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Sighting a new (to me) Sharps -- Need help


Cholla

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My range is patches of open areas in the pinon-juniper forest behind my house, so I have to be selective on where I shoot. I have my 45-70 Sharps hitting paper at 150 yards. I want to take it to 316 yards. My range is mostly tall grass, short trees, and brush, to watching the bullet hit dirt and work it to the target is not an option. If I am using 62 grains by weight of FFG with a 535 grain Lyman 457132 bullet, is there a formula of how far I need to raise the veneer sight from 150 yards?

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Well, usual way is to find your velocity (loading handbook or chronograph).  Then plug the bullet characteristics and velocity into an external ballistics program (like found on Hornady or GunData sites).  Or use a QuickLoad calculator companion program to work out the trajectory.  These steps make taming the rainbow trajectory into an understandable and repeatable arc.  I'm away from all my resources like that. 

 

Then, you have to know the MOA (click size) on the elevation part of your rear sight.   That is, how much MOA each click moves your point of impact.

 

Guessing you might be making 1200 FPS with that load.  My guess at your probable trajectory puts the bullet drop from 150 yards to 300+/- yards at about 75 inches. 

So, add 75 inches / 300 yards or 25 inches of MOA adjustment (higher).  You will be much closer to on paper at 316 yards.

 

That is a ton of guess work. 

 

I would locate a range where I could set up a large target at 300 yards or slightly more.   (Even if that is out in the forest service or BLM land)  One where bullet strike can be observed by a partner with binoculars or a spotting scope.    With that, in 10 shots or so I would be on target.  Calculating ballistics is a lot of depending on guesses at this point.   Especially for a black powder situation.  If you don't have good data AND a ballistics program and data for that really heavy slug,  then finding a proper shooting range is the ONLY sure fire way to achieve accurate fire.

 

good luck, GJ

 

 

 

 

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I’ll bet if you PM Original Limpy Gritz :P he’ll give you all the coaching you can take. He is very knowledgeable about those rifles.

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Short answer, yes, it is possible to compute the amount of elevation needed.  But you lack a significant amount of data to begin.  1st thing you need is a complete exterior ballistic chart for your intended range, which will necessitate knowing your MV, temp, humidity, wind speed & direction and the ballistic coefficient of your bullet and angle of the shot, (difference in elevation between target & firing position).  Then you need to know the amount of impact change for each gradient on your vernier sight.  Given the parabolic nature of the trajectory, this isn't simple arithmetic.  IMO, you're probably better off clearing your range & getting a spotting partner.  

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Just now, The Original Lumpy Gritz said:

Why are you only loading 62 gn?

How much are you compressing the powder? 

I started on this months ago and I no longer remember why I chose the loading I did. It was most likely due to the amount of compression I was needing to do to get the bullet in the case. Even using a drop tube I am doing a significant amount of compression. I think around 3/8" to almost 1/2" off the top of my head. I tried vibrating the loading block with the powder-filled shells today to so if I could get it to settle more but I saw little improvement. I am using a powder compression die from Buffalo Arms.

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I am using the drop tube that came with the Lyman BP measure..

 

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13 minutes ago, The Original Lumpy Gritz said:

If you're using a tang sight.

Come up 25-27 points.

Okay. I admit I am way out of my comfort zone. I watched a video. The guy was saying that his staff was marked in MOA with each mark on the right being 5 MOA. So when you say 25-27 points, are you saying 25-27 MOA so I would go up roughly five to five and 1/2 marks?

image.png.4507328c517cdcf57ffefa58e434f6a9.png

 

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The Green Mountain Regulators long range info is very helpful in learning a bit about LR and especially using your sights. Best advice I can give is learn your sights, then trust them. If you have consistent ammo, the sights will be very accurate. Much better than you can do by “Kentucky Windage”

 

https://d606ec8d-e0d0-4dfa-b093-f133cee7d078.filesusr.com/ugd/88618a_e5dc51f057274b46aacf8d1899458f5e.pdf

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image.thumb.jpeg.945e97660e6841abf77b5103edd578b9.jpeg

 

 

This is my rear sight. The front and rear sights are 34.5" apart

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9 minutes ago, The Original Lumpy Gritz said:

Not knowing your velocity makes this kinda a SWAG.

From your 150 yard setting, come up 25.

 

Do you remember Kirk and Spock on Star Trek? Do you remember when Spock made a guess and Kirk reacted as Spock's guess was fact because his confidence in Spock was so great? I have every confidence your SWAG will get me on target (as soon as I get a piece of plywood, paint it black, and haul it through the brush.). I thank you.

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I use the Lyman 457132 in my Trapdoor rifle and C. Sharps.  I use 68 gr FFg Goex and vibrate each case by its self.  What OAL are you using as I only have to compress the powder about 3/16".  I use Goex for SASS but load Swiss 1 1/2 or 2 if shooting targets for small groups.  I would check your OAL again.

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  • 2 weeks later...

Update: Here's what I have learned over the last week. MOA marks do not have any correlation to a ballistics table. None. Zip.

 

I was zeroed at 150 yards. My data:

FPS: 1135

Weight 535 grains

Bullet BC: .402

 

Using the Berger ballistics calculator table I printed out, the rear sight should be raised by 26 MOA to be dead on at 316 yards. Nope.

 

After walking seemingly miles, having the wind blow my massive cardboard and plywood target over as I got back to the shooting table, shooting another 20 plus rounds, I started getting desperate, raising and lowering the rear sight. Finally I heard bullet smack plywood. After everything was said and done I was an increase of 16 MOA on the staff over the 150 yard setting. I have come to the conclusion that the best way to do this is keep track of where it is hitting at various yardages and keep a log. So far I have two entries. I am sure there is a table to use, but for now I am done messing with it.

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Go get yourself a long piece of cardboard. A side panel of a fridge box.

Draw or staple a target to almost the top of it.

Aim dead on at this and fire a round or 2, at 100 yards.

Then start moving it backward in increments.

Always aim at the original target and do not adjust your sights as you move backward.

Now you have a record of your specific gun/load trajectory.

Now from here you can figure how to adjust your sight for each of your increments.

You might do this several times as you practice with your sight.

 

 

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This is my range book.

Pages are for a Pedersoli 1886 and Sharps Boss.

The neat ones are my new book which I started after I decided on my preferred loads. 

The messy one was when I was still working out loads and sights.

IMG_0376.jpg

IMG_0377.jpg

IMG_0379.jpg

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This was interesting. I recently got a 1873 springfield trapdoor carbine. Anyone know how to use a Buffington sight?  I did manage to adjust it and hit a target at 300 yards but would like to get more knowlegable on how to really use it. Not trying to steal the thread.

 

 

Hochbauer

 

 

 

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The numbers along the sides of the staff are in hundreds of yards. There is a line corresponding to each peep or notch on the blade. Align the corresponding line with the yardage markings.

 

Keep in mind these marking were calibrated for the original black powder loads.

 

Forget the videos they all suck.

 

 

 

 

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