The Savage Model 24 combination rifle/shotgun was in production for nearly 70 years (1938-2006). During it's lifespan Savage continually made changes to the Model 24's design resulting in numerous model and series groupings. The information below is a brief account of those groupings as originally drafted by odell23 and published on the CylinderSmith.com website.
The following is a brief account (meaning I won't cover every detail before the internet commandos start harassing me for lack of completeness and not covering every little feature) of the groupings of Savage 24's. This is not a concrete order of which grouping came first and does not mean the whole grouping was made before the next grouping was produced and offered for sale, this is just an easier way to see all of the varieties with similar features and minimize confusing the stamped designations.
Stevens 22-410: (Pre WWII has wood stocks, later years had tenite)
Savage 24: (Joined barrels the entire length; top of tang barrel release lever; right side button barrel selector on Model 24, 24A, 24B; 24E was the first with barrel selector on the hammer often referred to as the 24E conversion when found on the other models that had button selectors)
Savage 24 De-Luxe: Joined barrels the entire length; top of tang barrel release lever; 24-DL & 24B-DL had right side button barrel selectors, 24C-DL started with a left side button barrel selector and later had the hammer barrel selector;24D-DL, 24E-DL, 24H-DL & 24J-DL had hammer barrel selector; all models came with satin chrome finish receivers and gold triggers and the 24J-DL also had a black painted receiver variant with no gold trigger.
Savage 24S: (In this case the S stood for side lever barrel release) Joined barrels the entire length; lack of center tang in the rear of receiver. Models include 24S, 24S-A, 24S-B(not sure at this point it exists but follows logically in sequence so I include it) 24S-C, 24S-D & 24S-E.
Savage 24C: All came only in 22lr/20ga and 20 inch separated barrels; 24C Series M, 24C Series N & 24C Series P all had English straight stocks and toothpick style forearms and had top of tang barrel release lever; 24C Series R had the American pistol grip style stock and top of tang barrel release lever; 24C Series S also had the American pistol grip style stock but the front of the trigger gaurd sliding block barrel release.
Savage 24D: (This is one series I'm still figuring out) Separated barrels; Monte Carlo type stocks on some but always with checkering on stock and forearm unlike the standard stocks. Known models include (24D Series M, 24D Series N, 24D Series P)
Savage 24V: All came in only center fire cartridges over 20 gauge; Monte Carlo style stocks (some checkered other not); top of tang barrel release lever; separated barrels; Pay close attention to markings as this is exactly how they appear on the guns themselves 24V, 24V-A, 24V Series B, 24V Series C, 24V Series D. 24V & 24V-A had an unsightly monoblock breech which changed slightly on the 24V Series B and recontoured to a more smooth and eye appealing in the 24V Series C and 24V Series D. All models other than the 24V Series D were only chambered in .222Rem or .30-30Win. 24V Series D was Chambered in .22 Hornet, .222Rem, .223Rem, .30-30Win,.357 Magnum, & .357 Rem Maximum
Savage 2400: Made by Valmet for Savage, it featured the first Shotgun over rifle configuration in the Savage line up and the first 12 gauge. Similar in looks to the Valmet 412 externally, the similarities end there. It had a single trigger with the barrel selector as a small push button built into the uppor portion of the trigger sliding left to right or visa versa. Only chambered in .222Rem/12ga and .308Win/12ga. 12 gauge chamber only 2 3/4".
Savage 24 (Field Grade): Separated barrels, top of tang barrel release lever; plain standard stocks like on the early Savage 24's. Known models 24 Series N, 24 Series P, 24 Series S. Series N and P have top of tang barrel release lever while Series S the front of the trigger gaurd sliding block barrel release.
Savage 389: Made by an Italian Company for Savage, like the 2400 it was shotgun over rifle in configuration. It came with 2 triggers (one for each barrel so no selector) and was chambered in .222Rem/12ga and .308Win/12ga. This 12 gauge chamber was built to 3".
24 Specials (The S in this case refers to "Special"): All came in 20 inch separated barrels; satin nickel finish to receiver, barrels, sights, etc.; all came with rubbed oil finished higher grade wood stocks and a somewhat matching wood pistol grip attachment to replace the stock. 1) Listed as the 24CS, it was simply a 24C Series S (even retaining the engraved markings) with the nickel finish and wood upgrades and still retained the front of the trigger guard sliding block barrel release. 2) The 24VS was a 24V Series D with barrels shortened to 20" and the nickel finish and wood upgrades and top tang release lever. It was chambered in .357 Magnum or .357 Rem Maximum and only over 20 gauge.
Savage 24V/F Transition Model: I have limited information about this particular model. It has a 24V receiver, which is case hardened, with 24F barrels, and wood stock and forearm. The first time I saw one I thought it was a Frankenstein someone who didn't know better put together. I have since seen 3 of these and have one coming to me presently for inspection. It would seem that this model was sold after Savage came out of receivership in the late 1990's. I suspect there were left over 24V receivers sitting in back stock and the 24F was coming off the design table, so the remaining parts were combined with the new to deplete remaining parts. More details soon.
Savage 24F 12-T (the 12 stands for 12 gauge and the T stand for Turkey model): All metal has a painted black surface and unlike some of the early models, then engraving on the receiver is a scroll work instead of a game scene; Top tang barrel release lever; introduction of a cross bolt safety; hammer barrel selector; top drilled and tapped for scope mounts; Dupont Rynite black stock and forearm painted with a unique leaf camoflage pattern; factory chokes. This was marketed as a turkey hunting gun. Known calibers include .222Rem and .223Rem. I suspect there are others I have not encountered yet.
Savage 24F Predator: Same as the 24F 12-T except the camoflage stock, it was also available in a 20 gauge version. I do not know of a 20 gauge model with factory chokes, but there is reported to be a few. The early models retained the drilled and tapped top while a later produce version had an L-shaped bracket with a picatinny rail which mounted with 2 screws to a breech support bar on the right side. This was the last of the 24's sold to date. Known caliber combinations .17HMR/20, .22lr/20, .22 Hornet/20 or 12ga, .223/20 or 12ga, & .30-30Win/20 or 12ga
Hopefully this doesn't confuse all of you further, but this is really the simplest way to deal with this information. Every model designation I have listed here is a complete record of those produced that I either have in my possession, have seen, or have direct knowledge of. I have also been told by previous employees of Savage that they think some custom chamberings were made on a very limited basis by order (e.g. .38 special/ .410), but I have not encountered one nor can I verify this information.
As with any mass produced gun there is bound to be changes and improvements over time, and some subtle and some not. Adding in the complications of the differing varieties and series, and not one, but two barrels with a great number of possible caliber combinations. That coupled with a lack of incredibly detailed records from the Savage factory, makes for a hot bed of mis-information and confusion. The trick for me is to try and sort all of this mess out and present the information in a detailed book so the information is out there.
Again sorry for the lengthiness, but this should help others out there." ~odell23