Note: This post has been edited to reduce the powder load from H335 25.0 grains to 24.5 grains.200 Yard Tests with my Tikka T3 Lite .223 Remington
On June 20th (Father's Day), I headed out to the range to test my 65 grain Sierra GameKing spitzer boat tail .223 Rem hand loads on steel targets at 200 yards. We had 10-15 mph intermittent head and cross-winds but the Tikka shot great. Best group was 4 shots in 1.20" center to center (0.60 MOA) at 200 yards with 2 shots double-holing. This was consistent with my earlier 100 yard tests, the best of which were .575" ctc 5-shot groups. My second group (the bottom one in the photo below) was 6 shots in just under 2" (1 MOA). However, 3 of those 6 shots were in 1 hole so I was happy. These tests used 25.0 grains of H335 which proved to be too hot because I later found 12 out of 50 cases fired had split necks.
25.0 grains of H335 is not listed as a maximum load in the Sierra manual. Sierra lists a max load at H335 25.6 grains for AR-15's and 26.4 grains for bolt actions. My groups tended to widen as the barrel heats up, typical of a sporter barrel. So I would shoot 3 shots, then allow 2 or 3 minutes for the barrel to cool before shooting the next shot and so forth. (Thanks again for the advice, BgBamboo.) Front bag is a Caldwell TackDriver filled with unscented Jonny Cat kitty litter. My buddy had made some custom rear bags of various sizes using small polypropylene balls for filler so we got to test those too. They worked great, much more accurate than using your fist as a rear support. As luck would have it, one of the guys at the range had an expensive chron set up and invited me to chron my load. I took one shot and muzzle velocity was 3024 fps which confirmed my earlier chron tests of this load. As noted above, however, I had 12 split case necks and slight signs of primer flattening indicating excess pressure. So I don't recommend using 25.0 grains of H335. Top group is 4 shots, bottom group is 6 shots. POI was -1 mildot on 24x at 200 yards with a 100 yard zero. Better -- and safer -- 100 Yard Tests with Reduced Powder Loads
On June 27th, I tested new loads with less powder at 100 yards using 24.0, 24.3, 24.5 and 24.7 grains of H335. My best 4-shot group was 0.415" using 24.5 grains H335 chronned at 2948 fps muzzle velocity. I'm really happy with this load and see no signs of excessive pressure, although it's very accurate. So here's my final load data:Bullet: .224 Sierra GameKing 65 grainPowder: H335 24.5 grainsPrimer: CCI 400Brass: LC once-firedTrim-to: 1.750"COAL: 2.260"
Tikka T3 Lite .223 RemingtonBushnell Elite 4200 6-24x40 mildot side-focus Model 42-6242 on Leupold rings and an EGW picatinny rail.