Is this normal when sizing a Smith bullet?

[Bruce Cobb 1723V]

If anyone wants to do an experiment, you will find you can take a slightly undersized round 69 bullet (Unpatched) in a rifled bore and shoot it. When you retrieve it, it will have the rifling showing on it. Pressure is deforming and flattening it into the grooves .... I guess that darn ol physics is at it again.

[Harry Gaul]

Part of the answer is Inertia. An object at rest will stay at rest, and an object in motion will stay in motion unless the object is subjected to an outside force. Load, bang, explode, hot gases, lead deforms, picks up rifling, spins, hit a target, pieces fall to the ground (Gravity). Team commander calls time and the family behind the fence goes wild. Well done all around.

True Blue and Diamond Hard,
Harry
03626v

[bobanderson]

Part of the answer is Inertia. An object at rest will stay at rest, and an object in motion will stay in motion unless the object is subjected to an outside force. Load, bang, explode, hot gases, lead deforms, picks up rifling, spins, hit a target, pieces fall to the ground (Gravity). Team commander calls time and the family behind the fence goes wild. Well done all around.

True Blue and Diamond Hard,
Harry
03626v

Nailed it, Harry. Except some times the horn blows first.

[johnsymborski]

I've shot three Smiths over the years. The first was an original with a max bore (bottom of groove to bottom of groove) of around .518 - typical for an original bore. I used a .520 Smith round (20:1) sized to .519 with a Lyman Lubrisizer - no problems. The second was a repo. with a .515 max bore Rapine used to sell a mold at the time for repros (.515 dia.) that would come out of a hot mould at .517 and I sized them .516 - no problems. Now I have an original relined by Hoyt and it is .515 max. i use a Lyman 515139 mould (355 grain weight round) that comes out hot at .517 and is sized to .516 - no problems. (30 grain 3F powder charge, press a styrofoam wad over that plus a dab of lithium grease)

So the challenge is that your barrel at .510 is on the low side. No way you should try sizing a .520 round. You can get Lubrisizer dies by the thousandth from S&S (and at least one other), and lubrisizers push the base of the round into the die, which works better (and lubes at the same time). Still, a .517 round has too much meat on it. You can get a two-cavity mould from Accurate bullet molds in any O.D. you need, if there is not a suitable profile on their website already. .512 is what you need - then size to .511

Another alternative is to reline the Smith to .515

Johnny

[Maillemaker]

Hi Johnny,

As I said above, I believe my bore is .503, and my groove diameter is .513.

I think .515 will work fine, and they shot great in the black Smith tubes with 33 grains 3F Goex.

Steve