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Working the Ishapore part 4: Sight Alignment

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ozzlefinch View Drop Down
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    Posted: February 16 2014 at 8:23am
Working the Ishapore part 4: Sights

Welcome back!  It's been a bit of a delay since the last installment due to inclement weather and the extra work it generated for me.  But no matter, here is part 4 of my series on how I improved the accuracy my Lee-Enfield 2A1 Ishapore.  In this installment I will cover very briefly how to check the sight alignment at home, before going to the range and spending time, money, and bullets.  Checking the mechanical alignment before firing a live round will get you into a ball park zero and save you lots of time and frustration when you go to live fire.

The first time I fired the Ishapore, I had no idea where the bullets went.  None of them landed on the paper, no matter how carefully I aimed.  Only after using a fresh plywood backstop did I see that the bullets were landing several feet to the side of the aim point, and patterning about the size of a trash can lid.  Repairing the group size has been covered in my previous installments, now I will address the aim point.

In the interest of full disclosure, I am not a professional gunsmith, I do not make any claims that my methods are the best, and any and all modifications you make to your rifle is 100% on you. This series is for informational purposes only, and I highly recommend that any work on a firearm be done by a qualified professional.

The first step to performing any rifle work is to select the correct man-movie to watch.  Comfort first, work second. For this installment I will be watching the certified classic:  "The Green Berets" with John Wayne.  So gear up, grab your insect repellent, and ride a chopper into this installment with me. Move out, move out! We're burning daylight!


 


Safety warning:
Because it ALWAYS needs to be said:  NEVER WORK ON A LOADED FIREARM!  NEVER PULL THE TRIGGER TO SEE IF THE RIFLE IS LOADED! Tired of hearing that from me? Too bad, I'm not tired of saying it.
To unload the Ishy:
1. Pull the bolt all the way to the rear.
2. Drop the magazine and remove from the rifle
3. Observe the chamber.  Hold the muzzle to a light source and observe the reflection in the empty chamber.  If you can't see the light, then run a cleaning rod from the crown to the chamber. The rifle is clear when you see the rod in the feed ramp area.
4.  Take all of your bullets and move them to a different room in the house so you have NO temptation whatsoever of putting one in the rifle while you are working on it.  Better yet, let your significant other hold them for you.

Part A: Concept of Zero

This portion of the Ishapore project is very simple, very quick and costs nothing.  But it does take a bit of explanation in order to understand the concept of why I did what I did.  Without getting too complex into the physics of it all, the reason we want to zero a rifle is to align the axis of the bore with the axis of the sights.  This will place the sight picture on the target at a designated range where the angle of the bore, alignment of the sights and trajectory of the bullet will intersect at a "zero" point of impact.  

The distance this zero intersection will be depends upon any number of individual factors.  The ballistic characteristics of the rounds, the type of shooting to be done, and personal preference all add up to the distance a rifle will be zeroed at.  My rifles are zeroed at 100 meters because over time I've found that to be the best compromise between the ballistic characteristics of the rounds I shoot and my shooting style.
Take a look at Figure 1.

FIGURE 1


The angles are exaggerated of course, but the concept is correct.  Notice the dotted black line, this is the mechanical cut of the bore of the rifle.  When the bullet travels down the barrel, this is the fixed path it follows. 

The blue line is the actual path the bullet will take the moment it passes the crown of the bore.  Gravity will pull the bullet down (remember Galileo and the ball drop experiment?) while air resistance will start to slow the speed of the bullet.  These factors are non-negotiable, irresistible, and must be taken into consideration at all times.  And before you ask, the answer is NO, a bullet will NOT travel forever on the moon.  The moon has gravity as well, and it will pull the bullet down to the ground just the same as anywhere else in the universe.

The dotted arrow line is the sight alignment based upon the front sight post and rear leaf aperture. As you can see from the graphic, the idea is to align the sights within the parameters of the ballistic trajectory  of the bullet to achieve a point of impact somewhere that is predictable and repeatable.

Now, with all that said, there is a way to "cheat" a bit and align the sights to a point where the sights and bore axis line up and get a decent starting point for accurate shooting without actually using a live bullet.

Part C:  Bore Sighting Adjustments. 

Adjusting the bore sight is a simple process.  All I did was to follow a few easy steps using a few simple props.  First I selected object approximately 50 yards away that made a clearly visible target, in my case I used a high visibility rife target paper taped to a fence post.  I then removed the bolt from the rifle so I could see through the breech to the end of the bore.  I placed my rifle on a set of saw horses and secured the rifle with bungee cords so it wouldn't move. As you can see in figure 2, I used some common household door shims to give me easily adjustable alignment of the rifle. Then I looked through the breech end and adjusted the rifle until the orange circle of the rifle targetg was centered in the field of view.  From that point it was a simple matter of tapping the sights with a hammer and drift until the sight picture was centered on the target.

FIGURE 2


FIGURE 3


FIGURE 4


Observe figure 3 and 4.  Figure 3 is how the target looked through the bore. Yes, it's blurry but I add "photographer" to the list of professions I know nothing about. Figure 4 is another blurry photo of the sight picture, but if you look closely you can see the front sight is a bit to the right of the target.   A few taps with a sight alignment tool, another look down the bore, and the sights can be centered without too much fuss. 

I didn't worry about the rear leaf sight, it's adjustable and it will be taken care of at the firing range or out in the real world.  Only by firing live ammo will you learn which number  to set on the leaf for certain distances and targets.  For the purposes of bore-sighting, I set it to the 100m scale.


Observe figure 5,  notice the peen dots from the factory. That shows how much the front sight was off.  Way to go Ishapore QC department.

FIGURE 5


Part C: conclusion

As you can see, the front sight was WAYYY off from the factory, as the dimples clearly illustrate.  At the range, I placed a clean piece of butcher block paper behind the target so I could see any stray bullets, but when I shot, it was dead on target.  You will have to experiment a bit to find a good compromise between your preferred sight picture (some like a center picture, others like to "float" the target on top of the front sight post) and the kind of bullets you are using.

It's important to remember that bore-sighting like this will get you really close to a zero, but it will still have to come down to range time with real bullets to lock it in.  Doing a zero like this will save you a lot of time and ammo at the end of the day, perhaps a bit of embarrassment as well (hey, nobody likes to pull a beehive target paper when everybody at the range is looking!).  If your factory rifle sights were as bad as mine, then you will certainly benefit by checking it over for accuracy. 

That's pretty near the end of the improvements and my information series. I've done a lot of work on the rifle, it's been hammered, sanded, shaved and otherwise brutalized.  Now all I have to do is make it look pretty! And that, is to be continued.....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote A square 10 Quote  Post ReplyReply Direct Link To This Post Posted: February 16 2014 at 10:07am
another interesting installment , thank you , 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ozzlefinch Quote  Post ReplyReply Direct Link To This Post Posted: February 17 2014 at 7:22pm
Thank you A square.  I'm sure for the majority here this information is old hat, but I have encountered one or two shooters along the way that have no idea how the sights relate to all the rest of what happens when a bullet is fired.  Understanding the why of what is going on goes a long way to understanding what to do to fix a problem. 

Only one more installment left to go!  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote A square 10 Quote  Post ReplyReply Direct Link To This Post Posted: February 18 2014 at 12:30pm
told you up front that i was always reading this stuff , you never know when you might pick up a nuance that had escaped your notice before , im always trying to learn something new , and even if its old hat , i might pick up something i need , 

and as you say - there are newbys among us that i would encourage to join us here - this might be the thread to accomplish that , 
we need more members/posters to keep the site active and relevant , this is one of the best enfield sites and its active/alive , lets keep it that way 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Zed Quote  Post ReplyReply Direct Link To This Post Posted: February 19 2014 at 5:11am
Than you for these excellent write up's Ozzlefinch. spurred on by you previous one I stripped and polished the trigger on my No2MkIV* (.22 trainer) last weekend. As it was a bit of a rough feel compared to my other Enfields. I only had time for 5 test hots in the garden but already seems much better. I will be testing it at the weekend.
Looking at the photo of the front sight above, I spot a possible project for you to continue the improvements! The barrel appears to contact the nose cap between 12 to 2 O'clock. That may cause some disruption of your barrel harmonics. Could be worth a look!!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ozzlefinch Quote  Post ReplyReply Direct Link To This Post Posted: February 19 2014 at 6:47am
Right you are Zed.  That issue has been corrected already.  I didn't specify that fix because it comes under the umbrella of barrel harmonics which I alluded to in my last posts, but didn't get into details. There are a number of books and such out there already that cover Enfield harmonics and I didn't feel the need to repeat something that already has thousands of words written about it.  

Thanks for pointing that out, it's just one more reason to love and adore the Ishapore factory quality control team. 
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