Folks I'd like to learn about the history of quarter ribs on big bore rifles. What was the reason for them being placed on rifles ? And are they superior to the Island site base other than aesthetics.....I love the looks of them.

I think they have a German origin.

On a double, there is not much to put a sight on except a solid and heavy rib--wether it be 1/4, full, straight, or swamped. I think much of the equation would be weight and balance, too. The top rib on my 4-bore is 3/4" wide, nearly 1/4" thick, and 28 inches long. It must weigh as much as a small .22 rifle. Such a rib is only needed for weight. 1/4 ribs keep the weight balanced between he hands in addition to a solid sight base. Island sights must be mounted to something solid. On a single barrel rifle it is the barrel. On a double the rib must be beefed up to solidly accept it. Look at the bottom rib of a double, it can't support a sight.
Of course, Shootaway knew all this.
Cheers, mates.
Cal

Cal,
You make good sense
except for that last sentence before "Cheers, mates."

Quarter ribs on a bolt action are IMO cosmetic only..I like'em, they sure look nice, I have had them on a lot of my personal rifles, but I sure have shot a lot of game without them over the years. English quarter ribs are historically about 4 inches long and put the rear sight close to the eye. American classic quarter ribs go so far out that you could land a B-17 on them..I like the English version..

The 1/4 rib derives from the French Battue rib found on Battue ( driven hunt rifles)

The notion was that this sight arrangement brought the rear sight closer to the front sight making for very fast sight acquirement. It also gives the aiming eye a sight path to the rear sight.

This design found its way to double rifle design via rifles built in Europe and exported and finished as English for example Rifles finished under the Jeffery name hailing from Belgium. Double Rifles built in England by Rigby and Greener tended to keep to the principles of shotgun rib design peculiar to the maker ( mostly flat rib). We see 1/4 ribs on Jeffery rifles and H&H rifles.

Some of the early Cordite double rifles had "full length ribs". That added a lot of weight to the rifle.

The quarter rib was designed to allow for enough steel to mount the sights, then only a thin piece of steel top and bottom was necessary to join the barrels together, to the muzzle where again a larger piece of steel, would be attached to mount the front sight.

This allowed the weight foward on the barrels to be reduced, so that 1/2 of the weight of the double to be between the hands.
This makes for a perfectly balanced, perfectly handling double rifle.

On a Bolt rifle the Island sight is to allow the iron sights to be raised up enough so that it can be used with the same stock demensions, necessary for a scope.

On a Bolt Rifle the Island is cheaper and easier to fit than a 1/4 rib.

Is the Island site base that Ryan Breeding uses on his big bores his own proprietary unit? if so would he sell a one of those units? Ilike the look of that particular Island

I am not familair with Breeding island sight but most of them are about the same..Brownells, and NECG have a nice assortment of them as does Conn. guns.....

I like a two leaf shallow V on a low Island, but I also prefer low comb iron sighted rifles and I use a scope on them also with QD rings, I have no problem lifting my chin 1/8th to 1/4 of an inch to shoot a scope, been doing that since Weaver came out with the 2.5X Weaver and all mod. 70s were low comb. It worked then for all of Americas hunters and hey it still does today if you take time to try and get used to it. It sure works better than squashing your face down on a high comb and taking a lick, or having to look at that gob of steel on a high island sight, thats just plumb ugly..but to each his own. Not all of us were blessed by Weaver and Winchester in the early years.

Thanks folks I'm going to get a 1/4 rib when the time comes. I have a nice holiday with the family to pay for first though !!