The PR vent liner is certainly adequate to use, i imagine it is harden steel also (not stainless).

The stainless that Ron is using 18-8 stainless is not real close to 4140 or 416 steel used in barrel manufacturing.

Here is some information...

Stainless steel grades are iron alloys that contain more than 10.5% of chromium. Other alloys are added to stainless steel to amplify its properties. The grading is based on the metallurgical structure and nature of stainless steel. The grades of stainless steel are categorized into different families on the basis of the properties that they display.



18-8 (304 Stainless) is down the list in hardness in the stainless family, 416/4140 are on the other end of the scale. I think that is what I am reading on the net.

But what it really comes down to, is what is the correct hardness the job requires. I remember when I ask Dave why not 'harder' he had an engineers answer that I did not totally understand, but it boiled down to... 'to hard' was just a bad as being 'to soft'

I am not qualified to speculate on safety vs. non-safety but I tend to go to the safer side. So I would probably use something that has been engineered and properly tested. These products would have liability attached to them.

Do I think Ron's vent liners are unsafe - I have no idea but I would not have my son use it just for safety sakes... Myself i probabaly would if there were not other options available...