Puma + RD 240 +True Blue + Bad Shooter = Fun!

[mikld]

Shot some reloads in my Puma yesterday. RD 240 cast from wheel weights, .432" and alox dipped ala Ranch Dog, over 11.1 True Blue (starting load). Shot OK as I was working on new sights too. I had installed a Williams receiver sight and higher front sight and was still "sighting in". I was getting 6" groups at 35 yds., my fault I'm sure. I'll up to 11.5 or 12.0 gr. and see if any improovement. I know I need a lot more practice with my Puma; it's hard to work up a good load when you're a terrible shot!

[Ranch Dog]

Hmmm, that's not good. I suspect you need to put more pressure behind the bullet. The 11.1 grain load is only 22.0 KPSI. Max load of True Blue is 14.0 grains for 1560 FPS at 35.7 KPSI. A lot of what goes on with the bullet depends on the alloy and its treatment. What are you using?

[mikld]

Air cooled wheel weight alloy (semi-mystery metal ). Ramshot's recommendation start load is where I started. I chose lead bullet data even though thr RD 240s are gas checked. I'll go to 12.0 (Ramshot shows 12.8 as max.) and see what happens from there. I may go even higher but if a lighter than max. shoots good, I'll stay there. 1,000 fps kills paper and dirt clods just as dead as 1,400 fps.

[Ranch Dog]

1,000 fps kills paper and dirt clods just as dead as 1,400 fps.

I understand but there are other considerations in play as well. With Rossi's choice of a 1:30 twist barrel, the TLC432-240-RF will become unstable at 950 FPS. Better than Marlin's choice of 1:38 which raises it to 1525! That is why I say push the 44 Mags hard for accuracy with any bullet. Of course, it all depends on what you are looking for out of the rifle.

[mikld]

A 240 gr. bullet becomes unstable at 950 fps in a 1-30 barrel? That seems to be Special velocities, not Magnum (not doubting you/your info Michael). So for better accuracy would a velocity of 900-950 fps be better? Don't have a chrony so I can only guess at velocities...

Second thought; Or does the instability come as the bullet drops below 950 fps?

[Ranch Dog]

Second thought; Or does the instability come as the bullet drops below 950 fps?

This is the correct thought.

[mikld]

Excellent! This adds a new aspect on reloading/barrel twist/bullet stability vs velocity for me. I understood bullet length/weight and rifling twist as far as bullet stabilitty, but now I have added velocity to the equation. If you don't mind, how is the velocity/stability point found? Thanks for all the info...

[Ranch Dog]

If you don't mind, how is the velocity/stability point found? Thanks for all the info...

Calculators in any reloading software. There are numerous online calculations, here is the TMT product, his page shows the math in the calculator. TMT's reloading software is top notch as well.

[mikld]

Thanks for all your help Michael. I'm still working on that bullet/length/velocity/stability stuff, but in the meanwhile I loaded up some 240s with 12.5 True Blue and a few with 21.0 gr 2400. It'll be a while before I can shoot them and we'll see if there's an improvement...

Mike