New build ideas


Well-Known Member
Oct 4, 2008
SW Montana
I am beginning to realize I may never sell my Sendero for what I have into it so I might as well hang on to it and build something on it when money permits. It's a 7mm RUM.

I'd like something that can shoot a to mile and maintain 1500 lbft of energy as far out as possible, 1500 yards if possible???

I'm sure it's obvious I have no idea what route to go.

I already have a 338 Edge, a 300 Win Mag and a 7 REM mag so those are out. Any thoughts? I will have to keep the 0.532" bolt face and want a repeater with a Wyatt's box if possible. So far a 300 RUM with the 240 SMK's or the 7 RUM again with 200 gr Wildcats (not sure on availability) are my best ideas. An upgrade to a DM system some day would be nice too.

Thanks for any thoughts.
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I think your edge is about the max performance you will get out of that bolt face. If you can get 2850 with a 300 SMK, you should be real close to 1500 ftlbs @ 1500 yds, @ 5000' elevation. But your velocity will be below 1500 fps and hard to tell if it will expand.

With a 300 RUM, I could probably shoot a GS HV 177 @ about 3550, maybe more. Out to 1500 yds, the average BC would be about .62 and get me there with ~1700 fps velocity, ~1130 ftlbs of KE and ~42 lb ft of momentum. In my book, that's OK for a broadside shot in the boiler roon on an elk. The GS bullet expands down to 1600 fps. It would also have about 10% less wind drift and a lot less drop and shorter TOF than the 300 SMK out of the EDGE.

So although the EDGE get downrange with more energy, the RUM with the right bullet gets there with performance. A 177 gr 30 cal bullet that expands will do more damage than a 300 gr 338 cal bullet the pinholes through. Something the think about.

And... Berger is *supposed* to be coming with a higher BC 250 gr and 300 gr bullet in the 338 as well. GS is also developing a LR line of hunting bullets as is another interest in the monometals. These would far out perform the cup and core bullets way down range with a higher BC and a lower performance velocity... if and when they come out.... But they will likely require a minimum twist of 9 or tighter.

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I've considered those GS bullets, I just can't justify the expense.

How fast can the 300 RUM push the 240 SMK with a 28" barrel?

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