I have factory barrelled Model 700 in 7mm RM that I would like to optimize for some of the modern hunting bullets like the Barnes TSX or the Nosler Accubond. Using the ole stoney point gage with the 140 TSX it touches the lands at a COAL of 3.275". Seating the bullet for a .050" jump to the lands puts the bullet deep, and the case mouth ends up aligned over the first of the relief grooves in the TSX. I don't like that very much and it is eating up case volume. If I seat the bullet long so that only the boat tail is seated beyond the neck base in the powder room, the case mouth lands on the bullet "land" aft of the second groove which is much better. But this does lengthen the round to 3.365" COAL. However it looks suitably rugged enough for a hunting round and it fits the mag and action without issues.
To accommodate the additional cartridge length I will need to ream .090" plus whatever freebore "jump" is required. I have a throat reamer coming.... What could possibly go wrong?
Questions for those that have done this before...
- Do these numbers sound like reasonable objectives if I'm committed to handloads?
- Do I explore what amount of freebore jump the rifle likes with that bullet now (before lengthening the throat) and then add that to the .090" and use that for the reaming target depth?
- How much will seating the bullet .140" farther out of the case effect the internal ballistics and propellant charge requirements/limits?
