Hey is it true?…MC Hammer has a long lost son named Sherman Hammer? 
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Berger 245 EOL Best Cartridge
- Thread starter treillw
- Start date
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Yes my 300 RUM, 338 Edge and 375 RUM have suitable throats…
.245"
.250"
And .300"
.245"
.250"
And .300"
codyadams
Well-Known Member
Um......a 300 win mag is only 1 fps slower than a rum? With 16+ grains of capacity difference?
Sum ting wong.
MallardAddict
Well-Known Member
I've never heard of the 245 Berger over 3k breathing easy. Maybe I need a Sherman. 
(230 on the far right for reference)
(230 on the far right for reference)
jpndave
Well-Known Member
I agree but that is what it is putting out. 96.6% fill, 88.1gr VVN570, 2830. It doesn't track, the RUM should be on the top of the list. Anybody got real world on that one? Shows case volume at 112.5gr H2O. COAL at 3.598
elkaholic
Well-Known Member
Likely because the FB is way too short!
Thats woefully short coal with a 245 Berger unless its being jumped a loooon way! Thats why people who say capacity is everything, shape is nothing, etc are dead wrong!
That might be true with the pressure being equal for all of them, but if I'm understanding correctly, they all have different allowable pressure??
Doesn't shooting them all at the same pressure kind of defeat the purpose of different cartridges?
elkaholic
Well-Known Member
In this case, the rum should be faster, even though it isnt as efficient as some others. The most likely culprit, In my opinion, is the free bore being waaaay short! The 245 is a loooong bullet and if there is not enough FB, your bullet is taking up a lot of case capacity! This essentially reduces USEABLE capacity which in reality is the volume left behind the bullet when its touching the lands. A too tight throat diameter can cause early pressure as well as a lot of other things, but thats not likely in this case. The coal makes it sound like a VERY short FB which is like cutting capacity a few grains. But what do I know. Im trying to defend the rum and still get reamed by the EXPERTS!
You guys need to cheer up.
Life is good!
codyadams
Well-Known Member
Most people I see running a 245 in a 300 rum are running it WAAAAAYYY longer than that, like .3ish longer ha ha. That would likely make a significant difference. What did it list the OAL of the win mag, out of curiosity?
elkaholic
Well-Known Member
I just checked a saami rum and like I said, its way too short to take advantage of the case. Its .110" and should be at least 220" if not more for that bullet!
MallardAddict
Well-Known Member
Yep, I don't know of anyone running a rum set up for long range without something like a Wyatt's box and complementary throating.
Last edited:
3.9"+
Running a 26" 300 Win Mag 215 Berger OTMs seated .010 off the lands 2860fps. If you throat the Win Mag long and add a fast twist barrel you should nearly match the PRC within 100 fps. My rifle is a Sako with a 1/11 twist. The 220s are all it will stabilize. We single feed it the Bergers and Flatliners. 198 grain flatliners @ 3000 fps.
The Win Mag case is highly efficient and very similar to the PRC with the exception of the belt. If you throat it like a PRC and run a fast twist barrel ballistics should be within 100 fps or less of each other. Remember the 300 win mag case is basically an Ackleyed 300 H&H, highly efficient and accurate.
That said, I stand by my original recommendation. A 300 RUM is hard to beat in a 30 cal for long range hunting and if I were going to build a new 30 cal, especially if the availability of factory ammo was a consideration, that is the route I would go. JMO
