More Myths

[Daryl]

This concept of a "smooth and polished" condition being bad intrigues me. The guy who owned my rifle before me used a lead slug and valve grinding compound to get irregularities out of the bore, including a manufacturing burr that was cutting patches. Does that mean that now I need to re-roughen it? Won't that just increase ramming force and introduce random forces into the equation? Hmmm....Does our resident barrel maker want to weigh in on that one?

There is a big difference between polished as in lapped, and too slick as Roger describes.

[Darkhorse]

During my last 2 years of high school (yes I do remember 1970, or some of it) my family toured the Civil War battlefields for 3 weeks each summer. One thing you saw quite often at the respective museums were head on fused bullets. I remember seeing on at least one occasion a split rifle barrel that had been hit dead down the bore with a minie ball. Said ball was still in the barrel.
Lots of interesting stuff. Wish I could go see it all over again.

[roundball]

Well...I hope ya'll will forgive me...but my smoothbore barrels shine and reflect like brilliant mirrors and I'm not about to "pee down my barrels" to fix a non-existent problem
 

[Roger Fisher]

Well...I hope ya'll will forgive me...but my smoothbore barrels shine and reflect like brilliant mirrors and I'm not about to "pee down my barrels" to fix a non-existent problem
 

Very happy for you   Question arises how often do you shoot your smoothy at 100 - 150 or even 200 yds as is done with a rifle Hmmmm! My smoothy shines fairly nice also.!

[roundball]

The answer to that question is never  ...my smoothbores are zeroed for 50yds deer hunting in thick woods...never shot a deer with a smoothbore past about 35-40 yards.

I gather that you're saying a smoothbore's accuracy goes south if it's too smooth...what is the actual failure mechanism, event(s) that occurs to produce that result?

[Teach]

This is the result of a 50 cal ball on another 50 cal ball at 25 yds.

[Roger Fisher]

The answer to that question is never  ...my smoothbores are zeroed for 50yds deer hunting in thick woods...never shot a deer with a smoothbore past about 35-40 yards.

I gather that you're saying a smoothbore's accuracy goes south if it's too smooth...what is the actual failure mechanism, event(s) that occurs to produce that result?

Nope, I was refering to a rifle!    However, bringing up a smoothy raises exactly that question!

[roundball]

"... However, bringing up a smoothy raises exactly that question!..."

MAN...am I ever embarrassed !!
 

The whole time I've been thinking about smoothbore muskets...I went back and reread the thread and I guess when I saw the phrase "glass smooth" or "smooth as glass' it registered in mind mind as "smoothbore" and I never looked back...sorry about that!


But, I still do have the same basic question...whether rifled or smooth...what is it about a "too smooth" bore that creates a negative effect on accuracy?
 

[satwel]

I believe the missing teeth story is true. I remember reading about the large anti-war movement in New York city during the Civil War, especially in the immigrant community. A popular tactic to dodge the draft was to have your two front teeth knocked out/removed so you couldn't bite open paper cartridges.

As a previous post noted; the visitor center at Gettysburg had several pairs of mini balls fused together from collisions on display. I remember seeing them as a boy. One CW visitor center has a cannon on display with a damaged muzzle. It was hit headon by an incoming cannon ball. I think I saw it at Fredericksburg.

I've heard that urinating down the barrel was one technique early settlers used to clean their rifles. Not sure if I believe it. Never heard of it being used to improve accuracy.

[Daryl]

Ned Robert's book addressed rifles that went 'slick' and stopped shooting well, some method of 'roughening' the tube was needed to get them shooting 'right' again. He may have been talking about bullet shooters, not round ball guns, however I think he was talking about cloth patches having more wear factor than pure lead itself.  Roger here, has experienced just this shooting slick with his rifle.

Seems to me it happened tohis barrel with around 40,000 shots fired.  If this amount of shooting is indicitive of required loadings and subsequent cleanings to get that 'too slick' result, then most don't have to worry about their rifle shooting slick.

If you were to use an exceptionally slick lube on the patch, you could about duplicate the 'effect' of a slick barrel.  Switching to a less slippery lube will return shooting accuracy. The slicker the lube when shooting patched round balls, the more powder is necessary to get a proepr and efficient burn of the powder.  I found this when switching between spit and LHV.  To shoot well with spit or WWasher fluid for lube requires 55gr. 2F for 1 hole accuracy at 50 yards.  With LHV, to use 2F, I had to go up to 75gr. for same accuracy. 3F, on the other hand shot well with spit using 45 to 50gr., while with LHV, 65gr. was needed. This shows the slicker the bore or lubricant as in my case, the more powder that is needed for identical accuracy.

Therefore, it stands to reason that if one finds his barrel shooting as Roger's did, form being too slick, he might merely increase the charge 5 to 10gr. to re-gain the elevation and accuracy he once had.

[Leatherbelly]

Hmm, good point Daryls.

[roundball]

Sounds like its the same concept between two identical barrels...one rifled, one smoothbore...where the rifled velocity is slightly higher than the smoothbore due to the rifling resistance creating a little more pressure buildup.

The less smooth that a bore is...even comparing identical smoothbores...would create some of that resistance compared to a super slick bore.

[Daryl]

Sounds like its the same concept between two identical barrels...one rifled, one smoothbore...where the rifled velocity is slightly higher than the smoothbore due to the rifling resistance creating a little more pressure buildup.

The less smooth that a bore is...even comparing identical smoothbores...would create some of that resistance compared to a super slick bore.

1st of all, I'm not convinced the rifle gives higher velocity over a smooth bore, even though breech pressures are higher.  I do think the rifle will more completely burn, or perhaps more efficiently burn the powder than the smoothbore.
In order to test rifle against smoothbore, a sealed ignition source - OR - good locks that prevent gas leakage at the nipple must be used.  Using 2, .60 calibre arms, one smooth flint against a rifled flint brings up the vent size, barrel length and ball weight.  Otherwise identical guns, a rifled .60 and smooth .62 using the same .595' ball could be used, but then, the vent size & therefore pressure loss difference there makes the test pretty much invalid.

I know my 'accuracy' load with slower powder (2F) at lower velocity won't shoot with a slick lube without upping the speed some 200fps over what is achieved with the spit load, ie: 55gr./ 2F for spit vs 75gr. 2F for LHV.  For 3F, the difference in speed is more remarked than that, ie: 45/50 for spit and 65gr. for LHV with it's attendent higher speeds.  I also know a slicker lube as in an oil or LHV produces higher velocity than spit or water/alcohol/soap when using the same load - up to 200fps depending on the rifle - my .58 Hawken being the only one I have saved that data for.  The accuracy is what changes the requirements & that can, to me, only mean the powder needs resistance to burn properly and give even, uniform velocities. Higher loads give more uniform speeds with slick lubes and perhaps, slick bores.  Spit has always given me more uniform velocities than any oil, at lower speeds.

When I use the same lube in the patch, the slower 2F powder is required to match the velocity of the 3F to meet it's accuracy. Using spit, the same requirement is there, but the amount of difference between the loads is less by 5 gr. - go figure.

[roundball]

Here are the test results I got from two identical GM Flint smoothbore barrels, one of which I then had Ed Rayl add rifling to...as close to identical I could get for the test...and I agree, since they were not precisely identical its hard to draw rock hard conclusions, although the results are pretty interesting.
======================================================
05/23/08
Tested PRB velocities between two GM .62cal barrels.
One a GM smoothbore, the other a GM smoothbore that had been rifled by Ed Rayl.
With everything else being as identical as possible, the rifled bore gave a higher average velocity of 28 fps…standard deviations were about the same.


GM .62cal/.20ga Flint ‘Rifled’ barrel
100grns Goex 2F
.020" Oxyoke prelubed pillow ticking
.600"/325grn cast lead balls (Eddie May/Georgia)
Wiped the bore after every shot
Pact Pro Chronograph at 15 feet
Average velocity = 1270 fps
Standard Deviation = 25 fps
--------------------------------------------------------------------------------------------
GM .62cal/.20ga Flint smoothbore barrel - Jug Choked 'Full'
100grns Goex 2F
.018" Oxyoke prelubed pillow ticking
.600"/325grn cast lead balls (Eddie May/Georgia)
Wiped the bore after every shot
Pact Pro Chronograph at 15 feet
Average velocity = 1242 fps
Standard Deviation = 30 fps

[Daryl]

Interesting RB, as you noted, but still not conclusive.  Your results are about the same pro-rifle as our tests were pro-smoothbore. 

If you tested 2 identical barrels, calibre, ball and patch you can expect over 40fps difference between them, both being rifled or both smooth.  Add to those possibilities,  the different gas leakage of two guns at the ignition source and that makes the results even more shakey.

[flintriflesmith]

I know I shouldn't challenge all the re-enactors who have used this "fact" through the years to get a laugh, but I think the regulation requiring two teeth is a MYTH, at least for the Rev War period in Colonial America. It makes a nice story but the regulations I have seen simply say "able bodied" and set, at most, age and height restrictions.

I await a correction from someone who can post some specific regulations verifying the two teeth business. I bet if you had no teeth at all they would be glad to have you in some capacity! The army, then as now, was full of positions other than infantry--cooks, wagon drivers, artillerymen, pioneers (combat engineers who mostly dug earth works cleared roads, etc.) and so on.

Gary

[Dphariss]

1st of all, I'm not convinced the rifle gives higher velocity over a smooth bore, even though breech pressures are higher.  I do think the rifle will more completely burn, or perhaps more efficiently burn the powder than the smoothbore.
<snip>

Hi Daryl

Remember the British used to rough bore the first few inches up from the breech of a shotgun bore to increase penetration.

The first 16 bore rifle barrel I had was slightly larger bore than the current one as well as rough and tight for the first 8" or so from the breech. It was 150 fps faster with the same powder and lot# than the barrel I replaced it with with a smoother interior. Same Nock breech, same length etc etc.
The increased restriction creates more "load inertia" which makes the powder more efficient since the pressure rises higher initially than it would in a smooth barrel.

So the old idea that the rifles resistance to the ball because of the twist reduced velocity may not be true.

But it would require actual testing to make ironclad pronouncements.

Dan

[Artificer]

I know I shouldn't challenge all the re-enactors who have used this "fact" through the years to get a laugh, but I think the regulation requiring two teeth is a MYTH, at least for the Rev War period in Colonial America. It makes a nice story but the regulations I have seen simply say "able bodied" and set, at most, age and height restrictions.
Gary

I did Rev War and a wee bit of Seven Years War re-enacting (along with some primitive competition shooting) in the 70's.  I also did War of 1812 re-enacting in the later 70's and we had almost unbelievable source documents and diaries from Fort Wayne of the 1812-1816 time period.  I did War Between the States re-enacting for most of the 80's.  Then after I retired, I came back to my first love of Rev War.   I am NOT an ultimate expert on any time period, but am best on the "Un-Civil War" and I've never seen nor heard of this regulation in official sources either.  It doesn't mean it isn't there somewhere, it's just that I've never heard of it in any of the time periods I've done.  Matter of fact, before it came up here, I'd never heard it mentioned before.

[Daryl]

Dan- I remember that first 16 bore barrel you had and our discussions about it.  Still, I'm not convinced.  Barrel length might also have something to do with the old Brit. idea the smothbore outpaced the rifle, since their rifles were normally 24" to 26" and smoothbores 30" to 36".

On the other hand, note Lyman's .58 data - the 24" barrel almost matches the 32" barrel's velocity using the same powder charges.  Using today's GOEX 2F and a 70gr. charge, I get over 200fps higher velocity than Lyman's book shows for 70gr. GOX. I use a VERY tight ball/pach combo with either water based or Hoppe's 9 plus for lube- this one gives the same speed no matter the lube, which is different from any other barrel I've chronographed. Barrels are annomolies for sure.

[northmn]

The roughing of a shotgun bore was similar to choking a bore in that it slowed the wads to prevent them from hitting the back of the shot column causing donuts.  An old trick.  However, in line with the roughing of the bore for single slugs of whatever, there were studies that claimed a slight choke would increase velocities in rifles and even artillery.  I believe the Germans used choked cannons at one time.  Roughing a bore might also do the same for a slug of whatever design.

DP

[Dphariss]

The roughing of a shotgun bore was similar to choking a bore in that it slowed the wads to prevent them from hitting the back of the shot column causing donuts.  An old trick.  However, in line with the roughing of the bore for single slugs of whatever, there were studies that claimed a slight choke would increase velocities in rifles and even artillery.  I believe the Germans used choked cannons at one time.  Roughing a bore might also do the same for a slug of whatever design.

DP

But they were not rough bored full length just at the breech.

Dan

[roundball]

The breech...not near the muzzle?

[Dphariss]

The breech...not near the muzzle?

I can't find a citation right now. And its too late to look.
Will see what I can  come up with.
I have at least three books to look at...

Dan

[northmn]

When I read the roughing the bore I should have read closer.  the old trick was at the muzzle.  The breech roughing is a new one to me.  Might give higher pressures where they were more needed if at the breech?  At the muzzle you start getting a pressure drop off?

DP

[James Rogers]

There is a reference to roughing in many sources. I know George mentions it in Guns and Rifles. There are also several period references to this practice. Roughing the breech area was done in combination with relieving (belling out) the muzzle area. Some guns were relieved in the breech and muzzle as well.