I'm new to reloading and have had two boxes (qty 100 each) of Sierra Varminter 55 grain 0.224" spitzer I've been packing around for 30 years. I'm going to develop a load for my Olympic Arms AR-15 with 20 inch heavy barrel. I'm unsure of the barrel twist rate but assume it's 1:9. I see in the Sierra literature for these bullets #1345 that they recommend no faster twist than 1:12 or the bullet may "disintegrate in mid-air". I also bought plastic sabots from EABCO 30 years ago to shoot these 223 bullets (actually 0.224") loaded in 30-06 cases, similar to Remington Accelerator ammo. Can anyone recommend a powder and load for these bullets and the AR-15? Has anyone done the "accelerator" hand load and can you suggest a powder and load you use? Should I be worried about bullet disintegration in midair? I'd appreciate any and all input here as I'm currently tempted to toss the 2 boxes of bullets and start over from square one.