lapping to increase weight?

[Just The Tip]

I've posted a question in the alloy section about how my molds are dropping slightly under weight bullets with a certain alloy. These are coated using Hy-Tek and then used and sold for IPSC completion, with powerfactor being an important part of the game at major matches I want my bullets as close to the advertised weight as possible. Just to be clear this is a small scale manufacturing company, personally I'll just bump my velocity a bit to be sure but customers are finicky about advertised weights and I want to give them the best product possible. When lapping a couple hundred thousandths will the weight increase? Only looking for a grain increase. I have 3 sets of 8 2 cavity molds for my bullet master, this is not gonna be a quick process but it will be worth it in the end if it produces a better bullet.

Thanks for any input you might have.

[JSnover]

depends on how much weight you need to gain, lapping won't give you much. Be more specific about actual vs intended size/weight. Changing your alloy plus lapping your mold might get you where you need to be.

[Just The Tip]

Looking for .5 a grain. 147 grain 9mm drop at 123.5 average + - .5 of a grain 180 grain .40 weigh 179.5 same variance. I know I'm being picky but don't see how that's a bad thing.

[Just The Tip]

Changing alloys is an option but the supplier I have is by far the cheapest and 91-7-2 is the only close option for bullet making.

[JSnover]

Well that's not much, then. If all you need is half a grain, lapping would do it for that small amount. If you wanted to get really picky you could identify any cavities that cast consistently lighter and lap those first.

[Just The Tip]

I've got my old bottom pour and handles for the molds. I'll be going through 24 2 cavity molds to get them all uniform. As I said it's gonna be a long process but in the end will be worth it.

Thanks for the info.

[reddog81]

If all the molds drop uniform bullets currently I wouldn't worry about it.

[osteodoc08]

Run a cooler melt temp if you can still get acceptable boolits without wrinkling. Otherwise I wouldn't worry too much about it.

[Just The Tip]

Thanks for the tip, I'll turn it down a bit and see what I can get out of it.

[krems]

Slightly cooler casting temps and a slightly softer alloy should do the trick. Your molds sound very consistent to me. I'd be happy with them but I'm sure some customers are picky.

[runfiverun]

that's too picky.
the 2/6/92 alloy is plenty hard enough I'd do myself a favor and order some cheaper pure lead and throw in 2-5% to make up the weight difference.
hell 10% would be better.
you won't even see a bhn drop.