No. 4 Rifle; Zeroing Instructions Data Inconsistency?

[Alan de Enfield]

It is interesting to see the comparison of the FoM for the "Long Rifle" rifle compared with the SMLE which were recorded in 1904 during the SMLE trials.

Comparisons were also taken with rifles used by other countries.

[Surpmil]

As you say Johnson was a highly experienced shot, and the whole book is testimony to his devotion to accuracy and, by implication that of his superiors. He makes repeated references to the absolute necessity of accuracy in order for fire - and the solder - to be effective. The group sizes shown in the book as examples of what was attainable or desirable are much smaller than the acceptance levels of accuracy for the rifles and ammunition.

In the last few days I happened to be going through my stock of used front sight blades and examining them under magnification and yes, there are numerous examples of minor modifications to the blades. It would only make sense when a minor elevation correction was needed, but the lateral deflection was perfect. A new blade inserted would require the zeroing be repeated in both axes and that would be time-consuming process. The book makes reference to the soldier and his rifle being sent to the armourer at the range for adjustment as part of the zeroing process of the individual rifles to each soldier. With 30 or 100 rifles to correct one can see how an armourer might file a little off a blade rather than replacing the entire blade and effectively recommencing the zeroing process. Whether that was permissible practice I have no idea.

The proof of ammunition is interesting and I photographed the entire Canadian manual for that a few years back when I had access to it, but that process was about testing the accuracy of the ammunition, not the rifles.

Perhaps your point in citing that was to establish the accuracy standards of the ammunition and by implication that of the rifles? Alan d’Enfield has posted the acceptable accuracy standards for the rifles from the UK manual, and probably the same standards were adopted in Canada. And of course “Shoot to Live” was not written specifically for Canadian-made rifles or ammunition.

Regardless, unless ammunition of a higher than usual quality was used to test the rifles at manufacture, the accuracy standards for the rifles incorporate the expected and accepted variations in the accuracy of the issued ammunition. Can we now say where one began and the other ended?

The 6.5" MPI over POA mentioned in the UK manual gives no range of variation such as the 2 inches mentioned in Shoot to Live, but of course a range of variation existed in fact. Presumably it wasn’t thought necessary to mention as the NCO’s involved were expected to understand that some variation was inevitable and the measurement therefore an approximation? The lack of attention to this in the text implies it was not considered of great importance. A formation on the ranges to give the rifles their initial zero would soon find out what the particular lot(s) of ammunition on hand tended to do, and adjust accordingly.

My first thought was the same as yours that having the MPI slightly over the POA would be less desirable in combat than the reverse. That would depend on what if anything had been learned about the aiming habits of soldiers: did they tend to aim low or high in combat? Whatever the case, I mentioned it merely as an idea to be considered.

ARMOURERS' WING Precis No. SA/19A which implies the variation of MPI at 100 yards should be no more than 1.87".

What is the actual text and context? If this refers to the process of preliminary zeroing at 100 yards does it refer to the same variation which Shoot to Live gives as having an acceptable variance of 2 inches? Not a very large difference is it? 1.87" being effectively half of 3.75" one wonders about the context.

Regardless, Johnson describes this process as leading to a “rough zeroing”. Both manuals quoted refer to a MPI & POA coincidence at 300 yards. Shoot to Live states zeroes at 30 or 100 yards were preliminary and that the final zeroing would normally occur during advanced training and that this would be the zero that stayed with the soldier and his rifle throughout his service.

Logically the zero obtained at 30 or 100 yards would be mostly concerned with lateral error (windage). So considering that both manuals envisage a later final zeroing at 300 yards, the difference could amount to no more than where on the 300 yard target the respective authors preferred to see the first groups fired at 300 fall: higher or lower.

Perhaps you have already ruled out the types of targets used and the points of aim to be taken on them as variables that might explain this?

As we can see from this thread for example: h t t p s ://www.greatwarforum.org/topic/304772-external-ballistics-303-bullet/ there is plenty of debate about the rise and fall of Mk.VII ball and even about whether the formulas of the Textbook of Small Arms 1929 are entirely correct, so this variation between the two manuals is not so surprising in my opinion, nor significant given that the figures of 6.5" and 8.5" are merely points on a range of variation whose acceptable parameters overlap at 7.5 inches; whether that or indeed this whole matter has any significance in fact.

(The TBSA 1929 is of course based on the No.1 Mk.III and the harmonics of its lighter barrel and action rather than the No.4 Rifle; the No.1 Mk.VI gets only passing mention.)

[Alan de Enfield]

(The TBSA 1929 is of course based on the No.1 Mk.III and the harmonics of its lighter barrel and action rather than the No.4 Rifle; the No.1 Mk.VI gets only passing mention.)

MkVI vs MKVII is another subject :
comparison in trajectories of MkVI & MkVII

[Surpmil]

MkVI vs MKVII is another subject :
comparison in trajectories of MkVI & MkVII

I was referring there to the Rifle, No.1 Mk.VI, aka the No.4 Mk.I as it later became known.

[Rick]

I'll begin with a reminder that the Shoot To Live pam was released at the end of the war in 1945. For all the war years before that with the Long Branch No. 4 rifles, those troops and NCOs had been zeroing their rifles and using them in battle using the British instructions that specified the 2.5 MOA lower zeroing data. The rifles, the ammunition, those running the ranges; none of that changed - only the 1945 pam changed. And if the zeroing instructions changed for the same aperture sight, rifle, and ammunition after Shoot To Live, how much did the zeroing instructions also change for the sniper rifle?

How about the NCOs serving as SAI at the Canadian battleschools, training new recruits and zeroing their weapons prior to that pam - they just switched how they'd been zeroing rifles upon the arrival of that pam at the battleschools without thought?

None of those NCOs or soldiers still in service noticed? None noticed that their next trip to the range for qualification after Shoot To Live became doctrine, those veterans were suddenly told all their rifles were zeroed 2 1/2" low at 100 yards? And every single rifle zeroed and used in war prior to that pam was improperly zeroed? All 100% of them?

I certainly would! When we were the first issued the C7A2 and accompanying C79 Elcan sight, physically on the loading ramp while boarding the jet flying us to deployment in Yugoslavia, it took very few rounds downrange to zero those rifles after arrival to realize the initial zeroing data we received with the rifles and sights from the Higher Niner Puzzle Palace was FUBAR.

Perhaps your point in citing that was to establish the accuracy standards of the ammunition and by implication that of the rifles?

No, it was to point out that referring to the edges of two different groups shot with a 2.5 MOA difference at 100 yards would slightly overlap does not explain why one country, in one single pam, gave radically different zeroing instructions for the No. 4 rifle. Furthermore, the thought that you would start by deliberately sighting in too high, and then sort out that 2.5 MOA of error at 300 yards later, whether in advanced training or in theater while running confirmation ranges before heading into the FEBA, isn't logical.

Logically the zero obtained at 30 or 100 yards would be mostly concerned with lateral error (windage).

From my perspective as a SAI who has written many Range Instructions for zeroing and done many hours as an RSO on those ranges, what isn't logical is why the SAI senior NCOs running those ranges would only ask the gun plumbers to correct windage errors.

If they're going to fiddling around loosening front sight screws, applying cramps for windage errors anyways, why would those NCO's allow 100% elevation errors to remain unchecked until later at 300 yards - where they would be putting the screwdriver and cramps to 100% of the rifles on that range?

If all the troops have sighted in correctly (or what looks correct) at 100 yards, or the earlier 30 yard range (a holdover from before WWI according to pams from the early 1900's for the Mk1), then you minimize the fiddling around with front sights and cramps when you ultimately get to that 300 yard range. Every SAI and RSO in the military wants those ranges to run as smoothly and with as few little side-trips as possible.

If 60, 70, 80% or whatever of the troops who fire their sighters at 300 yards already have POA=POI with their 300 yard aperture and bayonet fixed, that is far better when the gun plumbers only have to deal with the remainder whose arrived to shoot and who AREN'T properly zeroed.

Do you want the interruption of your gun plumbers getting out their selection of front sights and cramps for 20, 30, whatever infantrymen from the Company on the range? Or for 100% of the entire company of 125 +/- troops? Less is more efficient range; less is better.

Perhaps you have already ruled out the types of targets used and the points of aim to be taken on them as variables that might explain this?

Yes. The target referred to in Shoot To Live sounds like the same aiming point as seen in the Second Class Figure Target specified elsewhere for 300 yard zeroing: THE second method of accurately zeroing the .303 rifle would be to use the standard 100-yard range. Here, we use the standard four-loot target with the hour-glass figure and a centrally-located auxiliary aiming mark shown as a white square.

Same dimensions of the overall target and same dimensions for the hourglass figure: 12"x12".

Can somebody explain how the Canadian targets in 1945 were different than the UK and Australian targets, and as a result, when actually aiming at bad guys in battle, the 1945 different Canadian targets and zeroing instructions resulted in a higher percentage of hits when aiming at real bad guys than with the previous zeroing instructions used throughout the war?

The sudden large difference in zeroing instructions that occurred in the Canadian 1945 pam (and was apparently unchanged after that) still remains inexplicable.