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Sears & Roebuck model 66

HM-UKHM-UK Posts: 18 New Member
I am looking for some help, or, advice? My son recently obtained a High standard model 66 shotgun, in very good condition, for nothing. The only problem was it was in bits. As it turns out everything was there, and I have reassembled the gun. 

My problem is that the adjustable pressure valve had been taken off, and I have been unable to find out how to set it up again. I have asked many here in the UK, gunsmiths included, but without success.

I do know that if there is not enough compression on the wavy disc springs, or, conversely too much, the gun will not cycle as it should. 

The gun itself is a Sears and Roebuck, with a poly-choke serial number #583606 about 1964'ish.


  • BigslugBigslug Posts: 9,866 Senior Member
    This is gonna take a little digging. 

    I looked in the back of my Blue Book of Gun Values for the department store brands crossover list.

    There's a chance that what you are calling the serial number is actually Sears' in-house model number structure.  There's quite a few of those that start with 583, but none immediately obvious that finish with 606, and most of them have a decimal point in there somewhere.  There was no federal requirement to serialize firearms until 1969.

    Is it possible what you have is a STEVENS model 66?

    If we can nail down what it is, we can probably pull up a schematic somewhere with the proper parts orientation.

    How is the gun not cycling properly?


    "Nothing is safe from stupid." - Zee
  • HM-UKHM-UK Posts: 18 New Member
    583.606 is the number. Everything is back together, and manual operation is fine. As it is gas operated to supposedly work with multiple cartridge loads, there is a slotted nut which can be wound up, or, down. This is the point that I am having a problem. There must have been a factory set up on how far to wind the nut down the thread, which is about 1-1.5 inches long. 

    As I say, I know that to much pressure, or, not enough pressure on the wavy spring washers will result in a failure to cycle correctly. When I have this information I will be able to fine tune the pressure regulator.
  • bellcatbellcat Posts: 2,040 Senior Member
    How about a couple pics?
    "Kindness is the language the deaf can hear and the blind can see." Mark Twain
  • BigslugBigslug Posts: 9,866 Senior Member
    I'll keep digging for you, but when deprived of a pilot's manual, be systematic.

    Figure it was probably sold as a bird hunting gun.  Start with bird hunting loads  - probably 1 1/8 ounces of shot in the 1200-1300fps range - and your regulator set at the extreme end of NOT allowing gas into the system.

    Also relevant:  Since you have a polychoke, I would start with that cranked to full choke to MAXIMIZE how much pressure stays in the bore.  (I once had to de-bug a Benelli M4 on which the owner had pimped it out with aftermarket crap until it stopped.  As the OEM parts were restored, it got progessively better, but a tighter choke was key to getting it to run on a particular brand of low base slugs)

    Run your collar progressively more open until the gun cycles, then open up the choke to see if it quits.  Open the collar more until it runs with the choke at both extremes.

    "Nothing is safe from stupid." - Zee
  • HM-UKHM-UK Posts: 18 New Member
    Thanks to AlleyCat, for some information passed onto me. I think that between this, and the information form Bigslug, I may be able to resolve the pressure regulator setting for various loads.
    May be a week or two before I can get on with the work, too may people here and not enough space, so will need to get of the suburbs in order to test fire. But when I have done it I'll let you know what happened, or, pick your brains some more if other issues come to light.
    Thank you all!
  • Big Al1Big Al1 Posts: 8,814 Senior Member
    It's a High Standard C100. 
    See the source image

    Not a lot of info out there, but I'll keep looking!
  • Wambli SkaWambli Ska Posts: 5,419 Senior Member
    I just realized you’ve been a member for many years.  Welcome back, drop in more often!

    It’s a °IIIII° thing 😎

  • Big Al1Big Al1 Posts: 8,814 Senior Member
    edited January 2022 #9
    High Standard C-1200, C-1211 12 Gauge Autoloading Shotgun Parts List Manual (usermanuals.tech)

    One of the features of the gas piston is that it was self regulating, it adjusts automatically to different power ammo. You may just have to wing it!! On the bright side, you'll probably be able to take it apart and reassemble it blind folded, until it's right!! B)

    Maybe a picture if the piston would help!!
    Find High Standard Supermatic Deluxe C101 Parts for Sale | Numrich Parts (gunpartscorp.com)
  • HM-UKHM-UK Posts: 18 New Member
    This is all great information, I also have the patent details, along with the schematic diagrams of construction, along with those of the poly-choke. But nowhere in all that information is a basic regulator pressure setting. So, it may end up with a combination of all the options, and as BidAl1 says, "just winging it".
  • Big Al1Big Al1 Posts: 8,814 Senior Member
    I have a book with dis/assembly instructions and nothing was mentioned about any pressure settings.
    Sometimes projects like these are a refresher course in Naval vocabulary!! B)
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