Straight Groove Rifling

[rickystl]

Hello all. Not sure if this is the right column for this question. So it might get moved.
Many of us have seen original guns with straight groove rifling. Especially German/Austrian/Jaegar type guns, primarily used for hunting. The occassional use of this style of rifling seemed to continue well after the knowledge of twist rifling being superior.
My question is: Does anyone know the historical purpose for this straight rifling ? It always been a mystery to me. Maybe someone out there has actually fired a gun with this style of rifling ?
Thanks for any help.

Rick

 

[nwtradegun]

it was for trapping fouling, possibly for easier loading.

 

[Tom Compton]

it was for trapping fouling, possibly for easier loading.

That is my understanding, also.

 

[Grenadier1758]

And as a compromise for shot, the straight rifling would not spin a shot charge and open the pattern.

Straight rifling was all the rage for those that wanted smooth rifles a few years ago. I am not aware of any real benefit to straight rifling other than if you believed it would work, then it did.

 

[54ball]

This concept goes way back. By the 18th Century you see it on Continental stuff as well as some American Rifles.

In summary a straight rifle will shoot a ball slightly more accurate than a Smoothbore. I do believe they can be more consistent. They are not as good as a spiral rifle but potentially better than a Smoothbore especially loaded in period fashion I.E. a Smoothbore with wadding vs a straight rifle with a patched ball.

One thing they can do well is shoot shot. Today many modern shotgun shooters use custom straight rifled barrels for shotgun competitions.

Next week my straight rifle barrel should be ready. It is based off a Early Virginia Rifle. So I won't know how it does until I get the rifle built.

 

[54ball]

Straight Rifling

 

[rickystl]

WOW !! Thank you all for your responses. Now I understand. Most helpful.

Rick

 

[dave_person]

Hi Ricky,
Others have alluded to this but there was a fashion during the late 18th and early 19th centuries in Britain for fowling guns with straight rifling grooves. You were supposed to use shot of a size that fit into the grooves and the effect was tighter patterns at longer ranges. According to Keith Neal, who owned and shot several of these guns, the method worked. However, you had to clean the barrel after several shots to keep the patterns consistent. Straight grooves were cut for other reasons described by several of the other posters but this was one application.

dave

 

[Many Klatch]

FYI, a lot of older modern era smoothbores were made with High Pressure steel tubing. The interior of some of those tubes have a lot of grooves as a result of the manufacturing process. In most shooting competitions today at the NMLRA, smoothbores with straight rifling must compete in the rifled gun classification.

 

[rickystl]

Dave and Many: Thanks so much for your responses.
My original hunch was that it was to allow for both ball or shot. But that was just a guess. Most interesting. Thanks again to all for clearing this up.

Rick

 

[Loyalist Dave]

Straight grooves were cut for other reasons described by several of the other posters but this was one application.

I remember when I first heard of this application for the use of shot, that it prevented arbitrary rotation of the shot column, and then about the same time I saw a new, Remington brand, screw in shotgun choke for turkey hunting...with straight grooves. :shocked2: What was old was new again. :grin:

LD

 

[coloradoclyde]

I wish someone who actually owns/shoots one would chime in....

 

[George]

The idea of straight rifling is very old, but writers in late 18th century make it clear it was considered to be of no benefit and was being discarded.

Cleator, 1790:

"The straight rifling of barrels, is an expedient, which, though not often practiced, yet deserves notice, as having the testimony of some amateurs to its efficacy in preventing the scattering of shot. Neither the workmen who make these pieces, however, nor the persons who use them, can give any satisfactory explanation of the principles upon which the rifling proves serviceable in fowling pieces;"

"Barrels of this construction have been in use upon the continent since the middle of the 16th century, but were little known and still less employed, in England, until within these last 50 years. The spiral rifled barrels, however, have entirely superseded the straight rifled ones, because although the latter prevented the rolling motion of the ball that takes place in a plain barrel, yet they do not communicate any other motion, that could serve to correct the variations that may occur during the flight."

"Having now fully explained the principles upon which rifle barrels produce their effects, our readers will be prepared to consider how far the straight rifling can be useful when employed for shot. These pieces are said to be very common in Germany, and are used by a few persons in this country; though we understand that the greater number even of these few are now less partial to them than they were at first."

And they were considered to be for use with shot in the colonies, according to ads in newspapers of the day.

The Pennsylvania Gazette
March 16, 1774
THO: PALMER Gun Smith AT his Shop, on the North Side of Market street, between Fourth and Fifth streets, hath for Sale, a Quantity of well made RIFLES, that he will dispose of very low for Cash. He likewise makes all Sorts of SHOT GUNS, such as straight Rifles, Cocking pieces, Fuzees, &c. in the best and neatest Manner, which hath gained the Approbation of some of the best Judges within the three Provinces.

Spence

 

[tenngun]

I recall reading a history of guns when I was a teenager. It said that groves were cut to collect fouling. The thinking was that by making grooves spiral you got more groove then the barrel was long. Serindipity ,the gun shot true.
I kinda doubt the story. They have been putting feathers on arrows and darts for a long time before demons started ridding spinning balls. It is a good story though.

 

[RAEDWALD]

W.W. Greener checked this out and concluded that any (slight) advantage over a cylinder smooth bore was temporary from leading building up to slightly choke the muzzle end and was still inferior to a true choke and the leading has to be cleaned out.

I can't imagine that any of us know more about black powder guns than he did and shotguns in particular.

 

[Elkeater]

I recall reading a history of guns when I was a teenager. It said that groves were cut to collect fouling. The thinking was that by making grooves spiral you got more groove then the barrel was long. Serindipity ,the gun shot true.
o

This makes me relate twist rate with fouling for the first time.
slower twist = less fouling

It's a great story, thanks Tenngun.

 

[Stophel]

I have a mid 18th century German image showing different types of guns, with the straight rifled gun being called a "schrot Buechse" (shot rifle). I also have a straight rifled barrel that I had made for me, but like everything else, it has sat languishing... and probably rusting away. I haven't made a gun in four years or more.

 

[58viktor]

This is a straight rifling barrel. Any idea of age?

 

[Relic shooter]

This makes me relate twist rate with fouling for the first time.
slower twist = less fouling

It's a great story, thanks Tenngun.

Greetings Elkeater,
I've shot a few straight groove rifles on paper & never could get them to produce any better groups than my smooth bore long guns guns that had front & rear sights. I'm not a shotgunner so perhaps there is an advantage there ?
For well over 50 years I have been shooting primarily original Jaegers & English sporting rifles with deep fast twist rifling.
When the proper combination of lubed patched round ball & powder charge is used I've never experienced any more fouling than rifles with slower twist rifling.
I have found that vintage rifles that have deeper rifling in the range of .012-.014 deep tended to produce tighter groups with heavier charges than modern factory produced rifles with shallow depth rifling in the .006 depth range unless they were fitted with very tight fitting oversize balls & thinner patching to prevent skipping & blow-by.
I think most experienced shooters on the forum can agree blow-by is caused by a poor patched round ball combination & is the primary cause of most fouling issues.
Relic shooter

 

[Jaeger]

I believe it falls into the same category as bloodletting as a medical treatment, except bloodletting was more popular, even though this "treatment" probably killed a lot of people.