After they are coated, a shot of any spray will go on forever and no I don't clean it off. If you sized prior to coating , you should clean with Denatured alcohol or acetone. Even if the bullets were clean, the die has been lubed at some point.
I use the cheap Wal-Mart spray lubricant, .99 per can stuff. You can use water also, that is what I use sizing before coating. Most anything will act as a lubricant.
Good Luck
Most of us who size for one reason or another BEFORE powder coating are simply sizing the boolits without any lube at all. Yes I was skeptical at first too but am finding absolutely no ill effects sizing un-lubed boolits with my Lee push through dies.
To answer the OP question I do it both ways depending on need. For my 91-30 Russian I don't size at all. I cast PC and load.
The ones I size then PC I do because I don't want to by another size die. So I size prior to PC and let the coating make my diameter larger. Since the boolits were all made uniform before coating they come out fairly consistent. Absolutely consistent enough for 50 yard sub-sonic use.
Motor
toddn84; If for one reason or another that you NEED to lube the bullets before sizing and powder coating use Dawn dishsoap. It rinses right off with tap water. Gp
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
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