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Joined: Feb 07, 2015
Posts: 129
Location: Huntington, WV

PostPosted: Wed Nov 11, 2015 3:34 am Reply with quote

This is a Potter Duplex ammo reloading press. It has 38S dies that come with it. Appears to be in perfect working order. The spent primer drawer is missing as shown in the pics. Please make an offer (via PM) if you are interested.
The Duplex line of presses involves three stations and four operations. The de-priming / sizing and priming operations share the first station (shellholder, left side). Pulling the main handle down deprimes, resizes and places a very slight bell on the casing. The casing remains in the left side shellholder for priming. The small lever on the left side of the base is pulled (Standard or Combination models). The machine picks up a fresh primer from the magazine tube via a brass slide bar, and shuttles it forward into position between the priming ram and the shell's primer pocket. Pulling the priming handle through its full range of movement will cause the priming ram to raise up from it's housing beneath the base of the press and seat the primer in the casing. The primer seating depth is adjustable by turning the screw on the front of the machine's base. -- On the Automatic Duplex there is no priming handle. The priming operation is completed upon the upstroke of the operating handle.

The second station is the powder measure. The operator must hold the casing under the powder measure with his/her left hand, while utilizing the operating handle with his right. Powder will dispense whether there is a casing under the measure or not! Many of us who use vintage reloading equipment know all too well what happens if you don't pay attention at this stage!

The third station is the right side shellholder. This die station will seat and crimp the bullet. Once all of the stations are filled with casings, a loaded round can be produced with each pull of the handle. The operator must manually move each of the casings around to the next station to keep the cycle going. It may appear confusing, but it becomes quite easy to do once the operator gets a rhythm going.

Dies are adjusted the same as modern dies in every respect. The only other adjustment which must be addressed is the primer slide bar. In order for the primers to be feed smoothly from the magazine to the priming ram, the hole in the primer slide bar must align precisely with both the magazine (to pick up a primer), and the priming ram (the ram actually moves upward, though the hole in the slide bar as it presses the primer into the primer pocket).

At the back of the machine, there are two screws mounted in the frame of the base, which are each locked in place by small hex nuts. These screws are the slider stops. They control both the rearward and forward travel of the slide bar. To align the slider hole with primer magazine, remove the magazine tube and look straight down into the magazine plate. Move the slide bar back to its most rearward position while looking down though the magazine plate. Adjust the rear slider stop screw until the holes line up, then lock the slider stop in place.

To adjust the forward slide bar stop, move the slide bar forward slowly to its most forward position. As this is happening, the priming ram will be moving upward. If you feel an abrupt stop, don't force it. Adjust the forward slider stop screw until the priming ram runs up smoothly through the slide bar, then lock the forward slider stop in place.


*Produced from 1936 to 1966 with 600 units manufactured

*Automatic primer feed via a brass tube (100 primer magazine)

*Manual primer seating lever - left side on base

*Priming system allows for change to/from large and small primers

*Uses proprietary 7/8 x 18 TPI dies

*Capable of full length resizing of pistol brass and neck sizing of rifle brass

*Sold with or without integratable powder hopper/measure

*Accepts proprietary sub-base assembly with spent primer catcher

*Unit weight with powder measure - 28 pounds. With sub-base - 36 pounds

*Produced from 1940 to 1966

*1,500 units manufactured

*Automatic primer feed via brass tube (100 primer magazine)

*Primer seating actuated by a one-piece connecting rod on the right side

*Automatic priming mechanism is internal to the base

*Manual priming is not possible.

*Priming system allows for change to-and-from large and small primers

*Uses a proprietary 7/8 x 18 TPI dies

*Full length resizing of straight wall brass and neck sizing of rifle brass

*Sold with or without integratable powder hopper/measure

*Accepts proprietary sub-base assembly w/ spent primer catcher

*Unit weight with powder measure and sub-base - 35 lbs.

*In 1945 this loader was advertisedas the "Victory Duplex"

*In 1964, a special version was offered for 7/8 x 14 dies.


*Produced from 1946 to 1966

*75 units manufactured

*Same capabilities and options as the Automatic Duplex

*Connecting rod on right side of press can be "disconnected" for manual priming

*Priming handle on left side of base for use in manual priming only

*Unit was set up at the factory to operate in "automatic" mode prior to shipping to the customer.


The best description about serial numbers on Potter machines comes from Kenneth Walters, Don't Pass Up a Potter article in the 11th Edition of the Handloaders Digest. On early Duplex presses a serial number was stamped on the flat portion of the base casting just behind the shellplate. The serial numbers started with 1 and continued sequentially for the total number of presses manufactured to date. Later, the stamping system was changed to a letter and number sequence. It indicated the type of machine and the year it was manufactured. S = Standard Duplex C = Combination Duplex A = Automatic Duplex G= Gem ST = Super Twin. It is not known if the Simplex was stamped. I am aware of only one Simplex and the owner indicates that it is not numbered.

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