MKIII Barrel Angle

[nijalninja]

Another highly specific question which may be nothing.

This mismatched MKIII I have seems to have its front sights canted to the left off of dead centre. The barrel being unnumbered does not bother me as the rest seems mismatched too, but this barrel seems off. A perfect chance to test my angle measuring whats-a-ma-jig.

I know there is some debate as to where to measure the angle of the reciever from so I tried both across the channel behind the charger bridge and then the flat on top of the reciever ring as 'Normal', and then the flat across the knox as the barrel angle.

I tried this mismatched Lithgow MKIII (Which appears off) and compared that to my matching BSA MKIII (Which appears fine).

The mismatched Lithgow angles on the reciever ring and across the channel seemed to match, but the barrel was slightly off, but in the opposite direction it appears to be when you look at it just with the eye.

The BSA I could only measure across the channel as the finish made it slippery and the wearing on the reciever ring made it near impossible to balance my angle device on. Then the barrel seemed to be only slightly off and in the same direction as the mismatched rifle.

As someone who wants to work on Enfields and understand things like this I ask: Am I looking too hard at it, or is this mismatched one at the wrong angle and need to to be screwed on further (It should still headspace fine with only this slight adjustment)?

Lithgow:Attachment 97124Attachment 97125Attachment 97126Attachment 97127

BSA: Attachment 97128Attachment 97129Attachment 97130

Information

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[browningautorifle]

How does it shoot? Is there a problem to zero at 25? Then when you move out to 100, then 200 so on, does the group move to one side?

[Woodsy]

The charger bridge is not the right place to set your angle from. The top of the bridge is seldom square with the action and is often not dead flat either. The barrel flat on the knox form should be true to the sights, and if you don't have the correct gauge, you should remove the fore-end and work off the under side of the action body. The proper gauge is a two piece unit which slips in the back of the action (with the butt stock removed) and is aligned with a tongue that fits between the ears that support the back of the trigger guard. The top is ground flat and square, and the second part is a bar with two parallel flats, one sits on the ground flat of part 1 and the other sits on the knox form flat. Any out of square angle is very obvious if the top piece rocks from side to side.

[nijalninja]

BAR, haven't had a chance to shoot it, it is a very new addition and this is something I picked up by eye and thought it was worth investigating. I understand roughly what should happen if this is in fact the issue but I wanted to ask first in case something else was at play I was not seeing.

Woodsy, yeah hence I didn't use the charger bridge and also why I tried two places on the reciever which seem to be pretty solid for measuring. Also yeah I don't have the correct armourer's gauge but I am substituting as best I can. I also have heard that the underside of the body is a good place but didn't have the time today to strip it entirely and then put it back together, but I will try it in the future.

[Bruce_in_Oz]

There is sight "cant" which should NOT be present on a correctly fitted barrel.

Then there is front-sight base "offset", which should be there, all 0.015 inches of it. The sight-protector "ears" on the nosecap are also offset to the left by the same amount.

This is supposed to be to compensate for the leftwards lateral drift of the left-hand spun bullet. This drift is minuscule at a couple of hundred yards but adds up out past 800.

Earlier Lee Metfords and Lee Enfields also had sight "offset".

[nijalninja]

I know of the sight offset, and of the story about how much they overreacted to it with the old Metfords and Long Toms. As BAR mentioned I should likely go shoot it and see if it even has an impact or I am being pedantic. Cheers bruce.

Also I should mention that I set the first angle on the channel behind the bridge and left it the same and just went by looking at the bubble in the following angles. I figured any difference would show up in the bubble, which it seemed to.

[CINDERS]

I was looking at the end of the bolt race and the flat section if you look where the wrist goes into the socket the right side of the flat in the bolt race is higher than the left which makes me think the action is not square to the butt but may be twisted to the left (Pic#5). Nijal have you checked the tightness of the butt stock bolt in may be tight enough to feel tight not wobbly but loose so as to move under firing it may be as simple as that I hope.....

[nijalninja]

I'll have to take a closer look there Cinders. It is my quite hard done by MKIII with what looks to be the original butt-stock so anything is possible. I know I did it up tight enough I could not get another 1/4 of a turn with just a screw driver but I never do this rifle up overly tight as it is not a shooter for the time being. The few times I have ever fired it hit where I am aimed (Took out a can at maybe 70 yards), but I am aware of the issues a loose butt-stock can cause. Cheers.

[30Three]

If it's held in with wood blocks, in a vice that's G clamped to a table, I'm not sure that's the best option to measure such stuff. Remove the woodwork and find an accurate support before worrying about the rifle.