Thanks. I just kind of randomly picked those, since they looked pretty effective.
I was playing free for all a bit ago, but it got frustrating. I'm not sure if it's lag or what, but having a guy trip a claymore, turning and firing nearly a clip into him then getting killed is annoying. Especially when, right after getting killed, I did fire a full clip into someone else then got blown up. It was time to go do something else.
Anyway, earlier, I also got hit with my own claymore. I placed it, then saw someone coming after me, we were both firing, and I think he got close enough to trigger it while I was still there.