7RUM Build reamer and freebore

[7RUMER]

I am Working on building a 7Rum to shoot the 195 EOL Berger's. Having a custom 8.3 twist barrel built and a custom reamer. My plan was to build the reamer to fit a dummy round with the 195 that has a COAL that would fit in the mag and allow me to touch the lands by shortening the throat. I know this has been said to cause some pressure signs earlier. Have any of you build a 7 RUM without the freebore like this and if so how did it work?

 

[dok7mm]

Based on my experience, you do not want to be anywhere near the lands with a 7 RUM. It looks like the standard freebore of .300" - .500" is crazy, but with this round, you need it to control the huge pressure spikes you can easily run into. I would consult several competent smiths familiar with the 7 RUM, PRIOR to going shorter than .300" freebore on your reamer. I found the Berger Classics and Hybrids to take the long jump very well.

 

[BRIT]

Hi.
The following link may be of use. Interesting forum and Nathan generally answers emails with very good advice.
7mm Remington Ultra Magnum

Brit.

 

[coyotezapper]

All with 26" Krieger BBL. BBL is throated for 180 Berger VLD's .060" freebore

180 Berger VLD 91.2 grs Retumbo 3160 fps - shoots in the .4's
190 Matrix VLD 89 grs Retumbo 3075 fps - shoots in the .2's when I am on

IMO I would shoot nothing below 168 gr bullets. My STW would shoot 140's faster than my first RUM with less powder.