My best shooting rifle was for years my Remington 700 ADL in .223 Rem. that I bought in the early 90's. After 3500 rounds, the group size started opening up quite a bit, so I traded for a Remington 700 SPS Varmint. I thought the best load in the ADL would also shoot well in the SPS Varmint, but it doesn't. The 52 gr BTHP shot best in the ADL but that weight doesn't seem to work in the SPS. I tried heavier bullets but they didn't work well either. I'm wondering if they might have changed the rifling twist. The ADL load works well in my Tikka T-3 Lite, my Savage M-25 Walking Varminter, and my Sportco .223's. I've been told the twist in the 700 SPS is1 in 12 and the savage is 1 in 9. I haven't been able to verify these. I just loaded some 50 gr HP for the SPS, perhaps they will work better. I've been using IMR 4198 powder and tried many others that didn't work as well. Are there other powders that usually work well in .223?