From: DAS
Subject: Re: [Air rifle] Is 4.5 mm the same as .177?

In article <39627@dog.ee.lbl.gov> biocca@csg.lbl.gov (Alan K Biocca) writes:
#In article <Cr9JnD.1EF@cscns.com>,  <bunbury@cscns.com> wrote:
#
##Yep, mine has definitely been deiseling...I didn't realize that it was a
##problem
#
#Well, it is only a problem if you are concerned about accuracy.  It
#causes great variation in pellet velocity...

#gary@ke4zv.atl.ga.us (Gary Coffman) replies:
#It's also a problem if you care about the longevity of the gun.
#Dieseling can destroy seals in fairly short order.

True, for non synthetic seals like leather. I've trashed a few of these
myself. Another thing to look out for is oil destroying the lether seal.
Soaking it in oil is a no-no. In spring piston guns a little chamber oil
goes a long way.

Some synthetic seals are immune to deiseling effects. I believe the old
Weirauch 35 had metal "piston rings". If I'm not mistaken, this rifle was
used with the Barakkuda ether injector to induce deiseling on purpose for
the purpose of increasing power. Naturally, normal wasp waisted air gun pellets
could not be used. I think there was a mold available from Beeman for casting
your own 25 grain spitzer bullets for it. An interesting concept.