I was just wondering why the US "Ma Duce" .50 caliber MG had to be cocked twice. I've seen this on some movies and on THC's Mail Call, where the gunner had to pull back the cocking handle once, then again, in order to prepare for firing.

I dunno, maybe to cock it, then to chamber a round?

First pull on the charging handle seats the round and the link, second pull on the handle places the round in the chamber. When you push down on the trigger (commonly referred to as the butterfly due to its shape) the round in the chamber ignites throwing the bolt to the rear and forward again to seat another round. Referred to as the sequence of fire. Another thing you do not see all the cowboys doing on TV is adjusting the weapon for head space and timing. This is a crucial first step or the weapon will not operate. After inserting the barrel in the weapon, back it off two clicks then insert the head space gage and by perfoming a Go/NO GO exercise you correctly set the space between the front of the bolt and the rear of barrel. Timing is when the recoiling parts are within a parameter established on the gage out of battery. Jeff normally has a manual handy and can provide you the specifics. Hope this helps.
DJ

Yes, as DJ states, headspace and timing are crucial for the M2 .50 cal. If you don't keep the headspace and timing within standards you risk sending the barrel down range (if you're lucky) or the gun exploding (if you're unlucky). Luckily none of my units had a M2 suffer damage from out of spec headspace and timing, guns were never mounted on my vehicles without setting and checking for correct specs, even when no ammo was involved.

Something else a lot of soldiers don't know - the headspace and timing gages must be calibrated to ensure they have not worn from use. Setting headspace and timing is sort of like setting the gap and timing on a pre-electronic ignition vehicle. The engines want run right if the plups and points aren't gapped within specs and the ignition timing is off.

I am sure glad I don't have to mess with gapping and timing my personal vehciles anymore!!!

Newer US machineguns like the M85 .50cal (an aircraft MG converted for use in the M60-series tank cupola), the M60 & M240 LMGs all have fixed headspace and timing. They still require periodic checking of barrel headspace by an armorer.

I remember all that from the good old days... I still use the phrase which mystifies civilans..as a warehouse supervisor type they think it is quite colorful they also love "wrapped around the axle"

Don't let these guys fool you!

There is no such thing as head space and timing.

People on TV are just pulling the charging handle twice to look cool...

Steve

Steve-- I am lost--- fixed head space and timing .50 Cal machine guns are certainly in the inventory, but my understanding is that we still have a majority of weapons that require this drill. Am I incorrect?
DJ

No, I'm just BS'ing you. Your's and Jeff's responses were so good it left no room for anyone else to respond!

Actually, it would be great to see a show on History Channel about how to operate these weapons. A 'kind of 'how to' episonde of "Tales of the Gun." They could include a few neat weapons like the M2, Mk. 19, etc.

Maybe the censors wouldn't approve that kind of show, but it would be very neat for people who will never get to play with the real stuff.

Steve

Newer guns, though not M2s are coming out with fixed head space and required no timing gages. A copy here in Nashville, TN builds M2s now. We also have a company in Murfreesboro that builds special weapons, like .50 cal sniper rifles and other Spec Ops equipment. Knew a guy that worked there but he couldn't discuss a lot of the contracts. COOL!!

Actually there is a guy here in the Springs, who has guns like this, Ma Duce, MG 34, MG 42, BAR, etc. that you can shoot. For a fee of course. I have no idea what he charges for this, but based on how much ammo must go for I'm sure it's a pretty penny. His name is the Dragon Man, and he also runs a paint ball field. Interesting character.

Thanks for the info guys. I was just curious, that's all.