Is 40 caliber the most accurate roundball

[alacran]

I was able to go to 4 or five interstate flintlock championship at Boonesborough, KY. It is all offhand shooting. The top shooters were using heavy but short barreled .32 rifles. When I went I was shooting on the Indiana team. You would think Indiana would be able to field a competitive 10 man team, but such is not the case.

[Daryl]

Alacran - at what range/ranges is that interstate competition shot, please?

[Stoner creek]

The Spring version of this match will be held this weekend at Altoona Pa. The fall match is traditionally held on the grounds of the Fort Boonesborough State Park near Richmond Kentucky. The fall shoot is held on the first Saturday in October.
 Most of the top shooters these days shoot a very heavy 10-13 lbs, shorter barrel 40 cal with a 1/48 twist and backwards double set trigger. Half stock guns and not much to look at but boy can they shoot.

[alacran]

An NMLRA 100 yard 8 ring black rifle target, and an 8 ring black 50 yard 6 bull rifle target.
The targets are first shot at 25 yards, and then again at 50 yards.
The fifty yard 6 bull target, is what separates the wheat from the shaff.

[Ezra]

To me, there is a clear distinction between an inherently accurate roundball caliber (which the title of this thread infers) and a roundball caliber that for a variety of other reasons like, recoil, amount of charge, muzzle blast, et al may be preferred by target shooters.  Now, I am FAR from a ballistics expert, but it seems to me, from a aerodynamics point of view, a ball is a ball.  Whereas, without treading too deeply into the non-black powder pool, clearly things like ballistic coefficient, length of bullet, etc, significantly contribute to accuracy in that world.  Is this not so?

Ez

[kyridgerunner]

Thanks everyone. Lots of different opinions, which I kind of expected, so I'll just keep on track for now and not make any changes.
That's some good shooting Mule Brain.
Daryl I've already done the muzzle crown like you suggest and that does make it easy to start. Tks.

[John SMOthermon]

For what it’s worth… I just shot a woods walk match with a Guy shooting a .40..

He hit every steel knock down target on the 10 shot event, but only scored a 9.

The head of the British soldier was hit, but did not fall.

So a .40 maybe a good choice for paper.. But when shooting steel at a distance I don’t think it’s the best choice…

[Candle Snuffer]

For what it’s worth… I just shot a woods walk match with a Guy shooting a .40..

He hit every steel knock down target on the 10 shot event, but only scored a 9.

The head of the British soldier was hit, but did not fall.

So a .40 maybe a good choice for paper.. But when shooting steel at a distance I don’t think it’s the best choice…

I seen something similar to the above at one of our Spring Rendezvous shoot's. A feller decided to bring his .32  that particular year and we just happened to be shooting "metal silhouettes" (30 / 50 yards). He certainly could hit them - but he couldn't topple them. (Our metal silhouettes are thick - at least 5/8" w/ flat metal squares on the bottom to rest on) Well, we all had a good laugh, even him... 

[Jeff Murray]

Good old Douglas barrels.  My .32 caliber has a 40 inch, Douglas XXX barrel with 1 in 66 twist rifling.  Not a commonly perceived optimum combination.  It takes a fair amount of powder to achieve optimum accuracy, but it is a tack driver.  It seems to me that there is an optimum rate of spin for a given weight of round ball that provides good accuracy.  That so called "sweet spot" could be achieved with a variety of Calibers and ROT's in a variety of combinations.  Any math wizards out there that could give us that formula?

[Scota4570]

....  Now, I am FAR from a ballistics expert, but it seems to me, from a aerodynamics point of view, a ball is a ball.
Ez

Close but no.  The frontal area of a sphere is calculated with a squared formula.  The volume of a sphere is calculated using a cubed formula.  So, a larger ball will have a higher section density and better ballistic coefficient.  The larger ball will shoot a little flatter and carry further.  The larger ball will also have more inertia and not be as effected by wind. 

https://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/web_apps/rb_ballistics.html

[smylee grouch]

Thank you Scota 4570 for that info. I punched in some number from 15 years ago from some crono work and it mirrored the published results. This will help a lot in future load development for sure.

[hanshi]

As for inherent accuracy I do not believe any caliber can possibly hold that title.  Accuracy comes from the quality of the barrel primarily.  Many variables also raise their hands for a bit of credit but the load is the other major mechanical factor.

The .40 definitely makes one of the sweetest shooting rifles one can get.  I had a .40 for many years with a heavy swamped GM barrel and that rifle could really shoot.  At 25 yds 30 grns of 3F was perfect squirrel medicine while 40 grns was my favorite load with an sd of 5 consistently.  The #2 favorite load was 60 grains.  At 100 yds it consistently gave 5-shot 4" groups; that was about as good as I could do with any rifle.  The surprise came when I decided to chronograph my two favorite loads.  40 grns gave around 1700 fps; but the 60 grn load reached a blistering speed of just under 2200 fps!  Obviously prb stability could be achieved from 1700 fps up to 2200 fps along with superb accuracy.

But my go-to .45 was even very slightly better with groups of 4" to 3.75" at 100.  My .50 matched that as well.  So I'd concur that an accurate rifle is an accurate rifle regardless of caliber.

[Daryl]

....  Now, I am FAR from a ballistics expert, but it seems to me, from a aerodynamics point of view, a ball is a ball.
Ez

Close but no.  The frontal area of a sphere is calculated with a squared formula.  The volume of a sphere is calculated using a cubed formula.  So, a larger ball will have a higher section density and better ballistic coefficient.  The larger ball will shoot a little flatter and carry further.  The larger ball will also have more inertia and not be as effected by wind. 

https://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/web_apps/rb_ballistics.html

I plugged in a .45 at 2,240fps (achieved in my rifle with 75gr. 3F and 85gr. 2F), 10 mph cross wind and got 12" drift at 100yards.
I then plugged in a .68" ball at 1,550fps and got 9" drift.
I then plugged in a .45 ball at 1,550fps and got 13" of drift.
I then plugged in a .68 ball at 1,225fps (82gr. 2F) and got 7.7" drift. Even though the time of flight was longest, the drift was less.
One other aspect of the .69 rifle, it always knocks over steel targets hit - or at least moves hangers to display hits on those. Some times, it breaks the chains, but hits at obvious, but so are .50's LOL- sometimes .40's are hard to see & definitely smaller calibres worse, especially in a bush, woods walk.
SOMETIMES, it's hard to keep the eyes on the target.

[smylee grouch]

Hanshi, was that 40 GM swamped barrel one that GM swamped? Gm did at one time make swamped 40s with a 1-56 twist. A 40 can be clanger hitter but will struggle knocking over some of the larger steel targets at the longer ranges. The Rams and maybe the Turkeys at 200 and 150 meters resc. at the Ben Avery Range in Pheonix AZ are hinged at the bases and reset with an air powered lift so if they are hit low and to one side they will torque against the hinge and even a 62 will some times fail to knock them over.

[Hungry Horse]

 I think the forty calibers reputation come from a combination of factors. It’s natural accuracy with a 1 in 48” twist, its flat trajectory, and its light recoil. All these factor made the .40 king of the hill for years. I also think that it will stabilize with several twists, makes it popular as well. Also having a caliber that you can load down and shoot small game with, and then turn around and load it up and shoot deer with, has its advantages.                     

Hungry Horse

[Ezra]

....  Now, I am FAR from a ballistics expert, but it seems to me, from a aerodynamics point of view, a ball is a ball.
Ez

Close but no.  The frontal area of a sphere is calculated with a squared formula.  The volume of a sphere is calculated using a cubed formula.  So, a larger ball will have a higher section density and better ballistic coefficient.  The larger ball will shoot a little flatter and carry further.  The larger ball will also have more inertia and not be as effected by wind. 

https://www.ctmuzzleloaders.com/ctml_experiments/rbballistics/web_apps/rb_ballistics.html

Thanks Scota4570!

Ez

[hanshi]

Hanshi, was that 40 GM swamped barrel one that GM swamped? Gm did at one time make swamped 40s with a 1-56 twist. A 40 can be clanger hitter but will struggle knocking over some of the larger steel targets at the longer ranges. The Rams and maybe the Turkeys at 200 and 150 meters resc. at the Ben Avery Range in Pheonix AZ are hinged at the bases and reset with an air powered lift so if they are hit low and to one side they will torque against the hinge and even a 62 will some times fail to knock them over.

Yes, smylee, it is a GM swamped barrel.  From their site I no longer see a swamped option for any of the barrels they list.  The rifle, in .40, weighed 8 lbs 1 oz.  The bore sustained a bit of damage and accuracy did suffer.  A year ago I sent the barrel to Bobby Hoyt to bore out to .45 and his job was nothing short of beautiful.  After the rebore that rifle lost weight and is now 7 lbs 11 oz.  Plus it shoots like a dream.

[Mule Brain]

For what it’s worth… I just shot a woods walk match with a Guy shooting a .40..

He hit every steel knock down target on the 10 shot event, but only scored a 9.

The head of the British soldier was hit, but did not fall.

So a .40 maybe a good choice for paper.. But when shooting steel at a distance I don’t think it’s the best choice…

That is correct, I used my .40 on a steel silhouette shoot. I ran a perfect knockdown score at 25yds, but then fell apart at 50, and 80yds. The .40 just doesn't have enough to knock the darn things over. Shooting steel I think a minimum of .50 is in order     

[Stoner creek]

Agree, however accuracy and knock down power are two different critters. Look at record offhand scores at Friendship and you will likely see the 40 caliber as king. Most of the aggregates include 25, 50, & 100 yard targets.
 I’m not a 40 cal shooter. I shoot a 50 primarily. Mostly because I don’t have to squint to see where my shots went.
 Steel gongs, I’m really liking this new 60 cal. That’s knock down power.
 Great thread.
 W

[Ezra]

It’s true, when I use my .58 Lancaster to shoot gongs or steel in general, well by God you know when you hit steel!  Everybody hears it!

Ez

[Frank]

The most accurate rifle I ever had was sporting a Getz 40 caliber 7/8ths x 42 inches long.

[Panzerschwein]

.40 doesn’t hit hard enough for some woods walks targets or other events. It’s also too light for anything much above a coyote. Some guys claim it’s good for whitetail, but I’m not convinced.

I’d rather have a big bore (.62 rifled) and let God sort out the rest. Can handle any animal in North America and reaches and and smacks any target with authority. Got to love the big bores. Not for the faint hearted.

[Jim Filipski]

I have used my .40 cal flintlock for many eastern woods walk events and have won a few in my time. I hunt squirrel with it but never deer.
I have killed a number of woodchucks with it up to 75 yards however!