.358 RCBS casts at.358

[jsteed]

So should I use a .358 sizing die? I'm using COWW and all are exactly .358 ( +.0002 because they are not perfectly round). Was hoping they would cast larger so I could use a .359 or .360 Should add that it is a 200gr fn design with GC. Just try them and see?

[bruce drake]

the throat of the barrel would fix that .0002 difference. shoot them as sized and see how they roll. Then determine if you need the extra step of sizing them. How do you plan to gas-check them without sizing?

[runfiverun]

if you put something besides lead in the alloy it will make slightly larger boolits.
I shoot 358 in my 358 rifle.
it however has a slightly smaller than that barrel and very close to that throat dimensions.

looks to me like you have 2 choices.
put some checks on them and try them.
or measure your gun and know.

[captaint]

If you have a conventional sizer, try running them through. The lube might not squirt all
over the place. Put the gas checks on and see what happends. Often a "same size" boolit will seal enough for it to work out. Mike

[mdi]

For a handgun, I'd say .358" is prolly good enuf. If you install a gascheck with a .358" die, no sizing should occur. You should know the dimensions of your gun just to be sure, and aid troubleshooting when problems occur, so slug the bbl. and cylinder throats...

[Le Loup Solitaire]

There is a school of thought that no cast bullet is perfectly round and that bullets should be "trued up" by sizing. Nothing wrong with that. For others its the fastest way to lube. A couple of other ideas; sizing damages the bullet so the less of it the better and lastly shooting them as cast is the best way. As with many other things it is probably best to experiment and see which path is the best to follow. Your gun and the size of the group will tell you. A secondary thought is that the barrel of the gun sizes the bullet anyway. Its kind of a "can of worms" to contemplate so probably the best way is to try the variables and see which way works the best. LLS

[Larry Gibson]

Was hoping they would cast larger so I could use a .359 or .360

Try adding 2% tin to the COWWs.

Larry Gibson

[jsteed]

Did run a few through using the .358 sizer and it did touch and size nearly all of the circumfrence of the bullet. Have a .359 coming and will try that soon.

[mdi]

I've found that lower alloy temperature when casting can produce larger bullets. I have one mold that casts .430"-.431" with my alloy, but if I use a bit more pure lead and cast with the alloy just above liquid stage, the bullets will drop at around .432"-.433"...

[Pilgrim]

I've not measured the diameter of my RCBS 35-200 FN, but when I run it thru my .360 die, the checks (Hornady) are seated, the boolits are lubed, and there is a thin film of lube on the outside surface of the boolit. My interpretation of this is my boolits are smaller than .360, which basically means I'm shooting unsized boolits. I don't have lube squirting out of the die or any other obvious problem. Works real well in my .358. It works so well that I've never slugged my barrel, measured the boolits, or anything else other than "size" them, load 'em, and shoot 'em. Try the boolits as cast, lube them by hand (8 or 10 of 'em), load 'em and shoot 'em and see what happens. Go from there. You may want a .360 die as well. Pilgrim