Depends what you using for primer, wad, and hull. A one ounce load with 17.5 grains in a taper hull, using Fiocchi or Winchester primers will be moving about 1200 - 1220 fps. More than enough to break targets robustly to 24 yds. FD
1145 for singles. 1200 for handicap. 1 1/8 oz loads. Most of your best shooters probably dont shoot over 1145 fps for anything on the concrete. Now for games, thats a different story...but thats for another thread
I've been shooting for forty years and did more than my share of pattern board work.The one thing that I have learned about shell speed is you must put "your shells" through "your barrel" over a chronograph that is the "only" way you will learn the true speed of your reloads or new be's in your barrel.
I have cronographed lots of loads and at my altitude we can shoot 2 grains less for the same speed as listed in the books. No wonder i was getting the kicked. A friend didn't believe me so we took two cronos and his by the book 1200 fps loads were 1325. Now finding the correct powder to work at different temps is a different thing. Low charges of a slow powder will not work well in cold weather. I have found that loads vary from 50 to 80 fps with a spread of 50 degrees. Not a problem if you start with 1250-1300 fps but bad if you start with 1125 fps. Hope this helps, good luck. Joe
You cannot tell the difference between 17.5 gr of Promo (I use that charge weight for 1 oz practice loads in AA hulls and 1-1/8 "target" loads in GM hulls) and 18.5 gr on the targets. You will feel it in recoil.
I suspect, looking at the data, that the difference will be less than 60 fps. Might affect your lead on a hard angle by 3 inches or so. But I miss by a lot more than that - LOL.
18.5 grains Promo in Rem Gun Club, once fired, with CCIM Primer, #7 1/2 and Windjammer wad=1200fpm by the Alliant book and 1289 ave. by the Chronograph.
I shoot in the neighbor hood of 1150 for 16's and doubles and step up to 1200 for Handicap. On a wind calm day 1150 fpm with #7.5 shot is fine for me from long yardage especially when I'm shooting the bird out of the house.