No 4 mk1 Front sight issue

madtrapper143

madtrapper143

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Steep Rock Lake NWO
Gentlemen, I have a very nice Parker Hale sported 1948 Faz No 4. It has a 22" barrel and original ladder type rear issue sight. The front sight is a PH sight base and an issue 015 sight blade. The gun shoots 3" high @25 yards with the battle aperture and 3" low @25 with the 200 yard setting on the ladder sight. I believe I need a higher front sight. Which numbered sight blade should I get? I know that due to being sported the yardage numbers on the ladder won't be reflective of the actual sighting distance. Any help would be appreciated. I am shooting 174 grain Hornady round noses at around 2300 fps.

Darryl
 
You do not say what you want to correct your sights to, but the calculation is easy enough. You work out the ratio. Measure the distance from rear aperture to front sight. Let's say it is 30". Lets say that you want to change point of impact 2" at 25 yards. 25 yards is 900 inches. 2" over 900" = x" over 30" therefore x = .067" Adding .067" to front sight height will lower impact 2" at 25 yards. You would probably use the 300 or 400 yard setting on the ladder to match to the battle sight (which was originally calibrated for 300 yard zero, if I remember correctly).
 
Last edited:
Potashminer has explained the math.
At what range do you wish to zero?
Which sight do you wish to use?
 
Thanks guys for the response. I would like to use the battle sight to about 150 yards. (for our rough country deer and moose hunting) It would also be nice to experiment with the ladder sight (smaller aperture) for shots out to 200. I set 200 yards as my extreme limit. I would prefer a POI of 3" high @100 yards. This should give me a usable trajectory out to 200 yards. Here are the numbers sight radius = 27" , sight height including base from center of bore 1.003". This help is greatly appreciated. It would be so much easier with a original No 4 but who can afford one now. I understand that the numbers on the ladder sight will not likely correspond with the POI due to the barrel being shortened.

Darryl
 
Using my numbers I get .037" added to my current .015 sight. So should I be looking for a new sight height of .052 or there about. I guess a .045 blade would work? Or at least very close. My math is terrible.

Darryl
 
I replied above before my first coffee and got the 25 yards to inches wrong!! I have now corrected the numbers - the ratio is still correct, however. The math only works for correcting at a given range. With a 27" sight radius, adding .037" to your existing front sight height will move the point of impact down about 1.23"" at 25 yards (5" at 100 yards). From what you said about wanting to be 3" high at 100 yards, you should take a couple shots at that range now, and then decide how much you need to change the point of impact. With a sight radius of 27", at 100 yards, you will get a change in elevation of 1" for every .0075" that you add to the front sight. If you want to bring it down 6 inches at 100 yards, then 6 inches x .0075" = .045" taller than the front sight you have now.
 
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