I would like to just pet one..
I petted one when our engineering class got to tour Barrett's manufacturing facility here in Tennessee about 7 years ago. I had no idea it was about 5 miles away.... very nice surprise.
"Fondle" works for me.
That's all a mere citizen is likely to be able to do. The 25mm is about .984 caliber. Definitely larger than 1/2 inch, and thus a destructive device. Plus the ammo is explosive, although nonexplosive rounds also exist. At the very least one would have to pay the $200 tax and beg your local chief LEO for permission, in many jurisdictions, you are just SOL on that, and in many others you can't own such a militia weapon at all.
But it would be nice, wouldn't it? :)