HW30s scraping sound

[wms]

Cold shooting today. About 38F outside. After about 20 min outside I am getting a scraping sound at the end of the cocking stroke -- about the last 3-4 inches of arc. Sounds like scraping wood.
Was totally smooth when I first went outside. When cocked, the barrel swings freely without any scraping sound. Could the stock be contracting in the cold? If so, what should/can I do about it?  Anyone else had this problem? I've only got about 750 pellets through her.

--Hol

[TCups]

I looked for a link to Paul Watts' "Tuning the R7" and find it no longer exists.  So, I am speaking from memory here.  The cocking linkage on the R7 and the HW30s have a design flaw.  The action of cocking the rifle can cause the linkage to scrape and score the undersurface of the receiver and the cocking shoe linkage tends to push the piston upwards, against the wall of the compression chamber.  This is made worse by a relatively loose "parachute" piston seal which allows movement of the piston.  

In short, it is possible through normal use, to have metal on metal scoring of the underside of the receiver, or worse, scoring of the compression chamber.  Beeman used to compensate for this by really over-lubricating the piston and spring, which made dieseling a common occurrence.

The correct "fix" is a custom tune that replaces the piston seal with a better seal, buttoning the piston, and altering the linkage so it doesn't scrape and gall the underside of the receiver.

See this old GTA link:
http://www.gatewaytoairguns.com/airguns/index.php?action=printpage;topic=9628.0

Google: Spring Gunning Paul Watts R7 HW30 Tune

and see what shows up.

[john gray]

i had the very same problem the other day with my beeman ,would cock fine but the last 3-4 inches were heck trying to close it up ,i broke it down and seen alot of metal shaveings ,it was comeing from the 2 metal washers on each side of the gun  ,i done away with them and now its a dream to cock and close up