.303 British Muzzle Wear Gauge

What tool(s) were used by the armorers to determine muzzle wear on the No4 rifles.

For US rifles in .30-06 and .308 as well, the set of Troat erosion and muzzle wear gauges can help rapidly someone to make a first assessment of barrel condition.

What is the common way of doing that evaluation beside looking down the tube and stating: Oh yes, there's nice sharp rifling in that barrel.

I also know about using a loaded round inserted down the muzzle end.

I have looked on the Internet and I have found only about .30 cal. tools.

Thank you in advance,

BB

Below is a Canadian .303 bore gauge that fits my 1950 Long Branch perfectly, it does not fit British made barrels.
(silly barrels must be metric) :rolleyes:

The bullet test is meaningless unless you know the exact size of your bore and the exact size of your bullet and place it in base first.

https://www.milsurps.com/images/impo...oregauge-1.jpg

https://www.milsurps.com/images/impo...regauge2-1.jpg

Hi EH,

Tks for quick reply:

Where can I find/buy such a tool?

Is it graduated like the US gages for .30 cal. barrels.

What is the spec value for LB barrels bore size?

Is this the technique/tool used by armorers?

regards,

BB

Quote:

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Originally Posted by Edward Horton

Below is a Canadian .303 bore gauge that fits my 1950 Long Branch perfectly, it does not fit British made barrels.
(silly barrels must be metric) :rolleyes:

The bullet test is meaningless unless you know the exact size of your bore and the exact size of your bullet and place it in base first.

https://www.milsurps.com/images/impo...oregauge-1.jpg

https://www.milsurps.com/images/impo...regauge2-1.jpg

---

Hey Salut Boom Boom! :)

Thanks Ed, that's a new tool I've never seen before.

Boom Boom, I wonder, if we get the specs, if we could get someone like "Gairlochian" to fabricate a few...

Lou

Boom-Boom

1. I bought this bore gauge at a British website along with a firing pin protrusion gauge and a stock collar (trigger guard bushing) measuring gauge and filing jig, they are no longer available.
2. It is not a throat erosion gauge and graduated for throat wear.
3. The Canadian bore specifications are listed below, this gauge is .303 diameter and fits the Long Branch bore, it does not fit in a British 2 or 5 groove barrel.
4. All the tools and gauges mentioned above are Canadian military manufacture and were used by Canadian Armourers.

All the information below is from Badgers “Lee Enfield On-line Knowledge Libraries (Index of Articles)” at the top of this web page. I donated all these Enfield manuals that NO ONE READS, the gauges are pictured in illustrations in: 2002 No.4 (All Marks) .303 Rifle Manuals (Complete Set)
2002 No.4 (All Marks) .303 Rifle Data Summary

http://photos.imageevent.com/badgerd...%20Summary.pdf


Bore Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.65 to 7.72 mm (0.301 to 0.304 in.)
Number of Grooves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 5 or 6
Rifling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 turn in 25.4 cm (10 in.)
Direction of Twist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 and 5 grooves - left hand - 6 grooves - right hand.


Barrel

Plug Gauge, GO 0.3009 in. . . . . . . . . . . . . . . . . . . . . . . . . . . Shall run through the bore.

Plug Gauge, NOT GO 0.307 . . . . . . . . . . . . . . . . . . . . . . Shall not run through the bore.

Plug Gauge, NOT GO 0.308 in. . . . . . . . . . (1) Shall not enter the bore at the muzzle end
more than 6.35 mm (1/4 in.); and (2) Shall not completely enter the chamber at the breech end.

Plug Gauge, NOT GO 0.310 in. . . . . . . . Shall not enter the chamber more than 6.35 mm
(1/4 in.) beyond the etched line.

Tapered Plug Gauge . . . . . . . . . . . . . . . . . . . . . . . . . . Shall not enter the chamber more than 19.05 mm (3/4 in.).

Please note my .303 diameter gauge is not listed in the manual above and could have been used for the .308/7.62 barrels.

Also note what you are looking for on the .303 British Enfield rifle is a .308 diameter bullet to check bore muzzle wear. ;)

Plug Gauge, NOT GO 0.308 in. . . . . . . . . . (1) Shall not enter the bore at the muzzle end more than 6.35 mm (1/4 in.)

NOTE: Gauge requirements may differ in country of barrel manufacture.
(which side of car the steering wheel is on) :yikes:

Hey! I've read a few! And refer to the 1931 instructions on a weekly basis! :D

Just a minute Ed......, I WROTE huge parts of the L2A3 Sterling and L4 Bren EMER............!

As for the No4 muzzle wear, then we say the GAUGE, Armourers, plug No2 .308" diameter No2 MUST NOT enter the muzzle by more than .25". If it does, then the barrel will be rejected and condemned. Even when the barrel rejects the gauge, where it (the barrel) is suspect, it will be range tested for accuracy and rejected if it fails.

The long and short is it will be rejected if it fails the accuracy test and/or the No2 .308" gauge

Next question............

Quote:

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Originally Posted by Peter Laidler

Just a minute Ed......, I WROTE huge parts of the L2A3 Sterling and L4 Bren EMER............!

As for the No4 muzzle wear, then we say the GAUGE, Armourers, plug No2 .308" diameter No2 MUST NOT enter the muzzle by more than .25". If it does, then the barrel will be rejected and condemned. Even when the barrel rejects the gauge, where it (the barrel) is suspect, it will be range tested for accuracy and rejected if it fails.

The long and short is it will be rejected if it fails the accuracy test and/or the No2 .308" gauge

Next question............

---

No insult intended Mr. Laidler, I didn't bring you into this because real Armourers don't use bullets to check muzzle wear. ;)

I also left you out of my posting because rumor has it you also helped write the Ten Commandments and have connections in high places. :yikes:

Signed
Ed (not yet old as dirt) :D

Salut Lou.....

I would take the MWG and go, no-go gauges as well.

I've seen Gairlochian post on repro gauges and will buy these.

Can you find drawings for the MWG and do the contacts??

BB

Quote:

---

Originally Posted by louthepou

Hey Salut Boom Boom! :)

Thanks Ed, that's a new tool I've never seen before.

Boom Boom, I wonder, if we get the specs, if we could get someone like "Gairlochian" to fabricate a few...

Lou

---

Hi EH,

Thank you for the elaborate reply.

About your statement ;

2. It is not a throat erosion gauge and graduated for throat wear.

I know and have used both gauges MWG and TEG) for the .30 cal. barrels and .30-06 and .308 chambers ( with a change of inserts)

The .30 cal. MWG is also graduated 0 or 1 up to 3 which means that it is slightly tapered. The gauge you pictured here, is it tapered or full cylindrical??

tks,

BB

Quote:

---

Originally Posted by Boom-Boom

Hi EH,

Thank you for the elaborate reply.

About your statement ;

2. It is not a throat erosion gauge and graduated for throat wear.

I know and have used both gauges MWG and TEG) for the .30 cal. barrels and .30-06 and .308 chambers ( with a change of inserts)

The .30 cal. MWG is also graduated 0 or 1 up to 3 which means that it is slightly tapered. The gauge you pictured here, is it tapered or full cylindrical??

tks,

BB

---

full cylindrical

Here's a link to the MSC catalogue showing a plain 0.308" gage pin for about $2. No fancy handle, but it'll work. You can get pretty much any size you want in 0.001" increments.

MSC Item Detail

Unless it states to the contrary (as in ....WILL be rejected), Armourers always used the gauges as a guide to back up their visuals. But the acid test, especially with the snipers, was always on the range - the accuracy and function test.

We cut up some old and worn Bren barrels some months ago for metallurgy tests and the bores were visually eccentric to the outside diameter. But before cutting, they were taken up to high temperature using burst fire and performed perfectly.

I've got stainless steel throat erosion gauges available for 6.5, 7mm, and .30-.303 caliber bolt action rifles in stock. They're turned out of stainless steel by a retired U.S. Government Armorer, are perfect and very handy. Email me at the shop if interested. I apologize for the shameless plug but these things are available if you know who to ask. They're also posted on the website. I may have some spare, original plug gauges around here too. Just ask and I'll have a look. Brian

I shouldn't think anyone ought to be discarding barrels on the basis of a muzzle gauge test these days - that was the luxury of a service environment with stacks of spare barrels available on demand. Nowadays the supply of new(ish) .303 and 7.62mm Enfield barrels is just about exhausted, and we have to make do with what we have.

There is, of course, little correlation anyway between bore size and rifle accuracy - especially in .303 barrels. We all know of "mint" barrels that cannot group, and "smoothbores" that perversely group like match rifles. Those who choose a rifle by inserting a round in the muzzle are deluding themselves if they think they're gaining any sort of reliable indication about the shooting performance of the rifle. The only absolute proof lies in testing by shooting.

I have to agree w/ the above, There's some wretched bores on some of my better shooting rifles. Even my L42a1 has a bit of old corrosion at the muzzle, and it groups ridiculously well! Also have a Gew 98 that has a roughish bore and a completely worn muzzle that shoots 3-4 MOA which is still well within acceptance standards for those rifles when new. There's more, but y'all get the idea.

I forgot to say but we were always pretty fastidious about machine gun barrels used for what we call 'overhad fire' or 'battle innoculation shooting' where you fire over the heads of advancing troops during training or suchlike. Then it was always a 'what the calibrated gauge says' attitude. I just get the feeling that the troops would feel somewhat peeved to find .303 and 7.62mm machine gun bullets dropping short in amongst them when they were out there. Even worse, just think what they'd say if a stray bullet knocked a hole in his tea mug! No tea! That'd get him pretty angry