Lead Bullet Sizing

Q

Quigly

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Southern Ontario
Hello All,

I bought three RCBS Moulds. My question is what diameter do I size the bullets to for optimum performance.

1) 458 caliber mould 405 grain flat point gas checked
2) 458 caliber mould 300 grain flat point gas checked
3) 30 Caliber 180 grain flat point gas checked

I have a couple of 308 win rifles, and a couple Marlin 45-70s I would like to fire them in once I get them cast and sized. If anyone can help me out I would appreciate it.
Mike
 
I shoot my 45-70 as cast at .459 and no gas check up to about 1600fps and have no leading in my 1886. As for 30 cal start with .309 and work from there. I shoot plenty on cast in my enfield sized to .314 which is size on for my bore and with a gas check, again never any leading. All are lubed with a double coating of Lee Alox lube.

Maybe I have been lucky, never had to fight with cast in my rifles.

If you are having a hard time getting big enough bullets, cut the alloy with pure lead and it will bring the diameter up a bit. I use 50/50 wheel weights and pure lead.
 
1% oversize is a common rule of thumb. Some rifles like less and some chambers won't accept cases with bullets that large. I've never had an issue with the firearms I shoot cast bullets in. .002 over bore diameter is the minimum I find that will give me acceptable accuracy. Larger diameter bullets like the 45 cal really seem to need more. With 30 cal .002 can be OK but it depends on your particular rifle.

Handguns seem to like .004 as well. This is just IMHO. Your firearms may want something different. Some firearms just won't shoot cast bullets well no matter what you do.
 
I never bothered slugging my bore, just trial and error. Try a couple of shots, if leading occurs try a larger bullet or different load. If you have a gentle touch you can try measuring the muzzle with some callipers and it will get you close. Just be careful not to scratch the bore and crown( seen a lot of people be very rough with callipers and it's makes me wince every time). If you have a 5 groove bore like an enfield, it will likely measure about .001 or .002 smaller than the actual dimension.

For powders I have had luck with IMR 4198 and am starting to play with 4895 to get velocities up for longer Range loads.
 
0.001" over groove diameter is the minimum. As large as you can while still maintaining a minimum of 0.002" neck clearance is the maximum​, and is my target size.
 
Everyone says that you have to slug your bores. I don't see ~.433 (.44) or .461 (.45/70) lead balls or bullets around anywhere...
 
I have the same RCBS molds ( 45-405FN and 45-300FN) and stopped sizing them. I seat a gas check, hand lube, done. They shoot and perform wonderfully in my 450 Marlin on deer out to at least 100 yards. Actually, if your 30 mold is the RCBS 30-180 FN I also have that one. Although I don't shoot that one much anymore I didn't size that one either.
 
big boar said:
I have the same RCBS molds ( 45-405FN and 45-300FN) and stopped sizing them. I seat a gas check, hand lube, done. They shoot and perform wonderfully in my 450 Marlin on deer out to at least 100 yards. Actually, if your 30 mold is the RCBS 30-180 FN I also have that one. Although I don't shoot that one much anymore I didn't size that one either.
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Thanks. I'll see what they measure at when they come out of the mould. I will probably do wheel weights, or a mix of wheel weights and pure lead.
 
aric84 said:
I never bothered slugging my bore, just trial and error. Try a couple of shots, if leading occurs try a larger bullet or different load. If you have a gentle touch you can try measuring the muzzle with some callipers and it will get you close. Just be careful not to scratch the bore and crown( seen a lot of people be very rough with callipers and it's makes me wince every time). If you have a 5 groove bore like an enfield, it will likely measure about .001 or .002 smaller than the actual dimension.

For powders I have had luck with IMR 4198 and am starting to play with 4895 to get velocities up for longer Range loads.
Click to expand...

Thanks for the info. I have both those powders. I'll be trying both.
 
NaviDave said:
Everyone says that you have to slug your bores. I don't see ~.433 (.44) or .461 (.45/70) lead balls or bullets around anywhere...
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Use fishing sinkers. Just make sure they're lead. You can buy lead free now which are zinc... would be pretty hard to drive those through.

Quigly said:
Yes, but I don't wanna slug the bore. Too much work.
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Don't be so effing lazy! Slugging a bore is actually a lot less work than cleaning a badly leaded barrel. Jeez, perhaps you should pick a less labor intensive hobby like napping...
 
sawzall said:
Use fishing sinkers. Just make sure they're lead. You can buy lead free now which are zinc... would be pretty hard to drive those through.



Don't be so effing lazy! Slugging a bore is actually a lot less work than cleaning a badly leaded barrel. Jeez, perhaps you should pick a less labor intensive hobby like napping...
Click to expand...

How does slugging the bore really help when a commercial rifle may have a bore that is not exactly the same diameter all the way through. What if there is a tight spot and all you're getting is the diameter of the tight spot. Slugging a bore is more appropriate for finding those tight spots, so that you can either hand lap them down or fire lap them down. I'm better off measuring the land diameter at the muzzle as one poster suggested. That's what I will do between naps, thank you.
 
sawzall said:
Use fishing sinkers. Just make sure they're lead. You can buy lead free now which are zinc... would be pretty hard to drive those through.



Don't be so effing lazy! Slugging a bore is actually a lot less work than cleaning a badly leaded barrel. Jeez, perhaps you should pick a less labor intensive hobby like napping...
Click to expand...

Not everyone approaches this hobby the same way and telling someone HOW they are supposed to go about their hobby is a great way to discourage people from learning and enjoying it. Maybe some should spend more time experimenting and less time patronizing...

As for the OP, let us know how you make out!
 
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