Quote Originally Posted by Benelli B76 View Post
Dave, I am interested that you say the piston seal is PTFE as this material is soft and malleable and would change shape when hitting the end of the cylinder. Most piston seals are polyurethane which is tough and hard wearing.People have experimented with PTFE seals and find they extrude into the transfer port. I think the only area you could use PTFE is in a piston ring seal where there is no impact, so is your material a harder compound mix ? Would be interesting as urethane is not the easiest to turn complex shapes on the lathe.

Baz
Hiya Baz,
The heads on both '45s are plastic (they are 110% not leather). These heads were certainly marketed and bought as being of ptfe. I am no expert on this so must assume they are. They are not the only guns I have them on. I have lost track all together but think I also have them on a couple of Anschutz 335s, an Original 50, a 50T01. I think the only gun that ptfe didnt work that well on was an early 35- but I was warned the business end of the compression tube was ever so slightly constricted on these. As you say ptfe is pretty unforgiving in that sense. I can only speak from experience and all the guns I have fitted these heads to work fine. I have stripped one or two over the years after some amount of shooting and have not noticed any degree of distortion.
I would say though that if I was engineering minded I would turn a steel piston head converter to revert to the later Diana standard piston heads. I know many would say that is moving away from originality but I have had a couple of instances where leather heads have expanded and sapped power dreadfully. I know power isnt everything- but if we have been given 12 ft llbs then I want to use it. Then again I dont punch holes in paper or shoot HFT. I recall on Anschutz 335 I purchased had a new leather head fitted by the previous owner and it had been soaked in oil and had siezed the gun solid. Plastic (ptfe I assume) soon had that one shooting sweet

Sorry for the thread hijack Nickos. I hope you get this '45 punchy and accurate

As I say- I am not an engineer- I just speak as I find and from my experience.

Dave