This is a very rough draft in continual improvement.Remember that all laws need to be understood and followed. NFA rules apply here.  The John Browning 1919A4 can be converted into a semi-auto long gun. A person is allowed to do this themselves. The right hand sideplate is considered the Receiver. The Receiver is considered "the gun".

"Parts Kits" contain all or most parts except the side plate, which is what you build.

There are at least 2 , maybe 3 different  ATF approved semi-auto 1919A4's in the marketplace. 

 

The parts and receiver to allow semi-auto operation can also be purchased.These are approved rifles for resale.All "Semi Kits" that are availible require at least 8 hours of building to produce a shootable gun. This is one of several  ATF requirements. The time frame does not reflect the real time it will take to complete the finishing and assembly of a 1919A4 semi. The sideplate that is approved has raised areas that allow only parts that have had slots cut into them to be fitted into the receiver assy. The original right hand sideplates were .187 inch thick, Thats 3/16 in..It is  flat plate steel. The Semi side plates start off as a .250 in.plate that is milled down mostly to .187 inch with areas left to appox .250 in. These raised areas fit into the appox .065-.70 areas that were machined away from the 3 main internal componets housed inside the receiver assy. This mod allows only modified internal parts to be used. I am still looking for additional info on heat treating of the plates.

 

A "80%" sideplate means the plate can not be attached to the rest of the "Parts Kit" with out additional machining.  Mounting holes and some deburing are needed. Most of the 80% FA plates only need simple holes drilled. The semi plate may need to be milled. It all depends on the design you use, and the money spent. The current thought is:

 

A  3/16 inch completed side plate is a machine gun, BAD

 

Having 3/16 80% sideplate with a unmodified parts set is a machine gun. A big No-No.

 

A 3/16 80% sideplate with modified parts kit is in a grey area,call it a machine gun to be safe.

 

A 3/16 side plate that has been "raised" by welding or brazing is still a machine gun sideplate. Dont go there.

 

A side plate can be made by using .250 inch stock.Starrets sells excellent blanks that serve the purpose well.There are dozens of different plates around for sale.

There have been several Men making 1/4 milled  80% plates.See  adds at 1919A4.com  or Bowers Boards.

 

Additional ATF requirements are the welding of the sideplates to the trunion block and a couple other places. This eliminates  modifying into a FA operation by replacing  RH plate.

 

The internal parts are modified in such a way that un-modified  FA parts will not fit inside the receiver box. And FA parts will not function within the semi-auto bolt,or trigger assy.

The internal mods that define this as a semi auto are: sear and trigger assy.The bolt is machined to accept a larger sear. A FA sear will no longer fit.The trigger has been modified with a sliding disconnect arm.

 

A FA trigger arm will not engage the modified sear and will not fire the gun. In the big picture this is a very easy conversion to semi-auto .

 

The "Semi-Auto Kits " may require  Your FA parts being sent in to be  machined into semi-auto configuration. This is just a quick over-view of this gun. If you buy the parts kit at say 250, Sarco inc. Then buy the semi kit, Lee tool, 475, finaly have the bolt, trigger housing, and barrel extension housing machined 150 your into this masterpiece for 875

 

There are many  consideration that need to be addressed if You plan to build your own 1919.

 

The gun you build must only fire one round per trigger actuation. ATF has been known to beat them with a hammer trying to get more than one round to fire.

 

It must not be readly converted back into original configuration. In fact after its modified it can never go home again. It will be welded together.

 

The modified side plates MUST be welded to the trunion.

 

Several problems have arose during the welding process. Welding causes the side plates to twist or warp if not done correctly. Clearances could have been exceeded, plates not "level". Or the welds look bad. The original rivot holes could be used to tack weld the 1919.

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If you read this far : The gun is of your design, It requires no registration , but a unique serial number of some type should be added. It can be letters, numbers , or a mix . You can build one gun a year for personal use.

 

This  Web page was made  from My personal stash of info. I needed to share the info with a friend  so I opened up this site. All info on this site meets ATF laws to the best of my knowledge and will stay that way. If I'm wrong on anything, PLEASE let me know

 

I recommend that you in turn share your information and experences with the group .This is a very active site for those that are intrested in semi-auto 1919's . I am not an expert! But "WE" as a group become experts. Have a good day, and keep your powder dry