If you load your .30 carbine cases with .224 bullets using plastic sabots, you can get AR-15 performance from your M-1 carbine:

http://homepages.paradise.net.nz/chapmanf/sabot/sabots/load-data.htm

Cartridge

Powder

Starting Load

Velocity (fps)

.30 Carbine	UNIQUE	8 - 12 Grains	3550
	IMR-4227	12 - 15 Grains	3525
	SR-4756	7 - 9 Grains	3100

You can also give your SKS or AK-47 varmint rifle performance using a .224 bullet and a plastic sabot:

Fighters are our salvation, But BOMBERS alone provide us with the means of VICTORY! - Winston Churchill

Fred,

The link I posted above if for a company in New Zealand that you can buy the sabot's from.  On their homepage they say that their sabots are designed to give very good groups.

As far rechambering the M1 carbine goes, there was a .256 caliber wildcat cartridge developed for the M1 carbine in the 60's or 70's.  I will post some more info on it later. 

The problem with the 5.7x28mm is that it is still a pistol power cartridge.  The M1 carbine cartridge case using a sabot can push a 55 grain .224 bullet to 3,500 fps.  That's 250 fps faster than .223 Remington in an AR-15.  The 250 fps increase is mostly attributed to reduced friction and better sealing due to the plastic sabot.

I've seen those barrels for rechambering an M-1 on sale by egunparts...I think that the round developed was called a 5.8 Johnson.

If memory serves...Back in the 50's the Army experimented w/ the M-1 Carbine rechambered to 222 Remington...I think it worked well

Fighters are our salvation, But BOMBERS alone provide us with the means of VICTORY! - Winston Churchill

Here is some info on Wildcat cartridges for the M1 Carbine:

.30 Carbine Wildcats

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. (Interesting sidenote: Lysle Kilbourn of K-Hornet fame helped Mel Johnson develop the finalized MMJ 5.7mm Spitfire.)

Mel Johnson briefly 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.

On the commercial side, Johnson "patented" his conversion and attempted to stop other 'smiths who offered similar wildcats. (Johnson's wildcat was not the first; an Indiana gunsmith, C.C. Rhetts, Jr., had sold such a conversion in the early '50s when 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.) Finally, the MMJ 5.7mm had been in the market for less than three years when Mel Johnson died in 1965, and it would appear that his 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 has been resurrected by the Houston, TX-based firm Israel Arms International (IAI) for their carbine clones, and conversion barrels and loaded ammo have been advertised by Gun Parts Corporation (nee Numrich Arms).

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, consider offering a "straight-pull" conversion: 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 won't need to chase their brass.

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. His 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. Given the lack of legally owned Carbines, it was dropped until the early '60s. Ruth mentions one gunsmith had produced a .256/.30 Carbine, not to be confused with the Universal "Ferret" .256 Win Mag Carbine³. Ruth notes that one of his fellow Carbine collectors has made a rimless .357 Magnum Carbine by the same method. The 9mm Win Mag 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.

Moving to even wider cases, Ruth makes note of a 10mm Auto conversion (8 rounds in a 15-round magazine, with a lot of work). Of course, there are potential wildcats on the longer 10mm IAI Magnum case. (Colt also experimented with a 10mm IAI Mag based wildcat during their MARS program.)

Ackley and Frank Barnes (Cartridges of the World) both note a .38-40 Rimless and a .30 Kurz based on cut-down .30'06 brass. 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, 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.

by Daniel E. Watters, Small Arms Historian