Quote Originally Posted by Surpmil View Post
What if any range of variation in MPI at 100 yards is indicated in the UKicon manuals?
I'm away from home putting my Griffon pup on some training birds over this Easter weekend, so I don't have my entire .pdf library at hand. But looking just at what I saved to my tablet, there is ARMOURERS' WING Precis No. SA/19A which implies the variation of MPI at 100 yards should be no more than 1.87".

In other words, no more distance than a change of front sight blade would result in then being closer to actual POA=POI. Each change of front blade size moves the POI either up or down 1.87".

If you were 2" in error from what POI should be, a change of sight blade should result in the POI being only .13" too high or low (as though that would be measured or measurable).

If your POI were 1.75" too high or too low, a change in sight blade would still result in a better zero. Now you'd be off in the other direction i.e. low instead of high or low instead of high, BUT now you'd only by off your desired POI by .1" of an inch.

By changing front sight blades, you should be no worse than +/- .9" inches from the desired POA=POI at 100 yards.

In the civilian world, many a front sight blade has given it's life to be put on a rifle and then the owner carefully dressed down the blade until they got the desired POA=POI with their desired load, at whatever distance they wanted one of the calibrations on their rear sight to be true at.

I would be surprised if more than a few regimental rifle teams DIDN'T do the exact same thing to get POI=POA as true as possible, rather than just "closest you can get with the front blades available".

If the MPI is given as 6.5 inches presumably the range of variation would be 5.5" to 7.5"?

The Canadianicon range of variation is given as 7.5" to 9.5" so one can see the two(?) estimations presumably in a sense meet at the 7.5" mark?
No. What you're visualizing is the overlap of the Figure Of Merit specified for the ball round/rifle combination by the Canadians versus the other commonwealth nations. Whether Brit or Canadianicon, whether the specified Figure of Merit grouping requirements are identical in size or different, you will ideally zero so that POA=POI is centered in the middle of the group within that Figure Of Merit.

You would adjust as best you could with the front sight height variations available to center on the middle of the group, whether the rifle put them all in a 2" group or a 4" group.

The 2 inches of vertical variation provided for in "Shoot to Live" probably reflected a variation observed in actual range firing based on variations in rifles and ammunition.
No. Or, no, I don't think so.

Remember that there are Figure Of Merit grouping standards for both the rifles and the ammunition itself no matter what Lee Enfield it ultimately ended up being loaded into out on the FEBA. Those Figures Of Merit are the limitations on what is allowed in variations in both the ammunition and the rifles.

I can't prove my opinion is right, but no, I don't think so. First, the author Johnson was an accomplished international Bisley/Palma competitor who had captained the Canadian team multiple times. That, and the focus of the book on SAIs effectively teaching the troops marksmanship doesn't lead to thinking the book was accepting of a completely different zero because that would somehow or other address mediocrity/lower quality rifles and ammunition.