300 win mag help please

[Arkrunner]

I have a pre 64 model 70 I'm wanting to have a custom barrel in 300 win mag. Here is my delemia. I'm wanting to use for long range. ie long bullets. 190 smk, 208 a- max. etc. My mag box is 3.390 inch. This is going to limit OAL. Any suggestions for Max OAL and do I just stuff them deep and shoot them.
I've also an oppurtunity for a benchmark barrel that will finish at 26inch but a 1-11 twist. Will this be ok or do I need to go with a faster twist for the longer bullets.
thanks. Elton

 

[Steve Blair]

An 11" twist should be fine up through 220 grain Sierras. As for OAL; you could always single-load them. You might need to remove the bolt to eject a loaded round. An OAL of 3.5-3.6 would put most "heavy" .308 bullets' bearing surface at the neck-shoulder junction.