Why is .30 Carbine not made in rifles other than the M1?

[kBob]

in my 20's a bud had a M1928 and a couple of 50 round drums as well as both 20 and 30 round sticks. We joked about it being his car gun as one needed a car to cart it about. Would have been great for a fixed defense where one would only carry it from storage to a firing position. Even a drum was emptied pretty fast on Full Auto. We thought it weighted more than another Buds Springfield M1A Rifle in an E2 stock and fitted with a bipod but never actually weighed the two. Actually I was very pleased at the time to have a M1 Carbine. Biggest problem I had with the Carbine was a girl friend that would shoot every last round of .30 carbine I had in the car when she would go shooting with me! One thing I noted in those days was that the Carbine penetrated more empty 55 gallon drums than most pistols.

-kBob

 

[Slamfire]

Yup. The history of the Blish lock is almost hilarious. They tried so hard to make a successful battle rifle using their dissimilar metals adhesion principal, and failed. Finally they conceded that it would only work with a pistol cartridge. Then John T. decided to produce a "Trench Broom" and the T-Gun was born, only to be quashed by the terribly inconsiderate secession of hostilities. The rest is well known up to WW2 and the 1921 and 1928 models.
Finally, the M1 Thompson redesign simply eliminates the Blish lock entirely, and goes to a straight blow-back, proving that it really did hardly anything at all.

A Thompson with the Blish mechanism.













A blast from the past:

Arms and the Man 1 Nov 1920



“John Thompson’s surprise Party” by Capt E. C. Crossman

General John Thompson

So the submachine gun was fitted out with felt oil pads in the rear of the receiver housing, over which or by which the bolt slides at each stroke. The “gun crew” has nothing to do with the oiling beyond squirting some more into the pads every 500 rounds or so. …

The locking bolt is the working out of a theory which I have followed for some years with much interest. Some years ago, trying to blow up a Winchester Model 1886, one of the best and most popular of the lever action type, I found much to my surprise that the bolt would unlock, and would back out of the length of the shell in firing. The conditions permitting this, were, the removal of the lever catch on the tang, and second the oiling of the cse, combined with an action pretty old and worn smooth and free of extra friction.

The gun did not blow open, it did not open under heavy pressure, it was entirely safe so far as that is concerned. It unlocked when the pressure was nearly off, and the bolt slid gently open, taking the fired case with it.

I wrote up this peculiarity, and a Navy Officer, Commander Blish, called on me, and discussed the matter. It developed that he had found by experimental work, combined to a few cases of inexplicable opening of the breech bolts of big guns, firing blank cartridges that any arm which has a bolt cammed entirely shut, as by a locking bolt of the type the M1886 referred to, is likely to cam itself open again when the breech pressure falls enough to “unlock” the friction surfaces the locking bolt in its grooves in the receiver and breech bolt.

The Thompson-Blish arrangement is in neither class. Nothing moves while the gas pressure is high, the breech is immovably locked. Not until the pressure falls does the bolt cam down the locking bolt, and start backward.

It is apparent that friction is the cause the locking tendency, and therefore, as oil makes friction uniform it may be, as pointed out, that the oiling system, helpful as it is to certainty of function, is a necessity.

Army Ordnance Magazine, March-April 1933

Automatic Firearms, Mechanical Principles used in the various types, by J. S. Hatcher. Chief Smalls Arms Division Washington DC.

Retarded Blow-back Mechanism………………………..

There is one queer thing, however, that is common to almost all blow-back and retarded blow-back guns, and that is that there is a tendency to rupture the cartridges unless they are lubricated. This is because the moment the explosion occurs the thin front end of the cartridge case swells up from the internal pressure and tightly grips the walls of the chamber. Cartridge cases are made with a strong solid brass head a thick wall near the rear end, but the wall tapers in thickness until the front end is quiet thin so that it will expand under pressure of the explosion and seal the chamber against the escape of gas to the rear. When the gun is fired the thin front section expands as intended and tightly grips the walls of the chamber, while the thick rear portion does not expand enough to produce serious friction. The same pressure that operates to expand the walls of the case laterally, also pushes back with the force of fifty thousand pounds to the square inch on the head of the cartridge, and the whole cartridge being made of elastic brass stretches to the rear and , in effect, give the breech block a sharp blow with starts it backward. The front end of the cartridge being tightly held by the friction against the walls of the chamber, and the rear end being free to move back in this manner under the internal pressure, either one of two things will happen. In the first case, the breech block and the head of the cartridge may continue to move back, tearing the cartridge in two and leaving the front end tightly stuck in the chamber; or, if the breech block is sufficiently retarded so that it does not allow a very violent backward motion, the result may simply be that the breech block moves back a short distance and the jerk of the extractor on the cartridge case stops it, and the gun will not operate.



However this difficultly can be overcome entirely by lubricating the cartridges in some way. In the Schwarzlose machine gun there is a little pump installed in the mechanism which squirts a single drop of oil into the chamber each time the breech block goes back. In the Thompson Auto-rifle there are oil-soaked pads in the magazine which contains the cartridges. In the Pedersen semiautomatic rifle the lubrication is taken care of by coating the cartridges with a light film of wax.

Blish Principle….There is no doubt that this mechanism can be made to operate as described, provided the cartridge are lubricated, …. That this type of mechanism actually opens while there is still considerable pressure in the cartridge case is evident from the fact that the gun does not operate satisfactorily unless the cartridges are lubricated.

Thompson Sub-Machine Gun: … Owing to the low pressure involved in the pistol cartridge, it is not necessary to lubricate the case.


The Blish affect was one of those concepts that sounded good in theory, probably worked well in a few prototypes, but eventually failed under extensive tests and testing. The period after WW1, much effort and ingenuity was expended trying to find lightweight, automatic and semiautomatic mechanisms that fired the full power cartridges of WW1. Mauser's first automatic rifle actually used greased ammunition and the 8 X 57 mm round. It could only be used in the Zepplein service, which normally were not equipped with mud or fox holes! Lots of experiments were made retarded, or delayed blowback mechanisms, and as you can see from Hatcher's article, the Thompson high power rifle had to use lubricated, ie, greased or oiled cases.



It might have worked had fluted chambers been known at the time, but, that was a later development. I read the Germans got the fluted chamber idea from a captured Russian airplane machine cannon during the Spanish Civil War.

 

[Tommygunn]

Really good pics and article Slamfire; thanks for posting them!

With regards to the Blish device & effect; it was originally believed that it utilized a differential in friction due to dissimilar metals. But a few years back, I read a great article by a couple of engineers who procured a Thompson and an extra Blish lock. They milled off the "ears" of the Blish lock so the only function it served was to lock the actuator to the bolt, which is required for proper function. The gun still worked, but instead of a @800 r.p.m. rate of fire it was 1000r.p.m.
Unfortunatly I've forgotten the whole point of their presentation .... but the bottom line was they determined that the Blish lock did work, but not because of friction, but leverage. The angle of the slots in the bolt is different than inside the receiver.
THAT'S what delays the blowback.

The fact that the M1 and M1A1 versions obtained nearly the same rates of fire, though, indicates that no matter how it worked, the Blish lock was a redundancy.

 

[bassjam]

My ‘43 Saginaw S.G. with a ‘44 Underwood barrel is unsatisfactory accurate for my original purpose. 12” groups at 100yds renders it impossible to shoot a competitive score in a carbine match. Unfortunately, it’s typical! Velocity with factory PPU ammo is in low 1,900’s. Barrel looks and measures new, but has something really wrong (throat?). Duplicating the original load of 15.0gr of H110 with GI brass, Win SR primers and a Sierra 110gr SptRN, yeilds 2,060fps and 10”groups at 100yds. My BlackHawk, shot offhand is actually better!

Given a well placed shot, it’s immediately lethal on deer. Problem is, accurate shot placement beyond ~40yds is nearly impossible.
This is what hurt the .30Carbine.

Interesting. My FIL recently gave me his Saginaw Carbine. I've only had it to the range once using mixed year LC stamped ammo but I was getting 3" groups at 25 yards off a bench, and I truly expected better than that. Maybe I shouldn't.

 

[someguy2800]

Really good pics and article Slamfire; thanks for posting them!

With regards to the Blish device & effect; it was originally believed that it utilized a differential in friction due to dissimilar metals. But a few years back, I read a great article by a couple of engineers who procured a Thompson and an extra Blish lock. They milled off the "ears" of the Blish lock so the only function it served was to lock the actuator to the bolt, which is required for proper function. The gun still worked, but instead of a @800 r.p.m. rate of fire it was 1000r.p.m.
Unfortunatly I've forgotten the whole point of their presentation .... but the bottom line was they determined that the Blish lock did work, but not because of friction, but leverage. The angle of the slots in the bolt is different than inside the receiver.
THAT'S what delays the blowback.

The fact that the M1 and M1A1 versions obtained nearly the same rates of fire, though, indicates that no matter how it worked, the Blish lock was a redundancy.

The details escape my memory at the moment and I'm too lazy to look it up, but I though I recall reading that the troops themselves discovered during the war that the guns still worked even if the blish lock thing was completely worn out or left out of the gun entirely, and so for the last couple years of production they just added some mass to the bolt and did away with it.

 

[AK103K]

Interesting. My FIL recently gave me his Saginaw Carbine. I've only had it to the range once using mixed year LC stamped ammo but I was getting 3" groups at 25 yards off a bench, and I truly expected better than that. Maybe I shouldn't.

My experience with the 5 Ive had (3 Inlands and 2 Winchesters) has been similar to yours. 4-6" at 50 yards off a rest seems to be about the norm. 10" or so at 100 is reasonable too.

Thats been consistent whether using Korean GI, PPU, and my reloads (15 grains of 296 under a Hornady or Everglades 110 grain FMJ).

 

[Gordon]

Argghhhh, the best Marlin 62 .30 carb I've seen in many years is on Gunbroker . Reasonable at $1200 , but I'd have to sell something, well I'll try unless one of you guys want it.! I had a .256 one and should never have sold it for $800 5 years or less back, they are very fast lever actions with a short stroke and John Marlin well made with no plastic parts !
https://www.gunbroker.com/item/838125693

 

[Tommygunn]

The details escape my memory at the moment and I'm too lazy to look it up, but I though I recall reading that the troops themselves discovered during the war that the guns still worked even if the blish lock thing was completely worn out or left out of the gun entirely, and so for the last couple years of production they just added some mass to the bolt and did away with it.

The Thompson will not work at all with the Blish lock removed. The device delays the blowback, but it also locks the cocking handle, or actuator, to the bolt. Without it, pulling the actuator back accomplishes nothing.

 

[someguy2800]

The Thompson will not work at all with the Blish lock removed. The device delays the blowback, but it also locks the cocking handle, or actuator, to the bolt. Without it, pulling the actuator back accomplishes nothing.

This is the video I was remembered about the redesigned Thompson with no Blish lock. I recall reading something somewhere about how soldiers were modifying the older Blish lock 1928 models to get rid of it. Perhaps they were modifying them somehow rather than just leaving them out. I don’t remember.

 

[someguy2800]

This may have been where I read that

https://www.popularmechanics.com/military/weapons/a25414/tommy-gun-thompson-submachine/

“There was just one problem: Scientifically, the Blish Principle of metal adhesion does not exist. In reality, the effect Blish was seeing was that his lock merely added mass to the gun's bolt, which, in a blowback gun, simply slows the travel of the bolt. People figured this out during World War II, and British troops using Thompsons frequently removed the Blish lock. Later, when the Thompson was simplified to create the M1, the Blish lock was also abandoned.”

 

[roscoe]

My question is not 'Why is .30 Carbine not made in rifles other than the M1?' but rather, why are not M1 Carbines made in other calibers?

 

[someguy2800]

My question is not 'Why is .30 Carbine not made in rifles other than the M1?' but rather, why are not M1 Carbines made in other calibers?

I’ve always thought an m1 carbine in 10mm auto would be really really cool. I wonder if there is enough meat in the bolt face and barrel to make one?

 

[WestKentucky]

I have a marlin 62 in 30 carbine. Love the little lever.

 

[roscoe]

I’ve always thought an m1 carbine in 10mm auto would be really really cool. I wonder if there is enough meat in the bolt face and barrel to make one?

.357 would be cool. I have always wanted a .22 Johnson conversion as well.

 

[Old Stumpy]

My question is not 'Why is .30 Carbine not made in rifles other than the M1?' but rather, why are not M1 Carbines made in other calibers?

Erma made a nice .22 rim fire M1 Carbine back in the 60s and 70s .


Chiappa makes a blow-back M1 carbine clone in 9mm Parabellum, with a birch stock, plastic bayonet lug and barrel band.
It uses Berretta pistol mags. In one review it had reliability issues.

 

[Tommygunn]

This is the video I was remembered about the redesigned Thompson with no Blish lock. I recall reading something somewhere about how soldiers were modifying the older Blish lock 1928 models to get rid of it. Perhaps they were modifying them somehow rather than just leaving them out. I don’t remember.

But nothing about how soldiers were modifying them? The British modified early Thompsons they got by moving the sling attachment point on the butt from the tow to heel, and did an unusually good job for wartime work. I doubt soldiers out in the field would be able to remove the Blish lock and make the weapon workable (you NEED that brassy doohickey to make it work!!!!) ..... and wonder why anyone would bother since, while the 1928s were over-engineered, they did work. And "if it ain't broke, don't fix it."

 

[WestKentucky]

I’ve always thought an m1 carbine in 10mm auto would be really really cool. I wonder if there is enough meat in the bolt face and barrel to make one?

Yes please.

the answer though is that the m1 carbine is heavy and complicated which translates to poor market and expensive production. Yes parts can be cast, stamped, CNC milled, but it simply does not compare well with more modern designs in almost any metric. The recently manufactured 22lr, 9mm, and 30m1c versions are all priced as competitively as they can be and are losing out to AR15, hi point, and ruger pistol caliber carbines. They were made as cheap as possible (yes cheap, not affordable, there is a difference) and the pricing still favors a basic ar15. I love an m1 carbine as much as anybody, but outside of the militaria aspect there isn’t a whole lot to love there comparatively.

on the strength of the bolt and barrel, I suspect the frame to be the weak link. 30 carbine isn’t near as much pressure or recoil as a stout 10mm. Something is breaking, bending, or otherwise being damaged. The bigger issue seems like it would be case support. Sure modern metallurgy can fix most anything, but at what expense?

realistically, it seems like the 10mm carbine market should be looking hard at Kriss, TNW, and hipoint. I hate that because I really do like 10mm and there should be more options, but a TNW carbine with the red color scheme looks pretty sweet.

 

[Tommygunn]

The carbine is hardly "heavy" at five pounds. I do think it may be a bit difficult to make on modern machinery and some of the commercial makers have simplified thebolt, leading to reliability problems in later versions.

... the answer though is that the m1 carbine is heavy and complicated which translates to poor market and expensive production. Yes parts can be cast, stamped, CNC milled, but it simply does not compare well with more modern designs in almost any metric. The recently manufactured 22lr, 9mm, and 30m1c versions are all priced as competitively as they can be and are losing out to AR15, hi point, and ruger pistol caliber carbines. They were made as cheap as possible (yes cheap, not affordable, there is a difference) and the pricing still favors a basic ar15. I love an m1 carbine as much as anybody, but outside of the militaria aspect there isn’t a whole lot to love there comparatively.

on the strength of the bolt and barrel, I suspect the frame to be the weak link. 30 carbine isn’t near as much pressure or recoil as a stout 10mm. Something is breaking, bending, or otherwise being damaged. The bigger issue seems like it would be case support. Sure modern metallurgy can fix most anything, but at what expense?

realistically, it seems like the 10mm carbine market should be looking hard at Kriss, TNW, and hipoint. I hate that because I really do like 10mm and there should be more options, but a TNW carbine with the red color scheme looks pretty sweet.

 

[MikeInOr]

The carbine is hardly "heavy" at five pounds. I do think it may be a bit difficult to make on modern machinery and some of the commercial makers have simplified thebolt, leading to reliability problems in later versions.

Yeah, I choked on the M1 Carbine being referred to as "Heavy" also. It is very close to the weight of a Ruger 10/22... only a few ounces heavier.

Too intricate to machine economically... yeah, I do agree with that. This is very true of MANY mil surplus rifles.

 

[Old Stumpy]

e answer though is that the m1 carbine is heavy and complicated which translates to poor market and expensive production. Yes parts can be cast, stamped, CNC milled, but it simply does not compare well with more modern designs in almost any metric. The recently manufactured 22lr, 9mm, and 30m1c versions are all priced as competitively as they can be and are losing out to AR15, hi point, and ruger pistol caliber carbines. They were made as cheap as possible (yes cheap, not affordable, there is a difference) and the pricing still favors a basic ar15. I love an m1 carbine as much as anybody, but outside of the militaria aspect there isn’t a whole lot to love there comparatively.

on the strength of the bolt and barrel, I suspect the frame to be the weak link. 30 carbine isn’t near as much pressure or recoil as a stout 10mm. Something is breaking, bending, or otherwise being damaged. The bigger issue seems like it would be case support. Sure modern metallurgy can fix most anything, but at what expense?

1) M1 carbine weight is 5.2 #. How much lighter does it need to be?
2) M1 carbines aren't complicated in operation at all. They are more expensive to machine and to produce than simple blocky blowback design though.
3) M1 carbines are not about being the least expensive rifle to make. They are, like Italian replica lever guns, about nostalgia at a price.
4) The militaria aspect is why people buy them, not for any practical reason. And that's fine.
5) As for pressure, SAAMI spec is 40,000 PSI for M1 carbine and 37,500 PSI for 10 mm, so no problem in receiver and bolt strength.
Unless, by "stout" you are referring to 10 mm ammo that exceeds SAAMI spec. But, since it's a nostalgia carbine and not a tacti-kool carbine, why would you use hot loads in it?
6) Since most people would buy an M1 carbine as a nostalgic miltaria gun, cheaper factory ammunition would be their primary concern.
So, they would most probably want it in 9mm so they can shoot cheap bulk ammo, and not 10mm.

I mean, it's sort of like comparing a replica S&W Schofield break-open revolver to a Model 29 S&W, and then criticizing it for not being being as strong or as practical.

 

[fpgt72]

My question is not 'Why is .30 Carbine not made in rifles other than the M1?' but rather, why are not M1 Carbines made in other calibers?

Because companies know it would not sell for the price it would need to be marked at....wood is expensive, and heavy.

The vast majority of the market wants black and plastic....thank your AR groopies for killing all.

 

[Robert]

I think we have covered this pretty well.