338 rum chamber question?


Well-Known Member
Feb 28, 2008
Northern, IN
Does anyone know what the over length a round could be just to the lands, for a normal factory chambering? Or point me in the direction so I can find it? Just trying to figure out if I need any free bore to shoot 300 SMK's with out seating the bullet super deep. This is the caliber I finaly decided on. So I need to get the project going before I cange my mind again.
You should be okay in a custom barrel. We have played with seating depth in a 338 Lapua and the 300SMK is pretty forgiving. It should allow you to seat to pretty much any depth you want. Most guys are loading 92.0 grns of H1000 without issue in factory throats. Consult with your gunsmith or barrel maker and they should be able to adjust accordingly.

contact Dave Kiff @ PT&G and ask hm if he has a reamer setup for the 338 RUM shooting the 300gr SMK and see what the freebore is.
If you are building a rifle with a 27" or shorter barrel, no reason to go with the EDGE. However if 28-30" barrel, definitely build the EDGE with the bigger case capacity.
Also, I think RoyinIdaho shoots the 338 RUM, send him a PM, or maybe he will chime in here.
Thanks guys. But I don't see how the edge, is that much faster? From what I read 2800-28500 is pretty standard. And my sierra loading manual they are getting 2700-2750 for 300 grain smk out of a 26" barrel and I plan on running a 30"
With a 32" Rock Creek barrel on a Savage Target action, we load to 2950 fps with the 300 gr SMK in the 338 RUM case. Can go faster, but we shoot in all temperatures.

To date, using WS2/Danzac coated bullets, this barrel has just over 1000 rounds down the pipe and is still very accurate at extended ranges. This past late season hunt provided two white tails does at 1863 and 1868 yards. Believe this round will go to 2500 yards.
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