I've been shooting the 221 for 30+ years. Picked up a 17 MACH IV in a bench style gun near on 20 years ago. Didn't want to hassle making brass, so rechambered it to fireball. I liked it so much I built another on a Sako action, with a lighter barrel. During this time I built a 20 VT on a Savage competition action with a medium lite barrel. It work very nicely also. I've only been shootin' PDs now about 3 years, but where I go the shooting can be extremely rapid. Over heating the barrel is a constant issue. Having 6-10 guns seems to be a good idea. I recently built another VT on a Ruger Predator action. When I first started load development, I was around .25". after installing a EC tuner and playing with it a bit, I put 3 in one hole. You still need Fireball brass to make your loads, or take a bit of time cutting down 223 brass. My buddy who is my gunsmith, has been working with a 20/222. Accuracy is super. Better than I've seen with my 204s. The longer neck helps, plus reduces erosion in the throat. Back to the 17s, in the wind they are a bit of a challenge. Planning on taking my PPCs and 6 br with me this next year. Haven't taken them in the past only because don't need that much lead to kill 'em. But when the wind comes up, I'll give 'em a try.