[EatMorRabit]

My M2HB barrel has the following stamped on it lengthwise:

26978 7266131 06 10 F5093 ZQ P M

(the Q could possibly be an O or a 0)

I believe 26978 is the cage code for General Dynamics, and 7266131 is the part number for a Stellite-lined barrel. Can anyone help me figure out what the other numbers mean? I'm curious if I can figure out the date of manufacture or other info from these numbers. Thanks!

 

[L999here]

...chrome lined...?

Welcome to the best firearms site. Believe that the 1-line markings denote a chrome lined bbl. The date stamp looks to be 06 10...which would be June 2010 for a mfg. date. I'm not sure when the switch from stellite to chrome was made...believe shortly after 1975 (?) after Viet-Nam.

 

[kkkriverrats]

26978 is the 'cage code" for General Dynamics Armament located in Saco ME it is the successor to Saco (SAK) originally a maker of textile manufacturing equipment which became a maker Post Korea of M1919A6 and barrels and other replacement parts it became Saco-Maremont (the muffler people) makers of the M60 GP machine gun.

7266131 is the 7 digit drawing/part number 06-10 could be the date of manufacture, the rest of the markings are likely heat treatment manufacturer production codes except for the "P" which is the proof mark.

Perhaps others can ad to this

 

[MG08]

Somebody was researching barrel markings, can't remember who or if it was here or gunboards, but I went and dug out a bunch of barrels I have here and got markings off them for him. Somewhere in the great wide interweb there has to be a list of code/ letter designations and what the markings mean. I had several variations in M2HB and aircraft barrel markings. Once somebody here finds it perhaps it can be a sticky in the 50 cal chain.....

 

[kkkriverrats]

Markings have changed over the years, drawing/piece mark/part numbers etc.. The simplest way to check for Satellite liner is to look at the breach end of the barrel if you see a concentric circle and a dimple between the inner and outer circles (its the locking pin) Its Stellite.

The picture is of a M1919A4/M37 barrel but as the old add for some fast food joint said "Parts is parts"

 

[EatMorRabit]

Markings have changed over the years, drawing/piece mark/part numbers etc.. The simplest way to check for Satellite liner is to look at the breach end of the barrel if you see a concentric circle and a dimple between the inner and outer circles (its the locking pin) Its Stellite.

View attachment 83441

The picture is of a M1919A4/M37 barrel but as the old add for some fast food joint said "Parts is parts"

Huh, mine doesn't have a locking pin like that. I was under the impression all new (relatively speaking) M2HB barrels were Stellite-lined, and when I look down the barrel with a light I can make out a little ring about a foot down from the chamber, which I believe is about how long the liner is. The barrel is definitely chrome-lined though.

 

[kkkriverrats]

Huh, mine doesn't have a locking pin like that. I was under the impression all new (relatively speaking) M2HB barrels were Stellite-lined, and when I look down the barrel with a light I can make out a little ring about a foot down from the chamber, which I believe is about how long the liner is. The barrel is definitely chrome-lined though.

The Stellite insert is held in place by the retainer which is actually the chamber which is screwed in to the barrel tube. Possibly the .50's were fabricated differently than the .30's but from what I have gathered the .30's mimicked the .50's the .30 Stellite liner is only about 5 inches long but it stands to reaason that the .50 would be longer.

 

[OREO]

Here is a link to info about the barrel you have identified.

http://www.parttarget.com/1005-00-726-6131_1005007266131_7266131.html

It is the typical current production M2HB stellite lined & chrome lined barrel. There are many different versions of barrels for the .50 BMG, including several HB and many aircraft barrel variations. I'll try to dig out my manuals/reference info and get a list of P/Ns for the various barrels to list it here.

I'll probably get some blow-back for this but in my opinion, chrome lining of a bore, especially here beyond the end of the stellite liner, serves only to protect the bore against corrosion and not otherwise prolong the throat(after the liner)/rifling life from firing. Here, chrome plating does little to lengthen barrel life; that's what the liner is for. In fact, some M2HB manuals say for a shot-out stellite barrel to chop off the breech end of the barrel forward of the liner and return that portion to an arsenal (Rock Island?) for recovery of the stellite liner for reuse. My understanding is that stellite barrels last between 3-5 times longer than non-lined barrels. I know I've never worn one out. The technology was developed near the end of WWII and used extensively on aircraft .50's then and thereafter plus was used a lot on 1919A6 barrels. My guess is that there were so many non-lined M2HB bbls. manufactured during WWII, that the M2HB stellite barrel was a low production item for a good many years. Of the heavy barrel stellite lined barrels I've seen, very few were dated in the 1950's and 1960's. I've never seen a 1940's dated one. (In fact, I purchased NIB US mfg'd. WWII dated barrels from Coles at Knob Creek probably 10 years back. They were all standard non-lined and non-chromed barrels. They were marked for export for the military assistance program. I'm guessing they were re-imported.)

Here are some pics of a cutaway of a stellite bbl. You can see the lining from the variations in barrel metals.

... and

. . . and

 

[EatMorRabit]

Here is a link to info about the barrel you have identified.

http://www.parttarget.com/1005-00-726-6131_1005007266131_7266131.html

It is the typical current production M2HB stellite lined & chrome lined barrel. There are many different versions of barrels for the .50 BMG, including several HB and many aircraft barrel variations. I'll try to dig out my manuals/reference info and get a list of P/Ns for the various barrels to list it here.

I'll probably get some blow-back for this but in my opinion, chrome lining of a bore, especially here beyond the end of the stellite liner, serves only to protect the bore against corrosion and not otherwise prolong the throat(after the liner)/rifling life from firing. Here, chrome plating does little to lengthen barrel life; that's what the liner is for. In fact, some M2HB manuals say for a shot-out stellite barrel to chop off the breech end of the barrel forward of the liner and return that portion to an arsenal (Rock Island?) for recovery of the stellite liner for reuse. My understanding is that stellite barrels last between 3-5 times longer than non-lined barrels. I know I've never worn one out. The technology was developed near the end of WWII and used extensively on aircraft .50's then and thereafter plus was used a lot on 1919A6 barrels. My guess is that there were so many non-lined M2HB bbls. manufactured during WWII, that the M2HB stellite barrel was a low production item for a good many years. Of the heavy barrel stellite lined barrels I've seen, very few were dated in the 1950's and 1960's. I've never seen a 1940's dated one. (In fact, I purchased NIB US mfg'd. WWII dated barrels from Coles at Knob Creek probably 10 years back. They were all standard non-lined and non-chromed barrels. They were marked for export for the military assistance program. I'm guessing they were re-imported.)

Here are some pics of a cutaway of a stellite bbl. You can see the lining from the variations in barrel metals.

View attachment 83453 ... and View attachment 83455 . . . and View attachment 83457

Thanks for the pics, and the explanation! Very helpful, I really appreciate it. I didn't know the Stellite-lined barrels went so far back, that's pretty cool. Now I gotta find a machine gun shoot to go to one day...

 

[OREO]

Per various manuals here are some of the M2 .50 cal barrel part numbers. I don’t believe this is a complete list.
Heavy Barrel
7266131 (lined) This is the number used in the 1968 TM-9. The current NSN is 1005-00-726-6131
7161814 (lined )

6528269 (unlined)

Aircraft
7265156 (lined)
7162259 (lined)
7162079 (lined)
7161580 (lined)

6528272 (unlined)
6535348A (unlined)
7162012 (unlined)
D35348A-(with suffix) WWII drawing number
D28272-(with suffix) WWII drawing number

Water-cooled
6528271 (unlined)

Note that these are mostly post-war part numbers. For instance the HB barrel WWII part number for the unlined barrel was the so called drawing number, D28269-8, D28269-11, etc. The suffix indicates the drawing revision number indicating a possible small change in the part (design, material, heat treat, etc.) or other drawing revision in an otherwise interchangeable part. In other words, sometimes you can see the change in the part and sometimes not. My guess is that there were a large number of drawing number changes for barrels and so a “-8” and “-11” is one of many variations in WWII unlined barrel part numbers. In any event the part, if still used, will have the last 5 significant digits (not suffix) in it regardless if it is a WWII drawing number, post-war number or current NSN.

 

[ajmdreammg42]

oreo or anybody else, I have a M3 barrel that has packing groove milled into it like a 1917a1 does. It has very faint drawing number D 35348-5 on it. It is a plain steel barrel and it looks new old stock. it is the same length and diameter as a M3 barrel. only thing I can think of that it was at one time a barrel for the early water cooled m2's then modified. It makes no sense that a aircraft barrel has a packing groove in it for water cooled gun. I have a original 45" m2 water cooled barrel and the packing groove is a totally different set up than this one. anybody got any ideals ?

 

[L999here]

M3...?

My question is whether or not the bbl shown is shorter than 45"...? If it's longer than the M3 aircraft bbl,I'd agree that it is a water-cooled M2HB bbl,as I also have one. Markings are crisp,clear and in a straight line...D28271-14-REP A1 SA 7-43 and has an expanded type of muzzle brake and is 45" long. If your bbl is shorter...might be an experimental type or for an earlier water-cooled,as you suggested.

 

[ajmdreammg42]

Len,
Same length and diameter and same end as a M3. Here are more pics comparing it to a 45" M2 water cooled barrel and 2 other M3 barrels

 

[L999here]

...yep...

Just as I suspected with your original description...a modified bbl. Thought someone else like Jman would intercede here,as I also thought it might be for the MG52 water-cooled .50. Learn something new every day in this 'hobby'...LOL.

 

[Rory]

Went to the OGCA show today to meet up with Heckinohio and his Rainbow brite.

while there I found a single item that needed to come home with me. First decent deal I’ve found at a show since knob creek ended.

26978 7266131 02 10 f4509 xc pm 2
M2hb barrel looks excellent condition.
$400!!!

 

[Rory]

Any help here. Got a barrel in and it’s missing the long string of numbers.
Only “ F765 PM”

 

[MWIL11264]

Anything around the barrel carry handle area? I bought one that was "unmarked" but after wiping it down with oil you could make out a really small stamped drawing number.

 

[biffj]

The M1921 Watercooled gun used 36in barrel unlike the later 48 in for the MG52 watercooler. The early guns have a waterjacket attached to the trunnion like the smaller 1917 brownings. The later MG52 watercoolers use the universal receiver and the waterjacket screws on to the trunnion just like the barrel supports for the heavy barrel or the aircraft guns. So the shorter barrels with the packing grooves are probably for the M1921 watercooler. Maybe they made up a dual use barrel for either the aircraft or watercooled guns as they did still have some M1921 guns in inventory at the beginning of the war.

Frank