Originally posted by lrgrendel
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If you are single loading, drop or push the cartridge into the chamber and let the bolt go forward. Has been done that way for years in High Power. That's how we get the bullet seated out farther.
At those distances it is a good idea to have the OAL as long as possible so there is as little jump as possible. You won't get enough more powder into a Grendel by doing this to make a difference but you will get better performance. In fact, there is nothing wrong with having the ogive just touch or just off the rifling. You won't get the huge pressure spikes you would if you jammed it into the rifling.
As to reality and ballistics programs read outs. The chronographs may be off quite a bit from a real velocity for a number of reasons. I suggest you take the mean velocities and understand that a real velocity could well be 50 fps greater or less than what the chrono is reading. I would pay attention to the SD read outs. Yours are way, way to high for performance at distances past about 300. You want a SD to be under 15 and ideally under 10. If your load is showing a SD of more than 10 or 15, you need to change something and get it lower. And remember that ballistics programs assume perfection in everything. If your bullet is nutating or precessing too much at those differences, you will have a bad time and never get it straightened out.
Depending on the precession or nutation of your bullet, at these slow speeds, at 1000 yards, in a transonic zone, my bet is that the bullet design itself may not be maintaining stability. May shoot fine at 600 but not so at farther distances.
Having been there and done that, my advice is for you to try bullet with more of a secant (conventional) ogive such as the hybrid 108 or 123 Lapua, seated just off the lands, and see how it does. If that doesn't seem to be on par with the .308's of your buddies, try a 140 or 142 Sierra Match King. It should have an easier time in a transonic zone. Do not try a 120 Sierra as you will never get it there even close to the speed of sound with a 30 grain cartridge. Sure, a ballistics program may say something else but it won't make it there with a 30 grain cartridge.
LR1955
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