As Russ has already suggested, the HW30 is probably best suited to the pistol weight "wadcutter" pellets rather than the heavier rifle weight types.
GECO, RWS Basic and Hobby are all good budget priced pellets that have their supporters and only come in the one weight type - so no need to worry about pistol or rifle weights.
RWS Meisterkugeln is a good value for money "premium" pellet and it is the most popular choice in our club. We also use these pellets exclusively in our Supported Air Rifle Shooting and the results we have achieved with these can be seen in the current results.
RWS R10 is a top premium choice but like the Meisterkugeln they are available in two weights and the lighter "pistol" weight would be the one to go for in your HW30S.
Premium pellets often have a choice of "size" that can be confusing, whereas the "budget" pellets usually do not. We use 4.50 size pellets in Meisterkugeln and R10 and they work well, but you could try some 4.49 if you wanted to experiment, but doubt you will be able to see any difference between them (we certainly can't).
Any of the above suggested pellets are relatively easy to find in sports and gun shops (or online) and would be a good place to start, and for 6 yard target shooting any of the above would work OK.
If you are keen enough, you could test them all (over a period of time) to see what works best in your HW30S, but always allow a few shots between changing brands for the barrel to "settle" into the new pellets alloy type/size/shape before making any final performance judgments.
Last edited by zooma; 11-09-2018 at 10:01 AM.
Rossendale Target Shooting Club. Every Tuesday and Thursday evening 7 - 10pm.