An Odd Characteristic of the SMLE

[Bindi2]

That sounds to me like a very fancy excuse for poor shooting, after the Boers had demonstrated that their 7x57 Mausers were ballistically superior.

Then why did the the Brits resight their rifles. You can not hit a target if the sights are not on.
This thread is very interesting. My thoughts are more to the offset being in the verticle not the horizonital. If this is the case the sight is not altered there would be two points or crosses in trajectory.
Having played with a Patt 18 i would have picked a mid point zero of no more than 18 inch rise and fall and locked the scope never to move it again. To increase the range aim off (up)

[Ridolpho]

Exactly Bindi2- the british were sending teir MLE's out very poorly sighted and I just pulled my MLE out to confirm there's no way to adjust front or rear for "windage". Needless to say, the Boers had well sighted rifles. On the subject of drift we shouldn't forget about the wind. Labudda and Skennerton provide one example (page 13, Accurizing and shooting Lee Enfields): "fresh Wind blowing from 2 o'clock....at 600 yards.....=42 inches allowance". Totally overwhelms spin-drift and the coriolis effect. Here in Alberta with a good Chinook blowing in from the west and a WW1 sniper rifle with scope offset to the left (zeroed at 300 yards) and shooting to the north, the bullet would cross to the left of the line of sight at 300 yards, then arc out further left before being carried far back to the right by wind. The wind here is about as constant as gravity so if you shoot at a north directed range you might see consistant behavior.

Ridolpho

[Paul S.]

I... This difference was related to the Corolis force ...

First of all, correctly it is called the Coreolis Effect. That's 'Effect' and not 'Force'. Secondly, it effects major masses such as high and low pressures systems in the atmosphere and ocean currents. It is why low pressure systems spin clockwise in the Southern Hemisphere and anti-clockwise in the Northern Hemisphere. It does not cause the water in the loo to spin a given way despite common belief.

People speculating that the Coreolis Effect could or would cause a bullet to move differently in north of the Equator than it does south of the Equator that causes me to believe even more that the whole story about .303 bullets 'crossing over' is speculation turned gossip turned 'gospel'.

[jmoore]

The rear locking of the Lee-Enfield action is well known to "compensate" at longer ranges but up and down NOT laterally. Maybe the old boy was heard incorrectly or had got confused.

I would be grateful for an explanation, as I still maintain that bullets have no memory. Without wishing to cause the slightest offense, "well-known" is not a scientific argument.

The compensation would be the tendency to have a larger vertical muzzle deflection with lower velocity rounds than high. At "close" ranges the slow bullets actually hit higher than the fast. My No.1 Mk.V displays an extreme version of the phenomenon.

[Patrick Chadwick]

Totally overwhelms spin-drift and the coriolis effect.

I absolutely agree. Personally, I have managed to land shots in the black at 1000 yards - on the neighbor's target!
I make the feeble excuse for myself that I was firing a BPCR with about 2.5 seconds flight time in a situation on a hogback hill with the wind corkscrewing unpredictably from left to right.
But the competition was won by a first timer! There is such a thing as natural talent, and he had it.

From my experience of not being able to do it, and observation of those who can, I reckon that the abilty to "read the wind" and aim off accordingly is far more important in long-range shooting than all the other more-or-less subtle effects that we have been discussing. How many Tommies had undergone any serious training in this art?

But returning to the original conundrum: I posited that the leftwards spin drift of a left-hand rifles barrel could, partially at least, compensate for the rightwards angle (relative to the barrel axis) of a scope with an offset to the left, beyond the range at which the scope had been adjusted for POI = POA.

Whether that is to be regarded as a very clever piece of Enfield engineering or a plain fluke will probably depend upon how cynical you are feeling at the moment.
Any comments on that, anyone?

[Bindi2]

Patrick a plain fluke, cynical not really the knowledge of long range shooting in general, the change over from black powder to cordite new rifles etc was at the begining of where we are today. The scope hight above the bore today causes similar problems for the new unwary shooter. How do i know this, looking for PBR with a new combo then need to know the adjustments out to 1000yds + by 100 yd increcements. The range books will only put you on paper maybe.

[newcastle]

Quick OT note on the Shane warney thing. Note with this it is not the SPIN of the ball when shane warne bowls that causes it to drift. He spins it anti clockwise as it goes towards the batsman and therefore if it were the spin it would actually drift to the left (or off side) as it travels. It is the spin of the ball which keeps the seam in a constant position relative to the air it encounters in teh diretcion it is bowled in. ie if viewed from above at any point down the pitch the seam would be at roughly 60 degrees across the pitch. it is this constant position on the seam relative to the airflow which creates a 'laminar boundary layer' and less air pressure on one side of the ball, thus the slight curve in the air. The spin helps it dip. Further note as an Englishman and leg spinner myself, but Shane Warne was bloody fantastic to watch, though obviously a crim and a scoundrel of the highest order.

[Surpmil]

Haven't read the whole thread, so maybe this has been said already, but perhaps what the original comment alluded to was the well known ability of the No1 and the No4 to "compensate" through the flexing of the action. This led to smaller vertical than horizontal dispersion at that sort of range, and so the horizontal dispersion would seem oddly greater than the vertical dispersion, when in fact the horizontal dispersion was quite normal for that range and ammunition, but the vertical dispersion was unusually small.

Sometimes it's all how you look at it.

[Patrick Chadwick]

Quick OT note on the Shane warney thing.

Thanks for the explanation. Not quite the same cause, but the same effect - lower pressure on one side.
Now I realize this is getting awfully close to being off-topic, but how do baseball pitchers produce the asymmetrical pressure for a curve ball?

[Bindi2]

Warney a crim and scoudrel no way, larrikin yes , spinner yes and very good . Dont know if he had a clue about Enfields though