Using a small chop saw cut the 223 brass at the start or the bottle neck. 1.38 length, lube and run it thru the sizing die. It will not size all the way down but you can prime it, get powder in and get the bullet seated. Firing it will “fire form” the brass and be able to be reused. Ive reloaded some of these brass 7 plus times. I found new 223 brass works best. 

Powder I started using 4 powders. The best results came from IMR 4227 and 2400 a distant second. Unique and Reloader did not perform well enough to cycle the action. 

IMR 4227 19 grains 1848 fps. Excellent accuracy and feeding/ejecting. 1.90 overall lenght.

These are my worked up loads and should be laddered. I hope some of this you'll find helpful. 

I have 2 1907 .351 made in the early 50s and a 1910 first year made .401 that I found challenging to find brass as well but over came challenges and it shoots great. 

Bore Diameter (top of the lands): 0.422" to 0.4225" (nominal SAAMI spec is 0.422", with production targets typically at 0.4224"–0.4225")

Groove Diameter (bottom of the grooves): 0.4285" to 0.429" (SAAMI specification minimum is 0.4285", with a +0.002" tolerance window up to 0.4305")

Rifling Twist Rate: 1 in 36 inches (standard for modern .44-40 lever guns)

Handloading & Bullet Fit Implications

Standard .427" jacketed bullets: Traditional .44-40 factory jacketed bullets measuring .427" will shoot safely, but because the groove diameter sits around .4285"–.429", accuracy with undersized .427" hard-cast bullets often suffers due to gas blow-by and bore leading.

Lead / Cast bullets: Sizing cast bullets to .429" (or soft-cast/20:1 alloy up to .430") generally produces optimal accuracy and a proper gas seal.

Chamber neck clearance: Because the .44-40 case neck is thin (.007"–.008"), loading a .429" or .430" bullet into modern brass (such as Starline) typically yields an outside neck diameter well within the SAAMI maximum chamber neck limit of .443", allowing rounds to chamber smoothly without neck-turning.

MidwestCrisis said

TXGunNut said

Zebulon said
Like Johnson's Model 63, the 07 is interesting (to me) because it is beautifully made and because it is built to work and last. Some of Winchester's finest craftsmanship went into these self loaders. And a lot of creativity to snake around all the Browning patents. 
  

Actually it goes back to Johnson's 1903 which is the predecessor to your 07. The 1903 was a very simple design that evolved to the Model 63 about 30 years later to take advantage of the improvements to 22LR ammo. As a blowback design it has problems but was a very good design for its time, IMHO.
 
Mike
  

After working on mine , I noticed things about it that every modern semi auto has.  It seems to be the grandfather and the Johnson the great grandfather.  It’s likely under appreciated due to the chambering.  It is definitely one of my favorites so far.  Easy tie with the 92 in 25-20.  They are just fun to shoot.  Ammo is hard to come by.  But 1 full magazine, they make excellent “truck guns”.  
  

I very much enjoyed researching and writing "T. C. Johnson and the Model 1903 Winchester" for the Winter 2024 Collector. If you haven't read it I think you may enjoy doing so. In fact, I enjoyed it so much I recently finished a "prequel" for a future issue. 

Mike

TXGunNut said

Zebulon said
Like Johnson's Model 63, the 07 is interesting (to me) because it is beautifully made and because it is built to work and last. Some of Winchester's finest craftsmanship went into these self loaders. And a lot of creativity to snake around all the Browning patents. 
  

Actually it goes back to Johnson's 1903 which is the predecessor to your 07. The 1903 was a very simple design that evolved to the Model 63 about 30 years later to take advantage of the improvements to 22LR ammo. As a blowback design it has problems but was a very good design for its time, IMHO.
 
Mike
  

After working on mine , I noticed things about it that every modern semi auto has.  It seems to be the grandfather and the Johnson the great grandfather.  It’s likely under appreciated due to the chambering.  It is definitely one of my favorites so far.  Easy tie with the 92 in 25-20.  They are just fun to shoot.  Ammo is hard to come by.  But 1 full magazine, they make excellent “truck guns”.  

Zebulon said
Like Johnson's Model 63, the 07 is interesting (to me) because it is beautifully made and because it is built to work and last. Some of Winchester's finest craftsmanship went into these self loaders. And a lot of creativity to snake around all the Browning patents. 
  

Actually it goes back to Johnson's 1903 which is the predecessor to your 07. The 1903 was a very simple design that evolved to the Model 63 about 30 years later to take advantage of the improvements to 22LR ammo. As a blowback design it has problems but was a very good design for its time, IMHO.

Mike

I believe your starting loads may provide clues to what it takes to cycle the 07 action. I like 296 in some RBH-only 45 Colt loads. Should prove interesting!

Mike

Having done some research, the balance of opinion favors very fast rifle or magnum pistol powders,  with some specific starting recommendations of 16 grains of 4227, 2400, or 296/110. 

Because I have good quantities of Olin 296 on hand and have had good experiences with it, all the way from 22 Hornet to 357, 41, and 44 magnum,  I propose to make up a ladder from 16 to 18 grains of 296, using Winchester WST large primers, Graf 180 grain brass plated RN bullets, in what are likely modified Remington brand 357 Max brass, now once fired. 

Ten of the Graf bullets have been seated to factory OAL and roll crimped in the cannnelure of once fired, dead/inert primered, FL resized, vintage Western brass. Loaded into a 5-round magazine, these were fed and ejected repeatedly using the operating rod sleeve, to test whether these bullets and the 07 feed ramp can get along. They can. 

When Winchester-Western discontinued their SuperX commercial ammunition  [W351SL2], the 180 grain softpoint bullet was advertised to have a muzzle velocity of 1870 foot seconds from the 20" barrel, producing 1400 foot pounds of muzzle energy. Not a pipsqueak cartridge. I'll chronograph my loads but all I'm looking for is from 1600 to 1700 foot seconds.

I'd welcome comment, particularly from those with reloading experience in the caliber. 

MidwestCrisis said

JWA said

Zebulon said
https://www.theshooterstent.com/?utm_id=120249938617030468
  

Dang it!  My patent attorney dropped the ball and those Texans beat me to it.
I put the XL on my Christmas list but will still shoot prone from my REI tent.
Thanks for the link!
Jeff
  

Now I’m confused.  Why is she shooting instead of picking up the brass?

Yellow light!! 

JWA said

Zebulon said
https://www.theshooterstent.com/?utm_id=120249938617030468
  

Dang it!  My patent attorney dropped the ball and those Texans beat me to it.
I put the XL on my Christmas list but will still shoot prone from my REI tent.
Thanks for the link!
Jeff
  

Now I’m confused.  Why is she shooting instead of picking up the brass?

Zebulon said
https://www.theshooterstent.com/?utm_id=120249938617030468
  

Dang it!  My patent attorney dropped the ball and those Texans beat me to it.

I put the XL on my Christmas list but will still shoot prone from my REI tent.

Thanks for the link!

Jeff

I have an uneasy feeling the requisite dinner will have to be some place so dim I can't read the menu,  the Maitre d' will have a posture like a cobra and his hand out for a C-note to avoid being seated downwind of the grease trap.

I probably could have bought a Korean brass finding robot for half the probable meal tab. Big D really is the Land of Wretched Excess.  

But I've grown accustomed to her face.

If your wife can't make it you can always pitch your tent and shoot from inside.  Not only will it catch all your brass but you will also be in the shade.  Make sure to keep the muzzle outside though or the window flaps fly up like Dumbo's ears every time you pull the trigger, just sayin'.....

Best Regards,

Mike