SKB Model 100 SxS Action Parts Disclaimer: My interest is limited to proper assembly/disassembly needed to access the action, clean and inspect parts for wear, and replace worn/damaged parts. Anything related to sear engagement, leaf springs, or "alterations" is best left to those capable of doing so. Cowboy Action Alterations you won't find them here. Go to the nice folks at SASS Wire forum to find who can do it right. There is a barbaric ritual to alter the inertial trigger to mechanical. Front sight thread is 6x48 Automatic Safety Operation   Double Firing [Doubling]    Parts SKBShotguns.com  Numrich Gunparts Ithaca Model 100 SxS   Parts List for SKB SxS Shotguns   Ithaca 1974 Gun Company Parts and Service Catalog Cornell Publications  20 gauge P/Ns start with a "3" 12 gauge P/Ns start with a "6" 12ga parts 6xxnnn and 20ga parts 3xxnnn same part description Butt Plate 316100 Butt Plate 316101 Butt Plate Screw 316102 Butt Plate Spacer NOTE: Use a #2 Philips screwdriver. Stock Bolt - Note the order of the washer, spring washer, and the stock bolt nut.                      NOTE: Use 10mm socket to remove Stock Bolt Nut.                                   Leave Stock Bolt threaded into Receiver Shank. 316001 Stock Bolt 316002 Stock Bolt Nut 316003 Stock Bolt Washer 316004 Stock Bolt Spring Washer 316005 Receiver Shank 316006 Receiver Tang Screw NOTE: Removing the stock can be a fun display of flying washers... Remove the buttplate screws. Remove the trigger guard rear screw.  To save yourself the enjoyment of crawling on the floor with a flashlight [ask me how I know...], remove the stock nut, then screw it back on about four threads. Now when you pull the stock away from the frame, the washers won't fly off... Now you can remove the nut. NOTE: SKB used a little thick grease between the Washer, the Lock Washer, and the Nut. This keeps the washers in place while running the socket up into the Stock Bolt bore hole. FWIW, a normal 3/8" drive 10mm socket fits the bore hole quite well, guiding the washers and nut into position. It works better than you would think... Sears [12ga part numbers shown]  606131 Sear Left 606132 Sear Spring Left 606133 Sear Sping Screw 606191 Sear Right 606192 Sear Spring Right 606193 Sear Spring Screw Right 606300 Sear Pin NOTE: The Sear Springs are fastened to the underside of the sears. Trigger [12ga part numbers shown]  609001 Trigger Assembly 609008 Connector Holder [fixed] 609011 Connector Guide Plate 609012 Selector Button 609013 Selector Spring Plunger 609014 Selector Spring 609015 Selector Spring Screw 609016 Connector Guide Plate Pin NOTE: Although the SKB is very well designed and machined, they had to leave enough clearance for assembly AND operation. You may find a bit of dirt and lube on the sides of the trigger where it passes through the Trigger Plate. Not hard to get at with a Nylon or Brass brush. Another area that could catch duff is the milled fore and aft slot in the Trigger Plate that the rear of the trigger sits in. That little "ear" on the trigger [mine is drilled and tapped] sets the trigger "angle". If there is some duff in that slot, that "ear" will rest on it and change the angular relationship of the Connector Holder to the rear ends of the Sears. More than that is mere speculation on my part. SKB Model 500 Trigger w/ Adjusting Screw   [from seller gatherhouseltd]    The SKB SxS Trigger [in some examples] is drilled and tapped for the Trigger Adjusting Screw. There is a Trigger Adjusting Screw Lock Nut on the upper side of the "ear". I know of NO description of how to adjust this screw to vary the sear engagement. Trigger Adjusting Screw Trigger Adjusting Screw Lock Nut Trigger Plate [12ga part numbers shown]  609400 Trigger Plate 609401 Trigger Plate Screw 609002 Trigger Pin 609003 Trigger Pin Something [ ? ] 609009 Trigger Spring 609010 Trigger Spring Retaining Screw Automatic Safety [12ga part numbers shown] 609700 Automatic Safety Lever 609701 Automatic Safety Lever Pin 609702 Automatic Safety Connector 609703 Automatic Safety Connector Pin 609704 Automatic Safety Connector Pin Snap [2x] 605110 Locking Piece for Model 100 Automatic Safety Operation  [Safety "ON", action cocked ] NOTE: This is MY SWAG. FIRE  Push Safety forward to "Fire" Trigger Lock slides forward ASL pivots forward [if not already cocked] ASL Connector pushes forward, ensuring that the locking lugs are engaged SAFE   Push Safety rearward to "Safe" Trigger Lock slides rearward ASL is free ASL Connector leaves Locking Piece forward to engage locking lugs Opening Action, Safety in "Fire" Position   Rotate Top Lever to Right Top Lever cams Locking Piece to the rear ASL Connector pushes ASL rearward Top of ASL pushes on front end of Trigger Lock Safety returns to "SAFE" position Double Firing  by Dirt Merchant # 61422 on SASS Wire Forum There are two primary reasons an SKB will double fire. FIRST: there is a $2.45 spring about half the size of an old ball point pen spring [Ed. Connector Spring] that controls the inertia reset mechanism. There were no 100/200's built after 1984 and most of the Ithaca/SKB's we use were built in the 70's. When the gun is disassembled for modification these springs that have been under tension for 30 odd years are shortened, trimmed, modified and such. The inertia spring is not strong enough to withstand shortening and expect it to retain it's tensile strength. That spring should be thrown away and start with a new factory spring which are still available. SECOND: the sears develop burrs and can actually change the way they lock up with the connector block [inertia system] which can also develop burrs and cause the same affect. When this happens doubling is common. A fine diamond file and a competent hand can fix this fairly easily. Johnny,Goatneck or Roughneck Rod can all do the work. Sure other factors can come into play but "limp shoulder" has never been one I have seen. It's really about the springs. Connector Block  [12ga part numbers shown] 609004 Connector 609005 Connector Pin 609006 Connector Spring 609007 Connector Spring Plunger 609017 Connector Pin Washer 609018 Connector Pin Spring-Washer NOTE: Without a factory guide, there are no details. My SWAG is if the Connector Block can be flicked rearwards and it smartly snaps back up against the Connector Holder, it is probably fine. But if the gun still doubles, disassemble Connector Block. Check the spring / plunger hole for burrs. Replace the spring [SKBshotguns or Numrich].