30 cal bore groove

[robbor]

Id like to get an extra barrel for my 300 rum or possible 30/338 lapua. I see some different bore and groove dimensions avail for 308 barrels.
What the recomendation for bullets in the 168-190gr, 3 groove,4, 5,6 groove???
I see a bore listed from brux of .308 and .298 and am thinking it could be beneficial for the big mangum cratridges erosion. I guess the norm is .308 and .300. I dont know if it would be beneficial to go to a smaller groove diam?

 

[Coyboy]

robbor, The 308-298, I believe is mostly for palma guns using the 155 gr palma bullets. 3 grooves were said to have better throat life, due to the wider lands. Not sure if that theory worked out in practice. I don't think it will matter much weather you have a barrel with 4,5, or 6 lands.

 

[KriegerBarrels]

The .298" bore was designed for a bullet with a short bearing surface such as the 155 grain Palma bullets from both Sierra and Berger. If you start pushing heavy bullets with long bearing surfaces through a tight bore, then add the high pressures of one of these cartridges (RUM or Lapua) to it you could spike pressures beyond a safe level. You would be better served with a standard bore/groove (.300/.308) with this combination.

We do not recomend a tight bore for any bullet heavier than a 168, and only in .308 Win or a lighter pressure cartridge.

 

[trueblue]

Stick with the standard bore groove of .300/.308.