What alloy for 310 Cadet?

[Craiger1987]

I'm new to casting (as in I've never cast a bullet before) but am good not to get into it for a specific round to start with. I have a BSA Martini Cadet in the original .310 Cadet caliber. It fires a 120 grain lead heeled bullet at about 1,300fps. I make my own brass for it and have been using the bullets from BACO made in an RCBS 310-120 mound and they cast it from 20-1 alloy, considerably softer than I'm used to in lead bullets. I lube them with Lee Liquid Alox and have noticed that after a few rounds there are considerable lead deposits in the throat and first couple inches of the bore. I'm thinking the lead may be a bit soft for the application. I was wondering what alloy I should be using to make bullets when I do, the midway hardball (16bn)or maybe lineotype (22bn)?

[waco]

No need to go that hard. Hard alloys sometimes lead worse than a softer alloy. Fit is everything. Have you slugged the bore? Size your boolits .001" larger than your groove diameter. Straight clip on wheel weights(coww) will work just fine I would think.

I'm sure others will chime in soon.

Welcome to Cast Boolits!

[Craiger1987]

I haven't slugged the bore yet no, never done that before either lol. Hopefully it's not over size b cause there are select few moulds available for that round and all chuck bullets between .321 and .323. The only issue there may be, for me anyway, in slugging the bore is that it's a five groove barrel and from what I understand you need offset calipers to measure that?

[curator]

Craiger1897:

I found air-cooled clip-on wheel weight alloy (about BHN 12) to work best with my .310 Cadet rifles. I too use Lee Liquid Alox as lube with no leading. Have you slugged the bore? With the Cadet, you can also measure the outside diameter of the case mouth to find the proper diameter for the forward part of your bullet. Your RCBS bullet mould may be a bit under size, as most leading is caused by gas-leaks around the bullet rather than bore friction. I am using a CBE bullet mould that casts at. 311/323 heel/nose diameter. You could also try a card wad or wax wad under the bullet to assist with the gas-seal. My recovered bullets show fully formed rifling marks all the was to the base of the bullet, and no evidence of gas cutting. My load is 4.5 grains of Unique and velocity right around 1250 fps.

[Craiger1987]

Yeah the loads I tried 4.5 gr of Unique to perform the best. I tried to measure the case mouth (tapered so a bit difficult lol) once it measured .3235 and usually around the .325 mark but that could be me trying to get as close to the mouth as possible and not quite getting it seeing as it's tapered. I may have to pick up one of those CBE moulds, I've heard they're the best, I'll have to measure one of the RCBS bullets to see what diam they are.

[JeffinNZ]

I use exclusively 40-1 alloy and CBE moulds with great results. That alloy is approx. 7.8 BHN. Your harder alloys will not slug up the heel. 5gr of Unique works best for me.

[Craiger1987]

Wish I had brought a bullet to work with me now so I cI'm you measure it. From what I've been reading now (wish I had before) the RCBS mould drops bullets at .318 which is way too small. What model CBE Mould are you guys using?

[Cast Bullet Engineering]

Craiger1987,
If you are using Bertram cases, one of the moulds with a reduced heel will probably work the best. The reduced heel designs were made to suit the thicker Bertram brass and still be able to chamber the round.
310 Cadet #2R is the most popular in a round nose style and 323-125RTL is a more pointed design, should you like that style.
A chamber cast would be good so you can measure the case mouth diameter, and it will also give you some idea of bullet diameter as well.
I realise it might be a PITA to post it to me, but I have V anvil micrometers and would be more than happy to measure any chamber cast or slug you might have.
Jeff is also correct in saying that softer alloys, like 40-1, 30-1, 20-1 will generally shoot better in 310's than hard alloys. Recovered bullets SHOULD have the heel section bumped up to engrave the rifling.

Thanks,
DC

[runfiverun]

20-1 is harder than most people realize.
switching to ww alloy is basically swapping one way to make 12 bhn for another.
40-1 would be a good direction to work towards.

[Craiger1987]

Thanks CBE I'll try to recover a bullet next time I'm at the range to see what the heel looks like. Currently I'm making my own brass from Starline 32-20, so a larger heel would prolly be better I would imagine, that brass is tracing paper thin. I'll finish shooting through what RCBS bullets I have and pick up a CBE mould that you suggest. I am very suspicious that that RCBS mould is dropping bullets that are way undersize for the bore, will confirm later when I get home.

[Craiger1987]

Thanks everyone for all the info so far. I wouldn't have even thought to consider that perhaps 20-1 is maybe a bit hard. But now that you mention it .22lr is made of dead soft lead and never leads up a bore (at least not any I've ever had).

[Ausglock]

I run the CBE 127gn RN at 323 and it works in 7 of the 11 guns at my club with no issues. the other 4 have tighter bores.
All are cast out of 2.6.92 alloy (Hardball)

[JeffinNZ]

I shoot the CBE 320-120 and CBE 325-125 and both shoot well. Be sure to use proper .310 Cadet cases from Bertram to avoid headaches. For a long time I fought with .32-20 cases I converted and found the necks were too thin and I got blow by of gas on the heel generating leading in the throat. Bertram brass (and Super of AU, no extinct, if you can get it) don't require sizing after shooting as the heel of the CBE bullets is a snug fit. Original .310 bullets from factory were swaged with a cupped base and this would guard against the blow by I got with thin wall cases much like in a .22RF.

This is the 320-120 in 40-1. Slugged up well.

[Craiger1987]

Thanks for that jeffin. If I'll deffinitly try proper cases if I can't resolve the issue otherwise. I do notice that my fired cases have almost no taper and they do have a bit of a shoulder. I was under the impression that the cadet chambers are straight taper with no 'real' throat or step of any kind. I'm wondering if mine is a 32-20 conversion that just wasn't marked as such. It will close on an unaltered rim.

[Craiger1987]

Here's a fired case. Don't know how well you can see the shoulder but this is the best picture I can get.

[JeffinNZ]

HHHMMM. Measure the inside of the mouth of the case and see what the I.D. is. What is the head stamp on that case? It is best to match the bullet diameter to fire case you see. Also, as David from CBE has suggested, best make a chamber cast. Sulphur (sulphur) is useful for this from the gardening section of your hardware store. Plug the chamber just ahead of the throat using a patch, carefully melt the sulphur and pour into the lightly oiled chamber, wait for it to set then push out and measure immediately. You may be correct that you have a rifle that had a .32-20 reamer run into it.

[Craiger1987]

Got some numbers. ID of the case .312, OD .325. Bullet diam .322 and Heel .309 (sadly too small to not have to size the cases) the headstamp is Starline 32-20, that's the brass I used to make them. Rim is unaltered and the block closes on it fine.

[JeffinNZ]

Really interested I know the neck diameter of the chamber.

[runfiverun]

you'd only have .001-2 spring back on the fired case.
i size my 32-20 boolits to 312 which is what your getting here.

I'm suspecting you might could get away without a heeled boolit here.

[Intel6]

I recently acquired an original .310 Cadet with no makings indicating it had been modified. I just got some new Starline 32-20 cases and the rims were too thick and there was no way I could even start to close the block. I have seen where some say they use un-thinned 32-20 cases but I have to think to do that the gun may have been modified, at least the rim recess deepened to take the 32-20 rim? I am having some 32-20 cases thinned for a lot cheaper than it would be to get the real .310 brass. I will see how they work an take it from there.

And pic of my new a rifle: