Originally Posted by smokepole
I thought you they recomended you seating the bergers close to the lans and that is impossible so what did you do just load it to fit the magizine?Thanks
I know that the 140sbt and sst are very explosive but It makes me mad to shhot a deer behind the shoulder and watch him run off like he has not been hit I I sit there scratchin my head till I go and find a small blood trail and have lost the blood trail till the next day. But I would love to see the big ultra mag put the giant whitetails bucks down as fast as the colt 7mm mag I got with the 7mm winchester 140gr silvertips.
A few observations I have about this discussion...
In a factory Remington 7RUM, the throat is too long to seat a 168-180 Berger at, or into the lands and still have the C.O.L required for magazine length. In fact, the SAMMI spec on the chamber/throat is too long for this, not just Remington. You will also find that loading 168-180 Bergers at, or into the lands on a factory rifle creates a C.O.L that is too long to extract without removing the bolt. A barrel chambered with a reamer cut to reduce the throat length is necessary for proper function.
Initially, you stated that you consider long-range to be 375-400 yards but many deer are at 175 yards. I have no issue with what you consider long-range to be compared to other's view of the subject.
My initial thought in your choice of bullets, distances you are shooting, and resulting lost blood trail is that you need to take into account impact velocity
. I don't know what your muzzle velocities are in order to calculate impact velocity at 175 yards, but given the abilities of the cartridge to produce substantial velocities with the 140gr bullets you have been using, I will assume it is still over 3000fps. At these impact velocities, your bullet most likely isn't staying together long enough to retain energy much less produce complete penetration. This is probably why you are seeing better results with the 7mm rem mag at lower velocities. If you are set on using a bullet in that weight range for the ultra mag, it would serve you well to consider a bullet that does not incorporate a core and jacket such as a Barnes Banded Solid 140gr.
I would suggest you try bullets in the 160+ class and reduce velocities to improve bullet performance at the distances you are typically shooting or switch to a solid.
Just my $.02