Based on this limited initial test, RL-26 works really well.
Alliant's maximum listed loads for different 150-grain bullets vary from 60.2 to 60.8 grains, with ALL muzzle velocities above 3000 fps from a 24" test barrel. I decided to start with the Hornady Interlock Spire Point, partly because they're usually very accurate, and partly because I have a bunch. I loaded up one round with 59.0 grains, then four each with 60.0, 61.0 and 62.0, guessing the bullets would have to be pulled from the 62.0 loads.
The test rifle was my O'Connor Commemorative Model 70 Featherweight with a 22" barrel. It's been very accurate ever since the first 100-yard group was fired two years ago.
The 59.0 grain load chronographed 2936, and I could have lifted the bolt handle with my little finger. In fact, there wasn't any hint of excess pressure with any of the loads, and all the fired cases looked identical.
The average velocities from the other powder charges:
60--2949
61--3011
62--3084
The chronograph was set up 15 feet from the muzzle, and another 15 fps would result in a close approximation of muzzle velocity.
I only fired 3-shot groups with 60 and 61 grains, due to adjusting the scope between groups. Those groups measured .45 and .76 inch. The 4-shot group with 62 grains measured 1.15 inches, but was strung horizontally, probably due to the quartering headwind kicking up a little. The first three shots were under 3/4 inch.
I used brand-new Winchester brass and CCI 200 primers. Next I'm going to see how 26 does with 150 Partitions, with fired brass.
