A Basic Guide to Para-Ordnance Pistol Sizes

by Harwood Loomis for The M1911 Pistols Organization

Before Para-Ordnance burst on the 1911 scene in the early 1990s, things were easy for 1911 owners. There were four sizes of pistol, and they were built on only two frame (receiver) sizes. The original, military-issue M1911 and M1911A1, and the civilian Government Model and Commander pistols were all built on the full-size frame and used magazines originally designed to hold seven rounds (later expended to eight rounds). The Colt Officer's ACP and the later Colt Defender were both built on a frame with a shorter magazine well and grip, and both used magazines originally designed to hold six rounds (later expended to seven rounds).

That was it. Other makers of 1911s generally followed this pattern, although some (such as the Springfield Armory Champion) used a 4-inch slide and barrel rather than the Colt Commander’s 4¼-inch slide and barrel. Everyone knew what models were what size, and which parts fit which models. Life was good.

And then a small Canadian company called Para-Ordnance burst upon the scene, and life for 1911 aficionados was changed forever.

Para-Ordnance began in 1985 as a manufacturer of paintball guns. However, within a few years they had progressed to producing a “gunsmith kit,” which included all the parts needed to convert a Colt Government model from a seven-shot, single stack pistol to a then unheard of 13-shot, double stack pistol. The “gunsmith kits” consisted of the double stack receiver, the magazine catch lock, the trigger, grip panels, and a double stack magazine. All other parts were simply transferred from the original, single stack pistol.

By 1990 the Para-Ordnance “gunsmith kits” had developed such a following that the company went to the next step and introduced their own complete pistol. The design had been tweaked slightly, so the 13-round capacity of the original “gunsmith kit” had increased to 14 rounds and the shape of the double stack magazine well had been smoothed and rounded a bit. The new pistol was initially offered only in .45 ACP and it was named, appropriately, the P14.45–the name immediately identifying both the capacity and the caliber.

Since the P14.45 was derived from the “gunsmith kit,” and used the same size mainspring housing as a Colt Government Model, things weren’t too complicated–yet. But that was soon to change. Unfortunately, the records of Para-Ordnance serial numbers and production dates did not survive the sale of the company to Remington, so the author has not been able to pinpoint the year with any certainty. By the mid-1990s (apparently around 1994) Para-Ordnance had expanded their line-up to include full-size (P14.45), mid-size (P13.45), and compact (P12.45) pistols, with slide and barrels lengths of 5 inches, 4¼ inches, and 3½ inches. A couple of years later they introduced the subcompact P10.45, with a 3 inch barrel and slide. But, unlike Colt and all the other single stack 1911 makers, Para-Ordnance used a different frame size for each slide and barrel length.

The new Commander-size Para was the P13.45. The Officer's ACP-size Para was the P12.45 (the author’s first Para-Ordnance pistol). The Defender-size Para was the P10.45. As the names convey, the magazine capacity of each was, respectively, 13 rounds, 12 rounds, and 10 rounds. The grip frames were sized commensurately, with each requiring a different length mainspring housing, different length magazine, and different grips. The P10.45 also required a different, shorter, grip safety. Not only was it now necessary to keep track of four mainspring housings rather than just two, gunsmiths now also had to figure out which Para-Ordnance models might use one of the two “standard” 1911 mainspring housings.

To make matters worse, around 2001 or 2002 Para-Ordnance introduced their own lineup of single stack 1911s. But they weren’t content to use the same two frame sizes that Colt and all the others used. Para’s lineup of single stack pistols included a subcompact frame that was shorter than the Colt Officer's ACP and Defender by approximately ¼ inch.

Confusion reigned.

Remington killed off Para-Ordnance (or, more accurately, the ParaUSA successor to Para-Ordnance) five years ago and sold all the leftover parts to Sarco and Numrich. As the supply of factory parts dries up, it’s more important than ever to know what standard 1911 parts fit which Para-Ordnance models. That’s the reason for this article. It is our hope to figure out and to report on what standard frame parts fit which Para-Ordnance pistols. To make things as graphic as possible, we’ll start by photographing each size of single action and double action 1911 on a 100-yard rifle sight-in target. These have 1-inch grid squares, providing a visual reference grid for comparison. For each photo, we’ve aligned the top of the slide with a horizontal grid line and we’ve placed the slide stop pin (which the Ordnance Department blueprints used as the primary reference point for most dimensions on the frame) on the target’s vertical centerline. We also photographed the Para-Ordnance pistols without magazines, because the factory Para magazines didn’t have flush floor plates and we’re interested in comparing the actual frame sizes.

First, the single stack pistols, to establish the baseline for comparison:

Single Stack 1911s

The following composite photo shows the four “standard” sizes of single stack 1911 pistols. Not shown here are the Para-Ordnance Slim Hawg and the Springfield Armory EMP, both of which are smaller in one dimension or other than the Colt Defender. [Disclaimer: The author does not have access to a Colt Defender. Since the Defender has the same size frame as the Officer's ACP, the 3-inch pistol shown here was created for the image by mounting a 3-inch Slim Hawg slide and barrel on an Officers-size frame.]

The photos illustrate that the Government Model and the Commander have the same frame height, and the Officer's ACP and Defender share the same frame height. Thus, for Colt and all "standard" single stack 1911 clones there are only two sizes of flush-fit magazines. The magazine capacity may differ based on what follower and spring combination is used, but there are only two sizes of magazine body that will seat flush in a single stack 1911.

With the baseline established, next we’ll look at the Para-Ordnance double stack lineup:

Double Stack 1911s

The following composite photo shows the four basic sizes of Para-Ordnance double stack pistols. It should be recognized that, over the years, Para (both Para-Ordnance and ParaUSA) offered a dizzying array of model names and designations, in both single and double action variations. Despite the nomenclature, all the double stack pistols were one of these four sizes;

What can be seen immediately is that each of the four slide and barrel lengths has a different frame height in the Para-Ordnance double stack lineup. And this means, of course, that there are also four sizes of magazine to choose from. “Flush fit” does not apply here because, except for the magazines supplied with the very first gunsmith kits (which had flush, steel floor plates), all Para-Ordnance and ParaUSA magazines had polymer bases that extended slightly below the bottom of the grip frame and magazine well. [With the exception that the early Slim Hawg pistols shipped with one flush-base magazine and one polymer base magazine. This was a special case, and only lasted one or two years.] When the 1994 U.S. federal assault weapons ban came along, Para responded by offering magazine variants that had the same overall length as their standard magazines but which limited the magazine capacity to ten rounds, regardless of the pistol frame size. After the federal ban expired in 2004 Para reverted to providing full-capacity magazines with most of their pistols, but they also continued making the 10-round, limited capacity magazines for sale in the several states that had magazine capacity limits after the expiration of the federal AWB.

Parts Interchange

The confusion arises if an owner wants to replace something like the mainspring housing on a Para-Ordnance double stack pistol. The MSH on the P14.45 (and similar sized P16.40 and P18.9) is the same as a Colt Government Model MSH, but ... what fits to other Para pistols? Let’s find out.

The above photo shows, from left to right, a Colt Commander, a Para-Ordnance P14.45, a Para-Ordnance P13.45, and a Colt Officer’s ACP. Allowing for some minor differences in the height of the rear sights on which the pistols are resting, we can see that the P14.45 MSH is the same as the Colt Commander (and, therefore, also the same as a Colt Government Model), and that the P13.45 MSH is the same as the Colt Officer’s ACP. All four of these pistols use standard grip safeties, with the same vertical length as the original M1911. The following photo shows the P13.45 “nested” to the Colt Officer’s ACP, confirming that the mainspring housings are the same height.

This tells us that the Para P13.45 (as well as the P15.40) isn’t a true double stack analog of a single stack Commander. Because it has a shorter grip, MSH, and magazine well, the P13.45 is actually more akin to a double stack rendition of a Colt CCO (which mounts a Commander-length slide and barrel on an Officer’s ACP frame).

In the Colt family of 1911s, there are only two frame heights and two MSH sizes. The Para-Ordnance P13.45 uses the smaller/shorter MSH from the Colt family, but Para offers two double stack pistols that are still smaller than the P13.45, as well as the single stack Slim Hawg, which has a smaller/shorter frame height than the Colt Officer’s ACP. What about those pistols?

The next photograph shows, from left to right, a Colt Officer’s ACP, a Para-Ordnance P12.45, a Para-Ordnance P10.45, and a Para-Ordnance Slim Hawg. The mainspring housings of all three Para pistols is shorter than the MSH of the Officer’s ACP, and all three Paras have the same height MSH. But the P10.45 frame is even smaller than the frame of the P12.45—how can they use the same mainspring housing? The photo tells the tale: the P10.45 doesn’t use a standard grip safety. The grip safety of the P10.45 is shorter in the vertical dimension than other 1911 grip safeties. (This means that the hammer strut is also shorter than a standard 1911 hammer strut.) The single stack Slim Hawg is the same height as the double stack P12.45, and like the P12.45 the Slim Hawg can accept standard 1911 grip safeties and hammer struts.


That’s the story. Four double stack pistol sizes, four magazine sizes, three mainspring housing sizes (only one of which isn’t a standard 1911 size), and one very non-standard grip safety.

Please go to this thread on the M1911 Pistols Organization discussion forum to discuss this article: https://forum.m1911.org/showthread.p...53#post1007453

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