Loaded for 7,5 Swedish Nagant Officers Model revolver using 32-20 cases and pure lead bullets, either 0,314" HBWC or 0,316" 32-20 bullets. I used full length 32-20 cases and seated bullets deep enough to allow cylinder to turn. Used 0,320" 0,060 fiber wads under solid base bullets but not under HBWC (which expanded to 0,321" bore). Powder was 2F 777. Best groups were from 0,314 HBWC, good enough to reliably plink empty shotshells at 15 paces.

IF your rifle has a smooth chamber, like that in 7,5 Swedish Nagant revolver cylinders, perhaps you can use full-length 32-20 cases as I did. I never had a supply of healed bullets so using standard length 7,5 Nagant cases was not possible.

What Gert said, plus: the case rim is thinner on the 310 than it is on the 32-20, however BSA did not control the chamber reamer very well and as a result some rifles need the rim thinned down and some do not. These latter will have a longer than standard chamber and it is worth making the cases longer to suit.
As for plinking at empty shotgun shells, I would be impressed if this was at 100 yds with a 310 Cadet.
Fred

Once you get your brass to fit, fireform it, and use the correct bullet from this mould:

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I use Linotype.

Tumble lube, thumb seat in charged case (I use 4.6grs Universal Clays) and fire for effect.

This load/method gives me 2" (+/-) @ 100yds with iron (peep) sights in my rifle.

I tried other " non Cadet " bullets, pretty much a waste of time.

If you would like to try some of the RCBS bullets, I'd be happy to make a donation.

Fred Boulton wrote on Feb 17^th, 2018 at 5:32am:


That was at 15 paces with Swedish 7,5 Nagant revolver. I cannot even see a shotgun shell at 100M!!

I believe that if your rifle will close with a 32/20 case in the chamber, that you have a head spacing problem. Proper 310 Cadet brass has a much thinner rim than 32/20 brass. I bought my first Martini Cadet in 1958 and all the Dealer had was Sako 32/20  loaded ammo, which chambered, but at that time I was unaware of "head spacing" so happily shot it with no problems. Enjoy your rifle.

FWIW
No cadet is in any real specs after 100yrs and people playing with them.
Mine slugs at 0.324-5" and starline brass is a bit thin on the neck for the 0.315 heel of the rbcs mould.
I made my brass firstly by using a tapered reamer in an old bit of drilled out pipe so as the shoulder of the 32-20 brass gets swaged down so it conforms the the cadet chamber somewhat.
Now I use an old cut down barrel chamber with the rim ground off enough so as the case gets sized.
I breach seat with a plugged case and something like 2.8 grns bulleye and a wad 1-200 thou off the powder.
I was getting less than an honest inch at 50yrds but soldered a washer on the rear sight so I can see the target with out so much fuzziness.
Haven't tested it since.
I did make up a re-decapper just for it.
A 32-20 'ol pliers type loader could be interesting with a little work.
I do just thumb seat with longer cases. But breach seating seems the best accuracy.
I cut my rims down with a hacksaw blade with the cases in a drill chuck.
Chamber cast and bore slugs should reveal all.
I bought some bertrum brass but its too short for my chamber to thumb seat with the step on the mouth end but it holds the rcb bullet firmly once fire formed.
It may be a little too close a fit 
Hope it helps.