ASSCLOWN & Others,

Still practicing PRE on other guns before I get back to 3030AI. 7-08/Rem700 because there is factory ammo and more data available and I know it very well. 30Gibbs/MarkX(commercial 98) because of its strength and I need to pin down my Elk loads soon.

With the Gibbs I am trying to get a better idea of where I am with pressures of loads I have developed or am developing. If it is not too much trouble and you have 30Gibbs on your computer, I would like to get an idea of where a couple of loads are pressure wise. Could you or anyone else see what pressures the computer kicks out for 30Gibbs 180XLC/61.5grH414, 165XLC/61.5grH380, 165XLC/64.5grH414? I suspect the H380 load is well into the red zone, but no primer/case failure that I have detected in the MarkX. I suspect that the two H414 loads are close to same pressure (the 180XLC has a proven case life of 10+ firings, etc.). BTW, it is very important to note that my Gibbs shoulder is about .005" further back (shorter) giving it a little less volume than the Gibbs specs I found on accu-load.

Thanks,
Deke.

Deke,



Here is what I came up with for your 30 Gibbs loads.



First off I am using a case volume of 70.1 grains of water. This is based off of R-P brass which typically runs close to Winchester, but a couple grains smaller than S-B.



Load #1

165 gr Barnes XLC

64.5 grains of H414

Muzzle velocity ~ 3170 fps

Chamber pressure ~ 67,800 psi

PRE should measure ~ 0.001" for a large ring Mauser (actual result was 0.00103")



Load #2

165 gr Barnes XLC

61.5 grains of H380

Muzzle velocity ~ 3071 fps

Chamber pressure ~ 66,500 psi

PRE should measure ~ 0.001" for large ring Mauser (actual result was 0.00101")



Load #3

180 gr Barnes XLC

61.5 grains of H414

Muzzle velocity ~ 2960 fps

Chamber pressure ~ 65,700 psi

PRE should measure ~ 0.001" for a large ring Mauser (actual result was 0.00100")



I would say they are a tad hot by SAAMI standards. Not surprised though that you aren't seeing any traditional pressure signs. I am also not surprised that you can get 10+ reloads from the brass.



ASS_CLOWN



EDIT - caught a mistake in the analysis, the correction are in bold face.

ASSCLOWN,

I'm impressed!

The chronographed velocities were all within 0-50fps. The only difference that I found was that the H380 PRE was .0003" more than the H414 loads (don't know if it makes up the difference, but the H380 loads were fired on a sunnier day that was 20o warmer..)

I do use R-P brass, but I fireform from 280Rem to 30Gibbs. Do you know if the internal of the 280 (or 270 for that matter) are any different than 30-06 brass (I know that 270 SAAMI specs are approx 6,000psi higher than the 30-06 with the 280 being somewhere inbetween)?

Ken Waters notes a max PRE of .0015" for a modern bolt. In your computers estimation, what would be the max H414 (I think the H380 may be too temp sensitive) loads for the 165 and 180 loads that would either produce a PRE of .0015" or give me less than 10 firing case life (don't worry, I will use the info as a reference, not the gospel)?

Thanks for your help,
Deke.