got 3" chambered 12ga set up to test loads with RE-17.
Many guys want loads for 3" chambered slug barrels as they
come from the factory., So I put extra 24" Savage barrel I had
on a Mauser GEHA bolt action. Rifled Savage barrel is modern
steel with .93" muzzle diameter. Original barrel on the GEHA
was only .82" at muzzle. I added an extra rear bolt locking lug
onto the Mauser bolt. Using up stuff to make test gun.

Any modern steel slug barrel, whether on bolt, autoloading,
pump, or break action gun with same muzzle diameter will handle
these RE-17 loads. Max loads were all 115gr of RE-17 in plastic
3" cases, all with seals and cushion wads. Can't get no more under
the seals, cushions and slugs in 3". Which is why I like 3.5"
chambers. With 437 gr Brenekkee and 420 gr in BPI sabot got
over 1900. With 520gr Lyman in shot cup 1850. With 600gr Dixie
got 1800. With 870 gr hard lead got 1600. This is 24" barrel,
so longer barrels will get more. In comparison to IMR4227 loads,
these are about the same speed as using 90gr of 4227. But this
powder is so much easier on cases and guns, with about .004"
less base cup expansion. It works great in 3" and really gets the
speed in 3.5" cases, as in 3.5" cases,as seal/wads about same,
extra length for powder. The 870gr load is max peak pressure of
16,000 psi. Muzzle pressure is about 3500-4000 psi.
I'll have pic of the Mauser in few days.ED