Retrieved: 06/05/2014
12-16-2010
I have needed a .075" breeching up washer for a No4 7.62 barrel, but after some have been back and forth to England and I've still not found one and I can't get one, and I got over it. I thought I'd get a tool maker to do one for me but I thought instead I'd make it myself. It will be good practice on my lathe and I'd make some new tools.
Any way I used a flogged out No4 barrel, so I suppose the materials the right stuff. It took ages, but next time I'd do it a lot quicker.
I was after .075 but got .080 thickness so if necessary I'll just relieve the barrel shoulder by .005", and that should also help to keep the washer held centrally, we'll see.
Anyway I'm glad I took the time and did it, after all I bought the lathe to make this sort of stuff. Here's the process:
Son
12-16-2010
interesting... I didn't know the No.4 was shimmed on the front face of the receiver ring. (my very limited No.4 knowledge showing again...)
The shims to index a No1 barrel go on the end of the barrel, not the knox. They used to be available in either .002" or 005". I would have thought they'd do the same job for the No.4... comments?
arado
12-16-2010
I use breeching washer for L1A1. Surface grind to need. Gary
tbonesmith
12-16-2010
The No.4 holds the tension on the receiver ring, the no1 on the face of the tennon. This barrel is a weird setup I haven't seen before, where you [I]need [I] a substantial washer to affect proper indexing, not a couple of thou, but 75. There were 2 washers supplied with the new barrel totalling 70 thou and while the barrel would index and headspace with these washers there simply and absolutely wasn't anywhere near appropriate tension on the barrel/receiver, though it was somewhat firm. So that's how I got to this...
Originally Posted by arado
I use breeching washer for L1A1. Surface grind to need.
I did my best to track some down, but could only lay my hands on .060 washers, and I needed more...
Alan de Enfield
12-16-2010
A couple of of Peter Laidler's old posts on breeching up :
Index of Peter Laidler's on-line series of articles
About 1/3 the way down in Peter's index of articles titled "Breeching Up"...
tbonesmith
12-20-2010
Update
I decided that I didn't want to use the last washer I made using the barrel, as the diameter was slightly smaller than that of the breeching up washer fo the L1A1 or the No4 one I had for reference.
So I bought some 31mm diameter medium carbon steel round hollow bar, and using the same method as above I made some washers, the same except for having an OD of about 30mm which is very close to the diameter of the shoulder of the No4 barrel.
I could not control the width of the washers precisely, as they always came off the lathe bigger than their measured width before releasing them from the bar by boring out the centre. I have no Idea how that worked, but it was how it was.
So I clocked in the barrel in the 4 jaw, and centred the breech end in a live centre(which centred, I checked), then using the compound slide I could take precise cuts off the shoulder, which also served to centre the washer.
Anyway, this was my first go at more than one of these operations, but I am posotive that the result is right.
The barrel is now correctly indexed, and extremely tight. It's taken me ages, but I'm finished for this portion of the job.
I suppose I next need to fit the 7.62 enfield mag, but I might get help there as I don't want to stuff anything.
Bearclaw
12-20-2010
Tom, that grey sure does show up against the black. How did you overcome the tapered barrel sitting in the chuck without it slipping.
Thunderbox
12-20-2010
Why do you need to use a breeching up washer for a military-profile (eg 303 profile) barrel? Those .303/7.62mm barrels were designed to fit the same as a .303 barrel - without washers. I've never seen a washer used on any of the converted No4s I had through. Only the heavy target barrels were supplied with a set of washers.
tbonesmith
12-20-2010
Originally Posted by Thunderbox
Only the heavy target barrels were supplied with a set of washers.
So I thought too, but hey, here's one that's an unused standard profile 7.62,
supplied with a set of washers, that needed a little bit more. What more can I
say?
Originally Posted by Bearclaw
How did you overcome the tapered barrel sitting in the chuck without it
slipping.
It can't slip into the chuck because it tapers up towards the breech, and it
can't slip out of the chuck because of the live centre supporting the breech
end.
Peter Laidler
12-20-2010
The last No.4 Parts list illustrates breeching up washers for the No.4 Mk2's. I have just spoken about this to Sgt Rxxx Sxxx and he's confirmed that many from the RAF ACF's and CCF's (Cadet forces) that went through the main workshops had them. This indicates to me that they will be the LATER Mk2's (maybe the UF's). The breeching up washers were not codified (didn't have part numbers) so they had to apply for them. They had them in stock as they used the L39/42's as required or for an odd size, machined up
tbonesmith
12-22-2010
Back together
Last night and tonight I fitted the mag, a new 7.62 extractor, extractor spring and suitable bolt head, and with a little adjustment, the rifle feeds and reliably ejects without milling the receiver, the second ejector screw or the mags ejector tab (missing)
I left the bedding as is for the moment (centre bedded by AGP), it appeared to be just right anyway and the rifle used to shoot fantastic before the barrel went completely. If it needs adjustment after range testing I'll look at it then.
I've wanted one of these for ages, and I've only seen one or two but now I've got a sweet No.4 Mk2 in 7.62 with a new barrel and mag in a sound unit. Looks good too, I'll let you know how she shoots!
I love it when they're back together!
img00666-20101222-2100.jpg
enscien
12-22-2010
The Enfield 7.62mm barrels and later .303" barrels had the shoulders cut back to accommodate a thick breeching washer used to control breeching up by the 'constant torque' method. There is a very good account of this on page 185 of 'The Lee Enfield Rifle' by E.G.B. Reynolds (long out of print).
As I recall, (from watching the operators doing it) the breeching washers came in thicknesses of about 0.060" to 0.080" in steps of 0.001". A thickness of 0.074" would be typical. At RSAF Enfield they selected the thickness which would allow you to screw the barrel onto the body hand tight, leaving a further 18.5 degrees 'breeching-up angle' for tightening to the vertical position with the breeching up wrench. The torque required to do this should then be 120 +/-5 lb-ft.
This was a post-war development because it was thought that slightly bulged chambers were resulting from some barrels being over stressed by having to be screwed in with an excessive amount of torque because the breeching up angle was too high.
tbonesmith
12-22-2010
Originally Posted by enscien
As I recall, (from watching the operators doing it) the breeching washers
came in thicknesses of about 0.060" to 0.080" in steps of 0.001".
But that was approved in 1956, long after No.4 production had ceased - which
is probably why such rifles & barrels are rarely encountered.
tbonesmith
12-22-2010
Originally Posted by enscien
At RSAF Enfield they selected the thickness which would allow you to screw
the barrel onto the body hand tight, leaving a further 18.5 degrees
'breeching-up angle' for tightening to the vertical position with the
breeching up wrench. The torque required to do this should then be 120 +/-5
lb-ft.
That's very interesting, and .074/.075 is what I judged I needed too. 120 lb-
ft is far less than I would have thought necessary, and probably far less than
I've got on. I'll have to get my torque wrench and get a feel of how much 120
lb-ft is. Anyway it's not coming out, but you learn new thing about this all
the time.
tbonesmith
01-01-2011
Got this bad-boy to the range today to run in the barrel, and run some hot loads through it and get a zero. No issues with developing headspace, no signs of excess pressue with the hottest load, and with a bit of hassle a solid starting zero for 100m. Small targets and grass butt stop made it a pain to get on paper.
No world records for the initial groups but at 3-4 inches for the first 5 shot group off a makeshift box/rest I'm pretty sure I can develop a load or tune the rifle as required to make it a very competitive piece for the year of upcoming competition. It will do for a start anyway.
Happy it appears properly functional and sound.
tbonesmith
01-08-2011
Made a very small adjustment to the bedding and got to the range today and zero'd the rifle at 300m. All looked good. Then I shot a 5 shot group, all inside the V bull in a nice round 4" group. Beauty! I have a very competitive rifle for this year.
Bearclaw
01-08-2011
Update on the barrel, it came from Lawance Ord. They might be able to fill you in more of it's origins.
tbonesmith
01-08-2011
Interesting, when did he sell it?
Bearclaw
01-08-2011
A few years back, he purchased it to replace the 25/303 barrel. I think they were going for 99 bucks each then. Sure the guys at Lawrence will know the barrels and their origin. I remember seeing the ad for them and they weren't the Paki or Indian made ones, as you can see by the quality. I do recall Ligthgow producing a large quanity of No.4 barrels in 7.62, that would explain no markings on the barrel maybe.
My mate did mention that it came wrapped in the orginal paper, but can't remember the info on it. At least it is some sort of lead.
tbonesmith
01-08-2011
It is marked with a Lithgow code AY or AX, I forget, and it has a Lithgow proof. No question it's a Lithgow.