Is the 270 a good choice?

[Marlin Junky]

I was looking at SAAMI chamber drawings the other day and noticed the 270 is supposed to have what looks like .3" of free-bore; i.e., a diameter of .2783" just after the neck, then tapering slowly (< 1 deg) to .277" in just about .3".

Is this a promising configuration for success with cast boolits? Is this how most 270 chambers are configured?

Thanks,
MJ

[felix]

Adjust freebore to boolit bearing length OUTSIDE of the neck. No more than 0.10? Throat seems fine as is. ... felix

[Marlin Junky]

Adjust freebore to boolit bearing length OUTSIDE of the neck. No more than 0.10? Throat seems fine as is. ... felix

Fine for only really long boolits? Fine for varminting at 200 yards? Fine for what?

MJ

This is what I was looking at. Is this a typical 270 chamber?

[Marlin Junky]

Would the 280 be more "cast friendly"? It's a little less of the same kind of configuration as the 270... more like the '06 actually. Looks like it's gonna need .286" boolits though which will probably require custom sizing dies (and possibly molds) to achieve the best accuracy.

MJ