What is the difference? Gilding material and Copper Jackets

[Utah Shooter]

I am sure it is a simple answer but what is the difference in these two jackets? Gilding material a mix of copper and tin or????

[MIBULLETS]

Gilding metal is usually 95% Copper and 5% Zinc.

Pure Copper jackets may have tendency to copper foul slightly more, but I don't know if that is verified.

[williamwaco]

gilding metal is usually 95% copper and 5% zinc.

Pure copper jackets may have tendency to copper foul slightly more, but i don't know if that is verified.

ditto.

[Utah Shooter]

Either inherently more accurate?

[runfiverun]

i'm pretty sure sierra uses copper in their target jaxkets.
the softer jaxket would have a tendency to swage up to fit a barell better, probably can be drawn to a thinner more consistent jaxket easier too.
just speculation on my part though.

and a lot of it may have to with your bbl's rifling and condition.

[GerryM]

not so Sierra use 4 differnt types of guilding metals 95 5 is one of them
J4 on the other hand may be copper only. One thing i do know J4 jackets are 30 to 40% softerand way more expensive for some reason.

[Grandpas50AE]

According to the Corbin technical bulletins I bought years ago, Gilding metal is 98% copper and 2 zinc. Different manufacturers use different percentage variations depending on intended use and cost factors. The smaller the amount of zinc, the deeper the draws can be before having to anneal the jacket material to finish the draw. Many of the 6mm and up rifle bullets require several drawing steps to get the final product, and the more zinc in the alloy the more each step hardens (and makes more brittle) the jacket alloy, and it costs money to stop the draws, anneal, then finish the draws. Pure copper (which I have used in my jacket maker) IS softer than Gilding metal, and will copper foul the barrel quicker at most modern rifle velocities. It is always a balancing act to get just the right material that is easier to form but doesn't foul the barrel too quickly.

I had originally posted this as copper an tin, so it has been editted to the correct alloy - copper and zinc.

[GerryM]

The 2% zinc is what makes it gilding metal there are many different grades. Sierra uses several.
The most common is C210 95 5 Thats what sierra uses for 22 cals and 6mm jackets
The military uses 90 10 They have been for avery long time.
As you have said copper fouls easier and also the accuracy is different . Due to the material , bullet design is different. from what i have read and been told copper needs a
bullet with more bareing surface

[Utah Shooter]

So all of sierra's are made from Gilding material? I think I read that somewhere else as well.

[GerryM]

Yes check their web site. I buy from Sierra now. I have switched from burger J4.
Best prices and best answer and service is at SIERRA''
The techs there are on top of most questions. NICE people there.

[Thetraveler]

I cant find any info on their site about their jackets

[Smokin7mm]

It is in their "Store". Here is the link. https://www.sierrabullets.com/index.cfm?section=store
click the view all jackets. They only sell 22, 6mm 30cal. And only one length of each.

Bret

[Thetraveler]

Found it thanks

Einar