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Blank Adapting the M1918 Series BAR

Date Written: 2/5/2008
Author: Chris Guska

Blank Adapting the M1918 Series BAR

There are a number of different options available for blank adapting the M1918 (a1,a2,a3) series Browning Automatic Rifle.

There are 5 main options available (that I know of to be currently available) –

  1. Bill Guiette – Guiette Manufacturing
  2. Tom Arter – A&A Militaria
  3. GI Surplus – Sarco / BMG Parts
  4. Internally Threaded Barrel
  5. Make your own

Whether you own a fully automatic M1918 ( a1, a2), or semi automatic Ohio Ordnance Works M1918a3 – the blank adapter will be the same.  What will vary is the size of the set screw apertures required for consistent operation.   Consistent operation will vary due to blanks, condition of the weapon, weather/temperature, lubrication, spring strength and other factors.

My experience is limited to the M1918a3 semi auto from Ohio Ordnance Works.  Always remember to follow the recommendation of the vendor from which you purchased your blanks for the correct size set screw aperture.  Start with the largest hole, and work to the smallest hole that will consistently cycle the weapon.  Keep in mind, that the BAR has an adjustable gas system – so use the set screw that will consistently cycle the weapon at the smallest gas port setting.  Open the gas port as the weapon gets dirtier to retain consistent functionality as needed.

Your options:

Bill Guiette – Guiette Manufacturing - http://www.guiettemfg.com/catalog.html

Guiette Manufacturing offers 2 different BAR blank adapters – a M1918 and M1918a2 style.

M1918 - $90.00 + Shipping

M1918a2 - $110.00 + Shipping

Both adapters use a ½ inch 20 NF set screw, that is screwed in and tightens against the front of the barrel.  The adapter comes with 3 pre-drilled set screws of unknown apertures.  These adapters are purpose made from a single piece of steel.


Tom Arter – A&A Militaria – ww2kkrad@hotmail.com

A&A Militiaria sells 2 different BAR blank adapters – one that is made for A&A, and recently some left overs from Stembridge Gun Rental / Saving Private Ryan.

M1918a2 - $55.00 + Shipping

The adapter made for A&A is center drilled and threaded for a 3/8 set screw. It is threaded from the back to the front – so the set screw tightens against the adapter itself, from the inside out.  The set screw does not tighten against the front of the barrel. The Stembridge adapter is center drilled, but not threaded – it can be easily threaded for 3/8 set screws, with a thread pitch of your choice.

This is the adapter that I am using.  I modified a Stembridge adapter – since that’s what Tom had in stock at the time.  I threaded it to use 3/8 NC set screws which are common to what I am using for M1 Carbines, Garands as well as a variety of .32 caliber pistols.

Here is a photo comparison of the Stembridge adapter compared to the USGI flash hider that came with my m1918a3.  BFA on top, USGI on bottom.

Front view – the Stembridge adapter was bored out, leaving 1 inch of steel at the base end of it, which I could thread for 3/8 set screws.  It is not a simple tube like the USGI flash hider.

View from the back – with the threaded end, pre-threaded for the muzzle threads of the BAR, then internally threaded for a set screw.  The set screw is inserted in this end, and tightens against a “shoulder” where the threads stop.  The threads only run deep enough into the center drilled hole so that the set screw will be slightly countersunk with the flat of the inside of the BFA.

Both adapters are purpose made from a single piece of steel.  I am unsure of what size set screw and the thread pitch of the set screws used in A&A’s finished BAR BFA’s.  I used 3/8 NC for the modification of the Stembridge adapter – as that was what is convenient for me.


USGI BAR Blank Firing Adapter – Sarco Inc - $17.50,  BMG Parts $79.99

This adapter is non-adjustable, as it is pre-drilled for the aperture.  You will need to gauge the aperture individually to find out what size it is.   The appearance of this BFA is distinctive, and looks nothing like the normal flash hider.  The only real advantage of this adapter is that it’s cheap – but you have to ask – why cheap out on a $3,500 semi auto, or a $10,000+ full auto?


Threaded Barrel –
You could thread the inside of your barrel, like has been done with M1 Carbines and M1 Garands – but the question is – Why?  Especially when there are several excellent options available from Bill Guiette and Tom Arter.  I’ll leave this one as is.


Make your own –

If you’ve got the lathe and mill skills – you could probably make your own.  Either by using an original flash hider as a pattern, or turning a plug, pinning or welding it into a stock flash hider.  Then center drill and thread for set screws.  An adapter in a flash hider will never be as strong as a single piece custom made adapter – but, it may get the job done, and for marginally cheaper than one of the purpose made ones.   Currently – USGI flash hiders are going for $35.00 + shipping.

BAR BFA Aperture Table

Blank Manufacturer

Decmial Size

Drill Bit Size

Richard Satterfield – Blanksguy



Joe Swanson



Atlantic Wall Standard



Atlantic Wall Hot


#28 or 9/64ths

Israeli / FN Longneck



USGI M1909





Magazines are extremely important to consistent function with blanks. Make sure that your magazines are dent free – to not impeded the follower.  There are special blank magazines available from Sarco, or from Joe Swanson.  The “blank magazines” have a slight feed ramp extension in the front of the magazine to allow for consistent feeding of blunt nosed short blanks.  Many BAR owners have used the Israeli / FN blanks that were a full length blank, with fake bullet crimp to assure proper feeding.  Recently – some BAR owners have reported good results using standard star crimp 30.06 blanks from suppliers such as Blanksguy or Atlantic Wall Blanks. 

The main issue with blanks is to ensure consistency – in using a consistent manufacturer, load, bfa aperture, and load count in the magazines.  Some owners have reported greater reliability in loading only 17 or 18 rounds in each magazine, as well as mixing the type of blanks used, such as 1 Israeli longneck, then a USGI m1909 crimp equivalent and so forth, with a couple of longnecks at the top and bottom. 



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