The elastomer spring is not designed as a seal. If it acts as one that is coincidental.In theory it shouldn't be in contact with the pump walls, but some do.The purpose id to keep the piston head at full extension,, but allow some give at the end of the stroke when the piston bottoms out againstthe ting swaged into the pump tube.That chunk of rubber is not spongy....on the contrary it is pretty darn solid.I have modded the 1977 pump assy for use in the 880's. In order to do it properly for the early brass tube guns a waferw/convex rim gets added to the front of the piston to take up the headspace between piston and chamber seal.That assy uses a square wire coil spring..........buh-bye elastomer spring!
Quote from: Ronno6 on August 26, 2023, 06:10:08 PMThe elastomer spring is not designed as a seal. If it acts as one that is coincidental.In theory it shouldn't be in contact with the pump walls, but some do.The purpose id to keep the piston head at full extension,, but allow some give at the end of the stroke when the piston bottoms out againstthe ting swaged into the pump tube.That chunk of rubber is not spongy....on the contrary it is pretty darn solid.I have modded the 1977 pump assy for use in the 880's. In order to do it properly for the early brass tube guns a waferw/convex rim gets added to the front of the piston to take up the headspace between piston and chamber seal.That assy uses a square wire coil spring..........buh-bye elastomer spring!I need some more rebuild kits.Don't need anything else besides that though.I love that spring piston you make...
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