Straight Rifling

[Canuck Bob]

I bumped into a site were a company was discussing the advantages of straight rifling in large bore trade or fowler pieces.

As a matter of interest only does anyone have experience with this? They said the PB flew better without a knuckle ball effect while shot loads were not affected.

Sorry can't find the site again.

 

[Stophel]

I'm having a straight rifle barrel made for me. It is supposed to make shot pattern better (you can get modern shotgun barrels with straight rifling). It will also, theoretically, carry a patched ball more accurately than a smoothbore.

 

[paulvallandigham]

Don't believe it. You may get more consistent accuracy out to 50-60 yds, but at 100 yds, the knuckle ball effect will be there.

Spinning any projectile gives it the necessary ballistics to overcome the weight, and energy of air and air currents. That is the same principle that allows a football thrown with a good spin to fly further, & straighter, than a football that is tumbling through the air.

 

[Mike Brooks]

Won't do much for your round ball but it will improve your shot pattern.

 

[flintriflesmith]

Here's my 2 cents worth.
http://www.flintriflesmith.com/WritingandResearch/WebArticles/straightrifling.htm


The first flintlock deer I ever killed was with an original, 1820s PA longrifle with straight rifling. It was about .46 caliber and would group 2 inches at 50 yards.

Gary

 

[dyemaker]

There was a post in another forum about this and the same things as Paul stated were stated there. It was said to be a gimmick. It was about Husqvara's Mynningsladdare Model 22a muzzleloading percussion shotgun made from 1877-1880. It had the option of smoothbore, straight rifled, or spiral rifled barrel.

 

[Mike Brooks]

No gimmick. I had a 1780's Durrs Egg that was a 14 bore and straight rifled, about 14 grooves or so. Fowling weight barrel, super thin at the muzzle.

 

[cgg]

When I was shooting a lot of skeet and trap in the 80's and 90's straight rifling showed up on some skeet tube sets, from Briley I think, but it might have been Kolar. The theory was that the straight rifling would stabilize the plastic wad column and not allow it to spin and "throw" fliers out of the pattern. The tubes shot beautiful patterns, but so did my "regular" Kolar tubes, so I was never convinced that straight rifling was worth the extra effort and expense when it came to shooting skeet with modern shotgun cartridges.

Shooting traditional shot charges with no plastic shot cup out of a ML fowler I don't understand how straight rifling will help the patterns? And by "help" I mean make them denser and tighter. If anything the straight rifling creates more surface area and edges in the bore and may "scrub" the unprotected shot more than a regular smooth bore and cause more fliers, but I am just guessing. Using a shot cup, plastic or otherwise, with the straight rifling may help create more uniform and dense patterns if those skeet tubes from the 90's are any indication. JMO

I have no experience with round ball shooting in smooth bores or in straight rifled barrels, so won't make any guesses about that.

 

[roundball]

No gimmick...I've spent many years on trap and skeet ranges, and the top shooters go after barrels with 4 straight grooves to eliminate any possible wad/cup rotation before muzzle exit shot...the same benefits would apply to muzzleloading smoothbores.

As far as round balls go, normal physics cause errant, varying amounts of unpredictable random PRB rotation to occur with every shot out of a smoothbore. But just like with wads, the straight grooves would lock every PRB into a straight track and eliminate the unpredictable shot-to-shot variation...less left/right/up/down at muzzle exit. Accuracy would improve, and that improved accuracy would carry further to longer than normal pre-groove distances as well.

 

[dyemaker]

I learn new things reading this forum constantly.
:hatsoff:

 

[bwhoffman]

What would cause rotational spin in a smooth bore???
be it a smoothie, a trade gun or a modern shotgun as mentioned above for trap and skeet?

I shot competitive trap a lot of years, consider myself a very accomplished reloader for pistol, rifle and shot shell as well as a lead caster. This shotgun spin has me baffled, other than gravity and rotation of the earth.

 

[dyemaker]

Well, I didn't make the statement but it is a good question. I'm just here to learn and I should just listen instead of adding comments. Besides what you mentioned the only thing I could think of is erratic burning of the powder in either a sidelock or centerfire shotgun. wonder if there is any difference in patterns between the two. Ok... I'll just be quiet now. I have no experience in this field at all.

 

[roundball]

The physics involved with the sudden acceleration being applied to a heavy stationary object cause forces to be exerted in all directions trying to overcome the inertia of that object.

As it begins to move, any little minor differences of shot cup tilt, off center weight, uneven drag, etc, are magnified under heavy acceleration and can cause the shot to start reacting / rotating by uneven conditions. And there is no reason to believe that the wad/shot configuration in a smoothbore muzzleloader would act any different.

None of these things are earth shattering in and of themselves...an analogy would be comparing 4F to 3F for priming powder...a lot of humans claim not to be able to physically tell the difference in ignition speed...yet through industry manufacturing specs and high speed photography we all know that 4F does ignite quicker and burn faster.

Up to each individual to decide which way to go, how important any of these things are relative to cost, etc...I have no plans to spend any money to have straight grooves added to a smoothbore barrel, but others might want to.

 

[Grizzled Roberts]

First thing if it has riflings it is not a smoothbore period.

At local museum they had this screw breech rifle with straight rifling. I was called because the museum thought they had a Ferguson Rifle. The Rifle
had been done over several times the action was Willets not Ferguson. On a Ferguson rifle The touch hole actually dumps out on the threads of the screw breech. A channel is filed on the breech
to guide the fire to the base of the plug. In this rifle the touch hole was drilled out like a regular muzzle loader in front of the breech.
But close inspection showed a touch hole in the threads just like a Ferguson. So in an earlier stage this rifle may have been a Ferguson type. But the rifle had been re stocked several times
the barrel was from a young Ezekiel Baker of London and was made for a lesser member of the royal family not the King. The barrel was half stocked with a rib, it had a bead on the front and flip up sights out to 300 yards on the back.
It had straight rifling. I would have given folding money to see what that rifle started out
as. Before you ask, this was years before my little digital camera so no pictures.

 

[redwing]

Some claim that straight cut grooves were the forerunner to more modern spiral cut rifling. The idea for straight cut grooves was to allow for more shots before cleaning. The straight cut barrels have shown up from time to time thru out firearms history. I have never seen any proof that they improved long range accuracy. In modern firearms they were produced to lower pressures another failure. Ole Rounball has it laid out in a correct manner. :thumbsup:

 

[paulvallandigham]

I agree about the shot pattern being much improved, Mike. Years ago, in a back issue now of Gun Digest, there was an article about Perazzi trying the straight rifling in their shotguns. They were able to obtain 98% patterns.

They believed that the straight rifling LOCKED the shot cups so that they would not turn and spin the shot as it left the barrel, thereby opening the group. It involves the reaction of the load of shot to gravity, and to the sudden push from behind as the gases are pushing the shot out of the barrel. The friction at the bottom of the barrel, and shot column was greater than at the top, and that the condition caused the shot and cup to begin to rotate ever so slowly as it moved out of the barrel. Locking the wad in the barrel kept this from happening, and greatly increased load performance down range.

It was an interesting explanation, and the pattern sheet shown certainly proved the value of the straight rifling in those guns.

 

[Mike Brooks]

The 18th century straight rifling was sensitive to shot size. Different groove size corresponded to different shot size. ....What I have read anyway, never have got to try straight refiling in person all though it has been one of my top priorities for 30 years.... :shake:

 

[jaegerboy]

There was a maker (high end) at Dixon's last year with a new "straight-rifled" gun for sale.I asked how it would perform.The maker and his son gave me a very detailed technical response about how it worked and that it would shoot wonderfully.
I asked if they had shot such a gun or knew anyone who had.
The answer was "No".
I walked away.
Hirsch

 

[grampaJ]

Hey Hirsch, been trying to wrap my mind around the idea of straight rifling. Best I can figger,a rifled barrel twists a chunk of lead and it goes straight at what you,re aimin' at. From what the smoothies tells me and from what I have seen, guns without rifling shoot straight too. What did I miss in this picture?...never did understand some Technological advances or hard to see their need sometimes :rotf: GrampaJ in NC.

 

[CoyoteJoe]

My Super Comanche .410 pistol has a conventional spiral groove bore with straight grooves in the choke tube to stop the spinning of the shot charge. It works as intended, shot patterns are very much tighter with the tube attached.
As to a straight groove bore with patched ball I have read that it offers no better accuracy than a smoothbore but I've never tested it myself.