MKIII Rifle All Matching vs Non-Matching Good OR Bad??

[Edward Horton]

I'm going to give Mr. jmoore a A+ for being "level headed"..........................

When the Enfield rifle was proof pressure tested an oiled proof round was used which put twice the force on the bolt as an unoiled cartridge and help seat the locking lugs.

The locking lugs are on the rear of the bolt and if the bolt locking lugs are not seated and bearing properly the bolt can lean to one side.

Now think about a mismatched bolt and the Leaning Tower of Pisa, with the bolt closed the mismatched bolt is pushing the cartridge off center with the axis of the bore. What this means is your group sizes down range are going to be much larger than normal.

Add to this the fact that our American made .303 cases are "smallish" and have thin rims and small base diameters the American cartridge case is pushed even further out of alignment with the bore. This fools "some people" into thinking that all British, Canadian and Australian Enfields have had their chambers drilled off center with the bore causing banana shape fired cases.

If you ever read the Australian PAM or "mini manual" on their Enfield sniper rifles the manual had two different checks or inspections for cartridge alignment. One check was for proper bearing of the locking lugs and the other check was to make sure the bolt face was making 100% contact with the rear surface of the cartridge with the bolt closed.

NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE
Also referred to as "The Case Gauge," this item is designed to measure:

1) The curved "banana" shape of the cartridge case;
2) The relative wall thickness variation of a cartridge case;
3) The cartridge case head out-of-squareness;
http://www.neconos.com/details.htm

Now if you reload the banana shaped case the act of full length resizing makes the "banana" shaped case even worse and misaligning the base of the case even further with the axis of the bore.

Go ahead and roll the dice and buy a mismatched bolt, if your an American and if you reload our American made cartridge cases in a British Enfield it can make your life miserable.

Below, please notice the angle of the cracked case and the red line showing the base misalignment with the axis of the bore.



My gauges NEVER tell a lie.



And as Son the Australian will tell you, Pratt and Whitney knows how to bore a straight hole for the chamber.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[jmoore]

Aside from headspace issues, I think the rather more important question is whether both bolt locking lugs bear evenly w/ the receiver. There's been several good threads regarding the issue.

[traindriver]

Great information, all viewpoints well taken. Thanks men!

[Son]

Great information, all viewpoints well taken. Thanks men!

Sorry we wandered off a little there- If you find stuff you aren't sure about a quick question here will usually get a good answer within a couple of hours, and once again you can't go past the MKL Lee Enfield On-line Knowledge Libraries (Index of Articles) for a reference.
Looking forward to some pics as your collection gets going!

[jmoore]

Here's a link to an older thread in which Alan de Enfield reposts an even older Peter Laidler post on fitting bolts to receiver bodies. (Post #3) Read and digest Captain Laidler's fit check before worrying w/ headspace issues!

Link below:

https://www.milsurps.com/showthread.php?t=20094

[smellie]

I DO hope our friend has grabbed that $200 rarity while we all have been yakking! If so, he now has something TO measure!

To the OP: Some brass is better than other brass, as I'm sure most folks will agree. You should check out what is available at gun shows and look for some WW2 DEFENCE INDUSTRIES brass or live rounds. This stuff was Canadian-made, noncorrosive, nonmercuric, Boxer-primed and it was made to MAX specs. In short, it is the best RELOADABLE military .303 brass ever made. The loaded ammo shot pretty well, too. You will find this as single rounds or in brown paper boxes of 48. It was made 1942 through to 1945 and it was extremely consistent.

Single rounds may be recognised by the headstamp: just 1943 DI Z in the case of the 1943 stuff. The boxes will be marked DI. One point: stay away from the boxes and the ammo marked DA: this is Gummint stuff and it is horrid, does all kinds of ugly things to nice rifles and you can't reload it.

If our Governments were not so insanely paranoid these days, somebody in Canada could send you 50 rounds. Shoot it, neck-size, anneal the necks every 10 shots and it will last and last. Can anybody help?

Good luck.

[Son]

Well done again Mr Horton. And a good bit of info from smellie as well.

No matter what you may read elsewhere that is given as gospel- there is no such thing as a chamber that was machined not concentric to the barrel bore. Perpetrators of this myth have misread the results of shooting undersize brass in the "generous" Lee Enfield chamber and sometimes with a missmatched bolt that didn't bear evenly on the locking lugs. The marks on cases they are reporting have very little to nothing to do with headspace either.

[jmoore]

No matter what you may read elsewhere that is given as gospel- there is no such thing as a chamber that was machined not concentric to the barrel bore. .

Maybe not in Enfields, but there are other, rather more modern firearms which have had non concentric chambers! As it doesn't directly concern this forum, I'll forgo the details, but it CAN and has happened- (don't trust that fancy CNC equipment to replace bore riding pilots on chambering reamers.)

[Peter Laidler]

Hey Traindriver, come a bit closer while I talk in a whisper as I don't want the rest of the forumers to hear this......... I was one of those bubbas who was responsible for changing numbered parts over in the past. Not just once or twice, but HUNDREDS of times, in Armourers shops the whole world over. From Aldershot to Canungra to Nui Dat to Ngaruawahia. The only difference between us Armourers and the them Bubbas was that we knew what we were doing. BUTequally, some of the bubbas were or could be pretty good themselves and if they changed parts - , say a bolt or a fore-end for instance, then if it was done correctly, then what is the problem? If the bolt has been changed and it fits and bears correctly, operates correctly and (more importantly) operates as it mechanically should AND gives the correct headspace, then whether that is by luck or judgement, then you can ask no more. When we did it, and I did, hundreds of times, then we'd gently and carefully file out the number from the back of the bolt and re-number. With fore-ends, if they were old used ones and properly patched and unwarped, then they'd be fitted to the new rifle, shot for accuracy and the old number would be barred out and the new one stamped into place.

Several years ago, when No1 rifles were still in service with Cadet Forces and more recently, with No4 rifles, it'd be most common to see backsight leafs, fore-end nose caps, fore-ends etc etc with many barred out former numbers. It's part of the rifles link with the past - , its history

What I'm saying is this. What is the difference between a good solid old workhorse of a No1 or 4 or 5 that's had a bit of a hard life, been through the Armourers workshop a few times with a few re-numbered parts but still shoots like a dream and a similar rifle that has been overhauled a few times by an owner who's read and re-read these forums and acquired a lot of skills along the way.

[Son]

Barred out numbers and re-used bits.... almost halfway to having had nine lives, but it isn't a cat! It's on a Sht .22 II