Headspace and Timing

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.

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.

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).

Pete, From way back when and then some

The posts start here.

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Originally Posted by Stan

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 :wry:

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

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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

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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.

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

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Originally Posted by 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


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

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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) ;)

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Originally Posted by tankfixer

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

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

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Originally Posted by tankfixer

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

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And for timing you would then use what?

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

Not to mention if you have a head space and timing gauge in an Inf Bn you're a lucky man. Those are worth their weight in gold in Weapons Co.

Pete

Less than a minute? How much less?
Changing the barrel of a MG 3 takes ten seconds at most (if you keep a minimal target silhouette). That's a 1942 solution and already outdated as quick change barrel concept.

A barrel change of more than 20 sec effectively denies a barrel change in many if not most combat situations.

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Originally Posted by Stan

Pete, From way back when and then some.

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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.

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.

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Originally Posted by 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.

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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

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?

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Originally Posted by Cavguy

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

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In retrospect that's something I should have been doing as the XO of a four-gun 175mm battery in 1980. The four M548 tracked cargo carriers in the firing battery had M2 .50-cals. Our main concern at the time was keeping the 175 rounds within 50 meters of our targets.

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Originally Posted by 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.

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Thanks, Neil (never could get your name spelled correctly) ;)

Something about all those fancy (ahem) upgrades to replace HST training (and result in death). Great video of what often means blowing the top cover off.

BTW, you may be the only person colder than I am here :D

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Originally Posted by Pete

In retrospect that's something I should have been doing as the XO of a four-gun 175mm battery in 1980. The four M548 tracked cargo carriers in the firing battery had M2 .50-cals. Our main concern at the time was keeping the 175 rounds within 50 meters of our targets.

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Jeez, Pete, don't you mean the M35 Deuce and a half? I only know of one other person herein that drove the M548 when Christ was a Corporal (Ken) :eek:

With that, a little history...

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INTRODUCTION
The author’s introduction to the “fifty-cal” was the opportunity to fire a few rounds for familiarization during infantry training in 1967.

That was after we had been shown the basics of its operation: how to load, cock, fire, and clear it. Such was the extent of our exposure to the legendary “MaDuce,” officially known as “Machine Gun, Caliber .50, Heavy Barrel, M2.”

The instructor explained that the M2 had been in use since 1933. Some of the trainees, including myself, gazed curiously at the guns placed before us, thinking that they didn’t look that old.

Observing a US mechanized rifle company “trim the tree line” with a dozen “fifties” made me appreciate that the receiving end of such fire was a place no-one would want to be.

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In his book Mounted Combat in Vietnam Donn Starry said the Cambodian incursion couldn't have taken place without the M548 hauling cargo but that the vehicle had reliability problems. Based on my experience with them I agree wholeheartedly regarding the maintenance headaches. Ours in 6/9 FA in Germany had ring mounts for the .50 cals.

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Originally Posted by Stan

Jeez, Pete, don't you mean the M35 Deuce and a half? I only know of one other person herein that drove the M548 when Christ was a Corporal (Ken) :eek:

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Hah, now you know three. I had an M548 in my Combat Engineer platoon in 1997 (used as a Volcano carrier). Generally referred to as the "Short bus" (I'll leave it to folks here to debate whether that was aimed at the vehicle itself or the operators).

When I was at Fort Ord we had an Officer Professional Development tour of the FMC Corporation factory up the road in San Jose. FMC was then making the Bradley as well as the M113 family of vehicles, of which the M548 was one. I asked the FMC guy who ran the test track why the M548 had such reliability problems and he said they checked each and every one before it left the factory, so it must have been Army maintenance that was to blame.

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Originally Posted by Pete

When I was at Fort Ord we had an Officer Professional Development tour of the FMC Corporation factory up the road in San Jose. FMC was then making the Bradley as well as the M113 family of vehicles, of which the M548 was one. I asked the FMC guy who ran the test track why the M548 had such reliability problems and he said they checked each and every one before it left the factory, so it must have been Army maintenance that was to blame.

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Getting a bit off topic here, but it is your thread, so hopefully nobody minds much. I recall thinking mine was a pain in the neck, but I always chalked it up to the fact that the 113s in my platoon drove all over the place. The 548 basically drove from AA to AA and then maybe did a Volcano mission then back to a hide site or the AA. So, anything that was getting ready to go on a 113, you'd find it pretty quick. The 548s tended to sit around more, so problems got a chance to fester. I also remember one of the mechanics saying to me that the 548s were a little harder to get into to work on and that there were easier leak paths for rainwater to get in to corrode things that aren't supposed to corrode. That jives with my vague memory of starter problems with the one in my platoon.

Also, when you change the center of gravity of the vehicle, I'd bet you change how it responds to abuse as well. Plus the thing was loud as heck to ride in, and having the crew compartment so far forward and high up (as compared to the 113) made for a bumpy ride.

On the whole, it was less than reliable, but not a "tremendous maintenance headache" on the order of an AVLB, CEV, or M9 ACE.

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Originally Posted by KenWats

Hah, now you know three. I had an M548 in my Combat Engineer platoon in 1997 (used as a Volcano carrier). Generally referred to as the "Short bus" (I'll leave it to folks here to debate whether that was aimed at the vehicle itself or the operators).

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Ken,
My comments were actually for our very own Ken White, not you. But, yep, now I know three 548 riders/drivers :D

I never got to ride in one, but did get to tow one with a 578. Does that count?

Some great pics here albeit a little earlier than 97 :D.

and it's newer than an M75 or an M41A1, it's probably wrong. ;)

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Originally Posted by Stan

Thanks, Neil (never could get your name spelled correctly) ;)

Something about all those fancy (ahem) upgrades to replace HST training (and result in death). Great video of what often means blowing the top cover off.

BTW, you may be the only person colder than I am here :D

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Thanks Stan.

Alaska is warming up, high's in the 30s this week. Breaking out the shorts after the -40 degree spells of Nov-Jan.

Actually lost most of my acclimatization while at NTC during Jan and Feb, and then some pre-deployment block leave to Hawaii. Rolling out the door to Afghanistan with our unit in the next month.

Niel <== :D

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Originally Posted by Stan

Jeez, Pete, don't you mean the M35 Deuce and a half?

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Back when we had the Deuce and a Half our rifles were of .45-70 caliber and our politically incorrect C Rations still had cigarettes in them. :cool:

Regarding the old C Rations, the Pork Slices w/ Juices could be turned into a good sandwich when combined with the round crackers in a can, what one of my guys once called "Field Frisbies." Spaghetti w/ Beef Chunks wasn't that bad either. The Eggs and Ham used to have a blue tint.

I'd best wind this up before a Moderator brings up the subject of me being off-topic again.

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Originally Posted by 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.

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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.

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.

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

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

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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:

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

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.

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.

Pete,
Back when I joined in the early 70s we had several issues with Vietnam-era NCOs. But most of the platoon leaders I had were real sharp and spent as much time learning as they did teaching. One of the things I noticed was that most of the enlisted had yet to complete high school. That put them in some meaningless jobs and MOSs. It wasn’t until 1985 that most would have to complete HS and retake their ASVAB. A lot of folks left the Army that year on Aberdeen, but the change and impact on a professional NCO Corps was necessary and profound.

I think only the Navy E7s are responsible for nurturing junior officers (by regulation that is). By 1980 as an E6 I rarely saw my 1LT and when he did show up it often meant something was wrong, or, he just got his ass chewed.

Of all the field exercises and training, none were more rewarding that the firing range :)

One of my battalion commanders who was also a Mustang like I was didn't think very highly of me and the efficiency reports he gave me show it. I was da*ned with faint praise. It wasn't that he thought I was incompetent as much as being lacking in the "bust a*s" quality that he wanted to see in his officers, having subordinates who treat every little task, no matter how trivial, as though their lives depended on it. His temper tantrums were awesome. He retired as a two-star, but when he commanded his battalion he turned the place into a U.S. Army Separation Point for all ranks, high and low. It was during the early 1980s when the Army was making a deliberate effort to get out of the post-Vietnam doldrums. That needed to be done for the good of the service, but a lot of the careers of good guys were collateral damage while it was happening.

Most guys wouldn't admit to having had something something like this happen to them on a public forum but it has a lot to do with that vague concept of "The good of the service." I was a soldier once and true.