I have worked up the following loads for my NEF 45LC/.410:

Using 9.3 X 74R Norma cases blown out to the NEF chamber size(.480").
CCI magnum pistol primers
28.0 gr H4198 (You could get more velocity with more powder but the pattern goes to heck)
A 7/16" diameter overpowder card cut from a plastic milk jug (.410 wads are too small)
A generous tuft of cotton (about a half of a cotton ball)
Ballistic Products .410 shot cup with the petals cut open at the top, seated hard by hand with a 7/16" dowel.
7/8 oz #6 shot with a dipper of BPI buffer.
A 7/16" diameter plastic overshot card sealed with waterglass

The above leaves a 20" tube at 1170 fps and has a usable pattern out to 20-25 yards with the choke tube installed. At best the choke would be classed as "Modified", more like "Imp. Cyl". This load has taken a pheasant and numerous rabbits.

Using blown out Remington, Winchester and surplus .303 British cases.
CCI magnum pistol primers
15.2 gr W296
A 7/16" diameter overpowder card cut from a plastic milk jug (.410 wads are too small)
A pinch of cotton (about a third of a cotton ball)
WAA410HS wad seated lightly by hand with a 7/16" dowel.
1/2 oz #9 shot.
A 7/16" diameter plastic overshot card sealed with waterglass

This makes 1250fps from my gun and is quite effective in breaking clay. The weapon is equipped with a Tasco 1.5 x 4.5 scope. At 1.5 it works pretty well for wing shooting.

I started the exercise in an attempt to improve the consistency of the weapon when used as a rifle. A .45LC case starts the bullet too far away from the rifling to achieve any sort of accuracy. The 3" long 9.3 X 74R case puts the bullet right at the forcing cone. This helps accuracy plus gives a case capacity approximately equal to the 45-110. I call it my 11.4 X 74R.

I have three rifle recipes worked up for this weapon. There is no published data for this cartridge so I started with loads listed for the 45-70 and 45-90 then worked my way up. I am not sure about the upper pressure limit on the gun. I have tried 30,000 psi .45LC loads in the NEF chamber with no ill effect but for safety have tried to stay below 25,000 psi. As always; what is safe for my gun may not be safe in yours so please use caution.

230 gr RNFMJ .451" Midway bulk bullet, 14.8 gr Unique, CCI Large pistol primer 1420 fps. This is a low pressure case forming load. It shoots into 4" at 100 yards and is quite pleasant to shoot. It is more than enough for a rabbit and is cheap to shoot.

300 gr JFP .452" Speer, 62.8 gr IMR4064, CCI Large rifle primer, 2050 fps into 2"@100 yards. Recoil approaches painful in the 6.5 lbs. NEF.

370 gr LFPGC .454" CBT, 46.0 gr H4198, CCI Large rifle primer, 1630 fps into 3" @ 100 yards. Stiff recoil. This load penetrated 24" of wet phone books then opened a ragged 6" hole in a piece of 3/4" plywood at the back of the box when exiting the target. For comparison a 170 gr 30-30 tested on the same target could only manage 14" of penetration into the phone books and never touched the wood.

The Norma cases have 20+ shots out of them. They seem none the worse for wear. I annealed them before I fire formed them. It took about 5 shots to fully expand them to the NEF chamber. I annealed them again after the 5th shot. They have been good since. I use a 45 LC Lee Classic loader to size the neck and crimp the bullets.

The .303 British cases have much fewer loading cycles but seem to be equally impervious to the use. Since I do not use them for rifle loads they may last forever.