Is it true that the 5.7x28 ammo has a "coating" on it that wears off if you tumble it before reloading?

Is this coating 'required' to run in the FN pistol?

The reason I ask is, Ruger came out with a new pistol for the 5.7. Does it require the special coated ammo to run properly?

Yes it has a finish on the brass. Most types of cleaning will take it off, but it is not needed on the pistol. The coating is there to help them feed in the 50 rd P90/PS90 mags.

That is one speculation of the coating. The coating is not slick, but more sticky. There are a few that from testing have shown that the coating is there to hold the brass in the 5.7 guns chambers slightly longer during blowback operation. User on FN forum removed coating on his brass and had cycling issues. People in the know who no longer work at FNH USA also expressed the same opinion on the coating.

Simple solution, if you want to reload this caliber, wash the brass in simple green mix, and be on your way. You'll get 5-6 loadings out of the cases. Scrap em and move on.

does the ruger pistol have to have the same 'coating' to function properly?

You buy factory ammunition with the "coating" on it.  You can't unselect it.  So as far as factory ammo- the question is moot.

With reloading,  there is a yes/no/depends argument going on.
I don't think the Ruger has been out long enough to experiment with, so for now the "tests" are on the FN guns...……

Here's another thread:

https://www.ar15.com/forums/Armory/5-7X28-Load-Data-Will-Ruger-s-New-Pistol-Spark-Interest-/42-506303/

thanks, I'll likely just take some factory ammo tumble it 'till the coating is off then shoot and see.... :)

i was more interested for the reloading purposes

Sure, Give it a try and let us know!

In the mean time, Buff has the best suggestion:

"......Simple solution, if you want to reload this caliber, wash the brass in simple green mix, and be on your way. You'll get 5-6 loadings out of the cases. Scrap em and move on...….."

No need to overthink this...………..

will do!

I have been shooting and reloading the 5.7x28 for over 10 years.  Yes, the brass does have a polymer coating on it but it isn't for lube, exactly the opposite in fact.  It's to slightly delay extraction to allow the bullet to exit and pressures to drop.  The use of abrasive type cleaning will remove the coating which is why I use an ultrasonic cleaner with mild detergents.  This cartridge is probably one of the most sensitive to very small powder increases.  It can go from perfectly safe to over pressure in just .1 grain.  For this reason, I use only very fine spherical type powders in a benchrest grade dropper and I still verify every 10th charge while casting.

Also, be mindful of the burn rate of the powder you are using.  Keep your burn rate in the vicinity of TrueBlue and ACC #7.  The pistol is a little more forgiving than the PS90, but not enough to risk a 50k+ psi detonation an inch from your hand.

As for the Ruger 57, remember that it was designed to shoot with coated ammo.  Don't risk extracted brass while it's still under pressure.