doublegunshop.com - home Forums General Discussion Classic & Custom Single Barreled Sporting Rifles @ doublegunshop.com Alex Henry sights..what were they doing?

In the process of putting sights on my Alex Henry, my thought was to make the sights so that a line from the top of the rear sight to the top of the front sight resulted in a parallel line with the bore center line. Checking the original rifle in the shop to confirm this, I find that the front sight on the original rifle (top of rear to top of front) is .160" lower as measured from the bore center line. Rear standing leaf is marked "100", and no alterations are apparent. This dimensional disparity seems logically excessive. Anyone care to measure up their AH sights? What am I missing?
Thanks in advance for your observations.

Jim

Jim,
So you are saying that the line of sight crosses the line of bore to an angular extent of .160" over the sight radius. Am I reading that right. If right then you could calculate the angle knowing the sight radius and then check against the ballistic tables.
I haven't shot Black Powder rifles for some time but my foggy memory tells me that for every one hundrea yardds of distance the sight increased by about .100". Again this is highly dependant on SR and my thought are of tang sights with 30 to 32" barrels.
By the way Hi and hope you are doing well.

Lynn,
Sorry for not being clear. Put another way, the sight-line of the original rifle is shooting downhill with respect to the bore line.
The chambering is .450 3 1/4. Distance between the sights is 20".
Jim

Hmmmmm....strange
Got to ask, sights are original? Any chance someone modified them sometime in the past?
Can you post pics of them, might stir some thought.

I believe what Jim mentioned sounds right, kinda. Isn't the sight-line supposed to look, not shoot, downhill. And, the bore shoot or point uphill compared to where the sights are 'looking'.

The front sight would have to be lower to counter the effects of gravity over a specified distance. If it were level, ie. parallel to the bore, holdover would obscure the target. See the front sight height caculator in a Brownells catalogue for the basic idea. The variance sounds about right to me for the given caliber.

Jim,
What is the height of the front sight to the bore and the height of the rear to bore?

Jim,
A 300 gr 45 bullet using nominal inputs would have a drop of ~9.9" in 100 yards. Your sight difference is .16" and that equates to 9.6" at 100 yards. (using the 20" SR)
I guess the confusion is, which is higher over the line of the bore, the rear or the front sight. If the rear then every thing looks correct; however if the front is higher then the bullet would impact about 20" low.

"What is the height of the front sight to the bore and the height of the rear to bore?"

Top of front sight to center line of bore: .665"
Top of rear sight to center line of bore: .838"

As mentioned previously, the front sight is the small (hard to see for old folks) typical AH bead which fits in a long dovetail following the barrel axis. While all the front bases and sights look identical in Winfer's book, it could be that they actually used a variety of sight heights depending on the application.



Rear sight. All appears original but unknown is how much if any was taken off the top of this sight in regulation.
Giving much faith to A.H. that the gun shot reasonably when completed, I have redone the bases to reflect the respective height differences and will find out Saturday at the range what is going on.....the disparity still seems excessive to me.
Here are the new sights.

The .173" delta between front and rear, with the rear higher seems about correct. My previous cal was with the bullet MV at 2000 fps when in reality 1700 for BP is closer. So the .173 seems right.
I have no idea why the front is so low and also do not think AH would have done it that way so I believe it has been messed with.

I like your front sight and for 100 yards with initial testing I would make the rear to be .200" high and then file in the notch until right on at the 100 yard distance.

Good shooting on Saturday, it will be a hoot I am sure.