Acceptable Cast Bullet Tolerance

RedHawk357 · March 10, 2010, 11:31 PM

So I am out in the garage weighing out some charges of Universal and TiteGroup for some new 158 gr SWC I bought on GunBroker. So I get 25 of each weighed out set my COL and seat all my bullets after checking COL of the first three. Rnd 43 or 44 I notice the brass and crimp groove are not matching up to cases 1, 2, and 3. My first thought I jacked up my trimming of my cases. I got the next twenty five cases prepped in the next loading block so I check the length of those cases. They are all within .001 of my desired trim length. Check dies everything is tight. Pull 15 bullets out of the bag and measured those. They vary in length from .700 to .714. Isn't .014" kind of on the excessive side? So the question is what is acceptable tolerance for cast bullets? I am considering learning to cast this summer; so I am also wondering what would cause a variance in bullet length as well. Thanks

AlaskaMike · March 11, 2010, 10:16 AM

The only thing I can think of is mould cavities that are not uniform. For example, in your case the mould that cast your bullets might have the shortest cavity measure .700" and the other cavities varying a bit with the longest being .714".

I've never seen variation like that from any of my moulds, but then I've never actually measured mine to see how uniform they are. I'd recommend sorting them into groups. It's tedious, but you won't have so much variation in the same batch of ammo that way.

Good luck when you start casting--I just started a couple of years ago and I'm loving it.

Mike

March 10, 2010, 11:31 PM	#1
RedHawk357 Member Join Date: September 7, 2008 Location: Colorado Springs, Colorad Posts: 63	Acceptable Cast Bullet Tolerance So I am out in the garage weighing out some charges of Universal and TiteGroup for some new 158 gr SWC I bought on GunBroker. So I get 25 of each weighed out set my COL and seat all my bullets after checking COL of the first three. Rnd 43 or 44 I notice the brass and crimp groove are not matching up to cases 1, 2, and 3. My first thought I jacked up my trimming of my cases. I got the next twenty five cases prepped in the next loading block so I check the length of those cases. They are all within .001 of my desired trim length. Check dies everything is tight. Pull 15 bullets out of the bag and measured those. They vary in length from .700 to .714. Isn't .014" kind of on the excessive side? So the question is what is acceptable tolerance for cast bullets? I am considering learning to cast this summer; so I am also wondering what would cause a variance in bullet length as well. Thanks

March 11, 2010, 10:16 AM	#2
AlaskaMike Senior Member Join Date: September 26, 2005 Posts: 941	The only thing I can think of is mould cavities that are not uniform. For example, in your case the mould that cast your bullets might have the shortest cavity measure .700" and the other cavities varying a bit with the longest being .714". I've never seen variation like that from any of my moulds, but then I've never actually measured mine to see how uniform they are. I'd recommend sorting them into groups. It's tedious, but you won't have so much variation in the same batch of ammo that way. Good luck when you start casting--I just started a couple of years ago and I'm loving it. Mike