I did a search and could not find answers to my specific questions.

I want to buy a Spike's .22 Conversion bolt so that I can train for a fraction of the cost. I need mags that will be able to be dropped without breaking and be able to be dropped on the ground in dirt, etc. I don't plan on abusing the mags, but which of the two are more durable?

They both have BHO followers, right?

Absolutely +1. If you want them to work, you can't drop them. I've learned the pocket maneuver. Out, to the left pocket, in from the right pocket.

Spec

Drop bag it is, then?

If you're running drills or IDPA/IPSC like courses of fire, you should be okay dropping mags out of the gun as long as the range surface is grass/dirt/pea gravel or something similarly "soft".  The mags will likely be falling on their base most of the time and as long as you don't step on them, they should be fine.  You can put some of the rubber magpulls on the bottoms or add some other kind of protection if you wish to help reduce the chances of damage to the mags.

If your range surface is concrete/asphalt or something similarly "hard", or you like to strip empty mags out and throw them to the ground, I would suggest NOT dropping them under any circumstances.

Best thing to do is try it with one mag and see how it goes.  The BDM mags are pretty solid.  I run the BDM solid black mags and they have been holding up just fine for me and I don't exactly baby them - they hit the ground during every reload on the clock or in practice.

Dump pouch––––YEP!!!!!!!!