Full length or neck sizing before flaring for cast boolits.

[Alpha1]

I normally use a Le Wilson bushing neck die when reloading full metal jacket bullets for my 7.62x39. I made up a batch of cast loads using new Lapau cases. I am about to reload the fired cases I am thinking about neck sizing them with the bushing die then flaring the mouth with a Lyman m die. Any body got any opinions on the correct way to go should I full length re size the cases before flaring or go with the neck bushing die and then flare.

[DanTheMan]

Do you really need to flare ? I mexican match russian milsurp steel cases with cast bullets (gas checked) and have never needed to flare.

[ovenpaa]

I neck size and then flare or more accurately step out with a mandrel turned to suit so in theory the flare is parallel to the neck, this means I centralise the neck and bullet to the chamber and do not shave the bullet when it is seated.

Dromia explained the rationale behind this and I have never deviated from my interpretation of his explanation.

[Alpha1]

I neck size and then flare or more accurately step out with a mandrel turned to suit so in theory the flare is parallel to the neck, this means I centralise the neck and bullet to the chamber and do not shave the bullet when it is seated.

Dromia explained the rationale behind this and I have never deviated from my interpretation of his explanation.

That is the same method I am using the Lyman M die is designed to do just that. I have also experimented with some home made expanders.
But up till now I have all ways full length resized first then used a M die to flare. I have loaded a few up to night and they look and feel fine.

[ovenpaa]

Are you flaring to suit the bullet and prevent shaving or to set the neck centrally into the chamber?

[Alpha1]

I am flaring to seat the boolit with out shaving lead. I am not sure what you mean by setting the boolit centrally in the chamber. Can you explain further.

[ovenpaa]

Chambers on SOWRs (Strange Old Wooden Rifles) are somewhat generous and a cartridge may not sit centrally to the chamber, in exaggerated form it could end up resting on the bottom of the chamber with the bullet sitting fractionally low of the bore which leads to accuracy issues. What you need is a cartridge that is aligned to the bore as near perfectly as possible. You can cold cast the chamber and measure the diameter of the neck area and flare your case mouth so it is a snug fit this helps to align the cartridge.

As an alternative to cold casting you can step up the flare until the case neck is tight fit to the chamber, measure the diameter of the case neck accurately and then flare it to suit. I find reloading for SOWRs with cast bullets fascinating, eeking out the last bit of accuracy is a very challenging and satisfying pastime.

[dromia]

Neck size and neck expand, M dies don't flare case necks.

Flaring to centre the case is when you cannot centre the round in the camber by having the boolit fit the throat, a flare to the case mouth equal to the throat diameter at the point where the case mouth is holds the round and more importantly the boolit concentric with the bore, assuming concentricity in your camber, thus ensuring the boolits enters the rifling without deformation leading to inaccuracy.

To be honest I only bother with that technique when shooting cast over 600 yrds, usually good boolit fit for the throat, groove, bore and good boolit QC is more than enough for 200-600 yrds.

[dromia]

Chambers on SOWRs (Strange Old Wooden Rifles) are somewhat generous

Not necessarily so it is usually down to throat wear rather than generously chambered barrels, to be honest for cast I prefer a bit of throat wear to get better boolit fit in the throat. When I used to shoot 303 competitively with cast when I fitted a new barrel I usually broke it in with 1-2,000 hot jacketed rounds before it was good to shoot cast. Fitting to the throat in a new 303 usually limited me to 190 or so grain boolits with a bit of throat wear I could get my preferred 220 gn boolits to fit. I could have got heavier bore riders to fit but prefer throat fitting boolits as they are easier to get to shoot and getting a bore rider to work means that you have two diameters to get right, bore size and groove size on the driving bands.

[dromia]

BTW what is cold casting the chamber?