Finally, a properly-Freaked SL-68 pump!

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  • DocsMachine
    MCB Member
    • Jul 2020
    • 2699
    • Alaska

    #1

    Finally, a properly-Freaked SL-68 pump!

    The drawback? It's not a drop-in. The body has to be machined to accept an insert. But, once it's modified, it can accept any Phantom barrel; stock, aftermarket or Phreaked, and you can still remove the bolt and hammer normally.



    I've been thinking about ways to Freak an SL for years- and you guys have been asking for it for years. But the overall setup of the SL made that tricky, as many of you well know. First and foremost, there was no breech face, like a 'Cocker or Spyder has, for the barrel to seat against, and which would retain an insert. The Carters and Rangers had that too- but in those, there's enough 'meat' to the barrel to make a 'captured' insert, one that slides in from the front.

    That could technically have been done to an SL, too, except the pump only takes a 7/8" barrel, rather than a 1". That won't fit the section on a typical Freak where the tip and back come together. And trying to make a 2-piece screw-together 7/8" barrel makes for really thin walls and tiny, fragile threads.

    An idea I'd been playing with for a while was a simple adapter. The back half sliding into the body like a regular SL barrel, but the fatter Phantom-threaded section outside the front, and in the space where it wouldn't interfere with the pump even all the way back.

    Problem there is you have an inch-long gap between the bolt and the barrel. I could have made them like the "sizers" I did for the Trracers, but what I wanted was for the bolt to chamber the ball directly into the insert itself.

    And no matter how I wracked my brain, there was no way to do that except to make an "insertable breech", and machine the body to accept it.

    I had an SL here of my own I was willing to sacrifice on the altar of the Pump Gods, so I found a chunk of heavy tubing in my scrap bin...



    And measuring on the fly, turned it into the first probable design for an insert.



    The threads were a little tricky- a short throw of stub ACME turned to an internal shoulder, using a hand-ground cutter- but I got an acceptable fit.



    Then, thinking slightly ahead, I turned a stepped plug, that fits the body in place of the barrel. Thanks to the turned-in-place soft jaws, the two diameters were less than half a thou concentric with each other.



    That fits in the body like so...



    And the whole cobbled fixture monstrosity looked like this:



    Considering there's pretty much no flat, smooth and level surfaces anywhere on these bodies... well, that was the best I could do. Believe it or not, it was referencing off the cast nameplate on the side.

    The plug gave me a reference surface for a coax indicator. I got that dialed to within less than half a thou of the original bore, and zeroed the DRO.



    Remove the plug, then re-snug the clamp bolt on a 3/16" hex wrench, so the 'ears' of the clamping portion are supported against the cutting forces (mild as they are.)



    Set up the boring head, whisper a small prayer to the machine gods, and ream that puppy out.



    Bore the hole to .002 over the size of the insert and give 'er a try.



    The insert is now the new barrel breech, and properly positioned...



    And internally, the geometry is set so that when the bolt is fully closed, the ball is just inside the bore of the insert, so an underbore can hold the ball in place, as it should be.

    And once it's all cleaned, oiled and reassembled, the mod is practically invisible.



    And, from a distance, unless you look close and see the Phantom muzzle ports, the whole gun looks bone stock.



    In use, the barrel simply unscrews like a Phantom (natch ) and as a bonus, once the barrel is out, the bolt and pump are still captured, making it easier for a quick clean on the field.



    But, when it comes time to remove the bolt to clean the chamber, just loosen the original clamping bolt, slide the whole barrel and adapter out, and the pump and bolt come out just like usual.

    For those that might be interested in this mod, I plan to run a batch of these adapters, now that I have the dimensions more or less settled, and will be sending them off for anno. I'll probably offer this as a service, since again the body has to be machined to accept it, though I'll probably offer the adapter for those that may have the ability to machine the body themselves, or want to have a local guru do it.

    How's it shoot? Noticeably better, which shouldn't be a surprise. For an SL, the only barrels I have on hand are an old DYE stainless that was turned down to fit years ago (689"), a couple of stock barrels (.691") and an old 'Cocker or Spyder barrel that somebody turned down (.688"). The freshest paint I have just barely falls through a .679".

    But there's a noticeable difference between the .688" barrel, and the 11" Phreaked with a .679". No way to do a side-by-side with this setup, of course, so my impressions are admittedly a bit subjective. I'm also kind of annoyed I neglected to do a before-and-after chrony, but hey, my brain was elsewhere.

    General impression, the tighter bore closed up the 'grouping' by maybe a third (again, subjective) and I'd wager gained maybe 20 FPS. I'd love to try this again with fresher paint and a 14" XL Phreaked.

    Oh, and that was all on CO2, since apparently I don't own a functional HPA tank that can screw in to an SL grip frame.



    Doc.


    Doc's Machine & Airsmith Services: Creating the Strange and Wonderful since 1998!
    The Whiteboard: Daily, occasionally paintball-related webcomic mayhem!
    Paintball in the Movies!
  • Swedgin!!
    Simple Space Monkey
    • Jul 2023
    • 894
    • 21.3330° N, 157.6976° W

    #2
    Wizard!
    Leave Feedback if you wants. https://www.mcarterbrown.com/forum/b...edgin-feedback

    Comment

    • DieManInTheRough
      Loooongtime Lurker
      • Apr 2023
      • 249
      • PeNsAcOlA,Fl, or Hell

      #3
      So good! I have a mint sl and ii I have been dying to field, but the paint here just falls right out. I had planned to turn down a TECHT style adapter since it captures from the front, and print a larger diameter pump handle, this is so much cleaner. Very interested.
      Feedback!: https://www.mcarterbrown.com/forum/b...rough-feedback

      Comment

      • RedLeaderSB
        Stock/pump/automag
        • Nov 2020
        • 227
        • SoCal

        #4
        The threaded barrel that prevents the bolt falling out the front is very cool part of this approach

        Comment

        • nerdcore
          Sweet Liberty, my arm!
          • Jul 2020
          • 512
          • Crashville

          #5
          Wow. Now i want an SL.

          Comment

          • Drcemento
            Tiger Stripe Enthusiast
            • Aug 2021
            • 733
            • NorCal

            #6
            Really nice to see this finally come into being- I know you've been noodling this for a long time, and I'm very tempted to sent you one of mine!
            After getting and modifying the the DW kit for the SL to work better and actually playing with a freak'd SL a couple times now, i'm convinced that almost as badly as it needed a freaked barrel, it also needs a reliable detent system. The SL's breach and bolt are gigantic and double feeding is still a huge issue, especially if you hand it to a newbie - you gotta pump it fast! I've tried the rubber bands, delrin balls on rubber bands anything i've seen mentioned over the years. - the bodies wall thickness and bolt diameter make it incredibly hard to get something deep enough to spring into the breach with each stroke. honestly I kind of remember this being an issue with the SL even back in the day. It was great to field one though, after all these years. lots of good memories of outlaw games in high school.

            The 68 special actually shoots modern paint surprisingly well because of the spring detent in the clamping slot at the bottom of the breech. almost wonder if your in there boring the the body out why not go deep enough to sleeve for a smaller (phantom) bolt and tighten up the breach diameter - it's only money after all 😁

            Comment


            • DocsMachine
              DocsMachine commented
              Editing a comment
              [gears turning]
          • BigBalla23
            Bunker Buster
            • Apr 2021
            • 108

            #7
            I need to have this done on mine. It's one of my favorite shooters as-is, I can only imagine this will make it even better. Awesome stuff doc!

            Comment

            • Funsi00
              MCB Member
              • Jul 2020
              • 219
              • Cleveland ohio

              #8
              Such a cool modification to SL-68 II. Plus phantom barrels are great!
              Feedback link https://www.mcarterbrown.com/forum/b...0’s-feedback

              Comment

              • Kit352
                Bunker Buster
                • Feb 2025
                • 406
                • Central mass

                #9
                This is awesome. It effectively brings an entire line of guns back into play.

                Comment

                • DocsMachine
                  MCB Member
                  • Jul 2020
                  • 2699
                  • Alaska

                  #10
                  I'm working up a second version at the moment, though I've got a bunch of manufacturing I need to catch up on. I'll have more this weekend, probably.

                  Main plan, as partially outlined above: I plan to run a small batch of these and have them annoed, and then will be offering them and the installation as a service. It's tricky to set the body up, as you can see, so it may be something like I'll run them in batches. That is, wait 'til I have several on hand- maybe six to a dozen, depending on interest- so I only have to set up the fixture once. (And yes, I've been trying to noodle a specific fixture, but other than the ASA and the barrel plug socket, there's not much to index off of on these things. )

                  Stand by, more to come.

                  Doc.
                  Doc's Machine & Airsmith Services: Creating the Strange and Wonderful since 1998!
                  The Whiteboard: Daily, occasionally paintball-related webcomic mayhem!
                  Paintball in the Movies!

                  Comment

                  • The Hobbit
                    Bunker Buster
                    • Jan 2022
                    • 487

                    #11
                    Is the sight rail properly perpendicular to the breech face? That looks like it is begging to be an index point for fixturing.

                    im sure you already checked that but the custom fixture guy in me had to ask.

                    Comment

                    • Bubkat
                      Newbie
                      • May 2021
                      • 11

                      #12
                      Amazing! I would like to on the list to get the SL barrel service. I would also like to be on the list for the modified window to hand load first strike rounds haha

                      Comment

                      • Dredgen
                        Newbie
                        • Jul 2020
                        • 8
                        • Riverside, CA

                        #13
                        Oh man, we were just talking about freaking an SL last week and now this?! Sign me up!

                        Comment

                        • DocsMachine
                          MCB Member
                          • Jul 2020
                          • 2699
                          • Alaska

                          #14
                          Just got in a pack of inserts specific to these threads. I've been running the bejeebers out of my machines this week (note to self; pick up more bejeebers) and hope to try and run at least a test batch maybe this time next week?

                          Are there any XL inserts below .679?

                          Doc.
                          Doc's Machine & Airsmith Services: Creating the Strange and Wonderful since 1998!
                          The Whiteboard: Daily, occasionally paintball-related webcomic mayhem!
                          Paintball in the Movies!

                          Comment


                          • TimmysCabin
                            TimmysCabin commented
                            Editing a comment
                            XL goes down to .675
                        • Chemical-x.....ahain
                          MCB Member
                          • Mar 2023
                          • 505

                          #15
                          somewhere out in the wild there are at least three cci barrels trimmed for use in the SL. But I like this much much more. Good work Doc!!!!

                          Comment


                          • DocsMachine
                            DocsMachine commented
                            Editing a comment
                            There's more than that, I cut down half a dozen or more over the years, myself, including some LAPCOs, and something in the .678" range, I think- possibly an Eigenbarrel?

                            Doc.
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