Bristol Fighters- frontal gun

[Lorraine CJ]

I need confirmation on these facts:

Apparently, pilots of Bristol Fighters carefully chose and loaded the bullets for the frontal gun themselves. This was because if the bullet had some kind of defect, it could get jammed and explode. This way they avoided problems with the ground crew.

Does this sound true? Has anyone ever heard this before? Or have any source where I can check this?

Cheers,

LCJ

[fitzee]

Experienced pilots on both sides would often select the ammunition and help fill their machinegun belts or fill a drum for a Lewis gun. Each pilot might also select his own mix of cartridges: tracer, incendiary or jacketted lead to name a few, depending on the mission. I believe this was common practice for their own survival as a defective round might result in never seeing the ground crew again! This did not eliminate the possibility of a defective primer which could result in a jam with lethal consequences

Fitz

[TonyE]

It was quite a common practice for pilots to "gauge" their ammunition in a spare barrel before loading belts or drums in order to prevent a misfeed caused by an out of spec. cartridge. This problem became less once selected "Special for RFC" or Red Label ammunition was introduced. This was carefully selected ammunition made from high quality components, principally to ensure precise rates of ignition with interrupter gear.

A defective primer was likely to cause no more than a stopped gun, and whilst this of course could be fatal in a dogfight, was not itself a problem. If in a frontal Vickers, it could usually be cleared from the cockpit by re-cocking the gun. Overwing Lewis guns that jammed were more of a problem in single seaters.

Some of the special purpose ammunition did suffer from both bore and muzzle prematures, but again this was more likely to put the gun out of action than harm the pilot. The more explosive incendiaries such as Brock and Pomeroy tended to be used only in Lewis guns for this reason. Also IIRC these rounds were reserved for home defence squadrons and were not officially supposed to be used in France.

Aircrew were trained to clear guns in the air, and there was even specially made "Purple Label" ammunition that was designed to cause stoppages in a Vickers gun for training purposes. One type had the bullet seated deeper in the case than normal to cause a feed jam and another, the Mark VIIRC, had a reduced charge to produce a stoppage. Another training ploy was for the instructor to remove one round from the belt or drum so that the gun stopped and the pupil had to clear it.

Regards

TonyE

[Lorraine CJ]

A defective primer was likely to cause no more than a stopped gun, and whilst this of course could be fatal in a dogfight, was not itself a problem. Some of the special purpose ammunition did suffer from both bore and muzzle prematures, but again this was more likely to put the gun out of action than harm the pilot.

Are there other reasons for a jammed gun, apart from what you mentioned before?

Thanks gentlemen for your expertise,

LCJ

[TonyE]

There are a number of reasons for a stopped/jammed gun. The most common is a mis-feed, either from the belt (Vickers) or magazine (Lewis), usually caused by a mis-alignment of the round as it is fed into the chamber.

If there is a misfire then the gun must be cycled manually to clear the defective round from the chamber. This could be caused by a bad primer, but if caused by a broken firing pin then the gun is useless pro tem.

It is possible for a round to fall out of a faulty (loose) belt due to vibration and of course this will cause a stoppage and the gun must be re-cocked.

A separated case where the cartridge case splits circumferentially and only the rear half extracts can cause a bad jam, as the next round is fed into the chamber and gets stuck in the remaining front half of the previous case. Usually that cannot be cleared by re-cocking. Fortunately, with good ammunition QC on Red Label ammunition that was not a common occurence.

Another possible cause of a failure to fire at high altitude is a frozen gun, but once it has fired then of course it will be hot. I don't know if it was common practice to test fire one's guns if expecting to patrol at high altitude.

Both the Vickers and Lewis were tough guns and if looked after properly gave good service.

Regards

TonyE

[squirrel]

I though that pilots test firing their guns was par for the course before flying in to the area where enemy aircraft would be encountered.

A chance to find a problem and rectify it before you met the enemy.

I'm sure I've seen it referred to in combat reports.

[TonyE]

I am sure you are right. It certainly was standard procedure in WWII.

It is not something I have actually noticed though.

Regards

TonyE

[fitzee]

I believe firing an air-cooled machinegun for more than ten seconds would cause the breech to over-heat and the gun to jam. The pilot would then have to wait for the gun to cool down before attempting to clear the jam. For this reason, pilots were trained to fire shot bursts at the target. I can only imagine in the heat of combat your impulse would be to "empty" your gun at the target.

Fitzee

[TonyE]

Ten seconds is an awfully long burst, even if under pressure in a dogfight! Whilst what you say is probably good advice, I would doubt if the guns would actually jam in that time. Remember that there is a 80 - 100mph slipstream cooling the guns in the air.

I have certainly fired longer bursts in a water cooled Vickers on the ground and I have seen air cooled .30 Brownings firing continually until the barrels glowed dull red and they still kept going.

None the less, given the limited ammunition available, short accurate bursts must always be preferable.

Regards

TonyE

[Greg Bloomfield]

I seem to remember reading several accounts of pilots, not just of Bristol Fighters, checking on the correct belting or loading of thier magazines or even in some cases doing so themselves.

Greg

[squirrel]

And accounts of pilots loading their own belts and magazines - Albert Ball is one that comes to mind.

[TonyE]

I have found the reference I was looking for; from "Handbook of Aircraft Armament":

"Every round should be carefully looked over for dents, deepset caps, defective bullets, split cases etc., before it is placed in the magazine.

The best service test applicable is to use a spare Lewis gun barrel and drop each round into it in order to see that the cartridge enters freely. The rims should be examined to see that, as far as possible by eye, they are not too thick.

Several cases have been discovered in England of the cartridge containing insufficient or no charge, so that it would be convenient if the NCO or man in charge of guns were able to test the comparative weight of each cartridge with a good one.

If possible U.S. ammunition should not be used as it has been found to be defective in various respects at this school."

Regards

TonyE

[Lorraine CJ]

Thank you everyone, all very useful as usual!