175gr. Nosler Partitions are routinly loaded past 3000 fps in the big 7. I hit 3100 eaisly and safely in a 24 inch tube....
69.6 of RS Magnum. The 3000fps mark can also be hit with 64.5 of IMR 7828. These are hot loads so work up to them of course, but like i said...no presure signs what so ever in my ruger. A slightly hoter load yet is 66.8 of Reloder 25. The idea of hitting the 3000fps mark in the 7 mag is not a new or novel idea. I have read of it in many a book, and have seen it done many a time. I personaly dont shoot the 175gr. loads very often as i dont hunt big bears, but i have loaded and shot a decent ammount of them just for the fun of it.
Mr Joe -
From your previous posts, you are making the following claims regarding the 7mm Rem Mag:
1. "175gr. Nosler Partitions are routinly loaded past 3000 fps".
2. You "hit 3100 eaisly and safely in a 24 inch tube...."
3. 69.6g RS Magnum will do it.
4. 64.5g IMR 7828 will do it.
5. 66.8g Reloder 25 will do it.
Here's a reality check:
1. The 7mm Rem Mag has a SAAMI limit of 61,000 PSI.
2. From a 24" tube, with 175g Partitions:
* 70.1g RS Magnum = 2852fps @ 58,200PSI (Fed 215 primer, Source =
www.ramshot.com)
* 61.0g IMR 7828 = 2702fps @ 58,300PSI (Source =
www.hodgdon.com)
* 65.8g Reloder 25 = 2873fps @ 58,100PSI (Fed 215 primer, Source =
www.alliantpowder.com)
All of these loads are considerably under 3000fps and much further under 3100fps.
Let's look at the IMR 7828 load...
From the Hodgdon 2007 Annual Manual:
Case: Winchester
Primer: Winchester LR
Barrel: 24"
Bullet: 175g Nosler Partition
57.0g IMR 7828 = 2549fps @ 49,800 PSI
61.0g IMR 7828 = 2707fps @ 58,300 PSI
So 4.0g more powder gains gains 158fps at the cost of an additional 8,500 PSI. In a linear world, another 4.0g, or 65.0g total, would yield 2865fps at a pressure of 66,800 PSI. In a linear world, you would need around 69.0g IMR 7828 for a velocity of 3023fps. Pressure would be in the neighborhood of 75,300 PSI.
But this is not a linear world. At top pressure levels, pressure tends to increase in a non-linear manner as additional powder is used. In other words, you suggested 64.5g IMR 7828 is probably well above 66,800 PSI - especially if 3,000fps is really being achieved.
In the real world:
1. Your RS Magnum load is below maximum most likely well below 3,000fps, even given normal gun-to-gun variances.
2. Your IMR 7828 load is 3.5g above maximum, probably dangerously so, and probably still well below 3,000fps.
3. Your Reloder 25 load is 1.0g above maximum and probably still well below 3,000fps.