22-250 case sizing analysis

[murf]

there is a current post regarding case neck tension that brought up a lot of questions for me. so, i made some measurements and drew a few conclusions.

your comments and opinions are most welcome.

murf

 

[murf]

there are a few answers here to questions i didn't ask:

the expander ball is .222" in diameter. it should make the neck i.d. the same diameter, but it doesn't. it looks like the necks spring back to .221".

the chamber neck in my rifle is a "generous" .256". the rifle is still accurate.

anyway, the main reason for running this little experiment was to figure out if i should use the full length sizer or the neck sizer. the next step is to check concentricity using the partial full size method.

murf

 

[fguffey]

your comments and opinions are most welcome.

In most cases I find that not to be true, I find it most disturbing it has more to do with the member that is responding.

there is a current post regarding case neck tension that brought up a lot of questions for me. so, i made some measurements and drew a few conclusions

Murf, interference fit and crush fit and measuring in pounds of resistance when seating and pulling and as always there is cold welding, I do not load ahead meaning I do not give cold welding time to weld. If I did or if I could find cases that were welded I could measure the amount of effort it would take to pull in pounds, to determine if neck tension was the problem check with other members that are very familiar with neck tension.

F. Guffey

 

[Ron Go]

There is always a little spring back with brass.
Concentriity looks good with no neck expander on the pull stoke.
I like to full length size without the neck expander or just neck resize using bushing die.
Then I use a neck expander on the push stroke.
Any imperfections are pushed to the outside of the neck then I can outside neck turn if needed.

 

[murf]

probably a good idea to leave a little carbon on the inside of the case neck, i guess.

thx,

murf

 

[fguffey]

the expander ball is .222" in diameter. it should make the neck i.d. the same diameter, but it doesn't

No Murf the neck inside diameter of the case after the sizer ball is pulled through will be smaller than the diameter of the sizing ball/plug. Once the reloader has figured out the difference in inside neck diameter and sizer ball the case will have been fired a few times. Firing and sizing the case neck changes bullet hold.

Years ago R. Lee made 'Target' die sets, the case was not sized, only the neck. After neck sizing the neck was reamed while in the die, the reamer was aligned with the case in the top of the die, the instruction recommended lubing the stem of the reamer to prevent it from locking up.

F. Guffey

 

[Ron Go]

There is a graphite powder and bead mixture I use that works well if needed to dip your necks for a quick lube Made by imperial I believe.

 

[murf]

the data in upright form:

murf

p.s. column four heading should read " body widest diameter". that data is the widest part of the case.

 

[murf]

fguffey,

i have a 22 caliber "donut remover" reamer. i was thinking of f/l sizing the case without the expander ball, then reaming out the i.d. with the reamer (the reamer diameter is .221").

the only drawback is making the necks too thin. i might try it and see what happens.

murf

 

[murf]

i also weighed cases and ran loaded rounds over the concentricity gauge:

weight variation surprisingly small.

those rcbs dies make some straight rounds.

murf

 

[fguffey]

Murf,

i was thinking of f/l sizing the case without the expander ball, then reaming out the i.d. with the reamer (the reamer diameter is .221").

That is the reason I mentioned R. Lee and his Target Model dies.

http://www.midwayusa.com/find?dimensionids=12783

I have the neck reamer die from RCBS for 243 Winchester. When forming cases I form donuts, when going from 30/06 down to 25 and 22 it is necessary to drill first then ream. When I ream the neck I find it is necessary to support the outside diameter of the neck.

I have a .350" reamer, when using it the neck expands unless the outside of the neck is supported, I can get the neck hot but not larger in diameter.

F. Guffey

those rcbs dies make some straight rounds.

When purchasing dies I have a choice, I have a lot of RCBS dies.

 

[murf]

fguffey,

didn't think of the neck expanding while cutting. the reamer is l.e. wilson, so only the body is supported. i guess i could cut once, resize and cut again, etc. until the i.d. is the right size. thx.

ron go,

there was a previous thread on using graphite in case necks. i believe there is a galling problem when using graphite. i don't remove the carbon out of the neck before sizing, so i think i'm covered. thx for the reply.

murf

 

[Ron Go]

Thanks Murf.

 

[Ron Go]

I always use a body then neck bushing die or a FL die, then the neck expander on the push stroke. I use the same brand of neck reamer as the expander die so the mandrel dimensions are the same. I always wanted to push all the imperfections to the outside of the neck so I can have all the tool marks on the outside to limit any more variables with bullet/neck contact. This allows me to have consistent neck thickness. If I needed the neck tighter after the fact I can always use a neck bushing of a particular size.

I use thudding competition match and the KM Precision expander and neck turning tools.

I am intrigued on the other way above and will look into it.