A couple No. 4 questions after a trip to the range...

[amadeus76]

So I got out to the range today to zero a couple LE No4’s I picked up. Both are 1943 Longbranch MkI*’s. The first rifle was dead on at 25meters... For a 400meter zero. I know that the elevation is set by the front sight post but I’m horrible at math, can anyone tell me which sight I need to get for a proper 200meter zero?

The second rifle keyholed all over the place. I’ve seen this before with AK’s but never experienced it with LE’s and am looking for possibilities of what might be causing it. The barrel looks ok but I haven’t run a borescope down it yet to really get a good look. The stock is sloppy loose so I wonder if that might have caused it, but it strikes me as unlikely.

Both rifles were shot with Hornady 174gr Match ammo.

Can anyone help me out?

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[browningautorifle]

Did you try elevating the sight ladder to 200 to see what the fall of shot is? Or did you just use the battle sight?

In the second case your bullets aren't stabilizing so they keyhole. Probably too long ro it doesn't like boat tail bullets, try some 150 flat base or 180 flat base to see...

[amadeus76]

Did you try elevating the sight ladder to 200 to see what the fall of shot is? Or did you just use the battle sight?

In the second case your bullets aren't stabilizing so they keyhole. Probably too long ro it doesn't like boat tail bullets, try some 150 flat base or 180 flat base to see...

I had the micrometer sight set at the 200m.

[CINDERS]

The best solution is to chose or reload one load or brand of ammo for them I would suggest reloading as you can tailor a load that suits each one or just find a load after copious amounts of range time like I did to get to a load that suits all my 303's 4's & MkIII's.
You could try the 150gn Hornady Spire points as they are .312" I crimp into the cannular leaving @1/16" of it showing they shoot quite well I would not be interested in changing the front sight till you get the keyholing episode sorted it could be as one member here says your barrel "Has had the hairy banana."
You do not say if its the Butt or fore woods that are loose, if its the butt then see if the stock bolts loose if the bottom fore wood is loose then that needs attention well they both do as having it like it is will only cause damage to the woodwork in areas that are the most important to the Lee run over all the screws see if the front wood has the collar under the trigger guard screw front (Think thats how the armourers here say it)

[amadeus76]

I’m not even considering changing the front sight on keyhole rifle right now... One problem at a time. My question about which front sight I need is for the rifle that didn’t keyhole and shot on the 400m line on the zero target.

As for what part of the stock it loose, it’s the bottom forewood. And like I said, I’ll probably get it restocked and set up proper anyway. In general I’ve stuck to the 174gr Hornady match ammo as it’s grouoed well in my other rifles, but I’ll try out some of the flat base bullets as well. Thanks for the words.

[CINDERS]

Ama well you may want to get a big cuppa or a long neck beer here's the drill on how to get the sight height Good luck if you have a sibling who is good a math then enlist them, my wife is really good at stuff like this me its all just ants on a page! Or anyone else who requires this formula.............

Calculating Correct Front Sight Height for Zero;

Principle,

There is a linear relationship linking the distances between:

1. The front and rear sight distance, and

2. The change in height needed for the front sight of the rifle and the actual location of the bullet, above or below the bull’s-eye on the target.

Equation
A = the distance from the rear sight to the front sight. Units are in inches and approximate.

B = the distance from the barrel of the rifle to the target. Example: 100 yards (3600 inches), 200 yards (7200 inches), etc. Units are in inches.

C = the CHANGE in height required in the front (or rear) sight. Units are in inches.

D = the height ABOVE or BELOW the bull’s-eye of the target. Units are in inches.

Note
1. On a SMLE the distance between rear and front sights is approximately 19.5 inches.

2. On a No4 MkI the distance between rear and front sights is approximately 28.5 inches.

3. On a No5 MkI the distance between rear and front sights is approximately 23.25 inches.

4. On a P-14 the distance between rear and front sights is approximately 37.75 inches.

Actual Relationship
A is to B, as C is to D. Therefore, the formula is as follows:

A/B = C/D

Restated: A x D = B x C or C = (A x D) / B

Examples
1. A SMLE (fitted with a +.045 front sight blade) shoots a 5 shot group 8 inches above the bulls-eye at 100 yards.

C = (A x D) / B. C = (19.5” x 8”) / 3600”. C = 0.043 inches. Therefore, you must INCREASE the front sight height by 0.043 inches.

(+.045 add 0.043 equals +0.088, closest sight +.090)

2. A No4 MkI (fitted with a -.015 front sight blade) shoots a 5 shot group 5 inches above the bulls-eye at 100 yards.

C = (A x D) / B. C = (28.5” x 5”) / 3600”. C = 0.040 inches. Therefore, you must INCREASE the front sight height by 0.040 inches.

(-.015 add 0.040 equals +0.025, closest sight +.030)

3. A No5 MkI (fitted with a +.075 front sight blade) shoots a 5 shot group 5 inches below the bulls-eye at 100 yards.

C = (A x D) / B. C = (23.25” x 6”) / 3600”. C = 0.039 inches. Therefore, you must LOWER the front sight height by 0.039 inches.

(+.075 subtract 0.039 equals 0.036, closest sight +.030)

4.A P-14 (fitted with a +.060 front sight blade) shoots a 5 shot group 6 inches below the bulls-eye at 100-yards.

C = (A x D) / B. C = (31.75” x 6”) / 3600”. C = 0.053 inches. Therefore, you must LOWER the front sight height by 0.053 inches.

(+.060 subtract 0.053 equals 0.007, closest sight .0)

With the proper height of front sight to correctly adjust for elevation zero, it can now be drifted within the dovetail to correct for windage zero and staked in place.

Using surplus MkVII Ball ammunition, keeping in mind that the rear battle sight on these rifles is designed for a 300 yard zero, a correct MPI at 100 yards should be 8 ½ inches (+/- 1 inch) above the point of aim. At 200 yards the MPI would be 4 ¼ inches (+/- ½ inch). If zeroing at 25 yards the MPI should be about 2 inches above the point of aim. If zeroed in this manner it will also ensure that the range adjustable micrometer sight is zeroed as well.

This last statement sums it all up Range time..... is the only way to get your DOPE and put it on a spread sheet or pocket book for consultation on the day we all had to do it with our handloads.

The equation is valid no matter what ammunition is used, however the shooter or handloader will have to figure out his/her own exterior ballistics information to come up with the correct MPI placement at any given range.

[amadeus76]

Stupid question, but since I’m shooting at a 25m target for a 200m zero, do I still use the 200m (7200in) distance for B?

[Bindi2]

There is a proper 25yd target with all the cross hazes for all ranges. Some have a half bull others are full bull for middle aim or bottom black aim.

[amadeus76]

There is a proper 25yd target with all the cross hazes for all ranges. Some have a half bull others are full bull for middle aim or bottom black aim.

That’s what I used...

[Bindi2]

Did you have a metric target or a yard target. The rear sights if adjustable is in yards . Half bulls and full bulls make a huge difference. Half bull for hunting and full bull for target shooting. There will be a number on the front sight this is how you know what to change to. There are posts on this subject.