Centercut per your recommendation I bought a new R5m long. Shooting my current stock of jsb King's at 34 yards I'm getting 5 shot groups of less than a quarter of an inch. I think I can do better with more practice. I was shooting them at about 920 feet per second. When I jacked up the speed to 940 the groups opened up to over an inch. You are willing to send the like 20 AA pellets for testing they work okay I may buy them off you.
I am running low on Kings and I'm wondering should I switch to MK2 Heavy's. Also bought some Grizzlies don't seem to group very well and shoot a little slow since there are like slugs. I'm thinking maybe I can machine a unchoked lothar Walther barrel and see how it works. I like the ballistic coefficient and pricing of the Grizzlies. In looking briefly at the dimensions of Edgun Barrel looks like a stock off the shelf lothar Walther Barrel we'll fit right in after threading two ends in crowning the muzzle.