QuickLOAD shows 110% load density charges of Norma MRP giving higher velocity than other powders @ reduced pressure levels in 8X68S with 23 1/2" barrel.

Is it feasible to get that much powder in with methods availible to the average reloader, and if so, what happens to actual pressures with loads compressed that much?

I can draw a parallel to black powder wich is my speciallity: When you start to compress BP the burning process changes. When less than 100% is in the case, then all cernels of powder ignites at once from the outside, and burn. When more than 100% is present, then powder is compressed and burning differs. Now the burning "starts" at the back of the case, and only travels forward trough the space between the compacted cernals. Therefore burning starts slower than normal.
A benefit is more uniform ignition! Hold two matches 1/16" apart and strike one. Now hold them so the heads touch and strike one. See the difference?
A parallel to BP again:
Measure the powder in a suitable container and pour it down trough a 20-30" tube with a funnel on top. The pouring should take something like 8-15 secs. The cernels compact and filling more than 100% is possible.

Hope i helped in some small manner.
Have fun and shoot safe.

I don't know how much MRP one can get into an 8X68 case. But I used to load MRP in the 7X57, and I could get at least 4 or 5 grains weight more of it into a 7X57 case than H4831 or IMR 4350, because it has smaller grains which seem to be more dense than those of other powders. I used to use 54 grains of MRP with a 175 grain Nosler Partition bullet, which produced 2720 FPS MVa I now use the same charge of RE 22, and it gives the same MV, but is more heavily compressed than MRP was in the same weight. However, the MRP load geve higher pressure signs than a like wight of RE 22, while both were producing identical muzzle velocities. The RE 22 load gives no worse pressure indications than factory 7X57mm ammo. I could load it even hotter, but can't get any more of it into a case!!

My loading software shows 100% density loads of Norma MRP to be @ the mid 40k and upper 40K range with .323 Nosler 180 B.T. and 200 Par. respectively. Velocities are also modest (both bullets around 2870fps)

When load densities get to about 109% for the 180 and 105% for the 200 that this powder realy starts to out perform the others (3150fps with the 180, 3000fps with the 200) @ theoretical pressure of around 60kpsi.

Of course this is theoretical of course, hence the desire for some real world feedback on how this powder reacts when compressed.

According to the computer model Norma MRP would be hard to overload in this case. The limiting factor would be "How much can ya git inner"

Loading to the max CIP pressure of 63816psi would add about 50fps to either load, but the theoretical performance of the 60kpsi loads would do just fine thank you.

[ 04-26-2003, 23:02: Message edited by: wildcat junkie ]