Smoothbore roundball question...again.

[Skychief]

My smoothbore is hitting 3" below point of aim at 25 yards from a bench.   this with .715 rb's.

My question is:  If I shoot .690's with thicker patching, will these strike 3" higher than the .715's at 25 yards (everything else being equal)?

Thanks for any feedback.

By the way, my smoothbore has a short barrel (28").

Skychief.

[Uncle Russ]

My question is: If I shoot .690's with thicker patching, will these strike 3" higher than the .715's at 25 yards (everything else being equal)?

Well sir, I personally don't think there is enough weight difference in a .690 and a .715 to make all that much difference when you say, "everything else being equal".

Three inches is a lot at 25 yds. and the weight difference in a .690 and .715 is not all that much, although I would have to look to see exactly how much it really is.
Should it turn out to be as much as 40 / 50gr then there is the possibility it just might work, but I doubt it.

My first thought is to increase velocity or use more powder, unless of course you've got a load that is really grouping well but just happens to be impacting low.
If that should be the case and you insist on "everything else being equal" take small amounts of the front sight down to raise that impact.

This would also apply to the .690 as well as the .715.

There are times, and I've been there, where you don't want to touch anything... just raise, or lower, the POI, and sight adjustment is still the most practical and easiest way to accomplish this.

Uncle Russ...

[Swamp]

Yep, what Russ said!

[Longhunter]

File the front sight down, that'll bring it up some

[pathfinder]

Show a little more barrel when aiming,in other words,drop the butt a little while keeping the sight on target.

[hankaye]

Howdy; If ya feel abit mathimatical...
Borrowed this from Bob's Blackpowder Notebook:
Substitute your Ball measurments for those used in the example an off ya go...
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Weight of a Roundball (Long Method) If the diameter of a roundball is known, the weight can be calculated. Using the .3950 in. ball from the exercise above, we proceed to:
1) Convert inches to centimeters:

Diameter = .395 in. x 2.54 centimeters per inch
Diameter = 1.0033 centimeters

2)Extract the radius:

Radius = Diameter divided by 2
Radius = 1.0033 divided by 2
Radius = .5017 cm

3) Cube the Radius:

Radius cubed = (.5017)3
Radius cubed = .1263 cubic centimeters

4) Then:

Radius = cube root of .1263
Radius = Cube root of (3 x Vol.) divided by (4 x pi)
.1263 = (3 x Vol.) divided by (4 x pi)
.1263 = (3 x Vol.) divided by 12.566
3Vol. = .1263 x 12.566
3Vol = 1.5868
Vol = 1.5868 divided by 3
Vol. = .5289 centimeters cubed

5) Find the Weight in grams:

Since Volume x Mass = Weight
.5289cc x 11.34 gm/cc = 5.9982 grams

6) Convert grams to grains:

5.9982 grams x 15.4324 grains/gram = 92.57 grains



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Weight of Round Ball (Short Method) A short-cut method of determining the weight (W) of a roundball when the diameter is known involves the use of a constant.
W = 1502.6 x (Diameter x Diameter x Diameter)

Example for a .395 roundball: W = 1502.6 x .395 x .395 x .395 = 92.6 gr.
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Have fun    

[waksupi]

I bend barrels to correct the problem.

[Capt. Jas.]

Work you load til your pattern is acceptable.
When you establish a consistent load you are satisfied with, then bend the barrel.

[Buzzard]

My 20ga english fowler shot low and after trying everything including barrel bending am much as i dared, i decided to wrap the forearm, just behind the entry thimble, with some deer skin to give me a raised area that looks like a repair, but is what i use to raise my POI. Looks good and works well. This piece shoots point on with shot loads, but shot  low with RB, and therefore the removable repair job.

[Captchee]

I would agree with  what others have said . But I would add in one more thing .
 You didn’t say what  smoothbore you have .
 Is it a trade gun , Tulle , Bess ,  English fowler ? Was it built for you ?
 The reason I ask is that  sometimes the issue isn’t in the barrel but in the hold .
  Before you do any filing  or bending . Try  sliding your face an inch or so back from where your  now setting your cheek . This will cause you to need to rise the barrel alittle more so as to align the sight .

 I have seen guys file the front sight near off  , trying to raise  a group . When all they needed was alittle different hold

[Gordon H.Kemp]

I would have to agree with Capt. on this issue . If all else is satisfactory with the load combination , change your hold . "Kentucky " elevation !

[waksupi]

Hold can definitely make a difference. On my old trade gun, I use the top of the wedding band, and the base of the front sight to bring it to point of aim.

[Capt. Jas.]

Won't sliding his face an inch or so back from where he is  now setting his cheek cause him to have to remove his cheek from the comb to see the front sight? (If this is a decreasing plane comb)

 The farther back your cheek sets on a decreasing plane comb, the lower you will shoot because you are in effect lowering the rear sight which is the eye. Maybe adding a cheek pad instead?

[Captchee]

Won't sliding his face an inch or so back from where he is now setting his cheek cause him to have to remove his cheek from the comb to see the front sight? (If this is a decreasing plane comb)

all depends  if the gun was built fo him with the proper drop then yes . if it wasnt then no .
 if the gun was built proper. when its shouldered and with your head un moving  you should be looking right down the barrel flat .
 unlike modern shotguns with very little drop .which   you step into . Ie you have to bring your eye down to the plain of sight ..

also  depending on the gun .  the design may not call for a forward shooting style . possably and erect one or even a back  like with the Tulle

[Capt. Jas.]

Even if the gun was not built to fit him, if he brings his eye lower (backward on the stock) either it will shoot even lower or he wont be able to see over the breech. Exception would be if he was crawling the uppermost nose on a pied de vache stock.

I am probably just worn out and cant think today.