More Small Arms History from Daniel Watters
Long before surplus M1 Carbines became available for civilian sale in 1963, wildcatters had begun to create new cartridges from the .30 Carbine case. Of these, a series of .224-inch wildcats appear to have been the most popular, with at least 14 major variations known. The list of gunsmiths who offered a .22 Carbine conversion is a “Who’s Who” of the industry, including: Melvin Johnson, P.O. Ackley, Bob Schuetz of SGW, and Dick Casull (of .454 fame). In Volume 2 of Handbook for Shooters and Reloaders, Ackley mentions a number of other gunsmiths, loading data, and even sources of conversion kits (complete w/ barrel and loading dies). Larry Ruth’s more recent War Baby! Comes Home also provides an exhaustive list of Carbine manufacturers and modifiers, including a variety of Carbine wildcat conversions.
The popularity of such conversions during the 1960s probably hinged on two factors: 1) Lots of cheap surplus M1 Carbines, parts, and brass, and 2) No real competitors in the .224-inch semi-auto centerfire market. (The semi-auto AR-15 and Ruger Mini-14 were still a few years down the road.) Moreover, most of the gunsmiths marketing such a conversion were pushing it as a varmint rifle, comparing it to the old standbys .22 Hornet and .218 Bee. As evidence of the relationship, Lysle Kilbourn of .22 K-Hornet fame helped Mel Johnson develop the finalized MMJ 5.7mm Spitfire. Some gunsmiths like Schuetz simply ran .30 Carbine cases through sizing dies for the .218 Bee and its wildcats.
Before entering the commercial marketplace, Mel Johnson pushed his MMJ 5.7mm Spitfire conversion as a military/police arm, with his usual level of non-acceptance. Army Ordnance still had a lot of members who held grudges over the very public tirades against the Garand vis-à-vis Johnson’s own rifle, not to mention his recent employment as an Armalite representative during the military’s testing of the AR-10 rifle. Police sales were hampered by the even cheaper availability of surplus .30 Carbine ammo.
Johnson claimed to have “patented” his conversion and attempted to stop other gunsmiths who offered similar wildcats. (Johnson’s wildcat was not the first: a California gunsmith, Ken Bucklin, claimed his .223 Scorpion wildcat dated back to 1945. In addition, an Indiana gunsmith, C.C. Rhetts, Jr., had sold similar carbine conversions in the early ’50s. In either case, the only Carbines in civilian circulation were in the hands of ex-G.I.s who had “liberated” them via duffel bags on the way home from WW II and Korea.) The MMJ 5.7mm had been in the market for less than three years when Mel Johnson died in 1965, and while sales continued for a few years, it would appear that Mel’s son Ed was not the showman that his father was.
Carbine clone manufacturer Plainfield offered unchambered .224-inch carbine barrels at one time for conversion to the .22 Carbine wildcat of one’s choice. In 1975, Iver Johnson Arms purchased Plainfield, rolling Plainfield’s carbine production into their own line of carbines. In the early ’80s, IJA offered their Carbine clones chambered for the original 5.7mm Spitfire. However, it would appear that they really didn’t know how to market it, and their 1987 reorganization killed the commercial 22 Carbine once again.
The resurgence of interest in the .22 Carbine during the ’90s was sparked by at least one of the earlier factors. Surplus M1 Carbines had once again become relatively cheap and plentiful, at least in contrast to the .223 Rem/5.56x45mm semi-auto market. Moreover, the old Carbine managed to slip under the radar of various “assault rifle” bans, and high-capacity magazines were still easily procured. The surplus market dried up once again, but interest in the wildcat has oddly continued. The chambering was briefly resurrected by the Houston, TX-based firm Israel Arms International (IAI) for their carbine clones. IAI conversion barrels and loaded ammo have been advertised by Gun Parts Corporation (nee Numrich Arms), and for a time, Fulton Armory was even offering conversions.
Without factory ammo, however, a .22 Carbine is only going to appeal to the dedicated hobbyist. I would have pushed it as an inexpensive semi-auto varmint/small game rifle, especially now that the comparable .22 Hornet and .218 Bee are undergoing a renaissance. For those with a defensive bent, I would try to ride the surge of interest in ballisticly similar PDW cartridges such as the .224 BOZ, 5.7x28mm FN, and 4.6x30mm HK. It is going to be hurt in comparison to the larger (and more established) .223 Remington, however. For jurisdictions that have included the M1 Carbine in semi-auto bans, Ackley had the answer back in the ’60s: a “straight-pull” conversion via a barrel without the gas port. The beauty is it doesn’t cost you anything extra to make or stock. A straight-pull M1 has another benefit: avid reloaders no longer need to chase their brass. This is particularly important with some of the harder to form wildcat cartridges.
Reliable load data is fairly scarce. While several respected gunsmiths and wildcatters promoted the .22 Carbine, reloading data of that era was often seat of the pants via a Powley Calculator and a lot of luck. In other words, if the case/gun didn’t rupture, the load was considered safe. Moreover, quoted velocities are often estimated velocities, as chronographs were not always used to acquire this data. Worse yet, specific brands of bullets and powders are often not specified1. OALs are also not listed, but one assumes that they are designed to feed from a M1 Carbine magazine. Thankfully, most of the data sources appear to agree on charge weights, but this is no guarantee of safety.
Ruth does not give reloading data or specifications on any of the other 22/.30 Carbine wildcats. He does have a picture of Gustafson’s chamber and cartridge specifications for the .22 SCHV carbine. Loading data, velocity, and pressure is also given. A side-by-side photo of the Gustafson round and the Johnson 5.7mm indicates that the Gustafson case has a longer body with a shorter neck. The .22 SCHV’s max OAL was 1.7-inch, and the capacity was 10 rounds in a standard M1 15-round magazine. Again, this case could be produced from cut down .223 brass2.
Of course, other wildcat and factory cartridges have been chambered in the M1 Carbine. Ackley states that the first .17 caliber cartridge was a 17/.30 Carbine wildcat (the .17 Pee Wee) in 1945. However, it was reportedly intended for single-shot rifles, not the M1 Carbine. The .17 Pee Wee did see a resurgence in the early ’60s with the release of surplus Carbines. More recently, there have been other micro-caliber wildcats based on the .30 Carbine case: the .12 Eichelberger Carbine and the .19 Badger. For many years, RCBS has listed a .14 Carbine among their special order loading dies, and the chambering list for the Competitor single-shot pistol lists a 5mm Carbine. On the larger end of the scale, John Donnelly created the 7x33mm Ballistek. It is not known if any of the last five cartridges have ever been chambered in a M1 Carbine. Ruth mentions one gunsmith had produced a .256/.30 Carbine conversion, not to be confused with the Universal “Ferret” .256 Win Mag Carbine3.
This said, Ackley offered .256 Win Mag and .357 Magnum conversions to standard Carbines. The French firm Gévelot introduced a proprietary round called the .30-222 Gévelot (cut down 222 Rem, necked out for .30″ projectiles). It was designed to circumvent French restrictions on the possession of military cartridges and the arms which chamber them. In this case, it allowed for conversions and civilian sales of surplus M1 Carbines. Ruth notes that one of his fellow Carbine collectors has made a rimless .357 Magnum Carbine by the same method.
The 9mm Winchester Magnum case, a tiny bit shorter than the .30 Carbine case, could be a source of similar wildcat conversions without all of the case trimming. For instance, after WW2 ended, Sako used a similar case for a small game round: the 7x33mm Sako. The Vihtavuori Reloading Manual claims it still has a small following in Finland. In the 1967 Gun Digest, Ken Warner mentions knowing of an Australian who had converted his Carbine to the Finnish cartridge. Judging from a photo in Jean Huon’s Military Rifle and Machine Gun Cartridges, the Finns even experimented with the 7x33mm Sako case necked down for .224″ projectiles. Prior to World War 2, the Hungarians experimented with a similar, but slightly shorter case necked to .30 caliber (7.65x30mm).
Marty ter Weeme of Teppo Jutsu has played with a variation on J.D. Jones’ 7.63mm Mini-Whisper in the M1 Carbine. Instead of using .30 Mauser cases, ter Weeme substituted 7.62x25mm Tokarev cases, loading them with .308″ rifle projectiles. Choices can run from 110gr supersonic loads to 168gr subsonic loads suitable for suppressed use. Jones’ 7.62mm Micro-Whisper (which uses .30 Luger cases) could conceivably be chambered as well4. Marty ter Weeme has even experimented with loading rifle bullets into cases for the French 7.65x20mm Long cartridge.
Moving on to even wider cases, Ruth makes note of a 10mm Auto conversion (eight rounds in a 15-round magazine, with a lot of work). Of course, there are potential wildcats on the longer 10mm iAi Magnum5 case. (Colt also experimented with a 10mm iAi Mag based wildcat during their MARS program.) Tony Rumore of Tromix has converted one M1 to 10mm iAi Mag for his father, but he has said that there will not be another.
Ackley and Frank Barnes (Cartridges of the World) both note the .38-40 Rimless, .375 Shannon, and .30 Kurz, all based on cut-down .30-’06 brass. The .30 Kurz was the product of Dan Dwyer, better known for his M1911 “Group Gripper.” One of the listed .38-40 Rimless gunsmiths was “Doc” Carlson (of Bell & Carlson stock fame); Carlson also once performed a .45 ACP Carbine conversion.
Going even further, Tim LeGendre of LeMAG has converted M1 Carbines for the 10mm iAi Mag, .45 Win Mag, and even the .50 Action Express. However, one wonders how safe or durable these latter conversions really are due to the reduction in size of the bolt face recess. Ackley refused to convert to any cartridge larger than the .357 Magnum, and even Dwyer admitted that he had seen bolt breakage with some loads in the .30 Kurz. Schuetz stated that with his .22/30 Carbine conversions, the right bolt lug would let go at pressures in excess of 45,000 PSI. However, this did not stop him from offering Carbine conversions as large as .41 Magnum.
Rumore has attempted to tackle the bolt face recess issue with the use of the .502 Thunder Sabre cartridge. Designed by Robyn Church of Cloud Mountain Armory, the 502 Thunder Sabre is simply a .50 Action Express case with the rim rebated even further to mimic that of the 7.62x39mm. Rumore is currently testing his prototype, a converted Universal carbine, but it appears unlikely that he will introduce the conversion commercially. Rumore has definitely ruled out attempting a “.440 Tunder Sabre” conversion (.502 Thunder Sabre brass run through a .440 CorBon Magnum sizing die.) Rumore fears that such a conversion would be particularly prone to shearing the Carbine bolt’s locking lugs.
1.- For instance, both IMR and Hodgdon have offered powders named 4227 and 4198 with different burn rates.2.- During the mid-’90s, Colt created a similar wildcat, the 5.56mm MARS for a cropped Commando variant.3.- Speaking of the .256 Win Mag, a .357 Mag case necked down to .257-inch, Guy Neill, then employed by Blount (CCI/Speer), once wrote me privately that he had once worked up on a rimless version for his own use. Intended as a cheap Minor Caliber carbine conversion for IPSC 3-Gun matches, Neill’s wildcat was based on a .223 case cut back to .357 Mag length, and run through a 256 Win Mag sizing die. At last check, he had not completed the Carbine, but has performed load development in a custom Thompson/Center Contender.4.- J.D. Jones has only mentioned playing with the 7.63mm Mini-Whisper and 7.62mm Micro-Whisper in a Thompson/Center Contender.5.- “iAi” refers to Irwindale Arms Inc, not the previously mentioned Israel Arms International. The 10mm iAi Magnum was introduced for the iAi Automag IV pistol. The pistol also appeared under the shifting banners of AMT, and finally, Galena in the more common chambering of .45 Win Mag. The company is now defunct, and the pistol is out of production, but the 10mm Magnum brass can still be had from Starline.
by , Small Arms Historian
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« Return to Top of Page »Recommended reading…Handbook for Shooters and Reloaders: Volume 2 by P.O. Ackley. Plaza Publishing, Salt Lake City, UT, 1966.
War Baby! Comes Home: The U.S. Caliber .30 Carbine, Volume II by Larry L. Ruth. Collector Grade Publications, Toronto, Canada, 1993.In re: .502 Thunder Sabre…30 May 2005
With respect to the .30 Carbine Wildcats, some of the information with respect to the .502 Thunder Sabre is in need of clarification.
I am a consultant to Pat and Robyn Church of Cloud Mountain Armory on their .502 Thunder Sabre product.
The .502 Thunder Sabre is no longer experimental, and is in commercial production (since 2003 actually). Tony Rumore is not associated in any way with the .502 Thunder Sabre product, and therefore he is not “trying to tackle the former problem with the .502 Thunder Sabre wildcat,” as your article purports. The only .502 Thunder Sabre being produced and sold commercially is manufactured exclusively by Cloud Mountain Armory in Newburg, Oregon (Robyn and Pat Church).
I hope that you could introduce these clarified points in to an additional articles or updates to existing articles that you author. Should you have any dispute with the above information, I have copied Cloud Mountain Armory on this request. Thank you for your time and consideration in review of this information.
Last Revised: 09/29/2008
This article was originally published at The Gun Zone — The Gunperson’s Authoritative Internet Information Resource. My friend and mentor Dean Speir has graciously hosted my articles at TGZ for nearly 16 years. These articles would likely have never appeared online without his constant encouragement and assistance.
With TGZ’s closure in early 2017, Dean encouraged me to find a new home for my scholarship so it wouldn’t be lost in the dustbin of the Internet. Loose Rounds has welcomed me with open arms. In the future, I intend to expand my legacy TGZ articles and add new contributions here at Loose Rounds.