun is chambered for 2 ˝ inch cartridges I can only assume that the best results were with these Eley 2inch number 7shot 1oz load having Fibre wads and rolled turnover.
Though I have found 2 ˝ low velocity cartridges with 1oz 6 or 7 shot loads having crimp closure and felt wads give very good repeatable results.
