SA80 barrel gauge, correct use.

Hi all,

First off, I am not an armourer nor have ever been. during a recent weapons inspection our boss (who is also not an armourer) was dropping a small metal bit of kit down the barrels to see if they were clean, upon closer inspection by my self I saw what looked like a small 2 1/2 inch long highly shiny metal rod with a threaded section on one end, I immediately thought ‘ah gauge plug bore for an SA80’ and I asked what it was. To this I got the reply ‘it’s a drop gauge for a rifle, to see if the barrel is clean’
Now this is the first time I have ever seen this bit of kit in almost 33 years service and I was curious, why would a ‘drop gauge’ have a threaded end, surely the bit of kit is intended to be fitted to a ‘bodge rod’ and passed through the barrel to prove the integrity of aforementioned weapon barrel I.e to ensure it is not bent. The idea clearly being if the barrel is bent the ‘gauge’ gets stuck in the barrel attached to the bodge rod so rendering the rifle with a bent barrel U/S so it needs replacement, also that would stop a soldier using a weapon that will never hit on target due to a bent barrel, even if slightly off center.
So my question is this, what exactly is the bit of shinny kit that his nibs was happily dropping down barrels Willy nilly for and how is it supposed to be used correctly? It seems to me that if it is designed to check a barrels integrity then it is a highly machined bit of kit and should not be getting dropped anywhere, also why the threaded section? If it is not to be attached to a bodge rod/guide rod. I am asking as this man is/was fixated with this bit of kit and it seems weird/odd that a bit of kit that no one has seen before suddenly is being used with mucho gusto to rip folk for potentially having dirty barrels.
 
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4(T)

LE
Dunno. As you say, a bore gauge is normally threaded onto a rod so it can be passed up and down a barrel under control and so that it doesn't get damaged by dropping.

Using a gauge to determine if a barrel is clean or not is new to me. The rifling lands would have to be heavily copper fouled to impede a gauge, and it wouldn't show anything about the state of the grooves.
 
I've seen it done before, normally by the armoury to ensure the barrel is cleaned properly.
I do have a plug bore gauge that is on a rope and pulled down the barrel rather than screwing onto a rod.
 
Dunno. As you say, a bore gauge is normally threaded onto a rod so it can be passed up and down a barrel under control and so that it doesn't get damaged by dropping.

Using a gauge to determine if a barrel is clean or not is new to me. The rifling lands would have to be heavily copper fouled to impede a gauge, and it wouldn't show anything about the state of the grooves.
Yeah, it's a bit odd - almost like they've seen someone else do it, and assumed that is what it's for.

I would have thought a normal piece of cloth (45x45?) on a pull-through would have been a better indicator?
 
If the weight didn't drop through your rifle barrel was still dirty is how the armourers saw it.
 
If the weight didn't drop through your rifle barrel was still dirty is how the armourers saw it.
But that’s my point, it is clearly a well machined bit of kit, so if you lightly oil your barrel as you are supposed to after cleaning it the gauge will more than likely stick due to oil lining the barrel.
As a few have said, I have never seen this bit of kit and I am suspecting it is an armourer bit of black magic that this goon has got his hands on somehow. Just wanted to have good selection of views from fellow arrests before I go and see our armourer and ask him.
 
Not am armourer myself but will ask my armourers as they use it all the time.
 
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This bit of kit used to be employed after endex after you thought your weapon was clean. Just an extra **** around factor which the blokes don't need!!
 
I think it's a barrel straightness gauge. Extract from the USMC FAL maintenance guide.
 

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I think it's a barrel straightness gauge. Extract from the USMC FAL maintenance guide.
That’s the badger, thought it was something to do with the barrel and it’s integrity.
Just need to track the authority down or publications so I can put our over zealous mini Hitler back in his box.
 

HE117

LE
OK.. this has been going on for ages, and it shouldn't be.. these "gauges" are for the most part out of spec gauges "obtained" from REME dustbins..

Bore gauges (..for this is what it is!) should only be used occasionaly by trained personnel for estimating bore wear. They should not be in the hands of lesser mortals and least of all armoury storemen. Bore gauges are expensive and delicate bits of kit that need to be carefully used and stored if they are to remain accurate. They are made from tool steel, accurately honed to very precise dimensions. Constant application to rifle barrels damages both the barrels (the gauge is much harder than the barrel!) and puts unacceptable wear on the gauge.

Using a bore gauge to estimate cleanliness is an utter waste of time as a worn bore gauge will alway fall down a worn barrel regardless of its state of cleanliness. I suspect most of the time the reason these "cleanliness gauges" get stuck in barrels is because the barrel is damaged (probably by the improper use of a gauge!)

Bore cleanliness is best estimated by visual inspection, looking for fouling in the grooves, or by the application of an oiled patch followed by an examination of the debris..

There used to be a wizened dwarf in a brown coat who lived in the armoury at Grantham who used to use one of these gauges. He tried it on me and did not get the reaction he was expecting..! (I offered to fit it to him internally if he could not produce the relevent EMER)
 
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Themanwho

LE
Book Reviewer
The REME armourer's method of inspecting an L85 barrel bore is as follows:

a. Visual looking from the breech end to check for cleanliness, bulges or obstructions, then rotating through 90 degrees three times to check for straightness of bore (using the shadow in the bore). If there is any dirt (or damage )this should be noted on the inspection, and the barrel should be cleaned before a bore gauge is used.

b. Dropping a bore gauge from the breech end down a vertically held barrel, it should travel freely throughout, but due to 5.56mm being such a diddy calibre and the gauge being commensurately teeny it often doesn't, and a light tap of the muzzle on the bench usually does the trick (in gauging 7.62mm barrels, there should be no need for a tap, the larger gauge being heavy enough to keep moving). Alternatively attaching a length of RCK cleaning rod gives sufficient additional weight to allow the gauge to override the friction in the barrel If the gauge gets stuck, the gauge will be removed the way it came in using a rifle rod inserted at the muzzle, followed up by a reinspection of the bore for any obvious damage. If necessary a bore clearance tool (effectively a bore gauge with a sharpened end) run through the bore from the breech end on a rod should remove any burrs (mainly around the gas port) or hardened carbon deposits, and the barrel should be regauged.

Nobody but a REME armourer should be using a bore gauge*, as unless they are trained they are not aware of what they are doing. Your untrained gadgy dropping an old gauge down the bore is basically making it up, and his classification of a clean barrel is basically pointless bolleaux.



*EDIT: Rereading this, I should clarify that I'm talking about using small arms gauges in the British Army here. Civvies / plod / other armies may do wtf they like as far as I care, they aren't constrained by EMERs or AESPs. Inspecting small arms using bore gauges is a task for a grumpy armourer in a dust coat, no one else; the purpose is not to ascertain cleanliness but to ensure the barrel is serviceable.
 
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"But what about the shiny ring?" :eek:
 

Themanwho

LE
Book Reviewer

Cutaway

LE
Kit Reviewer
Inspecting small arms using bore gauges is a task for a grumpy armourer in a dust coat and an impressive collection of niche porn, no one else; the purpose is not to ascertain cleanliness but to ensure the barrel is serviceable.
For accuracy.
 

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