J E Custom
Well-Known Member
I have been a fan of the RUM s for quite a while and have been playing with a "Improved"
version (That remains to be seen until all testing and evaluating is done) of the 338/375 Rum.
There have been several people instrumental in helping me coming up with this cartrige so
I dont want to take full credit.
I call it the super because it is all you can do to a 375 RUM case that is practical, moral and
usable to increase powder capacity.
At this writing hear are some of the results and features.
Case capacity (Water) before Final fire forming 115. grains.
Case capacity (Water) 122.3 to 122.5 AVG 122.4. after fire forming.
Case capacity (Retumbo) 118.4 as pored (No drop tube).
Accuracy was very good during break in= 5 shot .381 and after break in= .171 @ 100 yards.
these loads were fire forming and break in loads using the 200 gr Accubond and re 25
(Undisclosed amount) without a chronograph.
Load development will now begin and a chronograph will be used, and will be shot @
extended ranges (200 to 600 yards).
The test rifle is built on a Weatherby Mark 5 action And has a 31" barrel with a Ross Schuler
break.
After more testing I will post the reamer spec. and the brass forming procedure plus the loads
and performance of the round.
I will also post my opinion if it was worth the effort to wild cat the RUM case to this extent
for the amount of improvements in Velocity.
My intent is not to push the cartrige Hard just to see what I can get from SAMMI pressures
and extend the brass life.
I should have the final results within a month (With Christmas and Hunting season being the
reason for the delay).
Even if it does not work out to be practical it has been interesting and a learning experance.
J E CUSTOM
version (That remains to be seen until all testing and evaluating is done) of the 338/375 Rum.
There have been several people instrumental in helping me coming up with this cartrige so
I dont want to take full credit.
I call it the super because it is all you can do to a 375 RUM case that is practical, moral and
usable to increase powder capacity.
At this writing hear are some of the results and features.
Case capacity (Water) before Final fire forming 115. grains.
Case capacity (Water) 122.3 to 122.5 AVG 122.4. after fire forming.
Case capacity (Retumbo) 118.4 as pored (No drop tube).
Accuracy was very good during break in= 5 shot .381 and after break in= .171 @ 100 yards.
these loads were fire forming and break in loads using the 200 gr Accubond and re 25
(Undisclosed amount) without a chronograph.
Load development will now begin and a chronograph will be used, and will be shot @
extended ranges (200 to 600 yards).
The test rifle is built on a Weatherby Mark 5 action And has a 31" barrel with a Ross Schuler
break.
After more testing I will post the reamer spec. and the brass forming procedure plus the loads
and performance of the round.
I will also post my opinion if it was worth the effort to wild cat the RUM case to this extent
for the amount of improvements in Velocity.
My intent is not to push the cartrige Hard just to see what I can get from SAMMI pressures
and extend the brass life.
I should have the final results within a month (With Christmas and Hunting season being the
reason for the delay).
Even if it does not work out to be practical it has been interesting and a learning experance.
J E CUSTOM
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