Optimum chamber for 300 RUM with 245 berger

richhymas

Well-Known Member
Joined
Mar 3, 2012
Messages
85
I am a bit of a novice when it comes to having a custom rifle built and I have a design question. How do I determine the optimum OAL for a given bullet? Specifically, what is the optimum maximum OAL for a 300 RUM and 245 grain Berger? I think I want my bullet to just touch the lands at the maximum optimal length, so that I can work up a load with maximum powder capacity in the case. I do still need it to fit in the magazine but I do have an extended length magazine. I am having a bit of a hard time putting my question into words but hopefully that makes sense.
 

700Sendero

Active Member
Joined
Apr 25, 2014
Messages
42
You will probably be held back by your mag length, assuming it is a 4.0 box. I don’t have any experience with the 245 but I’m guessing you would be better suited single feeding those babies. I single feed mine with 215s and it’s a hammer. Good luck!
 

Wedgy

Well-Known Member
Joined
Feb 9, 2013
Messages
2,085
I run the Wyatt's 4" mag box(CFE9) but do not feed from it when shooting as recoil can deform the tips and in a friends case change the seating depth if you run light neck tension. Keep the mag loaded for bears then single feed when hunting. Your mag may not have these issues but they are definitely something to check.
 

richhymas

Well-Known Member
Joined
Mar 3, 2012
Messages
85
I run the Wyatt's 4" mag box(CFE9) but do not feed from it when shooting as recoil can deform the tips and in a friends case change the seating depth if you run light neck tension. Keep the mag loaded for bears then single feed when hunting. Your mag may not have these issues but they are definitely something to check.
I shoot with a 9” Thunder Beast suppressor and typically have 1-2 thousands neck tension so I doubt I will have recoil mag issues. I want to feel comfortable shooting from the magazine so I will keep an eye on it. I tried single feeding while hunting and I hated it. One more thing to worry about.
 

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