Line of sight???

[jeremytl]

Still playing with my newly acquired TC .50 flintlock, for those of you who responded before, and any of you who haven't and can help! I got my Grandfather's flintlock (from my Dad) and have been experiencing a new world of blackpowder 'fun and games'. Its great and you all's info has helped me. Currently: I am having a problem with my line of sight: I have finished practicing with it at 50 yards, thought I have only touched the surface of "mastering it" at that range (I'll leave that to our forefathers, and of course, you guys). At 50 yard it shoots fine ok? Here's dilemma: I shot three (3) shot groups at 100 yards with the same load (using 82 grains of 2f and firing a .490 roundball) and hit the target low CONSISTENTLY at about three inches low of bullseye about 1" ctc. OK? So today I went and using the same load, and same rest, and same weather conditions, i.e. little wind if any, shot about 1.5 " high of bullseye CONSISTENT. So what is the deal? Plus I'd like to experiement at 125 yards but now am afraid to. What is the line of sight for the 50 ball?
Thanks

 

[Larry (Omaha)]

Jeremy, I am not too sure what YOU mean, but to me line of sight is exactly what it says. Line the target up with the sights. Now if you are talking trajectory, now that's another story. There are lots of charts out there for bullet trajectory. What I think you are trying to determine if I can read between your lines is that one time you are low and then the next time you ended up high. I have seen this a lot just because of lighting and sighting a bit more or less front sight. 100 yard is a long range in my book for open sights, at least for just a few rounds of shooting. I think you need to consider your conditions and do a little more shootin. Sounds like the lower group is more than acceptable, and you didn't say on the high one. What I do is, (THIS DON'I MAKE IT THE ONLY WAY)get the sight picture I want, aim where I want (some like a 6:00 hold) and as long as I am grouping I adjust the sights and or charge to obtain my desired impact. Get your 100 to your satisfaction, then go for the 125, but not until then.
Please do not over charge your rifle cuz it could be hazardous.

:thumbsup:Flintlocks Forever
Lar

 

[Stumpkiller]

I think you're asking the wrong question. The "Line of Sight" is fixed until you adjust your sights. It is a straight like that extends to infinity based on the position of the front and rear sights. Think of it as a lazer beam aligned so that it passes over the center of the rear notch and then on to the top of the front sight, and extending on straight for as far as you can see.

Then, there is the line of the bore. That would be the line straight out from the breech of the barrel through the muzzle and on along that straight, infinate line. The projectile starts out along that line but begins to drop the instant it leaves the muzzle due to gravity. The trajectory is the parabolic arc the projectile follows from muzzle to point of impact.

So, if you are sighted on at 100 yards, the line of sight is from your eye, through the sights, and onto the center of the target at 100 yards. The bore line may be pointing to a spot 10" high of that center of the bull at 100 yards. The trajectory will be climbing to about 60 yards out (maybe 3" high at that distance) and then starting down until impact in the center of the bull at 100 yards.

Then there is the "point blank" range. That is the distance out to which you can hit a target, like the vitals of a deer, without needing to compensate for evelation hold-over. This one will depend on what distance the weapon is zeroed in at and the trajectory of the projectile. I zero 2" high at 50 yards and can hold center-deer out to 100 and still be in the vitals.

So, why is your point of impact changing at 100 yards when you have not changed anything? This could be caused by changes in pressure where you are bracing the forestock; like directly on the rest vs. hand between stock and rest. Change in lighting (shiny sights will tend to shoot low on a sunny day vs. an overcast one as the eye is fooled by the fight glare off the front blade). Changes in velocity (either via powder, ball weight or slipperyness of the barrel - you'd know if you changed one of these . . . unless it was due to inconsistant lube, air pockets in cast balls or damp powder).

I don't have a definate answer. 4.5" at 100 yards is fairly significant and would not be something like a small change in patch thickness or a primer brand change.

 

[Deadeye]

I believe your meaning trajectory when you say "line of sight". Line of sight refers to a straight line from your eye to the target. Trajectory is the path the bullet takes
above and below that line to arrive at the target and will vary depending on your velocity. 1" groups at 100, sounds like your rifle is shooting very good. Most folks wouldn't change anything. Your probably just seeing the sights different at different times. You may have unconsciously
held your front sight up slightly (only takes a few thousands) knowing that it has shot low before. Keep shooting until it's always shooting in the same place before changing anything.

 

[robinghewitt]

Streuth, if I was shooting .50 ball, 1" groups at 100 yards you'd hear my delighted whoop right across the Atlantic as I put my name down for the World Championships. What is the problem???

 

1" groups at 100yds. aside, the elevation difference can be as little as a 5-10mph wind blowing in your face before, or 5-10mph from behind, this time. 6" at 100yds. is from less than 10mph wind from head on or behind, and about 6mph from the side.
: Your load of 3 drams of 2F (82gr.) will provide approximately 1,600fps velocity. If zero'd at 50yds. exactly, top of the front sight at .85" above the centre of the bore, the ball will drop approximately 5.31" at the 100yd. mark. This is all mathematical(from a chart) due to the approximate ballistic coefficient of the ball(.070). At 125yds. with the 50yd. zero, the ball will have dropped an additional 5.99"(11.30 total) for the extra 25yds. and will also have dropped to approximately 879fps at that range.
: Now - WHY the difference on those two days - a difference of 4 1/2".
: A seemingly small breeze of 5mph will drift your ball, if covering the entrie range at 90 degrees, a total of 5.77".
: If the wind was from the front one day, and from the rear the next, it is quite easy to see that amount of drift.
: NOw, another possiblity is different possitioning of your barrel in the channel. If the barrel hasn't been properly bedded in the channel with Devcon or AcraGalss or ther bedding compound, you can expect different POI (points of impact) if you take the barrel off and replace it. As well, lack of bedding on a removable system generally causes a shifting POI with each shotlet alone shooting into 1" at 100yds. for 3 shot groups. A 1 1/2" to 2" group is amazing with patched round ball, by someone who is schooled in shooting with open sights. The average shooter barely keeps them inside 4" with "modern" rifles and their open sights.
: Shooting groups 6" apart on two different days shows either wind OR BARREL MOVEMENT or sight movement or sighting method.
: I suggest you have someone (or learn by doing it yourself) bed the rifle's barrel. Devcon Plastic Steel is the very best and easiest compound for bedding. Many Bench Rest shooters use it instead of the commercial bedding compounds. The most important areas are ahead of and behind the barrel wedge position. Just make certain you use a good coating of something for a release agent. Some people use shoe polish. I use axle greese with Devcon as works perfectly & is easy to put on and remove.

 

[jeremytl]

I believe your meaning trajectory when you say "line of sight".

Thats right, I meant trajectory. I meant trajectory when I spoke of line of sight, was just using wrong terminology. Its hard to relate my experience from centerfire rifle shooting to muzzleloading but I am learning a lot. I shot again today and didn't shoot quite as tight a group at 100 yards but was consistent. I think my problem was my patches. I had some prelubed patches and some patches I lubed myself. Today I shot all shots using the patches I lubed myself. I shot high about 3 inches at 50 yards and shot low about 1.5 inches at 100 yards, consistently. I'm throwing away my prelubed patches, I just can't get quite the consistency out of them, not to mention the fact that they're probably 20 years old. Thanks for the advice. My best groups today were two 2 inch groups at 100 yards. Trajectory much different than what I'm used to though!

 

Man - that's shooting GREAT- keep it up.
: I'd place a .50 RB max range on deer as 150yds. if I could still keep 3 out of 3 on a pie plate at that range. A .54 would extend the range, as long as sufficient accuracy accompanied it.
: Just this last fall, I was in a camp where an excessively long shot was taken on a Bull Moose. I would normally have placed the max range for a .54 at 120yd. on such large animals, & with the .50cal., 75/80yds. The moose actually ran 40 yards and fell dead. The load was 100gr. stricken RS Pyrodex load with .535 ball and .015" patch. The ball centred a rib going in, 3/8" thick, then 1st lung, then through the centre of the heart, then the second lung, between off-side ribs and stopped just under the hide. The range was a lazered 170yds.
: As well, this fall, a big Bull Moose was taken by a fellow with a rifle made by my Bro, a .50 cal. Long Rife loaded with 110gr. 2F, denim patch and .490 round ball. That hit was almost identical to the one with the .54, except the range was 100yards even. The bull shuddered at the hit, and dropped in his tracks. This isn't a normal result of a double lung hit from a .50 but that's what happened this time.