My Shotguns Page

  • Buckshot Sizes
  • 12 Gauge FH
  • P12 Prototype
  • SRM 1216
  • Neostad
  • AA-12
  • FRAG-12




Buckshot Sizes

0000:85 gr. 0.380"
000: 70 gr. 0.360"
00: 54 Gr. 0.330" 9/12 > 9-rd buckshot load=estimated 484 grains = 1.10 oz avg.
0: 48 gr. 0.319"
1: 40 gr. 0.300"
2: 29 gr. 0.270"
3: 23.5 gr. 0.250"
4: 20.5 gr. 0.240"


Interesting shotgun revolver from Baikal Russia - if anyone knows anything about this please email me:


12 Gauge FH

 - "From Hell"!  :) 

This is a creation from Rob, and Ed Hubel - who built the longest 12 gauge shell possible from a converted .50 BMG case.  At 3.85" long, it is safe to call it a Super Ultra Magnum! :)  Pressures have been reported to be up to 15,000 PSI.  Average modern shotgun pressures can max up to approximately 12,000 PSI.  Due to the relatively lower pressures of the shotgun load in comparison to .50 BMG pressures, the BMG cases seem to show very little signs of wear even after repeated reloads.  Cases are normally able to be removed by hand and are not "stuck" in the chamber due to high pressure issues.  Current estimates are 20+ reloads could be made from the cases before brass flow weakens the bases beyond safe limits.



Rims are machined from brass and threaded.  The BMG case rims are turned down on a lathe and threaded for the rims.  The rim is a lathe-turned custom ring made from brass tubing or rod that is threaded onto the base of the modified .50 BMG cartridge.  Threads can be sized to 5/8"-11/16".  My first threading attempt turned the brass down to just at the rim, and measured 17mm.  The rims are also sealed in place with loctite or low-temp solder. 

An alternative rim installation would be to press or sweat a salvaged high-brass base onto an appropriately sized base.  That alternative could be sealed with loctite and the surface area should be enough to secure it.  According to the Manual of Cartridge Conversions, bases can also be sweated on with low-temp solder.  The heat would possibly require the brass to be tempered to avoid excessively-soft brass. 

Yet another alternative would be to turn the base with a dovetail, then swage a matching rimmed base into place.  This swaging would essentially rivet the base on, allowing the rim to remain secured from the swaged base.

    Rims can be CNC etched:    

Case Sizing

The .50 BMG case shoulder is removed either by fire forming or resizing.  Hydraulic resizing may be an alternative but due to the thickness of the cases this may not be adequate.  Sizing dies will need to be created on a lathe and built for incremental sizers so as not to overload the press.  It will probably take between 5-8 sizers to reach the final size.  I am working on a sizing die set based on my 12 gauge Herter's die set.  The end goal is to enlarge the .50 sized neck to the .730 sized 12 gauge mouth. 


Cases can either use .50 BMG primers, or a more economical option is to convert them to use 209 shotgun primers.  In some cases a stronger hammer spring must be used for the harder BMG primers... depends on the shotgun. 

Primer conversion to 209 primers is achieved by using a 3/8" threaded insert made from brass tubing (or rod) that is reamed to accept the primer.  The BMG primer is removed and the flash hole drilled out.  The hole is threaded with a 3/8 tap to accommodate the primer insert.  Insert is secured in place with either loctite or low-heat solder. 


Suitable donor shotguns are converted by reaming the chamber for the longer round.  Conversion is NOT one-way... standard 12 gauge shotshells can still be used in the shotgun after chambering!  Only the heaviest locking actions can be used as weaker actions will probably blow apart from the pressures.

It is recommended to install shock absorbing inserts into the buttstock, and also to add lead weight tubes to further reduce recoil.  A shotgun so equipped with recoil-reducers reportedly has the same kick as a .30-06 rifle.  Recoil without the additional reducers/weights is reportedly "harsh".  :)

I'm building one based on the N.E.F. (aka H&R) Ultra Slug Hunter.  This is a proven build that is affordable and honestly a beautiful gun.  Only heavy-framed shotguns such as the Ultra can be used in this conversion.

Starting load - 100gr RE17




The SRM 1216

A "rotating tube" shotgun

The shotgun is intended for tactical/military applications.  The shotgun is tube-fed by a conventional tube design.  There are four (4-round) tubes arranged on a spindle so that when one is empty, the spindle is manually rotated 90 degrees to the next index point and the fresh tube is ready to feed its rounds. 

There are different lengths of barrel/spindle arrangements for up to 16 (4x4) rounds in the magazine tubes.  This multi-tube arrangement allows the operator to switch different loads at will, requiring only a rotation of the spindle and a cycle of the action.

This is expected to be for sale in the near future.  Color PDF brochure available from their website:  http://www.srmarms.com/



P12 Prototype


The "P12" prototype designed by Monolith Arms (company was reportedly purchased by Magpul) as a 12 gauge version of the venerable P90 bullpup, with the benefits thereof, such as compact design with full-length barrel, quick change magazine loads, and ambidextrous downward ejection.  The P90 magazine is a proven design that has been around for over a decade.

The magazine is capable of holding up to 20 12 gauge rounds.  A shim would presumably be installed for hunting/sporting scenarios.

According to the website (and Youtube vids) the P12 was to be announced at the 2008 SHOT Show.  The company was bought out before it went public, however, and no word on whether this prototype will ever be produced for sale now that the buyout (from Magpul) is complete.




Bullpup shotgun (South Africa)




Automatic Recoil-reduced Shotgun




AP Shot Shells

Latest military design, explosive fragmenting shell intended for AP and anti-materiel use.  This could be considered a shotgun-launched fin-stabilized grenade.  The body is machined (steel?) and features a self-arming fuse.

The FRAG-12 maximizes distance with pop-out fins that open after it leaves the sabot.  This is purportedly a 200-yard round.  The fin design is complex, but the concept could be adapted for special-application hunting purposes.  This extends the concept of the Brenneke "badmitton birdie".