7 sided polygon bore?

[Hightower]

I have an old caplock, small caliber appears to be around .36 but haven't measured it yet.  The bore is not round, but rather a 7 sided polygon.  I have read that an early and more primitive method of rifling created bores like this, I've heard it dubbed "Appalachian bore" even, but I am wondering if anybody can tell me more about it.  Like what time period this was common, what areas are known for it, etc.

I am at work now, but will take some pics when I get home in the a.m. and post them.  Its really a beautiful rifle, flamed curly maple with what appears to be a poured forend cap, typical brass buttplate and doubleset trigger.  I have never taken it apart to look for markings, there are none visible but haven't looked under the barrel or lock yet.

[Captchee]

Welcome to the Forum Hightower .

I cant help  you much with a definitive time frame .
 but i can tell you bout the one i have .
 The barrel is a hand forged ,42 inch barrel  with radius rifling .
 If you look at the muzzle , it looks to be a  polygon bore . IE the bore doesn’t look round
Even if you drop a bore light down the bore , it still doesn’t look round .
 For years  this perplexed me  as I couldn’t figure out how in the heck it would have been done .
 Now I could still be wrong about it , but I  have come to the conclusion  that it is in fact round and what im seeing is an optical illusion caused by the way the rifling was cut .

With my bore ,  if I look at the muzzle ,  the deep groves  exit  the crown just ever so slightly  from the corners of the barrel flats  on the top and bottom .  With one high on the side and one low  on the other .  The result is  a perfect 6 sided polygon  which is even more accented by the  octagon barrel .
 The one time  that I swaged the barrel , even the  swag came out   it also looked  polygon . When I used my Micrometer, it also  suggested polygon  as it measured flat  when measured across ,grove to grove . .
 But when I  took measurements up to that strait line distance , the center of the  lands  was less  ever so slightly less then the measurement taken right next to the grove ..
 But again , looking at the muzzle and the swag , it sure says polygon. The tail is only told  with a micrometer.
During my time at the M.O.I I saw several barrels like this .  While I have no writen proof of it , I hold the opinion that this may have been a principle of some makers . IE the  rifling should exit  the muzzle  so as a majority of the groves match  the corners of the flats  or at least as close as possible.. Now again , let me make it clear that im not saying this was fact . But I have seen enough original barrels done that way  to suggest  it  may be a real possibility .

 Also ,im not saying that’s how your bore is . The case could be that its an actual poly-bore .   I would have to look up  my reference material but  during the early 18th century,,,   I think it was possibly in Germany , there were a lot of experiments with  different bore shapes which resulted in  the need for specific  geometric shaped projectiles . Stars . Harts  and banded ball  designs come to mind .
 Earlier then that  you will find reference to Moorish barrels  which had square bores and shot a square , block shaped projectile .
 From what I have read these square bores were not a attempt at accuracy , but  more a fear factor being played against and enemies belief .

By all means , post some photos of your bore . It would be interesting to see.

[Hightower]

Thankyou for the welcome, and the info.

I just disassembled it to try and find any makers mark, but found none.  No marks of any kind on the barrel at all, not even underneath. Its possible it did have something near the breech end but if it did the browned over corrosion from cap fire has elliminated it. The lock plate has some scrollwork and bordering around the edge, and I can tell there was a maker mark of some type just in front of the hammer but it is all but completely worn off and nothing to make out.  So any identification insight will have to come from appearance and styling alone.

I measured the bore with caliper, it measures .370 from a corner of the supposed polygon across to a flat.  As I rotate the caliper with tension on the thumbwheel the bore measurement fluctuates between .360 and .380 as the caliper tip rides in and out of the corners and across the flats.  So I do agree that it is not quite as polygon shaped as it appears with the eye, but not quite round either.  I should plug and really see, as you have done on yours.  Definitely 7 sides though, or should I say 7 lands and grooves...

Unfortunately my wife has misplaced the camera but I'm sure she will find it for me soon and I will get some pictures up as soon as possible...I guess I kinda prematurely started this thread but I worked a 12 hour night shift and got a little bored!

I can't wait to show it off on here though, it has a couple very crude repairs that I think occured sometime during the 20th century which is disappointing, but as I imagine how it must have been when first built it must have been a good looker.  The pewter forend cap is definitely poured and has some style to it layed into the bottom of the forend.

It is not in very good condition, but its obvious that this gun was really used and used alot, and its fun to think about all the meals and possibly even protection it provided to more than likely at least a couple generations of family.

[Hightower]

Pics are from phone, its old so they aren't very good, but do the job I reckon.  Wife left the good camera at the in-laws, three states away...

I suppose the bore isn't really a polygon, as you suggested, just an old method that creates the appearance.

So anyway, everybody fire away with their opinions of when it was made.  Lock plate doesn't look as though maybe it used to be a flintlock does it?  The drum doesn't fit it correctly, but the lock plate doesn't have the holes from for frizzen and spring...although there is an extra hole in front of the mainspring screw hole

I really dig the pewter forend cap.

Notice the under rib is pegged to the barrel, not soldered.

[Hightower]

more

[Hightower]

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[Captchee]

that pretty darn close to an octagon bore  but i think it looks that way do to the wide lands and deep groves .
 plus as i said , do to the way they all end at the barrel , it give an  even greater illusion.
 Have you been able to shine a  bore light through the bore and see if the  pattern holds the shape  on down the bore ?
Im still thinking its just a finish  treatment  though

 Very nice gun by the way
as to when it was made ?? hard to say without actually holding it . but i would guess late 19th century  maybe early 20th .
 i dont think the lock is a conversion, despite the lock plate not fitting the bolster which would lead one to think it might be . but  what i see missing is the tell tail frizzen spring holes . of course they could have been welded up
 there is an extra hole by the main spring , but that leads me to believe that the lock was fitted at some time with a different main spring

[sse]

Very interesting...thanks for putting up the pics...

[Hightower]

Thanks for all the input Captchee.
very interested in hearing others as well

Everything seems original as far as lock, triggers, but plate and trigger guard - the inletting and workmanship remain consistent throughout.  Except one thing - the brass plate opposite the lock that serves the lock screw is definitely not original and was crudely added by who I would assume to be a previous owner.  It was applied to cover over a poor crack repair filled with epoxy.  That's the only real dissappointing flaw the rifle has, I mean the wear and age give it so much character but to have such a small and easily repaired crack botched up by some knucklehead makes me sad, as if the rifle had its own feelings hurt

[Stormrider51]

The lands sure look flat.  Here's an easy way to check.  Take a straight edge, such as a machinists metal ruler, and lay it across the bore.  Align it with one of the lands.  The human eye can be fooled but the ruler can't.  If the land is actually curved the ruler will reveal it because the land will look like the sun peeking over the horizon.  If the land really is flat you will be able to match the edge of the ruler to the edge of the flat and see the straight line.  Do this with all the lands and you will know the truth.

Storm

[sse]

I've always been in a quandary as to how a bore with flat sides could emit a round ball...

[Hightower]

http://firearmshistory.blogspot.com/2010/05/rifling-polygonal-bore-and-whitworth.html

here is very good article on Polygon bores, I know my rifle is not a Whitworth, especially since it has 7 lands rather than 6, just an interesting and informative article.

I will investigate the true shape in more depth, as suggested with straight edge, caliper, and the definitive casting a plug and measuring it which I think will give the absoulte answer here.

I read some other posts here where a guy had mentioned he'd seen this kind of bore before, maybe he'll chime in with some input too...don't remember who or what the post was originally about..

[Captchee]

if it is a polybore , it will care on down the bore .
 but as i said , just looking at the muzzle isnt going to tell you that  becouse muzzle treatments can  give the same apperance .

stormriders  way of checking will also very much the same thing i ended up doing . the diffrence is that i  swaged the bore , then laid the ruler from grove to grove , then measured down from the ruller to the flat in 3 diffrent places ..
 what i found was that on my barrel ,the measurment  at the center of the flat , is less then the measurement taken at each side of the grove

[Hightower]

I've got the breech end soaking in penetrating oil to facilitate disassembly, I'm hoping I do not have to apply any torch heat to unscrew the breech plug.  Once apart I will be able to inspect the bore more thoroughly and cast a plug to measure properly.

[Joel/Calgary]

I've seen photos of barrels that looked sort of like polygonal rifling but actually had very wide flat (not concentric) lands and very narrow, usually round bottom, grooves, in an exageration of the wide-land-narrow-groove rifling that seems to have been fairly common.  My recollection is that these were mostly 19th century U.S civilian rifles.  It's hard to tell from the current photo of the muzzle, but I think I may see a hint of narrow, shallow grooves in the corners of the rifling.  If this is an iron barrel, it is possible that the contrast between the lands and grooves could have been reduced further by wear to the lands.

How is the breech-plug removal coming?

Regards,
Joel