No level of skill and equipment will ever bring an inferior pellet's grouping up to match grade pellet standards.
That said I use loads of the cheapest pellets I can find in my B4 to plink with and when my arm gets sore from it I take it slower with H&N's and the difference in that cheap ass rifle is immediate and profound.
The next day with no wind I am going start using JSB's in my CFX. The H&N's are good, but I think Air Arms shot better in my CFX. I did not have enough pellets to confirm that yet. Thus it's JSB's now and after that it's AA's turn.
Milbro Caledonian's btw. shoot almost the same POI as H&N Field Targets in my B4 on iron sights. About a 3mm difference in POI below H&N. On a windy 17m and iron sights I could consistently hit a resetting target that was 3cmx3cm in size with the B4 and Milbro's. As crude as that B4 is made it's quite alot of fun.