Barrel exchange

[John Brown 0]

Are the barrels on the JSAR and Johnson machine gun interchangeable ?

[emmagee1917 0]

I think they will switch as far as sliding in and locking up. Headspace would have to be checked , of course . The difference in the mounting spacing of the front sights and the hight of the same would mean that you could not sight them in without some modification .

So , I guess it means what you mean by interchangeable.

Chris

[John Brown 0]

Would the front sight blade from the JSAR fit onto the machine gun barrel? The inside diameter of the JSAR sight being 0.560.

[emmagee1917 0]

The tapered holes ( bbl grooves ) are in the wrong place. The ID/OD may or may not be the same , but it would be no biggie to modify by turning or reaming .

Chris

[John Brown 0]

[bbl groves] Do you mean the grooves for the pins that hold the sight in alignment? The reason I am inquiring is that the barrel on my JSAR does not have serial numbers.It is a military barrel not Winfeild.The barrel collar has a 41 stamped on the tang.The Barrel at the collar stamped:

[J.A. 30-06],at12:00 -[ 45-506] at 3:00 -[Dutch proof mark five pointed star] at 6:00. Center guide Marked [30-06] at 12:00,[41] at 6:00 [M in circle]cast on right side,[A] cast on left.

Barrel tip O.D. 0.560 for one and three quarters of an inch,step up to 0.590 O.D.to three and one half inch's from tip,to 0.620 O.D. start of taper. The [bbl groves] are on top.There is only a modified blade,no ears, and no bayonet lug.

bottom - five pointed dutch proof mark. Center guide- 30-06 at 12:00 and 41 at 6:00

[Joseph Scott 0]

The barrels are interchangeable and will accept either set of sights and the bayonet lug. provided they have not been changed. You will need to use a 2/o taper pin reamer for the pins. The lmg sight has two diameters to fit the same steps as the rifle. There several versions of the lmg rear sight mount.

[John Brown 0]

Thanks for all the information everyone.Its nice to know that even though the records are incomplete there are knowledgeable people to help.

[emmagee1917 0]

Hi Joseph . The rifle has two grooves on the top front for the sight and one behind on the bottom for the bayonet lug. Are you saying 1) the MG sight will align with two of these grooves , or 2) that the barrels have both sets of cuts and they are hidden under the installed sight setup currently on it , or 3) either set will fit on all barrels but you have to add the appropriate cuts if changing around ?

Thanks , Chris

[Joseph Scott 0]

That is why I gave the taper pin reamer size. i align by sighting over the receiver and use red Loctite to hold the sight while reaming the pins. Seldom do the grooves align to a new part. Old grooves end up hidden under the new part.