From what I've read the key to shooting lead bullets in the newer ECM barrels is a bullet that is properly lubricated. Since most commercial range ammo today is jacketed it's not a problem as long as you avoid the unlubricated Blazer ammo. If you shoot reloads, make sure to lube the bullets and check for leading issues every 50 rounds with any new loading.
BTW, I tried 50 rounds of that Blazer in my 620 just once and won't ever make that mistake again. Just 2 strokes with a solvent soaked patch in the barrel left the patch in shreads. Then it took me about 10 hours of work spread out over 3 days using a brush and a peroxide/vinegar mix to get the barrel clean. I'll also note that had I failed to do that, the next range outing with jacketed ammo either would have resulted in a bulged barrel tube or a squibbed bullet, because the amount of leading I saw was that extreme. Still have a box of that Blaser left in my stash and I wouldn't even consider giving it away due to the bad Karma it would cause. Frankly, I don't understand why Speer still make that stuff, it's just flat out FOUL both during shooting and afterwards. However, the Blazer Brass is pretty good range ammo and Speer should really consider re-naming the Blazer to JUNK AMMO or something similar to avoid giving the Blazer Brass a bad rep due to it being associated with the aluminum hulled, plain lead, foul shooting, Blazer.