Lesson learned

[bullgator]

A friend has a couple of 5.7x28 firearms. A Ruger pistol and an AR type rifle. When he tried to resize the brass he either crushed them or most often got them stuck in the sizing die. He asked my thoughts and I offered only the basic possibilities, right die, right shell holder, properly lubed, etc.. He has this week off and he came over to have me give it a try. A little research beforehand made sure I had the expander adjusted as low as possible so it wouldn’t be in the way of the neck sizing process on the short case. First case....stuck!,and the rim torn off by the shell holder. We got that fixed and shelved the reloading while we went out back and did some shooting of suppressed .22s and ran a half dozen factory rounds of the 5.7 through his Ruger. I learned that, by design, the little 5.7 typically has the shoulder move .040”-.070” upon firing. Most bottleneck cartridges only expand about .001”-.006”, so that’s quite a stretch it goes through and therefore a lot of resizing needed. The other thing I learned was that 5.7 factory ammo comes with a polymer coating to aid in extraction.
After we shot and had lunch, we were just kind of hanging out a shooting the breeze when he took the brass out of his pocket from the factory 5.7 I just shot. I thought hit me...
I asked him how he cleaned the other brass and he told me in his pin tumbler. I said I bet that removed the polymer coating and we should go try the brass we just fired with the polymer still on it. BAM!......20 minutes later we had that brass loaded and they all fired and functioned fine.

I know one thing, that cartridge is more hassle than it’s worth.

 

[Nimrod71]

See you can teach old dogs new tricks. I feels good to learn something new.

 

[nmurph]

Good to know!! I have 5.7x28 dies and when I get a gun, ammo, brass, powder, and primers, maybe I can remember this lesson.

 

[rosewood]

So, do you think using a vibratory tumbler instead would solve the problem? Or would it remove the polymer also? How would you go about cleaning real dirty brass without removing the polymer?

Rosewood

 

[bullgator]

So, do you think using a vibratory tumbler instead would solve the problem? Or would it remove the polymer also? How would you go about cleaning real dirty brass without removing the polymer?

Rosewood

Ya know, brass doesn’t have to be nice and shiny to be clean enough to run through a die. I think a few minutes in a dry media might work. I’ve already read where they are simply putting it in a bucket with a diluted mix of Simple Green and water and just agitating it by hand.

 

[rosewood]

Ya know, brass doesn’t have to be nice and shiny to be clean enough to run through a die. I think a few minutes in a dry media might work. I’ve already read where they are simply putting it in a bucket with a diluted mix of Simple Green and water and just agitating it by hand.

I don't wet tumble. Too much trouble for little return. For those reloading to sell, that it one thing, but mine don't have to be spotless.

I typically tumble mine with Nufinish car polish in the tumbler. Something like that may make the brass slick enough to aid in resizing??

I wonder if there is any easy way to add back that polymer coating you speak of.

Rosewood

 

[Jester896]

Something like that may make the brass slick enough to aid in resizing??

 

[bullgator]

I don't wet tumble. Too much trouble for little return. For those reloading to sell, that it one thing, but mine don't have to be spotless.

I typically tumble mine with Nufinish car polish in the tumbler. Something like that may make the brass slick enough to aid in resizing??

I wonder if there is any easy way to add back that polymer coating you speak of.

Rosewood

Really hard to say because this is new territory for me as well. Like I said, it’s more work than it’s worth so I won’t be in the market for a modern cartridge with Hornet ballistics.
I’ll add that when we got the Hornady tech on the line he said all that case stretch happens in the middle and it’s not if, but when that case fails.

 

[Jester896]

that must be why most are looking for only OF brass for them