I have three J Point reflexes mounted on a 617, 620, and 610 using the J Point mount. I find it interesting that the Tasco 2000 looks to be the same sight as the J Point, previously it was sold as the Trijicon Red Dot, so it's obviously been around a while. I would recomend you use the mount from JP Rifles. The mount ships with 1 degree wedge shims and I can tell you that this shim may be necessary for getting the sight zeroed. On my 6 1/2 inch 610 the shim was not needed, on my 6 inch 617 it was a must, and my 620 is borderline without the shim when using 130 grain 38 spl.
The amount of bore transit recoil can have a huge effect on the amount of elevation adjustment needed to zero the sight. Just going from my usual 130 gr. 38 spl. to a 158 grain 38+P caused about an 8 inch shift in the POI at 100 feet, so you'll find that you become rather particular about staying with just one load once you have it sighted in. IMO, that's one weakness for the red dot sights currently out there, no vertical graduations that allow you to correct for differing loads visually. However, once your eyesight gets bad enough, they become the best choice on the planet in spite of the shortcomings. Point is, depending on the bullet weight you are using you may find you need that wedge shim.
