22 Camber Erosion

Anyone ever hear of cycling problems in 22s from erosion in the chamber from
the case crimp expanding and wearing a ring in that spot in the chamber 
affecting the cycling I have had one Gunsmith tell me that this is a thing
with older gun with a lot of rounds through them

That's a new one on me.  I've got borescope photos of .22 pistols with at least 100K rounds through them, and haven't see anything I would call "erosion".  What is often a problem is a ring of carbon that forms in that area, which can be very stubborn to remove.  If often extends back far enough to affect feeding and extraction. 

I thought I had posted an article I wrote about this here, but I couldn't find it.  Here's a link to the posting on the rimfire forum:

https://www.rimfirecentral.com/threads/have-you-really-cleaned-your-chamber.1275825/post-13039008 

Because fouling tends to build up there, I would expect corrosion more than erosion.  That would be due to storing the firearm in damp conditions without proper cleaning/oiling.

Have a local shooter with about 20 years and at least 200K rounds digested in his Pardini.  He was seeing failure to extract ALOT.  I scoped his bore and could see significant erosion at the rifling leade to the tune of about 3/16".

Depending on the vintage, I have heard that some early Pardini barrels were made with soft steel.  I think that usually manifest itself in terms of bore wear, not "erosion" in the chamber.  

I wouldn't expect damage in the leade to have any impact on extraction.  If the chamber looks OK, I would check the extractor spring.  Pardini over-stresses them, and they slowly get crushed over time.

Here's a posting I made on the TargetTalk Olympic pistol forum with some suggestions on things to look for in Pardinis with extraction problems:

https://www.targettalk.org/viewtopic.php?p=291016#p291016

Greetings,

I have seen several 22lr barrels with throat erosion.

The priming compound contains glass like material to aid the combustion.

Yes, older Pardini's did have soft barrels and wore more quickly. The latest Pardini barrels are heat treated to 40 HRC and will last longer.

As the erosion increases, it may be possible that the mouth of the case expands into the crater causing a delay in extraction. I do not have the tools to measure such an event.

Cheers,

Dave