I'd want more than 15x. A scopes optimal performance is within 80% of its mag range. 18-20x on top end, and shooting around 15X. I wish more Manufacturers embraced the 3-18 and 4-20 concept.
As new never mounted in the box Delta Stryker 3.5-21x44 mils with DLR-1 reticle $1375 shipped PP FF/Venmo If G&S add 3% and will be shipped signature required
rokslide.com
This is a good scope, made by LOW in Japan, same maker of Triji and Maven. 29oz these have been reviewed highly on the hide.