Thanks Kirk

I checked the ADI powders website for their equivalence info here. AAC 1680 and IMR 4227 are pretty close to ADI’s AR2205. IMR 4198 is ADI’s AR2207 rebranded so it will be easily available to me. I emailed the manufacturer of the bullets and he said 1600 fps without a gas check would be fine. He has some other customers running 45- 70 projectiles at 2000 fps OK. It must be a tough polymer! I think I know where I can borrow a chronograph.

Thanks everyone for your advice, it is much appreciated and will give me some projects for the next few months!

David