This illustrates perfectly why I don't believe in buying cheap ammo, not even for practice. If you want to save money on shooting, then get into reloading, and even then you buy only high quality materials.
Ammunition manufacturing requires a level of precision which just doesn't lend itself well to cost saving measures, so companies who manufacture bottom dollar ammo typically have issues with quality assurance, and as a result, their ammo lacks consistency not only in terms of reliability, but often times safety as well. ARMSCOR is unfortunately one such company, as I have read numerous reports of case blowouts with their ammo, and that's a shame considering that one of their subsidiaries is Rock Island Armory, which has a fantastic reputation for manufacturing quality firearms offered at relatively low prices.
You can save money by purchasing value-priced firearms and loading your own ammo at home without sacrificing reliability, but buying el cheapo brand ammunition begets diminishing returns, which considering the vital importance of ammo reliability, (not to mention safety) just isn't worth skimping on.
The absolute cheapest ammo that I'll buy is Winchester White Box, and only as a last resort. Folks can talk all they want about how their bargain basement ammo by Aguila, ARMSCOR, Tula, etc has never given them any trouble, and maybe it never will, but personally I would rather minimize the possibility of evoking Murphy's Law by selecting cheap ammo for training/self-defense.
You all know me, I'm no snob when it comes to firearms, nor do I have tons of disposable income to spend on expensive premium brand ammo, (I've still got a S&W Sigma SW40VE on Layaway at my LGS because I couldn't afford the astronomical upfront cost of $199 + Tax) so this isn't me being your typical repugnant rich-boy elitist who buys a new $1000+ firearm every week then posts pretentious pics of it sitting on the desk of his study besides a bottle of brandy and a steak dinner, (not that there's any one like that here of a places) it's just my personal opinion based on observation.