Unjamming guns in flight

[Demetrious]

I have a ton of questions about guns that jammed during flight. Could the pilot possibly attempt to un-jam the guns using the electric gun chargers, and if so, did they do it very often in combat? Did all aircraft even have them?

I learned about the electric gun chargers from a walkaround photo book of a Mustang:

The arrows point to the chargers- to me they appear to be a simple electrical solenoid that racks the slide and chambers the first round. Would they have enough power to possibly attempt to clear a jam? Could you keep on hitting the charging button several times to attempt it? Obviously, simply racking the slide will only clear some types of jams, but still, it would be better then nothing. Also, I know that the mass-production of ammunition resulted in ammo that wasn't exactly match-grade quality- one dud round would stop the automatic cycle and require the slide to be racked to get a fresh bullet in there. How many "jams" in combat were simply caused by that, and swiftly remedied by a quick hit of the gun chargers button? For that matter, did each gun have it's own separate button, or were all the chargers just slaved to one control?

As for jamming of guns in general, how common was it? I've read in at least one P-51B pilots account that the firepower of the B Mustang would have been adequate (though not exceptional,) if only one or two guns wouldn't jam on every mission. Anecdotal, of course, but did guns often jam in straight and level flight? It was always my impression that the kinds of jams that took out all the guns on an aircraft (like happened to the first pilot to intercept a V-1 in a Gloster Meteor,) were caused by the belt links breaking or some other definitively incapacitating malfunction when trying to fire while pulling very heavy G's. That's the only way I can see all of a planes guns going out at about the same time.

Forgive my intensive curiosity. I am a nerd.

Edit:

Ah, look what I found.

Apparently you could clear jams from the cockpit, but the B model mustang didn't have electric gun chargers to allow that. The D model obviously added that.

 

[renrich]

I believe that if a gun jammed in flight it was impossible to clear the jam until on the ground. It may be dependent on what type of jam it was. The B and C Mustangs did have a lot of problems as the feed to the guns was awkward since (I think) the guns were not mounted in an upright manner but rather turned at an angle. I also believe that guns mounted in the fuselage like many axis fighters had less jams than wing mounted guns like most Allied fighters. Gun jams were not limited to Mustangs as they happened to all types but early in the war Wildcats were plagued by many jams and I believe the A6M s had trouble with jams in the 20 mms under negative Gs.

 

[Tony Williams]

Most guns came with charging mechanisms, which they used to make the guns ready to fire (for obvious reasons, pilots preferred the guns not to be cocked on take-off). If a failure to fire was due to dud ammunition, then the charger could be used to eject the dud and reload another. Exactly how many times would depend on the type of charger: IIRC some were pneumatic and had an air bottle to provide the power. Once that was used up, no more recharging.

Guns could jam for a variety of reasons (the mechanism freezing up at altitude was a common one early in the war). Mostly the problem was connected to the ammo feed rather than ammo quality (which was much more of an issue in WW1). Belt separation under G forces could be an issue in some installations - especially the Me 262 - and in fact remained a problem as late as the F8U Crusader jet in the Vietnam War.

 

[HoHun]

Hi Tony,

>Most guns came with charging mechanisms, which they used to make the guns ready to fire (for obvious reasons, pilots preferred the guns not to be cocked on take-off).

It's my impression that Navy fighters tended to have charging handles that also served to lock the gun mechanism in order to guarantee a safe landing.

With regard to the USAAF aircraft, I don't think all of them had charging mechanisms ... at least the P-51 manual notes:

"The P-51D carries six free-firing .50 caliber machine guns, three in each wing. These guns are manually charged on the ground, and fire simultaneously when you press the trigger switch on the front of the control stick grip.

...

This manual isn't intended to give you instructions in gunnery, but here's a tip - before you take off on a gunnery mission, be sure your guns are correctly loaded and charged, and that you know how fully loaded they are. There's no way of counting the number of rounds once you're in the air."

Regards,

Henning (HoHun)

 

[Tony Williams]

Hi Henning,

Another exception I know of was the Hawker Tempest. The Hispano Mk V dispensed with the charger fitted to the Mk II, in order to save weight (and presumably because it was found to be unnecessary).

IIRC in the P-38 the cannon could be manually cocked by the pilot pulling on a handle, as the gun was sited right in front of him.