Seating Die Struggles


January 9, 2013, 10:30 AM
The other thread on this subject got too old so I had to start another. (the concept sort of hits close to home) Anyway, I am using a standard RCBS seating die for .308 WIN in a single stage press. Using a digital caliper, I was measuring the finished rounds from about minus 2 to up to plus 8 thousands. As was mentioned elsewhere, this couildn't be because of a variation in bullet or casing length. I changed to a new out-of-the-box die and sure enough the old one had metal fragments in it. Ah Ha! Trougle is.....this was an improvement but, while more were the correct COAL, there was some that were about the same error. Would a RCBS Gold Medal Seating Die, which has micrometer anjustment and a visible works, be any improvement? The latter runs about $70 and is the only brand not on reorder status. I still can't work out what is happening. Any help would be appreciated.

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January 9, 2013, 10:54 AM
Your rifle seater plug touches the side of the bullet, not the tip. Tolerances in the bullet itself lead to this. Handgun seating dies usually touch the tip, so you won't see as much variation. Bottom line, is that your variations are nothing to worry about. Save your $70!

January 9, 2013, 08:54 PM
^^^THIS^^ The bullet ogive/point of seating die contact is the same while the tip on the bullets you are using from the ogive to the tip is different on all the bullets you are using. Your seating die will never touch the bullet tip on a rifle die as far as I have seen on any of my rifle dies.If you used the plug on the seating die to be the top of the measurement instead of the bullet tip of the finished bullet they would all be virtually the same length I would bet. There is so little difference in what you have on the finished rifle bullet with regards to barrel contact variation it will make negligible difference. Shoot them and see for your self. Have you ever measured a box of factory Core Loct's or Win ammo?------Just WOW. There is a large difference but bullets shoot well despite this. This is not a great concern unless you are buying really really expensive bullets for long long range shooting.

January 9, 2013, 09:01 PM
See this about that:


January 9, 2013, 10:46 PM
Do you realize how small 8/1000ths is? Its almost 2/250ths.....

That variation is expected.

useless signiture

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