Footnotes for the benefit of the n00b OP...
Skip the bulk packs and economy-grade ammo, at least for the time being... Go to something boxed (higher quality)...
Bulk pack refers to .22LR that's packaged in a single box of several hundred loose rounds for $8-$20. However, many varieties of bulk pack- including Thunderbolts- are also available in boxes of 50, typically for less than $2/ea.
IMHO you shouldn't categorically swear off all
bulk pack. It's just that cheap .22LR is a hit or miss proposition- pun intended.
.22LR guns are invariably picky about ammo, and when you use different types of cheap ammo, you may get wildly varying results. You just happened upon a type of cheap ammo that your gun really dislikes.
It's a trial and error process.
Just as an example, my S&W Model 18- a very high-quality .22LR revolver- loves Remington Golden Bullets, a cheap load that many shooters consider to be absolute crap.
It shoots them much better than equal-priced Federal loads, and it absolutely will not shoot well with any cheap load made by Winchester. Why is this? Beats me, it's just the way .22LR guns are.
...sticking to plated ammo would likely solve the issue without necessarily having to resort to "high end" ammo.
Plated bullets have a bright metal, typically copper color, rather than a dark grey lead color.
Mid-priced plated bullet ammo generally sells for $3-$4/50 or $6-$8/100 and often comes in little clear plastic 100rd boxes. Common types include CCI Mini-Mags & Winchester Super-X Super Speed.
Not all non-plated low-priced ammo is bad. I would suggest trying Federal Auto Match, which is available at Walmart in loose-packed 325rd boxes for about $14, although many of my local Walmarts seem to be having trouble getting it right now; YMMV. I've found that this load shoots at least reasonably well in every semi-auto firearm I've tried it in, and it's nowhere near
as dirty as Thunderbolts.
CCI Stinger **
Remington YellowJacket **
**(If the pistol is rated for it.)
The reason for the "**" is that these are so-called hyper-velocity
loads, which are loaded hotter than high-velocity or standard-velocity .22LR ammo. Other common types include CCI Velocitors and Aguilla Interceptors. Most newer .22LR pistols can use these, but check the owner's manual to be sure.
Be aware that even if the manual says you can use it, these loads often use lighter 29-32 grain bullets rather than 36-40gr bullets like regular .22LR ammo. The barrels of most .22LR guns are not optimized for the lighter bullets, so accuracy may be poor.