From the www.doubletapammo.com website I found something I've never heard of before... It's hardcast bullets with polymer coating... Here's what DoubleTap has to say....

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220gr. Hardcast Heavy Hitter!

For the avid hunter or plinker that wants to shoot hardcast through their 10mm, here is your chance! This is the only factory 220gr load for a 10mm currently being produced. At 150yds this 220gr slug is still traveling over 950fps! This is equivilant to a .45ACP +p at the muzzle! These slugs are cast to 16 BHN and coated with a polymer coating to prevent leading even out of polygonal-rifled barrels.

Caliber : 10mm

Bullet : 220gr. FP Cast

Ballistics : 1125fps/ 618 ft./lbs. - Glock 20
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Anyone have any experience with these bullets? Do they foul your barrel with polymer?

$bob$