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La Invasión Española • Beistegui Hermanos • Unceta y CiaSpanish ProofsAstra 900 Disassembly

Unceta y Cia
Page 1
Revised 2007June06

No, the ASTRA emblem didn't appear
on any Unceta pseudo-C-96.
This one is on a Model 400.

Page 1
Astra 900 SeriesModel 900Model 901Model 902Model 903Model 904Model FModel E

Page 2
Model SummaryHolster/StocksSpecial OrdersStylistic EvolutionMarkingsProduction HistorySources

Pedro Unceta and Juan Esperanza started their company in Eibar in 1908. They moved to Guernica in 1913, and adopted the brand name "Astra" for all their pistols the next year. In 1926, Esperanza left the firm, and Esperanza y Unceta became Unceta y Cia (Unceta & Co.) Despite some trouble during the Civil War, the Unceta factory, its old production records, and the factory gun collection remained essentially intact. The firm stayed in business (albeit while suffering various name changes) until 1997. So considerably more is known about Unceta production history than is known today about either Mauser or Beistegui.

The Astra line in general is strange. Most basic Astra designs were highly derivative (that's a polite way of saying that they were ripped off from other manufacturers), and that is usually a sign of the poorest-quality manufacturers. Yet these ripped-off aspects of the Astra designs were almost invariably combined with original, and quite ingenious, design work, obviously home-grown at Unceta. The guns themselves are excellently machined, from good materials, and very well fitted and finished. So was Unceta a quality manufacturer, or a ripoff outfit? I vote for quality, myself. I own a number of different Astra designs, and while all have major eccentricities, they're undeniably good and solid guns.

900 Series

Unceta jumped into the ersatz Mauser market in late 1927 with the Model 900. Soon, in its race to keep up with the competition, more models would join the 900. Eventually there would be seven distinct models, all together making up the 900 Series - the Models 900 through 904, the Model F, and the Model E. So the simple designation "900" could apply to the model, or to the series. For instance, the Model 904 was part of the 900 Series, but it was of course not the same gun as the Model 900. Probably when Unceta named the Model 900, nobody realized that successive models would appear - if they had, the first model of the 900 Series would probably have been named something sensible, like the Model 901. But as it happened, the first model was the Model 900.

Successive 900 Series models added features (select-fire, larger magazines, detachable magazines, Largo caliber, and an auto fire rate reducer) and fiddled around with barrel lengths. All 900 Series guns were numbered in the same serial number sequence, starting with 1 and ending some twenty-four years later with 34336. A few small serial number blocks were skipped, so the total number of 900 series gun made was a bit shy of 34,336. Guns were made in batches of various sizes, so any year's production might be made up of several different models.

Unceta didn't devote heroic efforts to lightening every possible part to the same extent as did Mauser, so all 900 series guns were notably heavier than Mauser-made guns.


Here is a good representative Astra 900, even if most of the finish is still in China. This one has the later-type (and by far the most common) hammer, safety lever, and proof stamps. Early Model 900s had different hammers, grips, grip panels, and lanyard rings - all the stylistic detours are examined on page 2.

That certainly is a lot of pins through that frame. They are removed by pushing them to the left. Their left ends are covered and retained by the sideplate, so the pins won't fall out as long as the sideplate's on, and need not be very tight fits just to stay in place - an interesting and unusual design feature. The advantage of this arrangement is that all those pins can be removed and the gun stripped without fancy tools like presses or even hammers, although a couple of drifts might be handy.

Look Ma, no pins! (Well, two are visible, one not on the frame; close enough.) The sideplate covers all the frame pins except that square one which retains the sideplate. This gun has the sideplate with the 2-line "address" - which doesn't itself tell us much, as the sideplates are mechanically interchangeable, and most any sideplate will fit on any gun. Generally the only way to tell if a part is original to a gun is to check the numbers on the part and the gun, as almost everything is numbered - even some of the pins. The sideplate number is on the inside of the plate, and so is invisible until the sideplate is off the gun.

Here is an early Mauser Prewar Commercial to the same scale for comparison.

The two are almost identical in overall outline. The Prewar Commercial grip is very slightly narrower, and extends slightly higher into the frame area. So the Astra grip is slightly fatter (front-to-back) and stubbier. The dimensional differences are shown in inches, and are approximate (certainly not accurate to the implied .001"). The major outline difference between the two is the curved section at the top of the Astra magazine, which is entirely missing on the Mauser product (the upper circled area). That curved bit is very prominent, and visible from a distance - perhaps the easiest way to identify the Astra in photographs. It is also the reason why Astra 900s don't fit well in shoulder stock holsters made for full-sized Mausers. The front of the magazine of all 900 Series guns is straight, lacking the slight swelling at the bottom (the lower circled area) seen on all C-96 variants except the Schnellfeuer. The Astra looks relatively top-heavy, as the barrel extension is a bit taller top-to-bottom (and the frame slightly shorter in the same direction). The Astra is bulkier around the chamber area -

Mauser Prewar Commercial (top) vs. Astra Mod. 900

Aside from the curved area in front of the magazine, the specific difference easiest to spot at a distance is the large ring hammer on the Astra. (The earlier Astra small ring hammer was almost identical to the Mauser one - photos on page 2). From slightly closer, the Astra's overall pseudo-Flatside look, the lack of milled channels in the barrel extension side rails, and the pins (from the right) or the sideplate (from the left) become obvious. The pivot pin for the bolt lock, right in the middle of the barrel extension side rail, is usually a fairly conspicuous feature. And the Astra grip panels look much more like M-30 panels. But the M-30's hammer, step barrel, lanyard ring pivot, and Universal Safety lever are additional recognition points, making it easy to distinguish from the Astra.

Of course at that time the Oberndorf factory wasn't cranking out Prewar Commercials or M-30s. Its C-96 output consisted entirely of Bolos. The full-size Mausers and the Astra were definitely more formidable-looking weapons than the pipsqueak Bolo.

In chronological order, and more-or-less to scale - a Prewar Commercial, a Postwar Bolo, an Astra 900, and an M-30
The biggies make the Bolo look like a weenie-gun

The function of the upper assembly was similar to that of the Mauser original - barrel, barrel extension, tangent sight parts, bolt, firing pin, firing pin spring, bolt spring, bolt stop, bolt lock - except that the bolt lock was pinned to, and pivoted from, the barrel extension, the barrel was a separate piece screwed into the barrel extension, and there was a short spring in front which returned the barrel and barrel extension to battery, a job done by the mainspring in the Mauser design.

Early Astra 900, left; Mauser Prewar Commercial, right

The Astra tangent sight was almost identical to the earlier Mauser Prewar Commercial tangent sight, with the "900" range. The Astra sight retained the "900" which Mauser had dropped in the later Prewar Commercial days. Interestingly, while the numbers on the Astra sight still vary slightly, giving them that handmade look, they're slightly more regular than the Mauser numbers. During M-30 production Mauser would change to numbers made by a different process, and the handmade look would disappear. See the Sights page for the ugly details of Mauser sight leaf evolution.

The magazine arrangement on the Model 900 was identical to the Mauser (but not to the point that parts interchange reliably and gracefully, though Mauser magazine springs fit and function just fine).

However the frame and lock of the 900 Series were original designs entirely, bearing little mechanical resemblance to the Mauser originals. It was a straightforward layout, and while the overall impression lacks that excruciatingly ingenious quality of the German original, the Unceta design has proven to be sturdy and reliable. Everything rotated on, or slid on, or was positioned by all those frame pins, with a few more purely internal pins thrown in. Access to the mechanism was through the sideplate.

The insides of the frame and sideplate were "jeweled" (by a process also called "engine turning"), a very unusual practice - I've never seen it inside any other gun, including any other Astra aside from the 900 Series.

Some fancy hunting rifles have jeweled bolts, which I personally find stylistically inappropriate. Prewar Bugatti race cars were hog-wild with it - engine blocks, valve covers, firewalls, dashes, apparently anything which would stand still long enough. The sheet metal of the entire nose of Lindbergh's Spirit of St. Louis is jeweled. But all that's on the outside. The Model 900 jeweling is on the inside, so even guns in rough Chinese condition will often show it when opened up. The process is simple enough, just a rod with a rubber or wood tip and an abrasive paste compound, spun in a drill and held to the metal for a second. Then index and repeat ... index and repeat ... simple, but tedious.

The Model 900 was a good solid design and, apparently, a steady seller. It remained Unceta's basic semi-auto Series 900 offering from 1927 to 1941, with a total quantity of just under 21,000 made.
The Model 901 was essentially a select-fire Model 900. It must have been inspired by the Beistegui select-fire model which appeared in 1927. The sideplate on the left of the frame made it difficult for Unceta to put the select switch on the left, so it ended up on the right instead, where a right-handed shooter couldn't easily reach it. The switch was located in a shallow recessed area immediately aft of the triggerguard. The semi-auto setting was usually marked 1, and the full-auto setting 10. Very sensible, and it preserved that international flavor - much better than marking it in Spanish, English, German, or Chinese.

A prototype or experimental 901, serial number 1284, had a select switch in the front strap of the grip. This was apparently not a success, as only the one is known today. 1284 is a very low serial number for a 901. It has all the later stylistic features (large ring hammer, 12 groove grip panels), but Model 900s up to the low 7000 range had the earlier hammers and grip panels. Perhaps this experimental 901 was a production 900 grabbed at a later date, modified, and updated with later parts. Even examination of the part numbers wouldn't reveal the rework, as a factory job would be expected to have replacement parts numbered to match the rest of the gun. So, lacking documentation, this one remains something of a mystery.

The Model 901 was introduced in 1928. It did not stay in production very long, as the magazine was just too small for a select-fire gun, and it was allowed to die in favor of its successor, the 20 shot 902. Total 901 production was a mere 1655 guns.
The cyclic rate of the 901, at 900 rpm, emptied a 10 round magazine mighty quickly, so Unceta introduced the 902, with a fixed 20 shot magazine. This was loaded from the top with 10 round chargers or strippers, just like the old Mauser 20 shot Cone Hammers. The barrel was lengthened to 180mm (7.1 inches), from the 140mm (5.5 inches) of the 900 and 901. The stock length was increased by 40mm, from the earlier 360mm (14.2 inches) to 400mm (15.8 inches). The select-fire switch was most commonly marked 1 at the semi-auto setting, and 20 at full auto.

Strangely enough, the Astra 902 frame was the same size as the 900 and 901 frames. The extra magazine capacity was accommodated in a separate piece attached below the frame. Although the joint was visible on close examination, from a distance the 902 frame looked much like the Mauser 20 shot. The joint doesn't show well on the photo above, but it does on this gun -

The Model 902 stock had a detachable leather cover for the outer end of the magazine, much like that on the stock for the Beistegui 20 shot gun.

Antaris notes an oddball Model 902, serial 3796, with the selector switch built into the grip frontstrap. This must have been an experiment and was no more successful than when the same idea was tried out on a Model 901.

The Model 902 was by far the biggest, heaviest, and overall clumsiest model in the entire 900 Series. This was due to the lengthened barrel and the huge magazine housing.

In 1933 the Model 902 was discontinued in favor of the Model 903, after a total production of 7,075 guns (including both semi-auto and select-fire versions).

Semi-Auto Model 902

Antaris notes two small batches of Model 902s, in the 12600 and 26700 ranges, made as semi-autos only. Apparently factory documentation had little to say about these, and those two serial ranges were derived from actual observed serial numbers on surviving guns. Antaris refers to these semi-autos as "special orders" although he doesn't tell us who the customers placing these orders were. The guns looked exactly like other Model 902s, except for the lack of selector switches. They still had the 20 round magazines and 180mm barrels. Here is the case for one, serial 26705, from Erickson & Pate, page 231 -

The leather boot, which covered the lower end of the magazine, is visible here, clipped on the lower edge of the stock.

An interesting peculiarity appears on the label -



BARREL 180 m/m   20 Shots

FOR MAUSER cartridges cal. 7.63 m/m

The 180mm barrel and 20 shot capacity are correct for the Model 902, but that "Model 900" on the label is puzzling. Unceta undoubtedly referred to the Model 902 as the Model 902 - it wasn't some sort of "mystery 900 Series" gun. An undated, though obviously contemporary, sales brochure for the Model 903 tells us that -
Encouraged by the extraordinary success of our Pistol <<ASTRA 902>> due to its characteristic advantages of, <<LONG SHOOTING RANGE>>, <<ACCURACY>>, <<RESISTANCE>>, <<REDUCED WEIGHT AND SIZE>>, we constructed the new and improved <<ASTRA 903>>, which embodies the same features with the additional novelty of alternative methods of loading per clip and per detachable magazine. [etc.]
Hmmm. By "Resistance", above, somebody meant "durability". But "reduced weight and size"? The 902 was a porker, the biggest and heaviest of the 900 Series. So we know they're lying about one thing, at least.

Perhaps Unceta intended to sell this gun as a special order Model 900 with a longer barrel and larger magazine, rather than as a special order Model 902 with no select-fire capability. We can't tell from the gun's serial number, as Models 900 and 902 were numbered in the same sequence. Antaris says that Astra production records show that a batch of Model 902s, serials 26701 to 26713, were made in 1932. That block includes the gun which belongs in the case pictured above. So Unceta production records say it's a 902, even though the box says it's a 900. Unless, perhaps, Antaris fiddled with the production figures - I've never seen the actual factory data.

Although I still favor the theory that these guns were special 900s rather than special 902s, the books consider them 902s, so rather than cause confusion I will leave them here in the Model 902 section rather than move them into the Model 900 section.
By 1931 both Beistegui and Mauser had detachable-magazine select-fire guns on the market, so Unceta obviously had to come out with the Model 903, the first detachable-magazine Astra in the 900 Series. It was available with 10 and 20 shot magazines. The undated brochure quoted above claimed that the 903 was supplied with one 10 round and one 20 round magazine, the shoulder stock, a cleaning rod, and a spare bolt spring (!?). The width of the frame up front was increased to accommodate the separate box magazine, and a release button was added to the right side. The magazine arrangement was much like that of the Mauser Schnellfeuer, but the retaining latch arrangement was different, so the Astra magazines weren't interchangeable with Mauser or Beistegui magazines. Also to fit the new magazine, the front part of the barrel extension, around the ejection port, was widened. The diagonal chamber flat stayed in the same place, but the side flats were further out, so the line formed by the intersection of the flats was lower -

Model 900

Model 903

On the right side, the new wider side chamber flat extended further aft. The extended area enclosed a bolt catch mechanism, so that the bolt would be held open after the last shot without resting on the magazine follower. Without such a holdopen mechanism, it can be a real chore to pull an empty magazine out. The C-96 and the Spanish semi-autos used the cartridge follower as a holdopen. That was a radical idea in pistol design when it appeared in 1896 (although old hat on rifles), but it's fairly useless in a gun with a removable box magazine. The new catch latched into a groove in the bolt, just visible in this photo of a very late specimen, serial 31808 -

Another specimen, serial 26760, shows the proof triad moved down to just above the grip. (See the Spanish Proofs page for the story about proof triads.) The selector switch markings, 1 and 20, are the same as above, but clearer in this photo. These were the most common markings - others have been reported but not seen by me. Of course with a 10 shot magazine (as in the photo), the 20 setting didn't make a whole lot of sense, but I suppose it worked anyway.

Here is 31808 again. Externally, the left side of the Model 903 was identical to the Model 900, except for one end of the magazine release, visible just forward of the sideplate, the wider chamber diagonal flat . . .

. . . and the barrel length. The Model 903 dropped the barrel length down to 160mm - shorter than the Model 902, but longer than the Models 900 and 901. It stayed at 160mm on all later models, although guns with special customer order barrel lengths are known. The stock length also dropped to an intermediate value, from the Model 902's 400mm down to 380mm (15.00 inches), and stayed there for all later models (904, F, and E).

The magazine catch worked much like that on the American 1911 service pistol - a pushbutton extended across the frame, and at the far end had a small tooth or hook which caught in a slot in the magazine sidewall. The Astra pushbutton was on the right and the slot was on the left side of the magazine, a mirror image of the 1911 arrangement, but the basic idea was the same. The Schnellfeuer magazine catch caught a small projection on the aft face of the magazine housing, and so didn't need to extend all the way across to the far side of the frame.

The Model 903 was introduced in 1932, and the last batch was completed in 1940. Although for several years the only 900 Series guns being made by Unceta were the Model 900 and the Model 903, a surprisingly small number of 903s were sold - only 3082, less than half the number of its predecessor, the fixed-magazine Model 902.
These were much like the Model 903, but with a mechanism, the mechanismo moderador, linked to the hammer to slow down the cyclic rate of auto fire. The moderador was buried inside the grip; the wood grip panels were relieved on the inside for clearance. Only nine specimens of the Model 904 were made, all in 1934. Although they were numbered in the same serial number sequence as the regular production guns, they were probably experimentals to test the rate reducing device. The device apparently worked, as the cyclic rate was reduced from the 900 rpm of the other 900 Series full-autos down to a sedate 350 rpm.

On the outside, all we can see of the cyclic rate reduction mechanism is a pin which goes through the frame, just above the grip. That is part of the linkage connecting the mechanism to the hammer. The grip screw moved downward a bit, to provide some clearance for the reduction mechanism inside. Note also that the Model 904 had exactly the same magazine catch as the Model 903.

The machining of the barrel extension changed yet again. The widened area around the chamber was extended back slightly, and the upper part just under the sight leaf pivot machined down a bit more aggressively. This is sometimes nowadays called a "reinforced" chamber, but that's misleading. Relative to earlier models, the major difference was in material removed, rather than material added. Unlike the Model 903, both sides of the barrel extension were machined the same way.

The Model 904 had a unique sideplate marking, serving notice that it was indeed a Model 904 - see Page 2 for more about markings.
This model was designed to meet an order for 1000 pistols for the Guardia Civil. Special requirements were chambering in the standard Spanish service cartridge, 9mm Largo; and a cyclic rate reducer. The Model F used the rate reducer which had been successfully tested on the Model 904, although its integration with the selector switch was a bit different. While still on the right side of the frame, the Model F selector switch was further aft than on the 901, 902, 903, and 904, sitting directly above the grip. As there was already a bunch of mechanism crammed inside there, Unceta didn't mill the recess for the switch, as in the other select-fire models. Instead, the switch was entirely outside the frame, hanging out in the breeze. Lacking a milled recess to limit switch travel, stops had to be added. So the pin which ran through the frame just above the grip (which we saw on the Model 904) was extended out slightly on the right side, and did double duty as a stop for the selector switch when in the semi-auto setting. The switch stop at the full auto setting was a slightly lengthened sear pin. The switch was marked T (for tiro, "shot", apparently meant to be an abbreviation for tiro a tiro, "shot to shot" - still none too clear) and A (for ametralladora, "machine gun") at the semi- and full auto settings.

The T and A marks for the select switch don't show well in the photo above, so here's another specimen.

The Model F tangent sight ran to 500 meters, rather than the standard 1000 meters. Its sight ramp was modified accordingly, to a very low ramp almost exactly the same as the one under the 500m sights on Mauser's 1916 Contract guns. (Well, imagine that ... what a coincidence ...)

The sideplate marking on the Model F was unique - see Page 2. Why this gun was called the Model F rather than the Model 905 is a mystery to me, but the sideplate says it's the Modelo "F", so Model F it is. Perhaps the customer specified that their guns be marked with some designation of their own choosing, and as long as the guns were so marked, Unceta decided to use that as the factory designation too. Which would all be very sensible. But lacking documentation, it's all conjecture.

The left side is interesting, as it shows not only the sideplate unique to the Model F, but also the modified magazine catch. Or rather, it doesn't show the modified catch, because it doesn't extend through the frame. I suspect that after the Mauser Schnellfeuer came out circa 1932, Unceta tried to copy Schnellfeuer features wherever feasible, and the new magazine catch may have been modeled after the Schnellfeuer's. But this made Model F magazines incompatible with those of the Models 903 and 904.

The left side view also shows the modified machining of the barrel extension which was introduced on the Model 904. The widened part of the barrel extension, up forward around the chamber and ejection port, was extended back aft but milled off more aggressively at the top, just below the rear sight. The bolt holdopen mechanism of the Model 903 was deleted.

Model 900

Model 903

Model F

All the guns for the Guardia Civil order were made in 1934 and 1935 (most in 1935). Total production quantity was 1126 - the basic Guardia Civil order of 1000, plus a bit of an overrun. For unexplained reasons, in June 1935 only 950 were delivered to the Guardia, and the remainder kept by Unceta. These last ones were seized by the Republicans during the Civil War.
The 900 Series went to sleep for about six years after 1943. Then from 1949 to 1951 Unceta assembled 548 Frankenguns called the Model E.

These were an odd mix of Model 903 and Model F. They seem to have been machined from uncompleted parts meant for the Model F, but in such as way as to emulate the Model 903. The barrel extension and frame were the basic Model F design, but caliber reverted to 7.63mm, sights went back to 1000 meters, the cyclic rate retarder was left off, the grip screw moved back up to its old position, and the selector switch moved forward again to just aft of the triggerguard - the same place as on the Models 901 through 904. The T and A markings for the selector switch reverted to 1 and 20, and the sideplate markings changed to a new pattern, the 4 line address. The rest was pure Model F.

The major consequence of all this was that the magazines of the Model E were compatible with those of the Model F, but not the Models 903 or 904. Nevertheless, Unceta seems to have sold the Model E as the Model 903, which it closely resembled; hence the occasional (albeit unofficial) name, Model 903E.

In 1949, a small batch (33 guns, serials 33875 to 33917) was made in a semi-auto only version.

The Model E is not well recognized, and is often confused with the standard Model 903 even today. Here is a photo from Cormack's pamphlet, which had me guessing for a few seconds -

Hmmm. Four line sideplate address? Proof triad on the left side of the frame? Serial number in the 34 thousand range (hard to see in the scan, but so it is)? Model F-style barrel extension? That's not a 903, the "first of the detachable magazine Mauser-type Astras," but rather a Model E, the last of the detachable magazine Mauser-type Astras. The fact that the photo is credited with Astra as the source makes me suspect that even decades after production ended, Unceta (or Astra, or whatever its name was when the Profile Publications pamphlet was written) classified the E as a 903. So who started calling it the Model E, if not Astra?

All 900 Series guns in the serial number range 33789 to 34336 - the last of them all - were Model Es.

Onward to Page 2

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