tight balls and accuracy

[George]

For a time quite a few years ago I belonged to a group which shot at a very nice indoor range. We had monthly shoots, no competition, just a friendly gathering where only BP shooters were in the range. One evening I was shooting my .40 flintlock rifle, working on offhand targets and doing better than average for me. One of the young men in the bunch who was the current and past Kentucky offhand flintlock champion came over and admired the way the gun shot, asked if he could shoot a group with it. I loaded the gun for him each time and watched him absolutely eat the X out of the target. He said the gun was shooting very well, but he thought it would do better with a tighter patch-ball combination. I was shooting .395” balls with a .015” linen patch, and he suggested I go to a .400” ball with the same patch. The gun had a Douglas barrel with a land diameter of .403”. I tried what he suggested, and even I could see there was an improvement in the accuracy from the bench. That was a hard-to-load combination, though, so I soon went back to my regular setup. The .395” ball required a smart smack on the short starter, and the .400” sometimes required several

I’ve seen that many shooters believe accuracy increases as tightness increases, and have been curious why that might be true. What mechanism comes into play to cause the improvement? I can only think of two major possibilities, but would like to hear what the board thinks.

Number one, it seems obvious that the greased patch only partially seals the gasses behind the ball so that some gas always blows past the ball. Because of the way the patch folds and compresses differently each time, the amount of gas escaping can vary from shot to shot. The more gas which escapes, the lower the pressure and velocity. Variation of velocity is not compatible with high accuracy. Tighter patch-ball combos create a better seal, makes the blow-by more consistent.

Number two, The really tight combination forces the spherical ball into a slight cylindrical shape, with some slight length. When long bullets are properly stabilized by the spin induced by the rifling, accuracy goes up.The spin rate required for stabilization is inversely proportional to bullet length, longer bullets require quicker spin, short bullets tolerate slower spin. With really tight combinations we are shooting very short bullets instead of balls.This could be why such slow spin rates work well with ball guns.

What say ye?

Spence

 

[zimmerstutzen]

I suspect that with really tight combinations, the ball deformity causes groups to open up at moderate distances. It also depends on rifling. Wide grooves and very narrow lands seem to do well with a looser patch ball combination, or maybe it just seems not as tight because it is easier to load.

I think in some rifling configurations, there is a point at which tighter combinations do better and then as the combination gets even tighter, the groups probably open up.

I have seen shooters using mallets to start their patch ball combos. Seems too much for a round ball.

I figure the combination should be tight, but not so tight as to bruise the hand on the starter.

 

[Vaino]

I totally agree w/ both of your reasons for increased accuracy. W/ a clean bbl and a tightly patched RB, no evidence of "blow through" should be present on the patch after firing, especially the patch mat'l in the grooves. The lowest sectional density of a projectile would be found in half a ball which is highly impractical and a RB would be the next lowest sectional density of a "practical" projectile. As you said, a very tight PRB will acquire a tangental flat because of compression resulting in an increased sectional density which then makes it a bullet instead of a RB. That's the reason why dead soft lead should be used. Of course, practical, hunting type PRB fits won't produce the 2 above situations, but will suffice for hunting and most target shooting. Excellent topic, thanks....Fred

 

[paulab]

Spence....I agree on both counts with one minor correction. Bullets get wider, not longer if smartly smacked with a short starter. The bullet expands outward, not lengthwise. Still, you were correct when you stated that the end product was more like a bullet than a ball. cheers Paul

 

[George]

Spence....I agree on both counts with one minor correction. Bullets get wider, not longer if smartly smacked with a short starter. The bullet expands outward, not lengthwise.

Think of forcing a .50 caliber ball into a .30 caliber bore. The final shape of the projectile will be longer, I think. I believe in the very tight combinations the thickness of the patch, the part that is not compressible, reduces the effective bore diameter so that it is smaller than the balls diameter. The only way to get it into the bore is to "swage" it into a cylinder longer than the diameter of the ball.

Spence

 

[Bill Hall]

I agree with Paulab here, I don't think the ball will get longer in any way. I suppose if you forced a larger-than-bore sized ball into the muzzle, the lead would squish forward and back, making it a longer ball. But, going by everything I know, during the loading and firing of the ball, it's going to expand outward, not the other way.

As far as why tighter patch/ball combos are theoretically more accurate, I figure it's simply a matter of less wiggle room in the bore. The patch is compressed more tightly, during loading and then again during firing, so the ball stays more true to the alignment of the bore as it slides down the bore. It may be difficult to comprehend how a ball might get off it's path in the bore, but the slightest, unmeasureable deviation in the bore will be amplified the farther downrange the ball travels.

I say "theoretically" because I have experimented with increasingly tighter patches, to see if accuracy increases also. In one of my .54's, I came to a point where a tighter patch combo actually decreased accuracy, as the group started opening up. I was very careful not to distort the ball while loading, no hammering with the rod etc. I confirmed the result by switching back to a slightly looser patch, and the group closed back up again. Too many factors involved to say exactly why the tighter patch went wonky, I just know that it did.

Just my thoughts and experience. :grin: Bill

 

[hanshi]

I feel that as a general rule accuracy increases with a tighter prb. But it's possible to go too tight where former gains are lost. As long as your fired patches look good your combo is tight enough for all but the most formal and exacting work.

No prb combo can be hand loaded to the extent that no pressure escapes. In this respect a prb is only a partial seal. But with black powder and resultant low pressures a prb still does a reasonably fine job. It could be that a tighter prb affects velocity more than accuracy. :idunno:

 

[loki04]

Sir,

A thought on the final shape of the ball. My understanding was that the overall length of the ball decreases as it is forced into the the barrel. This reduction in length is due to the compression of the top half of the ball between the points of contact (the short starter and the equator of the ball.) What this reduction in length does not address is that the diameter of the ball is reduced, but only at the equator (enough to get it in the barrel) This means that as force is applied, the bullet becomes more cylindrical.

Essentially, unless you have a short starter that is the exact diameter of the barrel, the lead at the equator of the bullet that must be displaced to fit in the barrel will 'ride up' the side of the bullet. This will happen in conjunction to the deformation of the top of the bullet by the short starter, leading to a bullet that has a round back, a touch of swagging at the middle, and a squashed top half.

I believe that the end result of this long-winded and pompous verbiage is that a tighter patch/ball combo will reduce variability and will increase the accuracy only up to a point. Past that point, the reduction in variability of muzzle velocity and seating will be over come by the increasing variability in the shape of the ball and its concomitant reduction of flight stability

Regards,
Loki

 

[Larry Pletcher]

Yesterday, I short started 3 different sizes of balls for my .54. I was interested in the length of the rifling marks. I thought this would tell me whether the waist of the ball had more contact with the barrel. I just measured the largest one again front to back. It started as a .535". It's front to back measurement is now .531". So, it is shorter than it was, but it now has a longer waist (bore ride section) against the barrel.

The smallest ball was a .526". It now measures .531" front to back. It was the loosest fit but is now longer. It was so loose that probably doesn't count for this topic. I'll let you decide.
Apparently how tight a ball is patched makes a difference.
Regards,
Pletch

 

[loki04]

Sir,

You have me curious. Do you have more of the .526" balls? I would love the hear if the lengthening of a .526" ball happens consistently when you load.

Regards,
Loki

 

[Larry Pletcher]

Sir,

You have me curious. Do you have more of the .526" balls? I would love the hear if the lengthening of a .526" ball happens consistently when you load.

Regards,
Loki

I tried only one, but have more. To be a good test - the result should be repeatable. I'll try a few more and see if they do the same.
Pletch

 

[curator]

There are many factors in play with loading a muzzle loading rifle with ball and patch. After going to hundreds of competitions I noticed that most of the winners were loading a very tight patch/ball combinations with loading tools that were made to not deform the ball despite being driven by a heavy mallot. My work with Dutch Shults's technique, re-enforced my conclusion. Further personal experimentation has shown ways to get good accuracy with easier to load patch/ball combinations.

As several have mentioned, gas blow-by affects accuracy. Burned through patches do not happen when the load shoot accurately. My most accurate rifle, a .45 Green Mountain "hand-lapped" barrel with 1 in 56" twist has .450 land measurement and ..466 groove measurement. It is most accurate with a .016 pillow ticking patch and a .451 round ball. This combination is tight to start but loads easily after being short-started.

I can get nearly the same accuracy with a .445 ball and same patch if I back the powder charge off from 65 grains to 50 grains of FFFg. A full charge shows minor burn through on the recovered patches and groups open up significantly. Switching to FFg and I can increase the charge with the smaller ball to 60 grains before accuracy deteriorates. Going back to the original charge of 65 grains of FFFg and adding 25 grain (volume) of Cream of Wheat cereal on top of the powder before loading the smaller ball gave excellent accuracy. Recovered patches don't show any burn through.

My conclusion is preventing gas-leakage is essential to good accuracy. A large charge of coarse FFg powder may allow a portion of the charge to pack behind the loose ball and seal it almost a well as a plug of compacted cream of Wheat.

 

[pr.piburn]

I believe in bore dia. balls and .018 patching.
In my old 50 Douglas I used a .500 ball, In my
present 45 a .454 and my 58 Zouauve .575 and my
wife shoots a .410 in her .40 Our 45 pistol shoots a .451 and our 32's a .323. Our old 36
pistol a .360 dia. Here is a 100 yd target I shot
with my 45 from the bench It is a 10 lb Hawken style Flintlock open sights. At 50 yds all our
rifles will shoot 3/4 inch groups.

Webb Terry taught me about tight ball loads many
years ago.

 

[50cal.cliff]

When I first bought balls for my .50 I was told it might take either a .490 or a .495 ball. I figured if I couldn't shoot one or the other I could always melt them down and recast them, so I bought a box of both of them.

I shoot Wallyworld pillow ticking which is about .15 after washing.

I started shooting the .490 balls and liked them after time and getting all my ducks in a row I got where I could shoot a good group.

One day while shooting I thought about the .495 balls. I found that if the barrel was clean of fouling I could load them using the same patch. You do however have to hand walk the ramrod very carefully because it is just this side of being needing to be driven in with a mallet.

As far as accuracy I don't see an ounce worth of difference. I do however notice more kick so to speak. Which I think would translate into more impact. I have never shot it through a chronograph but I would suspect that it may also increase the velocity which might have an effect on the trajectory.

Now I know this post was about patch thickness but using the same patch and a larger ball translates into the same thing.

I can see why, there is that school of thought when you factor in that a tighter patch leads to greater velocity and therefore a better trajectory.
Honestly as far as I can tell there is not much difference in accuracy. Anyway that's my O2 on the subject!

 

[stormcrow]

As a relative newcomer to this I believe there may be something to it, but how people use an oversized ball is beyond my reckoning. In my .45 I use a .440 ball and .017 patch and it's all I can do to get the ball seated on the second shot- almost to the point where I'm afraid that I'm deforming the ball with the amount of force required. Maybe I'm missing something :idunno:

 

[pr.piburn]

Here is a video of me loading a .454 dia ball in
a measured .450 bore rifle. My wife's .410 dia
ball she shoots in her 40 Green Mt. barrel loads
just the same. You can push it down with your little finger on the ramrod. The short starters
we use have the same radius on them as the ball
we are loading so the front of the ball remains
round no matter how much you have to pound them
in to start them in the bore. Here is the link: http://www.youtube.com/watch?v=WV0qlOrMSZ0

 

[hanshi]

That was an easy load, for sure. Did you do anything to the bores or maybe the crowns for this to work so well?

 

[pr.piburn]

No, it's a old H&H barrel, but I do use Teflon
coated patching.