Round Groove vs Square Groove Barrels

[Rokon]

In the world of flintlocks, we constantly run into round and square groove barrels.

It has been my experience that square groove barrels, on the average, are more accurate and easier to work up a patch/ball combination for.

Round groove barrels are said to be easier to clean but I've never found square groove barrels to be a chore to clean. \

Round groove barrels require thicker patches than square groove barrels and often the shooter drops down in ball size to accommodate the thicker patch.

Is anyone a die hard round groove barrel user? If so, why?

 

[galamb]

You are probably not going to get any "scientific" answer to your question - it's all going to be "personal preference testimonials".

I prefer round bottom rifling - not because it's easier to clean at the end of a shoot (kinda don't matter - it's "some work" if you do it properly regardless of what style you shoot) but just because.

I also prefer Ford over GM.

Jason at Rice "believes" that round rifling is superior (although he cuts straight as well if requested), so do the boys at Colerain - and if I'm not worried about the cost of a barrel it will be a round rifled Rice that goes on my rifle.

I would suggest that the barrel makers who "will not" cut round do so because it's more work and possibly for no other reason.

I will NEVER be a good enough shot to tell the difference between the two - and do own both styles - and can't say that I find any difference from one to the other "the way I shoot and how I use my rifles".

I shoot with off the shelf pre-lubed .018 patches and balls .005" below bore size - all the time which give me all the accuracy I need and am looking for - so for my kind off shooting I don't need to fiddle endlessly looking to tighten my group by another .19" to be satisfied.

If I order a barrel and there is a choice I get it in round cut about .010" deep, otherwise I will take what they make or have on the shelf if the caliber, length and profile are what I'm looking for.

For exactly the same reason I prefer Ford Trucks over GM's (although I currently have a GM) - JUST BECAUSE.

They both work, they both do the job, they both require maintenance and care and both do what I need them to do at a capacity greater than I will personally ever need...

 

[wattlebuster]

Does'nt make a bit of difference to me. Both can shoot better than I will ever hope too and I have cleaned both and could not tell any difference. Every flintlock I own has round bottom rifling cause I ordered the barrels that way. Why? :idunno:

 

[jamesthomas]

I have 2 rifles with square grooves, but the third one will be a round groove Rice barrel. I'll let you know how they compare when I get to shooting the round groove rifle (sometime in Dec. Jan. I'm thinking.).

 

[hanshi]

Accuracy? I can't shoot well enough to tell any difference even if there is one. Cleaning? On average I use fewer patches cleaning my .50 Rice, rb barrel than I do with most any of my square cut barrels. Big difference? No, but there is a slight difference.

Currently only my .50 has a Rice rb barrel but a .32 being built for me will have a Rice rb barrel. I prefer rb barrels and I prefer swamped (even square cut) barrels. Why? :idunno:

 

[MSW]

You are probably not going to get any "scientific" answer to your question - it's all going to be "personal preference testimonials".

I prefer round bottom rifling - not because it's easier to clean at the end of a shoot (kinda don't matter - it's "some work" if you do it properly regardless of what style you shoot) but just because.

I also prefer Ford over GM.

Jason at Rice "believes" that round rifling is superior (although he cuts straight as well if requested), so do the boys at Colerain - and if I'm not worried about the cost of a barrel it will be a round rifled Rice that goes on my rifle.

I would suggest that the barrel makers who "will not" cut round do so because it's more work and possibly for no other reason.

I will NEVER be a good enough shot to tell the difference between the two - and do own both styles - and can't say that I find any difference from one to the other "the way I shoot and how I use my rifles".

I shoot with off the shelf pre-lubed .018 patches and balls .005" below bore size - all the time which give me all the accuracy I need and am looking for - so for my kind off shooting I don't need to fiddle endlessly looking to tighten my group by another .19" to be satisfied.

If I order a barrel and there is a choice I get it in round cut about .010" deep, otherwise I will take what they make or have on the shelf if the caliber, length and profile are what I'm looking for.

For exactly the same reason I prefer Ford Trucks over GM's (although I currently have a GM) - JUST BECAUSE.

They both work, they both do the job, they both require maintenance and care and both do what I need them to do at a capacity greater than I will personally ever need...

I am constrained to open my remarks with the offer of my most sincere condolences upon your choice of vehicles. Inasmuch as my experience with Fords has been universally negative, I cannot commend your decision to use them.

Having said that, however, I agree that, although there is no "scientific" evidence (i.e. a 'peer reviewed' study), you are likely to get enough anecdotal evidence to form an opinion.

I suspect that the opinion will be positive, and that the real question is something along the lines of "is it worth the extra cost?' the answer to which, in my opinion, is a resounding YES!

Now, by way of disclaimer: I am certified curmudgeon, (registry 314159) and I therefore get to express strongly held opinions without regard for evidence to the contrary or even simple logic. I just like the round groove (also called 'radius groove') rifling. Then again, I also like to cone my barrels, even though it widely held that this will ruin accuracy. Not in my experience, but then again, I'm not that great a marksman.

So: in my rifles, I use radius groove rifling with a cone. I may well be FoS, but I worry less and less about pleasing other people. You might want to contact Mr. Burton, here
http://fcibarrels.tripod.com/

and see if he has any input ... he has an excellent reputation, and I'd be curious to see what he says.

At any rate, I wish you the best of luck with your project: I hope it turns out well and you are able to make good smoke!

 

[roundball]

My personal experience with round bottom groove barrels has been easier seating, easier cleaning, and no difference in accuracy what-so-ever.
After I experienced my first round bottom groove barrel, every barrel I've bought since then has been a round bottom, an extra $40 well spent.
Even had one existing .45cal square groove barrel bored out and rifled to a round bottom groove .50cal.
Others mileage may vary...

 

[Zonie]

Speaking of that, round bottom rifling grooves just look neat!

They make for good conversation too.

Few people who shoot modern guns have ever seen such a thing and they usually jump to the conclusion that the barrel has to be at least 150 years old. :rotf:

As for cleaning them after shooting I think they are quite a bit easier.
They don't have all of those nooks and crannies that the fouling likes to hide in on square rifling.

 

[Many Klatch]

I have a .54 Getz barrel with round bottom rifling. I shoot a .526 ball and .012 patching. The muzzle has been coned. I can shoot 20 to 30 shots without having to clean as long as the humidity isn't too bad, otherwise I get 10 to 15 shots. A couple of spit patches and I'm ready to continue shooting. At the end of the day, clean up seems to be easy enough to keep me happy with my choice.

 

[galamb]

As I read further posts to this thread an old article came to mind regarding a (scientific) inspection of the rifling machine from the original Hawken Shop in St. Louis which ended up in the possession of the Missouri Historic Society.

Here's a bit of the article (from the 1960's, somewhat before the "Mountain Man" craze) -

Notes from the inspection of the Hawken brothers rifling machine: (by a Dr. Byrne and Clarence Fall ”“ NFI)

We found this rig complete and in fine condition although it shows much use. It is typical in design except much more metal was used.

It is approximately 10 feet long.

The threaded feed screw is metal with male threads, right twist. It can’t make a left-twist groove.

The indexor will permit a 7 land and groove cut.

The cutter mounted in the fitting plug has a slight curvature to produce rounded bottom grooves.

(The author notes ”“ from slugging original barrels - “All observed Hawken long guns have 7 lands and grooves with the grooves having a noticeable rounded bottom or curvature”)

So here's my new "reason" - if it was good enough for the Hawken brothers, it's not only "historic", it's also good enough for me. :grin:

 

[George]

Interesting reference. Can you be a little more specific about the where and when, please?

Spence

 

[Loyalist Dave]

I have square cut rifled barrels, and round bottom rifled barrels on my rifles. My .54 Colerain is round bottom rifled, and is extremely accurate, from a bench it shoots under 4" at 100 yards. My .40 GM barrel is also extremely accurate... my other square rifled barrels are TC's and not nearly as accurate, and neither is my Jukar barrel, nor was my Pedersoli rifle...

So.....

Well, I think it's more of a function of the quality of the machining and the materials rather than the "style" of the rifling.

When I started this reply I was just thinking about my Colerain, and was going to endorse round bottom rifling alone...but then I remembered my .40 is square... so have to say BOTH work just fine.

And I'm not trying to win an international competition...just trying to make meat and have fun.

LD

 

[zimmerstutzen]

It is over simplistic to ask a mere square or round bottom rifling question. Rifling comes in all manner of configurations and the question disregards the many variations of rifling that can be found. Whether the rifling is gain twist, progressive; What are the land to groove width ratios? Is the bore choked? Are the edges of the square bottom rifling truly 90 degrees or some lesser angle? Of the round bottom rifling styles, is the radius of the cutter surface less than the bore diameter or greater than the bore diameter. (A radius greater than bore diameter results in groves that are actually higher in the middle than at the edge of the lands.) Does the barrel maker actually cut a uniform radius, or is the groove more of a oval laid on it’s side shape, like Hoppy Hopkins made? Then we have depth of rifling to consider.
In the over all scheme of things, most shooters couldn’t tell the difference because they shoot offhand and do little bench shooting. When they do, the sights do not contribute to the fine accuracy necessary to perform the test. However, that does not translate to there being no difference. To truly compare would take a scientific test with similar sights and fired under like conditions. Meaning the shooter is sufficiently consistent from shot to shot not to introduce a variation with his loading and seating technique.
The current offerings from most barrel makers do not even make many of the various styles that were proven accurate over the years. In part most likely because of the cost, machinery and labor involved.
Another way to look at it, is will the style of rifling shoot even one point better than another over a fifty shots at a target. Between wind, lighting, inconsistent loading, shooter fatigue, etc, will the average shooter ever know? If not why bother? For him there is no difference, except perhaps for cleaning. For an avid light bench rest or chunk shooter with consistent loading and sighting skills, that one point in a fifty shots would be a really big deal.
I have round bottom, square bottom, smooth bore and a Hopkins barrel with modified Pope style round/oval bottom rifling and a choke at the muzzle. I will put the Hopkins barrel up against the others any day of the week. There is currently a Hopkins barrel on one of the gun auctions for $500. It could be well worth it, depending on your type of shooting. If all you need is minute of deer, it isn’t worth the extra money.

 

[gbeauvin]

Of the round bottom rifling styles, is the radius of the cutter surface less than the bore diameter or greater than the bore diameter. (A radius greater than bore diameter results in groves that are actually higher in the middle than at the edge of the lands.)

I've read of this before on these forums, but I seem to be unable to grok this. Does anyone have an image that illustrates the radius of the cutter being greater than the bore diameter?

thanks,
GB

 

[zimmerstutzen]

The only image I have, is in a book about Harry Pope's muzzle loading center fire target barrels. (And right now I can't find the book.) But it is the same principle on which Hopkins cut his rifling. I will try to find the book at home tonight.

 

[galamb]

Hey Spence, the article was published in bulletin #7 (Spring 1963) from the American Society of Arms Collectors.

The article was titled "ST. LOUIS GUNS, THE MECHANICS OF MANUFACTURE AND POINTS OF IDENTIFICATION"

Some of it (looks like someone scanned some of the bulletin at a later date and posted a PDF - some pages are missing but all the text is there) can be found here (article)

 

[George]

Thank you, very much.

Spence

 

[nkbj]

Of the round bottom rifling styles, is the radius of the cutter surface less than the bore diameter or greater than the bore diameter. (A radius greater than bore diameter results in groves that are actually higher in the middle than at the edge of the lands.)

I've read of this before on these forums, but I seem to be unable to grok this. Does anyone have an image that illustrates the radius of the cutter being greater than the bore diameter?

thanks,
GB

My shot at an illustration with black circles being bore and groove diameter and red representing a larger radius cutter.

 

[Zonie]

IMO, if the bottom of the groove has an arc that is larger than the radius of the bore, it might as well be just a flat bottom.

The larger the rifling bottom radius, the closer it comes to being just a straight line.

If the bottom of the groove had exactly the same radius as the barrel and it had any depth to it it, IMO still wouldn't qualify as a true "round bottom groove." It would still have the straight parallel sides cutting thru the bore surface that a regular flat bottom groove has. If it didn't have this straight in zone thru the bore surface to create some depth, it would be the same radius as the bore and wouldn't exist at all.

If it had a radius larger than the bore and didn't cut down thru the bore wall, it would make a hump that would look more like a series of flats which IMO would do very little to engage the bullet if it did anything at all.

 

[zimmerstutzen]

Well Zonie, all I can say is the few surviving Pope barreled guns bring thousands of dollars because of their superb accuracy. Unlike the diagram which shows an abnormally deep barrel groove. And extremely narrow groove, the idea is that the grooves are 6 to 8 times wider than the Lands. The grooves are only cut until the middle of the cutter makes contact with the bore diameter. The corners then are deeper on both sides of the land and the middle of the groove acts like a swale to help grip the ball/bullet.