Hornady's 8th Edition manual for .223 Remington has data listed for both Varget and Benchmark powders with the 55 fmj bullet. They used Win cases and Win primers in their test.
Benchmark--start 21.6------maximum 24.5
Varget------start 22.8------maximum 26.4
Haven't used either of these powders with 55 fmj's. I prefer Hodgdon H335 for my AR's with the Hornady 55 FMJ bullet. Hornady sometimes tends to be conservative but I added this info for your comparison.