# 9 MM Questions



## jflecken (May 17, 2011)

I am just starting to reload 9mm. I have been getting some 115 gr. FMJ (100) a few at a time. They have all been .355. I have now started looking into buying in bulk online and they are offered in .355, .356 and .357. What is the difference. I know that they are each bigger but what does that mean for reloading. I saw some that were .356 at a good price but I do not know what the size difference means. Also, I have seen bullets advertised as copper jacketed and some that are copper plated, what is the difference and what does it mean?


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## hud35500 (May 8, 2010)

You can use all those sizes, but I would stick with .355. You can also experiment with the different sizes to see which is more accurate. Alot of firearms have different size chambers in the barrel. The only way to accurately tell what size a chamber is, is to make a lead cast of the chamber, then measure the casting. With a rifle, this can be very important when you are trying to get the most accuracy out of it, but I wouldn't get that serious with a handgun. 
A copper plated bullet is just a thin wash of copper, while a jacketed bullet has a thicker jacket that is bonded onto the bullet. For casual shooting, I prefer the plated stuff(cheaper). With hotter loads, I go with jacketed, there's less fouling of the barrel. Try some of each and see what works best for you.


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## LeoM (Jul 7, 2011)

If you are looking at cast lead bullets, get .356. The seal a little better in the rifling and get better accuracy. If you are switching back and forth with jacketed and lead bullets, be sure to pay attention to the powder charge. Since lead bullets seal better in the barrel, they take a lot less powder to get to pressure, plus generally, one shoots lead bullets at a slower velocity. Good Luck


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