Sight-in question

[gmo]

I had just a short amount of time yesterday and needed to check the functionality of an unmentionable. Figuring that might only take a minute, I grabbed a new-to-me TC Hawken in .50 cal and my range bag.

After finishing the first task, I dropped 80 grains of Goex FF down the barrel and grabbed a strip of dry-lubed (Dutch Schoulz recipe) patches and a .491 ball and tried to short start it. The barrel would have none of it. My best recollection is this ticking was .018 or a touch over. So, I popped the ball back out and looked around to see what else I had. Nothing. Except a dirty t-shirt used for cleaning.

Not wanting to leave without shooting, I sprayed the t-shirt with some moose milk, doubled it, started the ball, and cut at the muzzle. Ball rammed down snugly and smoothly.

At 25 yards, I easily hit the six inch blob of spray paint on my target, pretty much in the middle.

Pleasantly surprised at this impromptu set-up, I backed up to 50 yards and repeated. Same result, but a little closer to the middle. Not bad!

With just a few minutes left, I backed up to 100 yards (verified via range finder; I was shooting in a field off the back of my truck), and wondered if my luck would hold out.

It didn't. This shot was 14-18 inches low...still in center line but low. I thought that must have been a flier, truck must have shook, foot slipped, or else I just lifted my head at the shot. Whatever, let's try one more.

Same procedure...same result. Holes touching...14 inches low.

I didn't have time to go to 75 for any data, so I left there wondering about the sight. The rear sight is in the lowest position; I didn't move a thing, that is how I received it.

I also got to thinking that when a rifle is sighted in, the projectile will usually cross the line of sight twice: once on the way up just out of muzzle and again as it falls farther down range. I am wondering if the results I saw were the balls hitting the "far 50," if you will, or if I just need to tinker with the sights. Seemed like way too much drop from 50 to 100.

I also suppose the weak patching could have caused the loss of a lot of initial oomph.

What am I overlooking here?

Thank you,
Gary

 

[Carbon 6]

The second crossing of the line of sight is usually near 50 yards not 100 with a muzzleloader. often below 50. Many guns have crossed the line of sight the second time before they they reach 50 yards.
None of this matters though until you find a proper load, patch and ball combination. Be sure to evaluate your spent patches.

Frankly, I would ignore it all and find your most accurate load, then adjust your sights to your desired or maximum point blank range.

 

[hanshi]

Very true reply from Carbon 6. My only problem is that when I shoot groups my foot keeps slipping every shot after the first one.

 

[fillwa]

Good find with the T-shirt patch.
I successfully use well lubed recycled flannel shirts and lounge pants.

 

[rafterob]

Yes, start at the beginning to find what load groups best. my guess is 65-70 grain range. I sight in at 25 yards and find that 50 is usually the same sight picture and POI. Then shoot at 100 to determine how much you need to adjust your back sight or your hold over.

 

[gmo]

I understand what you all are saying about working up a load, and that does make sense and is the tried and true method. Typing all of this on the phone with two thumbs, I was trying to get in all the details and wasn't clear with my question.

Is it typical for a ball to drop 14 inches from 50 to 100 yards?

If not, do you suppose I lost a lot of power from presumably weak patch? (The two patches I found looked good...not blown out at all.)

 

[deermanok]

Maybe next time try holding the front sight up a bit higher so you see more of the post in your rear sight, if you get my meaning.

 

[bang]

Sounds like you never crossed line of sight.
Drop with bp is like a rock.

 

[Griz44Mag]

Up your powder charge 10 grains and see. That will flatten out the drop some.
I keep records in my phone for guns I shoot multiple distance with - with appropriate powder charges - for each distance.
100 yards is considered at or close to max for most black powder hunting distances. I generally zero my hunting guns at 75 yards and that's good enough to keep them in min ute of deer from 50-100 yards.

 

[DJH]

I would say that a drop of 14 inches at 100 yards is not uncommon depending on how your gun is currently sighted. If your rear sight is all the way down, you've got a good bit of adjustment that you can make. To raise the POI, just raise the rear sight. 80 grains of FF is a decent load for a .50 cal. Your accuracy sounds good as you mentioned that the shots were touching at 100 yards. You may zero at 75 yards and then see what your drop is at 100 yards. My initial thought is that if you're zeroed at 75 yards, drop at 100 may only be 6" or so. I would then shoot again at 25 and 50 yards just to verify POI at those ranges as well. It sounds like your pretty close. Of course, you need to get your patch situation worked out as the old T-shirt patch may not be what you want for the long haul. Good luck.

 

[Kansas Jake]

The only other thing I would add is the 14" more drop at 100yards from 50 seems excessive. I would get proper patch material that you can load and shoot from a bench at 50 yards and then at 100 yards after you have a proper load. My TC likes 80 grains of FF as an example. If you were dead on at 50, I would suspect more like 4-5" drop at 100.

 

[hanshi]

With deer calibers my rifles are sighted in about 2"-3" high at 50-60 yards. This gives a point blank range up to 100 yards without any adjustments or hold-over. Very few times have I shot deer at that maximum distance; but I know it's within the rifles capability.

 

[Zonie]

I had just a short amount of time yesterday ...Figuring that might only take a minute, I grabbed a new-to-me TC Hawken in .50 cal and my range bag.

After finishing the first task, I dropped 80 grains of Goex FF down the barrel and grabbed a strip of dry-lubed (Dutch Schoulz recipe) patches and a .491 ball and tried to short start it. The barrel would have none of it. My best recollection is this ticking was .018 or a touch over. So, I popped the ball back out and looked around to see what else I had. Nothing. Except a dirty t-shirt used for cleaning....

At 25 yards, I easily hit the six inch blob of spray paint on my target, pretty much in the middle.

Pleasantly surprised at this impromptu set-up, I backed up to 50 yards and repeated. Same result, but a little closer to the middle. Not bad!

With just a few minutes left, I backed up to 100 yards (verified via range finder; I was shooting in a field off the back of my truck), and wondered if my luck would hold out.

It didn't. This shot was 14-18 inches low...still in center line but low. I thought that must have been a flier, truck must have shook, foot slipped, or else I just lifted my head at the shot. Whatever, let's try one more.

Same procedure...same result. Holes touching...14 inches low....

What am I overlooking here?

Thank you,
Gary

Something strange is going on here.
According to Lymans BLackpowder handbook, the 80 grain, 2Fg charge you say you used will give a patched roundball a muzzle velocity of around 1570 fps.

Using my Roundball Ballistics program and setting it to hit dead center at 50 yards, at 25 yards, it would be hitting 0.3 inches high which would look like your 25 yard description of what was happening.
At 100 yards the ball should be hitting the 100 yard target 7.2 inches low.

The next time you take it out to shoot, try to zero the sights to hit dead center at 80 yards. That would result in the shot hitting 1.2 inches high at 25 yards and 3.4 inches low at 100 yards.

 

[Carbon 6]

Something strange is going on here.
According to Lymans BLackpowder handbook, the 80 grain, 2Fg charge you say you used will give a patched roundball a muzzle velocity of around 1570 fps.

Using my Roundball Ballistics program and setting it to hit dead center at 50 yards, at 25 yards, it would be hitting 0.3 inches high which would look like your 25 yard description of what was happening.
At 100 yards the ball should be hitting the 100 yard target 7.2 inches low.

The next time you take it out to shoot, try to zero the sights to hit dead center at 80 yards. That would result in the shot hitting 1.2 inches high at 25 yards and 3.4 inches low at 100 yards.

I don't know if I'm the only one here that has done this, but you can physically map out your gun's bullet trajectory. It's not that hard and is a hell of a lot more accurate than any ballistic computer. It's dead on.

 

[Walkingeagle]

So... my .50 Lancaster shoots 2” high at 25, zero at 50 and 8” low at 100. This is with at 60gr charge of Goex 2f and .490 prb using .018” wet lubed with moose milk. I just did this range work about a month ago.
Walk

 

[Griz44Mag]

Drop is going to completely dependant on muzzle velocity.
Muzzle velocity is not going to be predictable from gun to gun.
Barrel friction, lubricity of the lube, gas seal, granularity of the powder, chemical makeup of the powder, energy added or lost due to the ignition system, etc....... You have to know the muzzle velocity to predict drop.
Now, measuring your ACTUAL drop is not difficult at all. Even the most sophisticated software allows you to adjust the input parameters (BC for example) based on observed drop at specific distances. Other factors (but not major factors) can be temp, wind, air density, direction of the shot, and several others.
All of this, and the time spent shooting, is all part of the time spent at our hobby - where learning the nuances of the individual gun and good marksmanship all come together. I get the best accuracy from the guns I shoot the most. (Go figure)

 

[Carbon 6]

That's what I'm saying, 10 targets, 10 yards, 10 bullets, a pen and paper.
Who needs a software program.

 

[Griz44Mag]

That's what I'm saying, 10 targets, 10 yards, 10 bullets, a pen and paper.
Who needs a software program.

For me, not a matter of need where black powder is concerned. It is fun to play with the numbers though.
I have not limited myself to just black powder though. I shoot long distance and have shot matches where long shots (out to 1300 yards) are made that do require an environment dongle and a software program if you expect to get a hit inside the 5 shots allowed at a specific target.
For those that shoot long range black powder, I'll let them speak for themselves. I have shot my .54 out to 200 yards using the "throw a couple out there and see where they land" method, then adjust accordingly.

 

[Carbon 6]

For me, not a matter of need where black powder is concerned. It is fun to play with the numbers though.

Numbers aside, being able to visualize your gun's trajectory is extremely useful.

 

[Zonie]

That's what I'm saying, 10 targets, 10 yards, 10 bullets, a pen and paper.
Who needs a software program.

That only works if all 10 of the targets are located exactly at the same height relative to a straight line that is exactly parallel with being "level".

Few people have access to a field that is exactly level and have the means of locating all 10 targets at exactly the same height.

Actually, ballistic programs are very accurate at calculating the amount of drop a projectile of a known ballistic coefficient will rise and/or fall during it's flight.
A good program even takes the altitude above sea level the shot is fired at, so the density of the air is taken into account.