Need help adjusting front and rear sights for zero on No4 MK1/2

[Peter Laidler]

See what I mean about keeping it simple chaps!
Foresight INTO the error, backsight OUT of the error is all you need to know in my humble experience

All I can say is that I'm glad that there's not a similar discussion to this regarding the No2 revolver or the old No2 Browning! There it was '.....well aim off a bit then......'

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[logandiana]

Parashooter, thank you thank you thank you. This is what I was looking for. And yes I am using factory loaded ammo. I have just under 2000 rounds so I don't plan on using any other loads any time soon.
I fully understand that I should probably just leave the front sight alone and just use the backsight for this by counting and recording clicks rather than using the graduation marks on the sight. This is really what I'd rather do anyway but my reasoning of establishing 200 zero at the 200 mark on the sight first using the front sight is to to give me an easily recognizable starting point. Like on my AR15, my 6/3 is zeroed at 25/300yrs. I can do -6 clicks from 6/3 for 100 yrds or -4 clicks from 6/3 for 50/200yrds. On the Enfield I am just looking for a good logical easy to remember starting point like 200 = 200 so that 1) I am not having to remember odd ball numbers like the half way point between the 200 and 300 yard mark on the sight really equals 50 yards, and 2) I won't have to count an absurd amount of clicks from bottoming out or from other starting point on the sight. The settings on the AR work well because I can always just quickly return to the 6/3 mark and go from there. Now I try to imagine if there was no 6/3 mark and the dial was just blank. What setting was I on again? Let me count down clicks to bottom out and then count clicks back up again to where I need to be. Woops I didn't hear that one, did it click or not, should I count that as a click? Start over... The entire point of my original question was this: If I establish my zero of 200yards at the 200 mark on the sight will I be able to use those remaining -3 clicks that I have available (bottoming out the sight) to put me right on at 100 yards? This is why I originally asked about the drop from 100yrd to 200yrds. In other words, if I am zeroed for 200 yards (with the sight set to 200 yards) and I am shooting at target 100 yards away then I should be about 2.5 high right? Then I just lower to the sight -3 clicks to bottom out and...

I've always used a center hold and zero for these types of rifles because it doesn't bring the size of the target into the equation as an additional variable that has to be corrected. If were to use a 6:00 hold then the POI changes with the size the target if I want to hit the center. In other words if were to hold at 6:00 on a 10 inch circle at 100 yards and I am hitting the center, then when I move to a 5 inch circle at the same range with out changing anything else then I am no longer hitting the center when I hold at 6:00. At this point if I want to hit the center then I have to either correct for it with the sights or try correct for it by guessing where to hold in the open space below the circle.

[Parashooter]

The entire point of my original question was this: If I establish my zero of 200yards at the 200 mark on the sight will I be able to use those remaining -3 clicks that I have available (bottoming out the sight) to put me right on at 100 yards?

Nobody can answer this for you because of the "it depends" factors -

• Is there significant backlash in your sight's elevation mechanism?
• Are you holding dead center or seeing it a little off?
• Is it sunny or cloudy? (This can make a big difference in perceived center.)

My No4's backsight gives 4.5 clicks below the 200 yard mark. If I need them, I'll use them - except that last half-click, which is really just backlash. If you want to use the 3 clicks below 200 that you report, go ahead. If some of them are actually backlash, you won't get the result you wanted. If you install the short front sight, what are you going to do on a day when you find your 100-yard group is a couple inches high with the rear bottomed-out? You'll be stuck holding low instead of just cranking down a couple clicks.

I have yet to meet a serious competitor using M1, M14, or M16 sights who relies on the graduations found on the elevation drum. (The 1/2-minute elevation drum on my AR-type doesn't even have graduations!) They count clicks from bottomed-out - quite a chore with half-minute clicks when shooting long-range, but worth the effort. You're complaining about counting just 15 very palpable one-minute clicks for a 200-yard zero on your Lee Enfield!? (If the clicks aren't strong, replace the detent spring - or the sight.)

If you really must look at the graduations, you should find those 15 clicks from the bottom place the marks aligned at 450 yards (unless you've got bad backlash). Is that so hard to remember?

Now you have some work to do (because you should learn this stuff for yourself) -

1. Measure the actual distance from the top of your front sight to the bore axis. (That's done by measuring from sight to barrel and adding half the barrel diameter.) It probably isn't the 0.8" I've used here.
2. Look up the ballistics of your ammo at Prvi Partizan Ammunition
3. Use those numbers to derive a ballistic coefficient at http://www.jbmballistics.com/ballist...culators.shtml
4. Plug the BC and sight height into JBM's trajectory calculator, along with Prvi's velocity and the atmospheric conditions of your choice.
5. Shoot some good groups at 100 yards to learn how much, or little, all this theory is worth.

[Patrick Chadwick]

Is there significant backlash in your sight's elevation mechanism?

To correct for backlash, you must always approach the final setting in the same direction.

Example:

Set the backsight to bottom out.
Go up the number of clicks you need to be in the center (at whatever range you are using, 100 is good).
Check the POI. It doesn't have to be dead center.
Go up 5 clicks.***
Come down 5 clicks.
Shoot again, to check the POI.

If you cannot see any difference, then you are lucky.
Chances are, there will be a difference. Caused by backlash.

To allow for this, bottom out the sight, go up to the setting for 100, and repeat the POI check.
Go up 5 clicks.
But this time, come down 8 clicks, then go up 3 again. You do not have to bottom out the sight, just be sure that you "undershoot" the setting by more than any likely backlash. I reckon that if the backlash is as much or even more than 2 clicks, then you should get a new sight before wasting any more ammo.

The POI should be exactly the same as when you started (allowing for shooter and ammo variations).

In other words, since the "bottomed out" position is the fixed end point for the sight, you should always go up to the final setting, not down.

Finally, please note that this method requires that you have some adjustment leeway below the setting for the shortest range you are going to use If you ignore what Parashooter wrote and insist on carving your blade to be dead on at 200, you may find that the "undershoot" readjustment to 100 is no longer possible.

***If the backlash is more than 5 clicks, you need to bin the sight!

[Patrick Chadwick]

I've always used a center hold and zero for these types of rifles because it doesn't bring the size of the target into the equation as an additional variable that has to be corrected.

Good for you, if your eyeballs manage it (mine don't). But Parashooter has pointed out that there still remains the lighting effect to be contended with. This effect will always be present if you are using a blade foresight.

BTW, it may be worth considering that if you did use the 6 o'clock hold, then you would have plenty of room for adjustment of the backsight.

[Peter Laidler]

Another point that we're missing is that as a rule, we zero our rifles at 25 or 100 yards and if there is any dispute the rifle is set up on the Enfield rest which eliminates ALL human error

[CINDERS]

logandiana you cannot beat range time surely you live close to some vacant spaces to get out amongst it, the only reason I drive an hour to a property is I am to bloody lazy to set up the boundary flags on the range as that takes the hour it takes me to drive to the property but there are ferals at the property so always a chance of smacking a Vulpse Vulpse.
I have found by trigger time that even with factory ammo though made to exacting standards has variations in the POI = POA its on the day and who can dope the conditions best and know where their weapon shoots from practice with this ammo - or more practice on the range with the reloads they are going to shoot all the time.

One hopes the 2000 Privi rounds you have are all the same batch so at least they should be close but you even get variations batch to batch, once I shoot one batch of projies out I have to find out where the next Lot # shoots may be stuff all in it but at 600Mtrs it does not take much to go from a bull to a 4 and I ain't a Robot or a machine rest.
If you are so hell bent on doing this then buy another back sight go to an area where you can do from 25 ~200yds and when after say getting 5 rounds at the POA = POI for the desired range then use a very fine centre pop on the sight for that range then all you have to do is go okay the 2nd pop mark = 100yd dead on hold so you just wind the sight to that dot and that's it job done no counting clicks or looking at weird range numbers that do not compute to the range being fired over (That's just a rough as guts Australian way of getting the job done and moving on with it.)

So now can we leave the slide rules got a big range day tomorrow 3, 5 & 700mtrs with my 6.5/284 trying the new Lapua Scenars 139gn out done the Meplat already.
Anyway you folks have a good week end and make sure you crank out a fair few rounds as I will be tomorrow, win loose or draw I love the smell of gunpowder early in the morning. Be that bloody cold at the range the projies will want to stay in the tube and not go towards the target. anyway we have fun........

Post script my shoot a 700m today I was pretty happy with my 6.5/284 I occasionally get it right

[browningautorifle]

Vulpse Vulpse

I had to go find out what those were...

Attachment 54222

[Parashooter]

Vulpse Vulpse

Funny how they spell stuff upside-down down-under!

"The red fox (Vulpes vulpes) is the largest of the true foxes and the most abundant member of the Carnivora, being distributed across the entire Northern Hemisphere from the Arctic Circle to North Africa, Central America and Asia. Its range has increased alongside human expansion, having been introduced to Australia, where it is considered harmful to native mammals and bird populations."

[CINDERS]

Thanks guys thought I would throw that one in well done on the research they were a product of the English Gentry wanting something to hunt from the Ol'Country as well as the Rabbits and thanks to that we have thousands of them and millions of rabbits.
The fox is a worthy opponent akin to the crow, and trust me our crows know the difference between a stick and a long gun! Never miss a shot at either one because what ever you used to lure them in wont work a 2nd time I know this from experience.

The fox is very harmful to our native fauna you got that right as well as lambs and poultry they are as cunning as a sh*thouse rat will kill 30 chooks just to perhaps eat one they are true thrill killers so I repay the compliments with a 308 with ballistic tips much red spray or the 22/250 just as good