Headspace and Timing

[Pete]

How many guys here remember how to set the headspace and timing on an M2 Browning .50-caliber machine gun? I had two periods of instruction on it in 1977-78, one in OSUT and the other in OCS. In each case the instructional pitch was, "Gather around and listen up" while an NCO showed how it is done, but in neither case was there actual hands-on for individual students. I wouldn't feel competent at it until until I'd actually done it four or five times to an instructor's satisfaction. Some guys say they can do it by feel without the Go/No-Go Gauge but they're usually people with advanced weapons knowledge.

[tankfixer]

Going by feel is always a bad idea though it will work. Spin the barrel in and back off two clicks.
A dime and a nickel can be used as field expedient gages.

[KenWats]

First time I saw it done was in ROTC, and my recollection is about the same as Pete's- the NCO showed us how, but I didn't get a warm fuzzy on how to do it and I didn't get any hands on (although I know I wasn't complaining at the time, I was freezing my butt off). Later, as a PL, I made my squad leaders teach me how to do it, but I don't recall having to ever do it myself (I had a good track driver who took care of it before the LT could mess it up).

[Stan]

Pete, From way back when and then some

The posts start here.

In the 70's at MacGregor Range (Ft. Bliss) just about every swingin' Delta had all three of these "tools" on him while operating the M2. Sadly, few actually knew the difference .004 (four thousandths of an inch) would make in head space (NO GO is .206 and GO is .202) and what .002 would do to the timing on either the .50 or .30 BMG.

The demo pocket knife almost worked for head space and the P38 was just .002 too much for timing FIRE for both the .50 and .30.

For some strange reason, the real head space gage and pair of timing gages were simply too difficult to use

BTW, the demo knife is not pure stainless and one should not use it for EOD work.

[Fuchs]

You guys still don't have the Fabrique Nationale Herstal quick change set that eliminates the headspace issue?

IIRC four of five such sets were developed decades ago by different companies, even including U.S. companies.

What`s your military budget? Half the world's military spending?
Still suffering from a 1919 machine gun design flaw???


edit:
globalsecurity.org says

The M2E2 Quick Change Barrel (QCB) Kit enhances the M2 with new features and design improvements that make the weapon easier and safer to use. The kit features fixed headspace and timing reduce the time required to change the barrel and eliminate the need to reset headspace. The quick change barrel itself has a removable carrying handle that provides soldiers with a more expedient and safer way of changing barrels. The barrel also has a flash hider that reduces muzzle flash, making the M2 night friendly. The kit was incoprorated into the type standardized M2A1 design, which also featured a modified bolt and trigger block. By Spring 2011, all new production weapon were to be built to the M2A1 standard and older weapons would be retrofitted witht he QCB Kit.

http://www.globalsecurity.org/milita...d/m2-50cal.htm

[Stan]

You guys still don't have the Fabrique Nationale Herstal quick change set that eliminates the headspace issue?

IIRC four of five such sets were developed decades ago by different companies, even including U.S. companies.

What`s your military budget? Half the world's military spending?
Still suffering from a 1919 machine gun design flaw???


edit:
globalsecurity.org says


http://www.globalsecurity.org/milita...d/m2-50cal.htm

Fuchs,
In principle the design seemed to be good and the E2 versions tested at APG, MD puportedly saved 10 minutes on a hot barrel change. But, most of us that trained and regularly qualified with the M2 can perform an HST (or HS&T) in less than a minute. The differences in barrels are ever-so-slight, that a seasoned marksman can be up and firing in less than a minute.

There are a number of issues that Global Security doesn't cover at the link such as Safety of Use Messages (SOUM) 06 and 07 from TACOM (AKO login required).

In short, and much like most SNCOs believe, this seems to be a training deficiency combined with money-hungry companies than a problem with the BMG.

I'd say keep it simple (KISS)

Going by feel is always a bad idea though it will work.

Yep, concur. Then there's this...

Spin the barrel in and back off two clicks.
A dime and a nickel can be used as field expedient gages.

And for timing you would then use what?

How many E-1s have a dime and a nickel at the end of the month?

[Pete]

Pete, From way back when and then some.

Thanks, I looked at the older thread. I wonder what Schmedlap is up to these days and I hope he's doing OK. He's a no-BS soldier's soldier, emphatically not a careerist or feather merchant.

[Cavguy]

In the Armor/Cav community a H&S gauge is pretty much found on every vehicle commander and gunner. Big deal if you blow the cover off and didn't check the H&S!

That said, H&S is usually set in the beginning and verified as part of Pre combat checks prior to roll-out.

[AdamG]

How many guys here remember how to set the headspace and timing on an M2 Browning .50-caliber machine gun? I had two periods of instruction on it in 1977-78, one in OSUT and the other in OCS. In each case the instructional pitch was, "Gather around and listen up" while an NCO showed how it is done, but in neither case was there actual hands-on for individual students. I wouldn't feel competent at it until until I'd actually done it four or five times to an instructor's satisfaction. Some guys say they can do it by feel without the Go/No-Go Gauge but they're usually people with advanced weapons knowledge.

There's three (sub?) tests - disassembly, reassembly and functions check - that anyone using the M2 should take and pass before being allowed on the range with one.
http://www.armystudyguide.com/conten...intain-a.shtml

Otherwise, you get 'derp' moments like thissun -
http://www.youtube.com/watch?v=dXn3AV9vBro

[Rifleman]

Never did it except on the EIB test but I can't remember how to do it now.

I'm not sure where M2s were at in a light unit. Didn't HHC have them to mount on 2.5 ton trucks?

[Granite_State]

How many guys here remember how to set the headspace and timing on an M2 Browning .50-caliber machine gun? I had two periods of instruction on it in 1977-78, one in OSUT and the other in OCS. In each case the instructional pitch was, "Gather around and listen up" while an NCO showed how it is done, but in neither case was there actual hands-on for individual students. I wouldn't feel competent at it until until I'd actually done it four or five times to an instructor's satisfaction.

Likewise. First time I learned how to do it, at TBS, I only got brief hands-on time and promptly failed it. Once I had the chance to do it a half dozen times in front of an 0331 sergeant I got the hang of it. Don't think I could do it at the moment though, it's definitely a perishable skill.

[Pete]

The problem with training the task is that it's instructor-intensive, one-on-one. It could be done as concurrent training, like at the rifle range for the guys who aren't firing. Instead of waiting around for their turn to shoot they could stop at stations for headspace and timing, first aid, NBC, etc.

[Stan]

As we reminisce over C rats, .45 and .50 caliber rounds it seems evolution has now been approved for the venerable Ma Deuce

By spring 2011, all new M2s coming off the assembly lines will be manufactured to M2A1

The M2E2 Quick Change Barrel (QCB) Kit will enhance the M2 with new features and design improvements that make the weapon easier and safer to use:

Sounds like a politician ranting about his recent kill at the White House.
Now maybe we could eliminate high school grads too

[Pete]

In around 1980 when I was a lieutenant I brought up the issue of headspace and timing with our battery first sergeant, who had been in the 1st Cav in Vietnam. He said the gun chiefs were doing it, but I don't believe it was true; they were only drawing the weapons out of the arms room and taking them along on field exercises.

All the talk that was going around at the time about lieutenants listening to their NCOs, or that one of an NCO's main jobs was to train lieutenants, was true in the abstract (especially when it pertained to the WW II and Korean War generations of NCOs, not as much with the Vietnam ones), but de facto it sometimes meant shut up and don't bother us ell-tee, with the practical effect of making weak junior officers even weaker.

Later at Fort Ord when I told my battalion commander that many of our soldiers probably couldn't disassemble and reassemble our M60s properly he acted as though the problem wasn't the deficiency, but rather my blunt way of of stating it, as though him having a subordinate like me might undermine the image of "outstandingness" and "excellence" he thought we should be trying to cultivate. Some decades later after my time the Army got PowerPoint and now there's the "show biz" element entered into the equation.

I wasn't the best Army officer that ever served, but I was far far from being the worst, and IMHO these kinds of things prevent the Army from being better trained than it is. One of our finest forum members has railed about the inadequacy of Army training so I thought I'd back him with my own personal experiences.

[Pete]

When you get military organizations where the officers want to be seen as being "outstanding," "excellent," and moving onward and upward, and on the other hand have an NCO corps that regards supervision as being undue interference in their "NCO business" you get shaky outfits. When placed in combat units like that will probably muddle along but they're not all they could be, like in the TV recruiting ad. Even though my service was a long time ago I still feel like a kid about these issues -- perhaps it was ever thus, and the units that landed on the beach on D-Day were just like that.