You can see from above posts I like Enfields and here is picture
of how we set up action for long case and a singlestack magazine.
We open bottom of action for length and use a lip type magazine
insert to feed cases single stack. And lips are springy so we
can load from the top.
Here is the second gun I did years ago in the 585HE, an old style
Ruger 77. And at that time I used the cases I made myself and
they work great in the gun, high pressure loads, and extracted easy.
Here is some math to show why I really like really big bores.
There is term called Average Barrel Pressure, which is the average of
all the pressures in a barrel, from the start where you have highest,
called peak pressure. to the lowest at the muzzle when bullet exits.
For high powered rifles average barrel pressure run 15-18000 psi.
There is a formula that can be used to get Average barrel pressure
fairly close if you know the muzzle energy.
We multiply ME times 12 and divide by barrel cross section x length.
Example a 458Win usually loaded to 5000 ft lbs, say in a 24" bbl.
ABP = ( 5000 ft lbs x 12) divided by (.17 sg in x 24") = 15,000 psi
Now you see there isn't a lot of room for big gains, as it would take
peak pressures damaging to brass and gun, to get say 50% increase.
Now example of 585HE in the 26" bbl we like, say a 7,000 ft lb load,
a real moderate load in this case.
ABP = (7000 ft lb x 12) divided by (.27 sg in x 26") = 12000 psi
The bigger bore allows for a much larger potential,
a 50% gain is easy to do.Ed