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Motard
10-17-2015, 08:28 AM
Cause availability resctriction I am stuck on Vhit N130 powder for my Marlin 18,5 inch barrel. I have developed until now good rounds with Lyman 457643, 400 gr mould and Lee 405-457 HB. Both dropping nearly 425/427 gr bulletts with .459 dia wich are perfect for my barrell (.456 sludge, no sizing needed). Average speed varing from 1.440 to 1.560 with 37 up to 38,5 gr of powder.
Now I would start to develop some hotter loads. Lyman 49 Edition Manual reports 21,400 Cup pressure for 41gr of Vhit n130 and 26,200 for 46,5 gr (medium strenght action rifles) and rise 38,700 Cup with 51,0 gr on strongher actions rifles. I am not interested to reach this peack, but would assume that 43-44 gr would jet be safe and handly? Or I am wrong?
PS: with a cast 385 bullet in front of 47,5 gr n130 I had record 1.850 fps, and a HUDGE recoil :(

dubber123
10-17-2015, 08:45 AM
The SAAMI max pressure for the 450 MARLIN is 43,500 Psi. I have never worried about running my Marlin 45-70's to this pressure if I so desired. If you have reliable load data that has been pressure tested, I would feel perfectly safe in working your loads up to the desired level with that data. Have fun ;)

runfiverun
10-17-2015, 11:50 AM
yes the pressure rise should be fairly linear between the two steps.
going from level one to level two using level one's top pressure and level two's bottom pressure means there is a step [or steps] in between that is safe enough for the level two rifles.

Wayne Smith
10-18-2015, 07:55 AM
For what its worth - your shoulder is likely to give out before that rifle does!

Tatume
10-18-2015, 08:58 AM
Just curious, which very old city?

jsizemore
10-18-2015, 09:29 AM
Are you using a chronograph to check speed and estimating pressure from the load data? That will work as long as the barrels are the same length or close enough. Figure 30-60fps/inch of difference.

If your hunting hogs that recoil will vanish.

Motard
10-18-2015, 04:41 PM
the city is Rome. I chrony my loads everytime I change a single component and try to keep record of external temp too intill now did'nt got too bad impact at the shoulder. or at least no more heavvier than a 12 gauge slug. the 12 seems more severe to me



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