Barrel Rifling

I know what rifling and twist are but what are "square" rifling and "radiused" rifling?

Simply it's the two different types of cutting technique. Most rifling is cut so that the rifling ends with a flat end, if you will. Another technique leaves the end rounded or 'radiused'. The second is usually considered easier to clean but I've never felt handicapped using standard rifling...I'll let some of the guys who do rifling for a living give you the fine points! :thumbsup:

That is right! I might add that the round bottom are often deeper.

Geo. T.

Thanks guys! Do either of you have a preference of either one and why? By the way, while on the topic of rifling, do you recommend any particular twist on a 42 inch barrel?

Let them know what caliber, I think that would change twist rate. I have a flintlock in 45 with a 1 in 56 round bottom that is very accurate. I have been told most match shooters prefer square bottom.

I have a Green Mountain barrel in 50 cal 1:70 twist that's square rifled - .012" deep.

My 40 cal Colerain 1:48 twist is round bottom - .012 deep.

My 54 cal Oregon Barrel 1:48 twist is square rifled .008 deep.

All shoot way better than I ever will.

I have a barrel from Rice on order that will be 45 Cal 1:66 twist, round rifled at .016 deep.

If you want a round ball barrel, while you get differing opinions as to what twist is best, generally somewhere around 1.25 X caliber is considered sufficient.

In 50 cal the "major" builders make twists of 1:70, 1:66, 1:56 in their round ball twists - so no total agreement there.

1:48 will stabilize a round ball and many conicals.

Faster twists will stabilize "longer" bullets.

If you ONLY wanted to shoot heavy conicals a barrel with perhaps a 1:28 twist and .004 rifling would be ideal.

Shallow rifling is preferred if you are not using a patch. The conical has a better chance of sealing against the rifling if it's "shallow".

Bo Harden said:

preference of either one and why?

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The first time I tried a round bottom groove barrel was for a .58cal Early Virginia I was having built.
Asked the folks at Rice Barrel Co. about accuracy.
They asked if I normally compete at the national level.
I said no.
They said I'd never see any difference.
Benefits are easier to load, unload, and clean.

I was so impressed with the Rice .58cal round bottom groove barrel that I also used round bottom groove barrels on .45 & .50cals as well.
I probably won't buy / have built another Flintlock at my age now but if I did, no question it would have a round bottom groove barrel on it.

Drago, well what I am really looking at is a TVM Southern Rifle 50 caliber straight barrel plain maple with a dark stain but while filling out one of their forms noticed a few things of which I am asking now. I did not notice, and still am not able to find what brand barrel or what twist/depth they use with their rifles. Oh, and by the way, I only use round balls, no conicals. No real reason except that I do not get to shoot to much and have kind of tuned myself to shoot balls and would have to start over with conicals.

Galamb, that is also exactly what I needed to know! Thanks!

I am just a starter, about 2 years muzzleloading, but as the president of our local ML club says, we(you) have one hooked. It is just going to take me some time to learn. :bow:

Serious competitive shooters tend to prefer square rifling. Like I said, "for me", I can't tell any difference in accuracy, but I use my rifles for hunting and plinking and sometimes the choice boils down to "what's in stock when I want it NOW".

I believe TVM uses Colerain barrels as one of their "regular" barrels (among a few they offer as "standard"). If you could get a Colerain it will be round bottomed with .016 rifling (50 cal).

As was noted, the round bottom do load a little easier (but that's kinda subjective), they still "foul" like a square bottom but they are a little more forgiving so you can fire a few extra shots before you have to swab out.

There are some who will say that you get a better seal with round rifling. I don't patch so tight that I could comment on that one way or the other.

And in general they do clean a little easier, but the process is the same and they still have to be cleaned.

So if you are looking for a general purpose, hunting, plinking, a little target type rifle and Colerain was the available option on a straight barrel I would certainly go that route.

I wouldn't pay the premium for a Rice in a straight barrel. Most of the extra cost is incurred in how they are finished - particularly on the "outside", so unless YOU are doing the building and want to save a step or two I don't see the 100 buck premium as worth it (and yes, I just said I have a Rice on order, but that was because I wanted a specific swamp pattern and 7 groove rifling which Rice offers and the other "major" barrel makers do not).

"Serious competitive shooters tend to prefer square rifling. Like I said, "for me", I can't tell any difference in accuracy, but I use my rifles for hunting and plinking and sometimes the choice boils down to "what's in stock when I want it NOW"."



What I find interesting on this forum is that no "serious line shooters" (rifle or pistol, National Winners) from Friendship or Phoenix post here. Wonder why?

The old line shooters, rifle and pistol is where you learn things, not from key boarding.

Richard Eames said:

What I find interesting on this forum is that no "serious line shooters" (rifle or pistol, National Winners) from Friendship or Phoenix post here. Wonder why?

The old line shooters, rifle and pistol is where you learn things, not from key boarding.

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Perhaps they want to avoid arguments with someone who heard this or that from "some guy" and now treat it as gospel and will argue the point to the death with no real first hand knowledge.

Or perhaps their style of shooting is so specialized that it only barely resembles the average shooter on this forum. (???)

I readily admit that I have little interest in weighing/taking a caliper my round balls - using a micrometer on my patches - mixing concoctions for lube etc in order to put 5 balls through the same hole at 50 yards (or whatever).

I hunt and I plink (because shooting is just plain "cool"). I use a commercially produced ball (Hornady) and a pre-cut, pre-lubed patch (with wonderlube).

I want my first (and only) ball to be within 2 inches of where I aim (99 times out of 100 - you have to count on a "flier" every now and then). Bambi or Bullwinkle isn't going to stand there and check my ability to "group".

I don't want to have to use a mallet to get it started etc etc.

We may shoot similar styled rifles and use similar ammunition but the "technical aspects" of our respective sports may be no more similar than a small engine mechanic technique compared to the pit mechanic at an Indy event.

(just a thought)

Well square rifling generally means the bottom of the grooves are cut flat, and radius rifling means the bottom of the groove arch usually to a segment of the greater circle made by larger diameter of groove orbit.
Radius rifling is also called round groove where the groove is actually half a circle in cross form and a small portion of of the bore diameter.
There are dozens of differing rifle forms and generally the one that can adequately grip the naked lead or patched ball with the least amount of deformation to the ball or bullet, is the most accurate. Mike D.

M.D., that is actually what I was referring to. Will a square rifling have any influence on the patch, like cutting it? Will it make grooves in the ball? Etc., etc. What about the radiused rifling and the aforementioned things? I did read the other peoples thoughts and they do help a lot but believe they were slightly confused. I believe, as you mention, that TVM is referring the cut in the groove running down the barrel and not the part at the end of the barrel. Is there any preferences? I did read several peoples posts who lists the "groove"/rifling depths/cuts and that is very helpful. I am going to ask TVM, in a few minutes, what the depth of their rifling is. My guess is that rifling that is too deep will allow gas to around the patch and ball and therefore slow the ball down and possibly knock it off kilter. Just curious.

As for the "radiused" grooving at the END of the barrel that most people are referencing....most of the people, in the club that I am a member of, do not like those types of barrels. For example, the gun I most often shoot, my TC Hawken, has a rounded end barrel that causes too much condensation to gather in therefore causing bad, wet soggy powder to gather in. This, obviously, affects the shot and sometimes it does not fire at all. So, hearing that TVM uses a rounded end barrel is a little disconcerting. It sounds like getting a gun with a "square" end would be easier to clean accurately and at the end of the day.

All advise is greatly appreciated and, believe me, taken to heart.

Here is Colerain's own description of their rifling:

"Rifling depth is .016” per side for all but the 36 and 40 caliber barrels which are .012” deep per side. We cut round bottom ( radius groove ) rifling. This is an old form of rifling that because of the lack of corners in the grooves is much easier to clean, and also allows the patch to better seal. All rifling is 6 grooves."

With square rifling you will get some advice to "lap it" with valve compound to "knock down" the edges. Or to not finalize your sight settings until you have shot 100 rounds (which by then you have knocked it down some).

How YOU will use your rifle will have more to do with what will work best for you. I would suggest you don't over analyze the situation. You could spend years researching your barrel before making a decision and then you still may (regret) what you chose wishing you chose A over B.

Just about any barrel you potentially choose will be more than you actually need. If you are looking for one barrel that satisfies all the nuances tossed around - best seal, easiest to clean, et al, you won't find it, which is why they are made/built "differently". You need to pick what is most "important" for the style of shooting you will do.

If you are going to shoot PRB for anything other than competitive target, round bottom rifling will load/clean a little easier and a patch will more than fill the "deep groves".

If you plan to shoot conicals, then there isn't many semi-production barrels out there well suited for that - a custom barrel with a fast twist and very shallow groves would be in order.

If you try for one barrel that will "do it all" you will get a mediocre barrel at best that does nothing exceptionally well.

That's why you should own multiple muzzle loaders - you can get "all" the styles/options represented in your collection and then do some "self testing" :grin:

Bo Harden said:

As for the "radiused" grooving at the END of the barrel that most people are referencing....most of the people, in the club that I am a member of, do not like those types of barrels. For example, the gun I most often shoot, my TC Hawken, has a rounded end barrel that causes too much condensation to gather in therefore causing bad, wet soggy powder to gather in. This, obviously, affects the shot and sometimes it does not fire at all. So, hearing that TVM uses a rounded end barrel is a little disconcerting.

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I'm worried that there might be a terminology problem or misunderstanding...I have no idea what this means...I've put a few thousand shots through several T/C Hawkens year round, over many years and never experienced what you've described (in blue) above.

It sounds like getting a gun with a "square" end would be easier to clean accurately and at the end of the day.

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Don't know what this means...can you clarify?

Recessed breech (as in patent/chamber) as opposed to flat faced??

galamb said:

Recessed breech (as in patent/chamber) as opposed to flat faced??

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No idea, terminology problem...and TVM doesn't use barrels with Patent Breeches

there is sooooo much more than just square cut or radius cut that it boggles the mind. Rifling configuration vary on 1) twist, 2) depth 3 width of grooves vs lands 4) shape of the grooves, etc.

For instance, a barrel may have a gain twist, the rifling my have progressive depth. It might be a choked bore rifle. Radius means that it is shaped like the uniform curve of a circle. radius rifling grooves can still be wider or narrower than the lands The radius itself can be a tighter curve than the bore diameter or a larger curve than the bore diameter. Most of the radius groove barrels made today have deep grooves of a tighter curve radius than the bore diameter. In addition the grooves of such barrels are usually about equal in width to the lands. My personal feeling is that such barrels are indeed easier to clean and load, but are not really
measurably more accurate. Thirty-thirty five years ago, a small barrel company made some unusually good target barrels. H&H barrels had much wider grooves than the lands, The grooves in H&H barrel were cut with grooves that looked like half of an oval laid on its side. It wasn't really a radius, but was curved and based on a larger radius than the bore of the gun. The result was a groove that was actually deeper along the sides than in the middle. H&H barrels also had a choked bore at the muzzle. An unused H&H barrel recently brought over $500 on an on-line auction. They really are that good. The idea is based on Harry Pope's form of rifling adapted for muzzle loading barrels.

Pattern 1853 Enfields had rifling that was deeper at the breech than at the muzzle. progressive rifling.

Gain twist rifling is rifling that increases in twist and the ball picks up speed and ends up spinning faster at muzzle than even half way up the bore.

Then there are the odd ball geometrical shaped rifling. The Whitworth with it's hexagonal bore. The belted ball, In colonial Days a company in England sold stock in a company that developed a square bore rifle. (For shooting worlocks or something) An uncommon modern style rifling, I have seen is a "v" shaped groove that is so close together it looks like the grooves are touching. I think it is used only for 22 Rf, but is sure out of the ordinary.

In other words, the closed end of the barrel, the one connected to the breech plug, is not flat. Therefore, when I try to clean my barrel, which I do after every shot, collects condensation. Because, which ever method you are using...spit, sometime of cleaner, etc., etc., you are leaving a bit in the "radiused" end because you cannot get all the powder out because most, if not all, ramrod ends are square and not rounded therefore not allowing the cleaning patch to get to that last bit of the breech plug/barrel end. I have tried rounding square breech plug/barrel end scrapers, with a file just to be able to reach that last amount of burnt powder but can never get all of it. So, IMHO, it seems that a flat breech plug/end of the barrel would be easier to clean, or scrape, with the typical barrel scraper to get that last bit of powder.