[45Auto]

You can’t use .40 S and W in the 10 mm Glock Model 20. And you can’t reconfigure the Model 20 to use .40 because neither the factory nor anyone else makes .40 S and W chambered barrels nor magazines of the proper dimensions to convert the Model 20. Get the proper ammo if you can; otherwise, one other option is to reload. There is a third option; you can buy a complete upper end (assembled slide, barrel) and magazines to convert the Model 20 to the Model 21 and shoot the more available .45 Auto round.

[Hoodat]

I would prefer using 10-mm ammo. I'm just not sure what kind to get. Do I go with heavier grain or lighter grain? Does any particular manufacturer brand have an advantage over others? I found some online, so I am trying to make a decision before placing an order.

I suppose I am also in the market for purchasing a new firearm for my wife. Any suggestions?