I've been using shootsteel.com's auto poppers for a few months, from 100yds out to 700yds, and they've turned out to be great targets. The Magnum has an 8" diameter plate and is rated for up to 338 Lapua, and the standard has a 6" diameter plate and is rated up to 308. Though my friends and I sent some 300 Mag and some 556 at them, we mostly shot them with 308 since that's what our long range rifles are chambered for.

I was very impressed with the attention to detail their construction revealed. Even the paint was perfectly applied even though everybody knows you're just going to shoot it off, then repaint over and over and over again.

The plates are actually tuned so they are louder than other steel targets on the market, so you get a very loud "ding" even if you hit the stem and fail to knock the plate back. They are laser CNC cut so the heat treatment of the AR500 is preserved right up to the edge. We made quite a few hits on the edges with no notching that you'll get on other plates.

I've been very impressed with Evan, the owner, and what he's trying to do with his company. He's offering a discount of 15% off all steel targets with code "twangnbang" through August 31st, and if you haven't priced out their targets before, you really should. They also leverage flat rate USPS priority mail boxes quite well, which means that you'll pay less for shipping than you probably think you will, and you'll get your targets in 2-3 days.