Okay, I am playing on Challenge Mode, and I have purchased a bunch of Alpha Mods. The weird thing is that even AFTER I purchase an Alpha Mod it is STILL AVAILABLE for purchase. Since I had like 8 Million bolts and have bought all the Omega weapons, I tried an experiment. I purchased the "Aiming Mod" which I already owned, to see what would happen. After purchasing it again, it was STILL available for purchase. So I just decided to waste a million bolts and purchased it ten more times, and even after like 13 total purchase of that mod, it is STILL available for purchase. What gives?

Oh and I am not worried about bolts since they are absurdly easy to come by. Plus I discovered a trick with the Deadzone challenge called "End Zone."

Because there are such a ridiculous amount of enemies, I can get several million bolts in the span of a couple of minutes. I thought I found something new until I checked online and this seems to be a very common and old find. Anyway, what gives with the Alpha Mods?

Alpha Mods are different from Omega Mods. Each individual Alpha mod you purchase can only be used on a single weapon at a time. Unlike Omega mods which can be used on any/all appropriate weapons once purchased.

The good news is that means you can stack Alpha Mods on a given weapon. Put two or three bolt multipliers on the Mega-turrets in the Endzone Challenge at DreadZone station and watch the bolts come pouring in. Similarly, you can pump up the experience Ratchet gains from using a given weapon. Hope that helps.