Mould issue, #68 Saeco 4 cavity

[stubbicatt]

Guys. I purchased a Saeco 4 cavity #68 H&G design 45 ACP SWC mould. It throws undersized bullets. I was casting at a target temp of 725*, but my then new, now back at RCBS for warranty service, Pro Melt wouldn't hold temperature, so I cannot say for certain what temp the melt was.

I know there is shrinkage with bullets cast at higher temperature, but these bullets are coming out at .450 to .451" No bueno.

I wonder should I return the mould to Saeco for one that casts a little bit larger? Or should I wait for the Pro Melt to return, properly repaired and in proper working order, and try casting at 650* or something to see if I can get this one to work? If indeed it is a shrinkage issue, as opposed to a cavity issue.

I've always been happy with Saeco moulds, but I think this one has "issues." I would much prefer a .453" bullet so it sizes properly in the lubricating process.

Thanks for your considered recommendations.

[Bohica793]

Alloy composition can affect size as well. What is you lead/tin ratio? I think I would wait for the ProMelt to return and try again before givingup on the mold.

[stubbicatt]

The alloy measures out at at least 16 BHN per the Lee hardness tester. I do not know its exact composition. To a 20 # pot I have added about ½ pound tin. I did not notice any difference in casting before or after the tin, but I attribute that to the infernal pot shutting itself off and the alloy turning mushy.

[Dragonheart]

I just purchased two NOE #68 Brass 4 cavity molds and they produce perfect bullets and all cavities are .453. I have always been a fan of Saeco and have a number of their molds, but the NOE molds are less expensive. The brass is a heaver mold, but I can live with that for this kind of quality. If the Saeco are undersize I would return the mold or it would probably be fine if you powder coat.

[GSM]

Try adding something with a bit more antimony in it.

650 F will work, but it will be frustrating - it's just on the edge of minimum temp. You may end up with a lot more culls due to poor fill out at the lower temp.

Lyman / Ideal used to have a small cheat sheet showing shrinkage amounts with a variety of alloys. The closer you get to pure, the more the shrinkage (if I recall correctly).

[bobthenailer]

Saeco specs there moulds with Lawrance mag bullet alloy , your alloy of 16 bhn should be fine !
My Saeco 8 cavity #68 mould will cast boolets at .452 or slightly over with WW alloy and are sized @.452 dia I usually run my RCBS pot between 650 to 700 degrees .

If the problem is a undersized mould ? Saeco will fix or replace it if it has not been modified.

I have about 13 Saeco moulds and all will cast boolets large enough with WW alloy to be sized at there normal sizing dia for that caliber.

[stubbicatt]

Thanks fellas. Once the Pro Melt returns from RCBS I'll try experimenting.