I've been trying to determine if this ammo with the headstamp
"TPZ KOPP" is corrosive. It is made by Tula in Russia in the
early 90's when the US banned Russia made ammo. Tula
sold this ammo to a man named Kopp who repackaged it and
shipped it to the US as made in the Czech Republic.

I tried to find info on the internet and nothing definitive came
to light.

Figure any old Russian or Chinese 7.62 ammo is "mildly" corrosive...

Kinda like being a little bit pregnant.

Clean everything with hot soapy water, dry/lube the parts and you'll be fine...

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"I also cook."

It is for this reason most quality AK barrels are chrome lined. I've shot thousands of rounds of Russian ammo, maybe 10's of thousands in my lifetime and never had any issues other than the squid ink finish on a pricey AK washing off when sprayed with brake clean. It only makes sense to me to clean a firearm after I have used it other than a magazine to test fire and even then if I took it home it got cleaned. I never trusted Chinese ammo although have probably fired a couple thousand rounds of that stuff as well, it is dirtier than Russian and it pays to take your magazines down for a good cleaning every thousand rounds or so. I love the AK platform and appreciate it for all of the reasons it has been so successful and would trust one with my life over the standard issue M-16 I was familiar with in the early 70's.

You need to treat any 7.62x39 of unknown provenance as corrosive.

I bought a case of Russian Brown Bear back in 2004. (1000 round case for 80 bucks) They came in 20 round boxes. The box says Berdan primed and non-corrosive. Steel cases.

I checked my records and the last time I fired my AK with that stuff was 2 years ago. I cleaned it with Hoppes. Just checked the bore and it is perfect.

The guys I know who have 7.62x39 platforms (not all are the AK or SKS variety) treat all foreign ammo as being corrosive to one degree or another. An abundance of caution possibly, but they feel the small extra cleaning effort is better than a nasty surprise.

Read this and learn!

Pull a bullet from one round and dump out the powder. Do the same from a round that you know to be non corrosive. Clean a piece of mild steel. Put each case mouth down on the steel and pop the primers with a hammer and punch. Put the steel with the two deposits of residue in a garage or enclosed outdoor porch overnight. If the round in question has corrosive primers the residue from it will start to rust immediately. I have tested a lot of ammo this way and then you know for sure instead of guessing.

The test proposed by alwslate is a good way to find out for certain, otherwise, treat it as having corrosive primers.

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VCDL, GOA, NRA

This is always the best policy. For a period of time there was an abundance of Yugo brass cased stuff, some felt it was non corrosive and it turned out being corrosive. The only people I know that had problems with corrosive ammo were people that rarely take the time to clean their firearms. I had a few beater AK platforms that I would hand over to my son's friends when we went shooting, they never got a thorough cleaning except maybe twice a year depending on use, I never saw any signs of corrosive damage. On a side note many people are under the false impression that black powder substitutes are safe to use and not keep clean like black powder use. I have found after receiving firearms used with substitutes, primarily Pyrodex that it is worse than black powder if left uncleaned. I picked up an 1858 Remington repop that was used by a guy for cowboy action due to cylinder swap quickness. The nipples in his "favorite" cylinder were corroded so severely that four came out with great difficulty, the remaining two had to be drilled and re-tapped.

My limited experience with 7.62X39 ammunition tells me that it hurts when it hits you in the arm, in the buttocks, and in the head. I learned these things over 50 years ago and have tried my best to stay far away from that stuff ever since.

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Life of the party until 8:00PM

Someone will recommend cleaning with hot soapy water. And that will do the job wonderfully, but is not an absolute necessity.
I don’t think it needs to be hot. Maybe not even soapy.
But I would at least run 2 or 3 water soaked patches thru the bore and chamber area, or some of the old type Rifle Bore Cleaner that the US and other military organizations have used for cleaning for about 100 years. It is still available. ( Must have at least a 50 year shelf life ).
You can test for mercuric primers by taking a cartridge out and pull the bullet and dump the powder. Find a flat piece of steel that has no traces of paint, oil, plating, etc. on it. If it is rusty, brush it down to shiny metal with a dry, clean wire brush. Now put the still primed empty hull in the chamber. Place the muzzle of the barrel almost right against the steel, and pop the primer. It will leave powdery residue on the plate. Take the plate in out of the weather, and check the primer residue deposit every day for a week for new corrosion or a green acidic looking color. Either one of those things means corrosive primers. If nothing changes, the primer was not mercuric/corrosive.
Go through your ammo and see if they all have the same date and / or manufacturer’s code head stamp. If they are not all the same I would test at least one round out of every different head stamp or lot number.
During WW I, WWII, and Korean War you can bet the farm that the troops rarely had access to hot water in the field, so that when they needed to clean a gun, they used the old Rifle Bore Cleaner or cold water on cotton patches, with good results. The water will remove the salts.
If your rifle has a chromed bore, that is good protection against rusting from the use of mercuric primed ammo. That’s why most post WWII Eastern Bloc military rifles had chromed bores.

Smootshooter makes some good points about the temperature of the water when cleaning a firearm after shooting corrosive ammo. Hot water will likely dissolve the corrosive salts faster, but it's not likely a requirement. There are also solvents that are effective at removing corrosive salts.

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VCDL, GOA, NRA

When was Russian ammo banned in the early 90's?

Do you mean Chinese ammo instead?

It was the Chinese ammo that was banned in 90s along with the cheap AK clones and SKS rifles. The SKS gurus rue those days as a Chinese SKS with Chinese ammo was often a 1.5 MOA gun.

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Release the Kraken

This was true with just about any of the well cared for SKS models made in Block countries like Yugoslavia, the Yugos had a funky front sight that allowed for use with rifle grenades, otherwise they were superior to Russian made SKS models. The one many people prized was the Albanian model, it had a cocking lever similar to the AK, more of a curved affair than knobby bolt.
Whenever I used to hear someone talking about a "sniper" quality AK-47 variant I used to laugh. There wasn't an AK variant made that came anywhere close to sniper-1" at 100yds quality. The larger rifles like the Draganov and PSL are a totally different story, as well as the Yugo-82 in 8mm. The Yugos were the reason whenever you see pictures of Seriavo back in those bad days nobody is ever seen walking or strolling along anywhere. I had a Chinese marked AK variant made by Norinco and exported through Pomona, Cal. with the thumbhole stock. It had a milled receiver and excellent barrel. I had a Chinese guy I knew interpret what the Chinese script meant that was stamped on the side of the receiver, he said "Very Accurate Weapon." It was sold by an outfit in California and labelled "Match Quality", I think it was the same company that marketed the Norinco built "Legend". It was the most accurate AK platform I ever fired and with iron sights was capable of holding 3" at 100yds, it was easy to repeatedly bust milk jugs at 100-150yds, nice rifle....the last one I let go. Another one I liked was a Yugo SMG in 7.62x39 it was the largest action and barrel I had in the platform and had an action so long and lazy that you could get near full auto fire by keeping just enough finger on the trigger to engage trigger slap as easy as a three round burst on an AK-47. I nearly got kicked off a range that did not allow auto fire for dinking around with it one day at 100yds, it was a nice rifle with folding bipod, 40rnd mags. Typical to all in the platform is that legendary reliability, just like a Glock. I don't ever remember a FTF that wasn't caused by a bad primer, etc.

I had several Russian SKS and a Chinese. Maybe a Yugo? None were super accurate with the run of the mill import ammo. Maybe palm sized groups at 100 yards if all was perfect. The most accurate steel cased import ammo was the blue box S & B in my experience with those rifles. Better than average mil stuff. I did not really invest in expensive brass case stuff for comparison. My M1 carbine is easily alot better accuracy.

I think its fair to place the AK platform on roughly the same footing as the M1 carbine, I've messed around with a few of them as well as Ruger Mini-14's in .223 and 7.62x39. I was never impressed with the M1's stopping power, although it does put alot of rounds down range quickly and is handy in close quarters. Dollar for dollar the AK platform out performs just about everything and is able to be used as a hunting caliber with results very similar to the venerable 30-30.
I never went to the trouble of re-loading the AK, ammo was at that time cheaper to buy than reloading components and boxer primed cases, by the time I had collected enough brass cased, boxer primed stuff I had moved out of the platform and let it all go with the last AK. I know a few people that are still messing around with my favorite high capacity platform and getting some decent results. Today I know more people using a better cartridge in the 6.5 Grendel or 300 Whisper and getting excellent accuracy results as well as good solid knock-down, better quality firearms result in some pretty nice weapons platforms but again dollar for dollar its pretty tough to beat an AK.

Just to make sure, field strip your AK, use a funnel and pour very hot water down the barrel (from the breech down to the muzzle) to wash out the salts that attract moisture and cause corrosion. Follow the hot water rinse with soapy water scrub using patches. Follow that with another hot water rinse. Dry out the barrel with clean, dry patches. Follow that with an oil soaked patch. Follow that with a dry patch to remove excess oil.

The problem with using corrosive primed ammo in SKSs or AKs is that the firing residue gets into the gas tube above the barrel, not just the bore. The bolt face also needs to be cleaned even if chrome plated. So it's best to test ammo before investing in a quantity and avoid corrosive primed ammo period if you can. But, that's me because I like shooting better than cleaning.

If unsure whether or not your ammo. is corrosive it's best to treat it like it is...Buy yourself a can of Ballistol and follow the instructions on the can about mixing it 10:1 water/Ballistol for cleaning after firing corrosive ammo. Doing it this way you shouldn't have any issues.

About 20 years ago I had both a Romanian AKM and a Colt AR in 7.62 x 39.
Tens years ago I bought my first Mini-30 and have had a pair of those ever since.
I've not seen ANY corrosive imported ammo in that time, except for Yugo M67.
The M67 ammo utilized a mildly corrosive primer in order to extend shelf life. It has a real nice annealed brass case with well sealed primers.

I read all the comments about treating all 7.62 x 39 ammo as potentially corrosive.
Well, if you have been sitting on some ammo made in the 40's or 50's, yes, it could very well be corrosive and should be subjected to the test that has been mentioned above.
The only ammo you have to worry about these days as being corrosive is the M67 Yugo, and that is no reason to avoid it.
The M67 is above average in accuracy and velocity. I clocked this batch recently at 2520 fps from a 17 inch barrel.

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Plain water will work as well as anything to clean corrosive primer residue. I usually pour warm water down the barrel or anyplace else exposed to residue. WWII/Korea GI bore cleaner was just an oil-water emulsion, and it works well because of the water.

I know some guys like Windex, but I have always used hot soapy water, just like I do with my BP guns. It has always worked well. Back when new in the cosmoline Chinese SKS's were like $85.00, I also picked up a case of corrosive Chinese ammo. It was accurate in that rifle, and reliable. Only took a few minutes to clean it. It shoots just as well today.

Larry