CZ-52 rollers/barrel change out.

[Hermannr]

I just purchased a new barrel for my CZ-52 from Numrich and received it today.
 
Now I have a couple questions:
 
First, after taking a 3/32 punch and driving out the pin, I remove the rollers and the retainer.  Well, I found out too late? that the hole in the rollers are not the same size (end to end).  One end the 3/32" punch (about 2.3mm so the hole is probably about 3mm) will fit into and go almost the whole way through, but the hole at the other end is only 2mm (the 3/32 punch will not go through)
 
So, question #1:  what is the correct orientation of the holes in the rollers?  Large holes to the slide and small holes to the barrel assembly? (that is how I assembled it)
 
Question #2:  The inside of the barrel is smooth, but coated with some black substance that is hard.  Ideas as to what the substance is? and how to clean it out?
 
I did reassemble, (large hole to slide) and did fire.  The new barrel definately improved the groups, but the black stuff only rubbed off the peaks of the lands. (using soviet surplus 7.62X25mm)  Only new problem I encountered was the slide did not lock back when it was empty (only with one of the two magazines I have).

[DeeDubya]

I would definately try removing the "black substance" before shooting any more. It's probably dried cosmoline. I would patch it with a good bore solvent and brush it clean. I've successfully used naptha to clean cosmoline. It can be stubborn. If one mag locks the slide and the other does not, then it's the mag (possibly not seating high enough).

[Hermannr]

Thanks DeeDubya. 
 
I have tried Hoppe's #9, Liquid Wrench penetrating oil, brushed and brushed...a lot, and the black stuff does not budge. (a wet or dry patch comes through clean)  Maybe I will try soaking it in Kerosene next.  I don't have any Naptha, unless Hoppe's has some in it?
 
The two magazines I have do have appear to be of different vintage, though they are identical in design.  On one the phosphate coating on the heel is quite dark, and the spring is very stiff (to the point of: it is difficult to load). 
 
On the second magazine, the phosphate coating on the heel is considerably lighter colour, and the spring is noticably lighter.  Both feed without error, but the one with the weaker spring is the one that didn't lock back when it was empty after I changed the barrel out. 
 
When I obtain some more ammo, I will check the magazine seating.  Right now I am down to 16 rounds, and I consider that as being out.  An empty firearm without ammo is no better than a hammer.

[DeeDubya]

I wouldn't hesitate to call Numrich and ask them what's in the barrel and how to remove it. Although it might be news to them too. Unless it's lubricant or cutting oil left over from tooling at the factory it would have to be some kind of rust inhibitor.

[Hermannr]

Hej DeeDubya!
 
Thanks,  The black stuff is very hard, almost looks like paint, and Hoppe's 9 does not touch it> Unfortunately I do not have a black light to check..I understand cosmoline will floresce and show up as a blue or green glow under a black light?  It appears a little too black and too smooth to be phosphate?  They wouldn't phosphate the inside of a barrel, would they?
 
Anyway, I just made up some homemade bore cleaner (kind of like "Ed's Red", but I didn't have exactly what Ed called for so there are a couple substitutes, and not as much acetone as he called for. I used Marvel Mystery oil for the ATF, and there is some old WWII mil-surp bore cleaner in their too)  I think I'll let it soak a couple of days and see what happens.  If it is a paint, the little bit of acetone that is in there should break it loose.  Next time we go to town (couple days) I'll pick up some more acetone.  If it isn't gone by then, I give it a couple more days with a quart of fresh acetone in it.
 
If that homemade bore cleaner doesn't work, I'll give Numrich a call, thanks for the suggestion.
 
Actually, I broke down the 52 and except for the firing pin, firing pin retainer/block and spring, and the grips, the whole weapon is soaking in the stuff right now.

[DeeDubya]

What kind of external finish does the barrel have? Just wondering if someone forgot to plug the barrel and throat when they finished it. I think letting it soak is a good idea.

[Hermannr]

The outside of the barrel is that same black finish.

[DeeDubya]

I think that might explain it. Someone didn't plug the barrel when finish was applied. Not the normal procedure. You might want to check with Numrich.

[Hermannr]

Well guys, I have come to a conclusion as to my new barrel and the black...it is parkerized with manganese phosphate, and yes, they did the inside of the barrel too.
 
Smooth as a baby's behind and clean enough there is nothing on a clean swab.  Ok, it looks great if you don't notice it is black inside, except for the edge of the lands where the bullets I have pushed through it cleaned it off a bit, it is smooth as glass.  Oh well, the barrel works great and is easy to clean, that is what counts..
 
Thanks.  I would still like to know is the large holes in the rooolers are out, or in.