With apologies for the length.

Your question is rather complicated because you are really asking several questions, and also because there are many Mauser copies and variations to consider. I would strongly recommend that you get Frank de Haas� Bolt Action Rifle book which discusses many of the Mauser variations as well as related bolt actions such as the Husqvarna, Brno and CZ. Much of the discussion below comes from that book, plus Ludwig Olson�s Mauser Bolt Rifles, with a little bit from Jon Speed, Walter Schmid and Reiner Herrmann�s Original Oberndorf Sporting Rifles and Stuart Olsen�s The Bolt Action.

First things first. In terms of strength, safety and gas handling, you should generally avoid any pre-98 actions, including the M96 you listed among your options (but see exception below). The M98 action has better strength and gas handling than its predecessors.

Of the actions you listed, the FN (Belgian), Santa Barbara (Spanish), VZ-24 (Czech), and Mark X (Zastava from Yugoslavia) are all standard length actions. The FN and Czech are generally considered the best built, with Zastava and Santa Barbara actions rated lower in quality. The early post-war Husqvarna rifles were built on FN actions, the later ones were built on Husqvarna�s own actions which according to Frank de Haas were improved M96 actions and not a modified M98. This action is one exception to the general rule above about avoiding pre-�98 actions (but see further discussion below). You can distinguish between the FN-based Husqvarnas and the later rifles because the FN-based rifles are large ring action and the later Husqvarnas are small ring actions.

Mauser �98 actions can be subdivided into �small ring� and �large ring� actions. Small ring actions have a receiver diameter of about 1.3�, whereas large ring actions have a diameter of 1.4�. Small ring actions would be most suited to light rifles with standard calibers such as 7x57, whereas large ring actions would be considered more suitable for larger diameter cases such as .300 H&H. One way to tell visually is that when you look at the left side of the action at the junction between the receiver ring and the left side-wall, there is always a step down from the ring to the side wall on a large ring action, whereas usually with a small ring action there is no step. The one exception to this that I am aware of is the Czech VZ-33 and 33/40 which does have a small step-down, however unless you are very lucky these actions are outside of your price range.

Another consideration when it comes to cartridges such as the .300 H&H is action length. The standard �98 Mauser action was designed around cartridges such as the 7x57 and 8x57, and can accommodate cartridges such as the .270 and .30-06 without difficulty, however, it is a bit short for .300 H&H length cartridges, requiring some metal removal in the receiver ring, compromising strength. While this has been done successfully with high quality actions such as the FN (which was used by Weatherby for his magnums prior to him coming up with his own action), it is not considered the best way to go. A magnum length action is a better alternative. Of the actions you have listed, only the Brno ZKK-602, CZ 550 and the magnum length Mark X fit this description. The 7x57 can also be used in the "intermediate length" action of which the most common in the US is probably the Mexican Mauser.

From the point of view of a modern sporting rifle, the primary weaknesses of the military Mauser are the lack of a bolt handle and safety adapted for low scope mounting, lack of provision for scope mounting, and double stage military trigger. The inconvenient floorplate release is also a deficiency, and the stripper clip notch and hump is unnecessary. Thus, sporterizing a military Mauser generally addresses these points.

In terms of modifications, mods which improve function include improved triggers and modified bolt handles to clear low scopes, and these are commonly designed into commercial models. The post-war commercial Brnos (and the CZs) from about 1948 onwards have double square bridges with integral dovetails for scope rings. Commercial models frequently have hinged floorplates and releases in the trigger guard. However, other modifications may be made to save costs and may or may not improve functionality.

For example, safeties to clear low mounted scopes can be a mixed bag. The original Mauser safety was quite ingenious in that it blocked the firing pin and locked the bolt in the fully safe position, in the intermediate position blocked the firing pin but allowed the bolt to cycle to empty the cartridges, and also assisted in easy disassembly of the bolt for cleaning. However, because it pivots vertically through 180 degrees to achieve all these functions it was not compatible with low scope mounting. The common �improved� button safety located beside the bolt shroud on the right side does allow for a low-mounted scope but usually only blocks the trigger, which is a less secure system.

In terms of gas handling the original Mauser design is one of the best. Among its features is an internal collar in the receiver ring, which was only interrupted on the right side by the extractor slot � the so-called �C collar�. Gas escaping on the right side was vented out the ejection opening. On the left side, gas escape was largely blocked by the collar, and any gas that got past that was vented out the thumb notch. Gas that got into the bolt was vented into the left locking lug raceway and out the thumb notch. Finally, there was a flange on the bolt shroud to deflect any remaining gas away from the shooter.

Commercial actions based on the Mauser such as the FN and Zastava (Interarms Mark X, etc.) eliminate the thumb notch, which strengthens and stiffens the action (de Haas� book shows a photo of a late WWII Mauser action cracked at the bottom of the thumb notch) at the expense of less effective gas handling in the unlikely event of a case rupture. Furthermore, in the FN, except for the very earliest post-war actions (roughly pre-1948-9), the internal receiver collar was cut out on the left side as well as the right, a cost-saving measure which further compromised gas handling. The Zastava also has the internal collar cut on both sides, whereas the Santa Barbara retains the C-collar internal ring, as does the Brno and CZ. Some actions such as the Brno ZKK and CZ omit the gas deflection flange on the bolt shroud for a more �streamlined� look.

If you want to have ALL of the gas handling features of the Mauser �98 then you�ll have to go with a military action or early commercial actions with thumb notch. However, the general consensus seems to be that converting a military action to a sporter is not cost effective these days. In addition to the modifications already mentioned, the magazine box, follower and feed rails may also need to be worked on because Mauser actions were actually built around the specific cartridge they were designed to be used with. Thus, when a Mauser action is rebarreled for a different cartridge there can be issues with reliability of feeding. But there are still lots of �sporterized� military rifles floating around at reasonable prices which have already have these modifications done, and if (BIG IF) the mods are well done and the price reasonable such a sporterized action could be a cost-effective alternative to a commercial model.

Of the military models the 1909 Argentine Mauser is particularly desirable - hence expensive - because it is the only military model with the hinged floorplate and release found in commercial Mausers (and custom rifles). If you have to buy the bottom metal separately from Sunny Hill, Blackburn, etc. it�ll cost you around $500! Otherwise as others have already mentioned the most desirable military actions are the Czech VZ-24, Argentine 1909, and FN, along with DWM and Oberndorf. Wartime actions (WW II) are less desirable because of concerns about workmanship and metallurgy.

If you can live without some of the gas handling features of the original design then commercial actions have the advantage of having many of the desired modifications built in. In the case of the .300 H&H, they also come in the appropriate length.

TC1�s comment also raises an interesting question � what constitutes a true Mauser action? It can be argued that the essential characteristics of the Mauser action are the dual opposing locking lugs, cock-on-opening firing pin system, third safety lug, non-rotating extractor with controlled round feed, and breech and gas handling system including the internal collar and flanged bolt shroud. Secondary features include the bolt shroud lock to prevent rotation when the bolt is open, ejection system and bolt stop.

When looked at in this light, most commercial FN actions as well as all Zastava actions could be classified as modified Mausers because of the extra cut in the gas collar which degrades gas handling.

On the other hand, the Czech (Brno and CZ) actions up to the present time retain the full Mauser internal gas collar and in this respect are true Mauser 98�s. The early postwar Brnos up through the ZG-47 also retain the ejector system, bolt stop, and safety on the bolt shroud, although the safety design differs from the Mauser and thus, I would argue, would qualify as �true� Mauser actions.

The ZKK and CZ differ from the Mauser in the ejection system and bolt stop, which closely resemble the Winchester M70, and the bolt shroud, which lacks the gas deflecting flange, as well as the different safety and trigger system. The bolt only has a relatively small gas vent hole compared to the dual large vents in the Mauser bolt. In addition, the external shape of the receiver is quite different and requires significantly different inletting into a stock than a Mauser. In his book, Ludwig Olson considers these modifications put the ZKK and successors outside of the Mauser system. However it could be argued that the ZKK and CZ breeching system, which retain the C-collar internal ring and Mauser-type extractor, is closer to the original Mauser design than the later commercial FN and Zastava, which modify the breeching itself by extending the left lug raceway slot through the internal gas collar itself. It should be noted that there has been some controversy about whether the CZ as currently sold, is still a controlled-feed design. It is not clear to me at least whether this is due to design modification or a quality control issue.

The Husqvarna, as mentioned, appears to be a modification of the Mauser 1896 design and lacks the internal collar of the �98, as well as having a gas escape management system marginally inferior to the original 1896 design according to de Haas, albeit comparable to the Winchester pre-64, Enfield 1917 and Springfield. Although it is strong enough for modern cartridge pressures due to its quality materials, it cannot be considered a Mauser 98-type action IMO.


So, some desirable Mauser actions:

Original and copies:
Oberndorf Mauser military and commercial (expensive)
DWM military
FN military and pre-WWII commercial
Czech VZ-24
Argentine 1909 (probably too expensive)
Czech VZ-33 and G33/40 (small ring, probably too expensive)
Mexican 1910 and 1935 (small ring, designed for 7x57)
Early post-war (pre-49) FN commercial actions
Brno 21/22 (expensive)
Brno ZG-47 (expensive)

Modified Mauser-types
FN post-1948 (also found in early Husqvarna, JC Higgins M50/M51, H&R, Browning, Firearms Intl, Western Field)
Zastava (Interarms Mark X, Charles Daly, Remington 798) � generally considered lower quality than FN, but Interarms version had a magnum length action
Brno ZKK 600 series � comes in magnum length action
CZ 550 series � comes in magnum length action

Of course, this is just my opinion and I could be wrong.