I have a 7mm Rem Mag Ruger No.1 with quite a long throat.

The barrel is 26 inchs.

I am trying to work up a load with Retumbo and 160gr Accubonds.

I measured the OAL length using the bullet jam into the lands technique and the average came out to 3.520.

Should I start at 3.505 or 3.490?

Will I get more velocity closer to the lands or further away?

I know that pressure will rise sooner the closer I am to the lands.

Anyone have any experience on long throat chambers and if MORE distance to the lands increases velocity?

I am hoping to achieve 2950-3000 fps without pressure signs(of course with MOA accuracy). I know Retumbo would be better with heavier bullets but I wanted to give it a try anyways. I have tried H-1000 in the past but had trouble getting over 2900 fps without getting pressure signs. I also have some RL-22 but haven't tried it yet because of its "rumored" temp sensitivity.

Its a single shot.Put the boolit right in the lands.Start with a low charge and work up.

quote:

Originally posted by OLBIKER:
Its a single shot.Put the boolit right in the lands.Start with a low charge and work up.

I agree!

quote:

Its a single shot.Put the boolit right in the lands.Start with a low charge and work up.

That is the best way to do it. That is how I load all my #1 rugers and three other single shots.

I think you will find the #1 sensitive to oal. A 7mag I had did not like any bullets less than 160g and I believe it was due to the fact that it liked a longer oal. My 6.5 x 300 is more sensitive than a liberal a/b oal and will not group up to it's potential unless the bullets are seated to a specific oal. Just work w/ the oal til you find the one it likes. Good luck.

70 gr IMR-7828ssc 20 thou off the lands with 160 Sierra GK HP was the most accurate load in my #1.Was because I re-barreled it to 6.5 WSM