Why???
Switch to a 30gr slug, when you can get a .25 pellet weighing 31.1gr....same weight, same impact potential, same fpe, same velocity, same accuracy, for half the price?
Look at the pellet industry as you would view the golf or fishing industry. Tried and proven equipment does the job, and does it well. However, as a business, they need a new "product hook" to lure new buyers, and tempt old buyers to begin to switch to "new and improved" equipment.
Everyone likes to believe progress never ends in their personal sport of preference, but sometime you reach a point where a golf ball is just a golf ball, and a projectile is just a projectile...only so much change is practical, then you are simply maxed out on performance...the rest is eye candy.
While I will allow a long, sharply tipped, boat-tailed, slug would provide ballistic improvement over a JSB diablo shaped pellet, at extreme ranges, I have never known a slug of similar weight to out-perform a name brand pellet of the same weight, at normal airgun distances of 25 to 150 yards.
Now...some of the .257 performance guns can make some incredible shots at extreme distances using custom poured slugs...this I can't deny. What I can't find is any conclusive evidence over the years to show sufficient performance improvements to pay double for the same end results! Granted...it's always fun to experiment, but I'm very old, and to me a sub MOA group at 100+ yards makes no difference whether it's produced by a 30 gr pellet, or a 30 gr slug. Every critter I've shot with 31 gr pellets were dead on impact...the domed shaped head provided excellent penetration, and the skirt flattened out as well as any hollow-point I've shot. That's why I stick with my 31 gr Barracudas...I like them, my gun likes them, and the creatures on the receiving end of them get dead all of a sudden!
Bear in mind this is the rambling of an elderly shooter, there will be disagreement of course,
and in no way should my comments be considered an "argument", or "insult" to any posters. This is simply my experience, and the experiences of others, which I have read in forums over the years.
Experimenting with new ideas is fun, and I'll be the first to admit I'm wrong...but please show me any viable benefit to shooting expensive slugs, at pcp velocities and ranges, and I'll change over myself!!! The important thing is we have fun...an important part of that is disagreement...which promotes dialog and new testing...if for no other reason than just to prove the old fart wrong!!!
Kindly 'Ol Uncle
"...my uncle Earl tried slugs once at a restaurant, he put salt on them and the damn things melted before he could eat them. Never got his money back neither!"