smoothbore,maybe?

[david50]

recently bought a .62 caliber smoothbore that has straight rifling in the barrel,can i shoot shot loads in it without worrying about gas escaping around the wads through the rifling,and can anyone tell me who makes these barrels...thank you!

[david50]

nobody?

[roundball]

I don't know who makes a straight groove smoothbore barrel as a normal stock item ahead of time...wouldn't think anyone would due to what I assume would be a virtually non-existent market for them in the big picture scheme of things.

If someone was purely interested in just improving PRB accuracy, thy would have had it grooved with actual rifling grooves.

You didn't mention groove depth...I think the groove depth could reveal a lot as it would determine if there might be any appreciable gas blow-by...if shallow enough I suspect there could be enough wad expansion from the gas pressue at set back time to fairly well seal the bore, certainly from a practical usability point of view.

Leading me to speculate that someone had that barrel made  (or it was a smoothbore and they had the straight grooves added)  in an effort to improve round ball accuracy some which straight grooves will do...but was counting on the shallow grooves to still allow the barrel to be used for shot loads like a smoothbore.  And if they are really shallow, leading may not be much of a problem at all.

If you have a mic or caliper, it would be intersting to try and measure the groove depth.

[Pete G.]

Skeet shooters who just have to have the latest thing send barrels to Briley for a very shallow straight rifling to be cut into the bore. Supposed to stop wad spin It probably doesn't hurt anything, just adds velocity to the credit card.

[woodsrunner]

The controversial "Square Breech" rifle that David Dodds made (I own it) has straight rifling, though the original now in  the National Park's posession was conventional twist rifled. I don't know what the furrow depth is, and I have no way of checking it, but it looks a little shallow and is round bottomed. David's idea was that with a felt WonderWad over the powder it would pattern very well with shot. It's a .60cal, so that's what...about a 20ga? I've never tried working up a load with shot, so I can't offer an opinion on this. I can tell you this, though! This piece kills on both ends .  The butt profile is the cause, I think! Remember the old plastic stocked single shot 12ga shotguns sold by Sears Roebuck? This "Square Breech" piece is a LOT worse on recoil! Shoot it 3 times without thick padding on your shoulder, and you'll call 911 to come pick you up!

[rsells]

In the back of my mind, I am thinking that Chuck Edwards has made pieces using straight rifling.  I can't hang my hat on why I remember that or where I seen the info, but I do remember trying to understand why one would do this unless it makes it a bit easier to load when shooting a patched ball.  If it was Chuck, he may have gotten the barrels from Getz.  If so, I am sure that Don can answer your question.
                                                                              Roger Sells
           

[Dphariss]

The grooves allow a straight rifled bore to use ball and shot easier. It loads easier with a patched ball due to the grooves.
It should shoot RB better than a smooth bore and shot about as well.
20 years ago or so I saw a 16 bore European rolling block shotgun with straight grooves something like 12 or 16 IIRC, about equal lands and grooves as I recall.
Why straight grooves in a breechloader I cannot say without experimentation.

Dan

[northmn]

Daryl had a double barrel with one barrel twist rifled and one straight rifled.  A cartridge gun.  I think it permitted the use of shot in one barrel.  Straingt rifling in a shotgun, as mentioned is supposed to eliminate any spin, but probably works best with a shot cup.  It may retard the wads for a better pattern?  again you get into an issue that if some one thinks something is needed it does not really matter if it is.  May not hurt anything, but I doubt if it would be legal in a smoothbore match.  If i were to build something with it I would take that into consideration.  My smooth rifle is not legal in a match and is purely a hunting arm or possibly good for "primitive" matches.

DP

[david50]

i will probably only ever use it for turkey hunting,i may try it for deer if it groups well,i have yet to shoot it. my main consern was gas escaping around the wads when shooting shot. by the way,it was built by Jack Garner. thanks for all the replys.

[T*O*F]

Just a personal opinion, but I think that many of these old rifles that are assumed to have straight rifling actually have very slow twist.  It was not uncommon for large bored guns to have twists as slow as 1-120.  They were shot with fairly heavy loads at distances around 200 yards.  In looking down the bore of a rifle with a less than 4 foot barrel, one turn in 12 feet would look almost straight.

[northmn]

Just a personal opinion, but I think that many of these old rifles that are assumed to have straight rifling actually have very slow twist.  It was not uncommon for large bored guns to have twists as slow as 1-120.  They were shot with fairly heavy loads at distances around 200 yards.  In looking down the bore of a rifle with a less than 4 foot barrel, one turn in 12 feet would look almost straight.

I have thought of that also.  The Baker rifle was 1 120 and used 110 grains.  Bigger bores can use slow twists.    

DP 

[Daryl]

My double with the smooth and straight rifling was meant for and factory loaded with both black and smokeless powder with shot in paper cases for the smooth left barrel, and black powder and round ball in brass cases for the straight rifled and larger right barrel.  

Straight rifling is supposed to give better accuracy with round ball than a smooth bore, yet allow use of shot if needed.  How much gas leaks by would depend on how tight the wads were, just as how much gas leaks past a patched ball in a rifle depends on how tight the patch and ball combination is. Some people have difficulty in loading the necessarily tight combinations - in either gun. The patch or wad is a seal, but only if it is large or thick enough.

[Snow on the Roof]

i will probably only ever use it for turkey hunting,i may try it for deer if it groups well,i have yet to shoot it. my main consern was gas escaping around the wads when shooting shot. by the way,it was built by Jack Garner. thanks for all the replys.

Are you sure it is rifling? I've a .20 ga Fowler built by Mr. Garner at the time he was preparing to sell TVM to Matt and Toni Avance. My gun has shallow groves in the bore as well, however on closer inspection the groves are not evenly spaced as rifling would be. This, and the fact that I ordered a smoothbore, leads me to believe that these "groves" are machining marks and the sign of a poorly bored barrel. I keep the gun as it does seem to shoot faily well, although this is the only smooth bore I own so I have nothing to compare to. It certainly gives reason to hesitate doing futher business with the gunsmith though this is in no way a reflection on Matt and Toni nor the current arms being produced by them under the TVM name.
 
John McCreary

[Daryl]

Longitudinal machining marks? Don't blame you, John - I'd stay clear too, if that's what they are.  I don't much like the radial variety either.