Some 25 years ago I acquired a 310 Martini Cadet that had been converted to a 32 Winchester Special. 
I fired maybe 3-4 rounds of factory ammunition at which point I realized something was terribly wrong. Not only did it not hit the inside of the barn I was in but the pressures were stupid high.

Roll the clock forward to today, it is time to make it a plinker / shooter with reduced loads. 

Slugging the barrel; the Bore / Groove is .311 / .316.?. At any rate it is obvious that the factory jacketed bullets at .321 was at least part of the problem. 

So here are two questions I hope someone will comment on;
I found 100 new Hornady 30-30 brass cases which I want to modify to 32 Winchester Special. Given their dimensions are so close it should be a no brain-er. 
 
1,   Should I Fire Form to Fit or just modify with the 32 Win Sp dies ?
2,   Should I anneal the cases first..?

After casting the chamber it is apparent that the reamer used during the conversion process was .025 longer than SAAMI spec.
And there is basically no freebore in the bore or leade from chamber mouth into the rifling.
I guess I could trim my brass to 2.040 (SAAMI spec) and use the excess chamber length as my freebore... ???

Finding a bullet has been somewhat of a rabbit hunt. 
The twist is 1/20. Necessitating a bullet of no more than .74" using the Greenhill formula. 
 
I could have a mould made utilizing a healed design like the original 310 Cadet or perhaps a design using a stop ring like the 8.14 X 46R [180 gr, RN--.915"] (Buffalo Arms) shortened for my twist.  Unfortunately this design has a stop ring of .326 which I don't know if my groove of .316 just couldn't handle that..?

One last observation;
In your opinion is the groove depth of .0025 enough to grip 1/20 lead projectile. Seems a might shallow to me. Thoughts?

So before I spend $$$ on a mould I thought others might have some experience with such issues.

Thanks to all in advance. 

RJ in St Augustine

Marlin Guy,

Thanks for the referral and the recommendation 

I'll take a look at the Western bullets
although I think the 165 grain projectile is going to be unstable in my 20 twist rifle.
Thanks again
RJ

Are you sure the groove is 0.316" they do vary.
The 5 groove can be hard to measure.
Just saying before you go off and buy stuff.

The way I read it is you are wondering about using a 0.335"?? case neck diameter bullet base with a 0.311" nose of about 120 grns. 

I have no idea if it would work in a chamber if it has no chamfer to it at all.
Starline make the longer 38/55 brass that may help some.
Just putting it out there.