Author Topic: rcbs mold question  (Read 954 times)

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Offline Jason F

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rcbs mold question
« on: March 28, 2012, 04:26:40 PM »
I have a mold that is advertised to be a .406 diameter mold but it is dropping. 411 diameter bullets with pure lead, i am sizing these down to. 401 for my smokeless muzzle loader.  I know the trick for bumping up bullet diameter but how can i get them to cast a little smaller.
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Offline Jason F

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Re: rcbs mold question
« Reply #1 on: March 28, 2012, 04:29:35 PM »
This is a rifle mold for 405 winchester that is special order from midway supposed to drop a 260 grain bullet but they are 290 frain after sizing.
handi rifles- 22 mag      22 hornet    223      7mm-08      308 chip shot     30-30 x2     30-06 shorty      358 cheez whiz     357 max     35 remington     375-08    410 rifled slug     454 casull     460 s&w     45 smokeless muzzleloader x2     45-70    50 huntsman    50-70 government shikari     20 ga.ush     12 ga.ush    12 ga.3 1/2     10 ga.imp.cyl. slug gun

Offline Nobade

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Re: rcbs mold question
« Reply #2 on: March 29, 2012, 02:22:59 AM »
Well, since a 405 uses .411-.412 bullets normally I'd say your mould is right where it is supposed to be. Since you are casting with pure lead they are coming out as small as they are going to get. As long as you have a good press mounted push through sizer, you are all set. I like to fill the lube grooves first before sizing so they don't collapse and usually have no trouble sizing down that far. If you want a smaller mould, there are lots of custom mould makers now who can make you a nice lathe bored mould to your specs for a reasonable fee.
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Offline Larry Gibson

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Re: rcbs mold question
« Reply #3 on: March 29, 2012, 04:38:32 PM »
Get some "mould realease" from Midway and spray the cavity(s).
 
Cast at a lower temperature (alloy around 650 - 670)
 
Do not "pressure pour" if using a ladle
 
Adjust the spout of the bottom pour to pour slower
 
Cast slower and do not over heat the mould
 
Larry Gibson
 

Offline Jason F

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Re: rcbs mold question
« Reply #4 on: March 30, 2012, 04:26:14 AM »
Thanks for the info.
handi rifles- 22 mag      22 hornet    223      7mm-08      308 chip shot     30-30 x2     30-06 shorty      358 cheez whiz     357 max     35 remington     375-08    410 rifled slug     454 casull     460 s&w     45 smokeless muzzleloader x2     45-70    50 huntsman    50-70 government shikari     20 ga.ush     12 ga.ush    12 ga.3 1/2     10 ga.imp.cyl. slug gun

Offline Lloyd Smale

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Re: rcbs mold question
« Reply #5 on: April 02, 2012, 02:05:10 AM »
lead alloys with less tin usually cast a bit smaller but if your allready using pure theres not much you can do.
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