Took my 930 SPX apart for cleaning the other day & couldn't locate the Gas Seal Ring that is shown in Fig 10 in the owners manual. Then I removed the threaded ring that holds the spring in the lug welded under the barrel & the gas ring was under the spring. When I re-assembled the gun I put the seal ring in front of the gas piston as shown on the diagram (Fig 10, page 12 of the owners manual) but I'm not 100% certain that's correct. Anyone know where it's REALLY supposed to be located? I tried called Mossberg but couldn't get a live person to speak to.

Thanks