My steel target load for the last few years in a 10" 30 herret has been Hornady 150gr spire point in front of 21.5 gr of H-4227. Well this weekend I finished up the last of my supply of 150gr bullets and the last of my H-4227

Since H-4227 is no longer available it looks like I'm going to have to work up a new load. Rooting around in my bullet locker I found a relatively large supply of 180gr Sierras. It got me thinking. What about taking the 30 whisper retro and shoot some heavy slow bullets out of the Herrett. Anybody ever try it? I know it would hurt the trajectory but for woods walk course where most shots are under 150 yards they should work fine.

You are going to have to run those 180's pretty stiff to get them well stabilized from the 10" Herrett. My concern is that they would be on the edge of becoming unstable and not provide the accuracy you desire. Tried it with a 32-20 several years ago and got a bunch of keyholes...but it has much less capacity than the Herrett.

The Whisper gets away with the heavy bullets and low velocity by putting a ton of spin on them before exiting the muzzle. Typical Whisper twist is 1 in 7". Your 10" Herrett will be 1 in 10".

If you can get then to 1500fps, they will stay supersoinc to about 350yds...well beyond your needs. From a 100yd zero you will have about +1.2" @ 50yds and -6" @ 150yds.

No more H4227....HUH??!

can only get IMR4227.....H brand has been discontinued.

That's correct no more H-4227 for now. When Hodgdon bought out the IMR powder line they saw having two 4227's as redundant and dropped the h-4227. I have been looking at gunshows and small shops for several months to try and find some old stock but with no luck. I have loads for the 30 Herrett and the 35 Herrett that I used H-4227 in. Looks like I'll be doing some more load development work. Although they are similiar in burn rate they are not the same. I have seen a rumor on the net suggesting that they may return it to the line but the cans are to be clearly marked "Made in Australia" and contents will be the familiar greenisth color. IMR 4227 is grey.

As for barrel twist in the Herrett, I'm not positive but I believe my barrel may be 1 in 8" twist. I believe when I did my original research on the 30 Herrett that there were different twist rates out there depending on the age of the barrel. Based on my calculations I believe I may be able to get close to that 1500 fps your talking about Dan.
I won't have a chance to get to the loads for a couple more weeks as I'm traveling on business but I'll post results when I get them.