Getting sighted in at 100 yards

[WadePatton]

if'n i was on at 60 and off the paper at 100, and i couldn't get more/bigger paper, i'd move the target to 70 and then 80 and then 90. 

can't fix what you don't know is happening.

i got cocky once with my bore-sighting of a modern and started at 100.  flew 2 or 3 rounds clean over the pond bank (20' over target) into a pasture of bovines.  lucky i didn't have to eat a lot of steak over that one.

i say that off the paper is a sign that the paper is too far away/too small and that nothing but speculation can be hung on that.  hope it works out to be a simple fix.

[Daryl]

I go in for a knee replacement on monday so this will have to go on hold till I can go out again. The bent barrel idea intrigues me. Hope it aint so. Thanks all for the comments. Also is an 80 or 90 gr load common in a 45cal? FRJ

With an oiled patch, I have to use 85gr. 2F GOEX to shoot well at 50yards. I would expect 90 would work very well at 100 and that 85 might be just fine as it will put 5 shots into 1/2" at 50.

[Burgess_rudy]

I know this is an old post, but I was following it and never had the chance to try out some of the suggestions to the original poster. I have what sounded like a similar problem. A Chambers Virginia Rifle in .62 caliber. It was shooting tight groups at 50yards at the bullseye with 75 grs FFFg and a cotton canvas patch. When going out to 100yards (The range has only 50 and 100yards stands) I couldn't hit the target except by luck. I tried adjusting the powder charge but to no avail. I next switched patching material to denim which was slightly thicker. That seemed to cure the problem and for the first time I was shooting good groups that I was actually aiming for at 100 yards.

[WadePatton]

You fellas that are hampered by the conditions of public range use, and find youselffs in this here predicament could well also try to get some shots over a chronograph.  Seems like everybody has one now.  With your actual, observed MV, you can nail down the trajectory with mathematics.  Then hold accordingly.

MOF you can make up a chart of round-ball trajectories for a range of velocities* before you leave the house.  Then you should only need one shot to get a "picture" of how high/low you are at any distance.

Windage is all on you of course.

*so if others report x observed velocity with a load like yours then you use that velocity and then three or four steps above and below for your chart.

conversely if you know how high/low you are at enough distances you can calculate actual velocity. 

[Dphariss]

I've been slowly working on a 45cal flintlock that I bought several months ago. Shooting 70 gr of 3F it hits dead center at 30 yards and groups 3 shots into one ragged hole. Move out to 60 yards and its 6" high and centered. Go to 110 yards and I cant hit the paper!!!!! I've shot holding dead on and 6" high and 6" low and cant hit the paper. I'm using standard copier paper approx 8" X 11" with a 2" red dot in the middle. Although I cant see as well as I did 50 years ago I can still keep them into 2" with my other rifles. Anybody have any ideas what I'm doing wrong? FRJ

You are 2-3" too high at 60 yards.
Using a larger sheet of paper is the best idea.
20" x 20" at least or the back side of a 24"x45"  silhouette target with a aiming spot added.

Dan

[Dphariss]

To elaborate somewhat.

If its a new barrel it may need the steel wool or finest grade Scotch Brite treatment to shoot well.

30 yards is not much of a test. The groups at 60 should also be a ragged hole.
Rather than being on at 30 and 6" high at 60 it should have a trajectory more like this 50 caliber ball with 100 yard zero. The ball should not be more than 2-3" above LOS going to 100 if the load is in the 1800-2000 velocity range.


On at 30 and 6" high at 60 defies physics unless the sights are far above bore centerline.
Finding out if its bent may require debreeching since its really necessary to know WHERE its bent in order to straighten it so there are not 2 bends in it. One attempting to cancel the other.
So assuming that its on at 30 and 6" high at 60 there is a problem that shooting and polishing the bore will not likely fix.
RB rifles in the 45-54 caliber range using about 1/2 ball weight of powder and sighted for 100 yards plus shoot very flat to 120-140 yards.

Dan