Re: I need to push a 180g 30cal over 4000fps what are my options
If he runs the 177g GS HV bullets out of his RUM he can get to 3500fps. I am running them out of my 30-338 Lap imp @ 3660fps. That is with a 30" barrel. As far as I know he is not going to get much faster than that.
At .638 bc this will out run the big heavy bullets out past any practical distance for drop and drift.
He will need at least a 10 twist to run this bullet. If he is planning on hunting past 500 yrds 10 twist is just right. If he is hunting under 500 yrds then he would be better served with a 9 twist. This has to do with the bullet tumbling on impact. I have not experienced the bullet tumbling on shorter shots but they say it could happen with out the faster twist. I think that the RUM will run them fast enough with a 10 twist to work at any distance.
4000 fps is fun to think about, but I don't think he is going to make it with out going to smaller calibers. GS Custom built a 22-06 Easling that they are running @ 4700 fps. They hunt Afican game out to 400 yards or so with it, and claim good barrel life using the HV bullets.
My .02, Steve
To hunt... or not to hunt...? What a stupid question.