Powder charge & RB point of impact?

[Skychief]

I shot ten roundballs from my fowler today, just monkeying around. (I talked a friend out of 5 .590's and 5 .600's).

I used 70 grains of Goex 2f with all ten shots. I was shooting at an 18" gong 60 yards away.

I hit the gong with all 5 of the .600's. The .590's were a bit scattered. :haha:

If anything, the shots went lower than desired with both sizes. Not a surprise.

I know that I can show more of the breech to bring the impacts up, and may in the end.

That being said, if I were to up the powder charge to say 90 or 100 grains instead of 70 grains, what do you think would happen to my points of impact? :idunno:

This is asked, of course, with everything else staying constant.

I'm fairly new to launching balls from a smoothbore, but believe I have found a new "itch to scratch"!

Penny for your thoughts, Skychief.

 

[BrownBear]

I'm betting it would shoot a lot flatter, POI depending on how the sights are set up. In my own 62 smoothie the ball just about falls off the table down at 70 grains. Mine is most accurate up at 120 grains, and coincidentally is really flat shooting. I tried that charge because it shot so well in my rifled 62, letting me sight in dead on at 75 yards while being only 4-6" low at 100 and around an inch high at 50. Groups compare well between rifled and smooth out to 50 yards, but start opening up past that. Just a matter of grabbing the rifle if longer shots are anticipated and no inclination to stretch the range with the smooth.

 

[Grenadier1758]

If you up the powder charge, the impact may go up or not. So much depends on the stock architecture, how you react to the change in recoil and the alignment of the barrel to the sight path.

With your 20 gauge fowler, 70 to 80 grains is probably the upper limits to the powder charge. Your gun may well be capable of handling the charge, but such a large charge isn't necessary for an effective range of 50 yards. Yes, I've read the threads on the positive effect of more powder. Not entirely convinced that huge powder charges and extremely large shot loads are good for much than increasing the size of the bruise at your shoulder and encouraging flinching.

Your best method to raise the impact at target is to let your eye seem more breech and barrel. I like to see just about as much breech and barrel as the height of the front sight.

 

[ncmtmike]

Well Chief,my 20 is on point with 80grs.3fff,.600 ball & tow,don't know what you used between powder& ball,but mine hates cards :nono: and forget the patches in mine. So I wish you luck,but I would be as nervous as a long-tail cat in a room full of rockers,loading a 100 grs down the barrel. just me :2

 

[ncmtmike]

Now before anyone takes offense at me not loading a 100 grs of powder,let me say,there is nothing here in the lower 48 that needs a 100 grains to take down. BrownBear's turf is a different story. :wink:

 

[19 16 6]

Sasquatch ?
O.

 

[ncmtmike]

19 16 6,,Sasquatch is a national treasure :wink:

 

[Leatherbark]

I think the main idea about using the heavy charges is keeping the ball above the speed of sound out to a hundred yards to keep the ball stable and accuracy consistent as it is been written that when the projectile slows down through the sound barrier it takes wild directions.

We either start the ball under the speed of sound or way over it for accuracy. Or so I've read

That might cause one to miss a Sasquatch

Bob

 

[Loyalist Dave]

Gravity is a constant. The time of flight from exiting the muzzle at point a until it hits the target at point b is the flight time...often this is a fraction of a second at the distances that we shoot at targets and deer. The flight time then is also the amount of time it takes for the ball to go from a to b while gravity pulls it down. The faster the time, the less the downward pull effects the bullet path. In some cases the advantage gained by increasing the powder and thus upping the speed so lowering the flight time is negligible...other times it is dramatic...and will raise the point-of-impact on the target.

LD

 

[Billnpatti]

Go to this site http://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/rbballistics.html Go to the bottom where it says "CLICK HERE" and enter the required data. It will generate the exterior ballistics such as trajectory, kinetic energy, etc. for your particular caliber, ball, MV, etc.

 

[Rifleman1776]

talked a friend out of 5 .590's

Where did he get the .590s ?

 

[Rifleman1776]

Now before anyone takes offense at me not loading a 100 grs of powder,let me say,there is nothing here in the lower 48 that needs a 100 grains to take down. BrownBear's turf is a different story. :wink:

A friend from a former forum used 90 gr. in his 20 ga. with rb to take down a bison. Not saying he needed that, but it is what he used, and effectively.

 

[Skychief]

talked a friend out of 5 .590's

Where did he get the .590s ?

I don't know Rifleman and doubt that he remembers. These balls came from the Hodge-podge section of his gun room.

 

[George]

That being said, if I were to up the powder charge to say 90 or 100 grains instead of 70 grains, what do you think would happen to my points of impact?.

If you locked your gun down so that when fired it was pointing at exactly the same spot with both charges, you would see a small rise in the point of impact. It would be measured in fractions of an inch to an inch or so, depending on where along the path of the ball you measured it and how much you increased the charge. It would not move enough to solve your problem. My experience when working on this problem was that only a different sight picture made enough of a change in POI.

Spence

 

[Skychief]

Much appreciated all.

I have moulded about 150 .600 round balls with a mould lifted from a friend this afternoon.

So, let the fun begin. :haha:

I'm betting you are right on the money Spence. I plan to experiment with some heavier charges first, then, move on to different sight pictures as needed.

Heck, I may even file a dovetail on the top flat and slide a rear sight on this honey if the mood strikes me. :idunno:

Whatever transpires, I'm banking on the fact that I'm gonna have a ball piddling with a new-to-me facet of blackpowder fun. :thumbsup:

Best regards, Skychief

 

[George]

Whatever transpires, I'm banking on the fact that I'm gonna have a ball piddling with a new-to-me facet of blackpowder fun.

By George, I think he's got it. :grin:

Spence

 

[roundball]

I'm gonna have a ball piddling with a new-to-me facet of blackpowder fun.

SC, FWIW, every one of the half dozen 28 and 20ga smoothbores I've owned / hunted with always got noticeably tighter groups with increased velocity in 32" GM barrels, 38" Rice barrels, and 42" Rice barrels. As far as I'm concerned, 70grns is pretty much an entry level, 25 yard tin can plinking fun load out of a big bore 20ga.

The higher velocity from more stout charges seems to keep the balls under a good head of steam further towards a more distant 50-75yd hunting distance, eliminates / at least minimizes the chances for the knuckle-ball effect. And my experience was POI raised with that increased velocity.
My most accurate smoothbore PRB hunting loads are:
28ga=90grns Goex 3F
20ga=110grns Goex 2F
Smoothbores are very versatile...hope you enjoy yours

 

[BrownBear]

...knuckle-ball effect....

I kinda wondered if that was going on. Accuracy really does go haywire as you stretch the distance with lighter charges. Conversely, as you go up the charge scale, the better the groups when the range stretches past 50 yards. Trajectory flattening with the larger charges isn't really a factor until you stretch out to 70 yards or so, at which point it's really noticeable.

Guys can match their charges for their needs, and if lighter charges pop your cork, go for it. They just don't match with my shooting circumstances.

 

[George]

I think 'knuckleball effect' should be changed to 'knucklehead effect'. :haha: :haha:

Spence

 

[BrownBear]

Could be, but in my 62 light charges that manage 4" groups at 50 yards won't do 8-10" at 75 yards. I don't know enough to be sure of the knuckleball effect, but they sure do open up lots as the velocity falls off. Groups at 75 yards get lots smaller as I bump charges up the scale with a corresponding jump in velocity.

That doesn't mean anything to folks who don't hunt my mix of tight and open terrain. Adding 25 yards or so to my range potential is huge to me, though.

Mix moose and elk hunts into the deer prospects and there are additional reasons for larger charges. If you have a large population of brown bears sharing your hunts like I do, you'll redefine "adequate" charges once again.

Rifled or smooth, 120 grains is just right for my guns and hunts. You're sure welcome to come on up and load with 70 grains. Can I watch? I'll even bring a camera! :rotf: