Hi John,
The guns with the cascabel ring are the Blomefield pattern guns introduced in the 1790s. Captain Thomas Blomefield was a Royal Artillery officer who redesigned British guns so they could use newly the improved "cylinder powder" developed by the English in the 1780's. The new powder apparently increased chamber pressures, bursting "old pattern" guns during testing.
The new Blomefield guns had the obvious cascabel ring, thicker breeches and thinner chases (the barrel forward of the trunnion). This gave a stronger gun without an increase in weight. Decorative elements were removed from the Blomefield pattern ordnance.
The Blomefield pattern was the standard Royal Navy weapon during the French Revolutionary and Napoleanic conflicts. If you are modeling the Victory at Trafalgar, this is the correct configuration.
For the 32 pdr., a breeching rope, of 7 inch circumference (2 1/4 inch dia), was simply threaded through the cascable ring, without any seizing at the breech. 5 1/2 inch (1 3/4 dia.) rope was used for 12 and 18 pdrs.
For English ships modeled prior to ~1795, use the old spherical cascabel button.
The gun equipment would be the same as for the prior decades. The different types of powder were differentiated by lettering colors (red - cylinder powder, blue - ordinary powder, and white for recycled powder). The cylinder powder was reserved for longer range work, where combustion consistency was required for accuracy.
Just one more technological advantage over the French and Spanish.
If you are seriously interested in this period, I would recommend getting Brian Lavery's "The Arming and Fitting of English Ships of War, 1600-1815". Search on www.addall.com. (reference for the above info) Goes for $40.00 to $60.00.
If you are seriously interested in this period and have stock options maturing soon or a wealthy relative in the comfort care ward, I'd recommend Jean Boudriot's "The 74 Gun Ship". Goes for about 10X Lavery, but is worth it.
Good luck on your project,
Alan