Q: I want to develop some reduced loads for my .223 Remington and .243 Winchester rifles using Trail Boss powder. Lightening the recoil and limiting their range, these loads will be more pleasant for my kids to use plinking tin cans and for rabbit shooting. Can you give me a load for the .223 with 45gn bullets that duplicates the .22 WRM and one for the .243 with the 87gn Hornady?
A: The great thing about using Trail Boss for reduced loads is that you can’t really load enough of it into the case to be dangerous. With Trail Boss, fill the case to where the base of a seated bullet would be, then weigh the charge and regard that as a maximum load. Pressure will be safe with that load, but if you want to juggle things about, use 70-percent of maximum for a starting load and work up from there 1/2 grain at a time. The .223Remington case holds 8.5 grains, so 6 grains is the 70- percent starting load. In my Sako this not only proved accurate but also duplicated .22 Magnum ballistics. In the .243 Winchester, follow the same procedure, but in the larger case, start with 75 percent of the charge, and load 9, 10 and 11 grains behind the Hornady 87gn bullet. Groups should tighten up as the charge is increased and a reader reported getting 3-shot groups at 100 yd. measuring 3/4 MoA. Between 9 and 11gn of Trail Boss velocity increased by 140-foot-seconds from 1352 fps to 1492fps.