.428 with .429 bore

[Trailrider]

First of all, the reason Uberti/Cimarron "discourage" the use of reloads through their guns has to do with their product liability exposure.  Since they can't control the loads that handloaders might put in their guns, they don't want to be responsible for blowups. Good, standard loads listed in the Lyman handbooks should be fine.  Just do NOT go ABOVE or BELOW the range of loads shown in those manuals.

I've used Master Craft bullets for years. They can size to anything from .427" to .431". They show a 205 grain bullet, but say they are not to be used in Winchester 1866 or '73's!  Not sure why that is, unless it has to do with the shape of the bullet and feeding. (The bullets I got from them years ago, and still have a good supply weigh out at 213.5 gr, but they no longer show those on their website. They have a 200 gr. bullet, but don't show the shape. Best would be to contact them directly.

I use .430" bullets in my M1860 Military Henry (Navy Arms), and '92 Rossi's in both .44-40 and .44 Mangle-em, as well as my Old Model Ruger Vaqueros (with the TIGHT .425" throats in .44-40...they are hard-cast and squeeze down through the throats, but re-exoand when they enter the forcing cones!  ).  I use regular (not the Cowboy) RCBS .44-40 dies, with the expander plug from the .44 Magnum dies (ordered separately), and Winchester brass, which is thinner.  If .429-.430 bullets and Winchester brass won't chamber, then you might have to go to .428".  Hope this helps.

[Coffinmaker]

I have a simple question.  Numerous times, I have seen the claim that once a bullet is swaged down (reduced) in diameter it immediately pops back to it's former diameter??  After having swaged bullets to size for many years and having them remain the size swaged to, I can't quite get my head around to bullets that pop back to previous size after passing thru a tight throat??

Like wise, I don't buy into the claim that undersize bullets "bump up" to groove diameter when fired.  Undersize bullets remain undersize bullets.  Bullets that pass thru a "too small" throat stay too small.

[Cholla Hill Tirador]

I have a simple question.  Numerous times, I have seen the claim that once a bullet is swaged down (reduced) in diameter it immediately pops back to it's former diameter??  After having swaged bullets to size for many years and having them remain the size swaged to, I can't quite get my head around to bullets that pop back to previous size after passing thru a tight throat??

Like wise, I don't buy into the claim that undersize bullets "bump up" to groove diameter when fired.  Undersize bullets remain undersize bullets.  Bullets that pass thru a "too small" throat stay too small.

  Let me address this backwards....

  Bullets can and do bump up, it's called obturation. The expanding gasses from the burning powder smack the bullet in the hind end, while the front of the bullet is meeting  resistance from air or atmosphere, so in essence the bullet is being squashed by two opposing forces, which causes it to get "fatter". Dave Scovill of Handloader magazine demonstrated this by removing the barrel from a Colt SAA revolver (45 Colt), firing a cartridge loaded with one of the soft 250 gr. RNFP's and catching it in some soft material that did not damage the bullet. He then mic'ed the bullet and its diameter was roughly the same as the throat of the chamber from which the cartridge was fired; .456" as i recall. That said, there has to be a certain ratio of pressure to bullet hardness for this to occur. In other words you can't fired a hard lead bullet from a low pressure load and expect any obturation. A fellow named Veral Smith wrote an excellent book on cast bullets and somehow came up with a multplier (that escapes my memory) by which one can calculate the chamber pressure required to obturate a bullet of a given Bhn hardness. The late John Korth, who posted on this forum, likewise demonstrated that the old Winchester rifles with their often oversize bores, we're still capable of accuracy because the soft lead bullets would obturate to fill the grooves. Sort of the same principal as the hollow base bullets used in muzzleloaders.

  That said,  I agree with you on the first part, once a bullet, fired from a revolver, exits the cylinder and the gasses for the most part escape through the BC gap, the bullet will not increase in size as most of the needed pressure has already escaped.

  CHT

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[William R. Foster]

  Uberti/Cimarron does a very good.job with their cylinder throats. I have a very new Uberti 44-40, I'll try to remember to measure the cylinder throats when I get home.

 CHT

Any chance you snagged those measurements?

[Cholla Hill Tirador]

Any chance you snagged those measurements?

 Good grief! I got busy and forgot!

Measured two throats and they were both right at .430"



 CHT

[William R. Foster]

Excellent. Thank you. Now a follow up question. If my math is correct starline states their walls are 0.0065, now you add that to .430 with the addition of the wall on the opposite side and im at 0.443. How exactly is that going to work? Honestly playing with all the 44wcf sized bullets the math doesnt add up. I figure im just tired and doing the math wrong, but figured id check.

[William R. Foster]

Gah. Nevermind. Im an idiot. I was thinking about the charge hole of the cylinder. Not the throat. Tired thinkin is not good thinkin.

[Cholla Hill Tirador]

 Shoot first and if things don't work out, try something else.

[Coffinmaker]

SO.  Contrary to popular belief, Old Dogs can learn new stuff.  Rather than continue my belief about the possibility of cast lead bullets expanding upon firing, I went researching.

It is true that cast lead bullets can expand upon firing.  CAVIAT:  This phenomenon requires the lead alloy be carefully for Brinnell Hardness to the pressure level of the cartridge.  If one is shooting common commercial cast lead bullets the probability of those bullets obdurating at the pressure levels we shoot at is ....... Nil.  If one is shooting Bevel Base bullets the probability of obturation is ..... zip.  Likewise, shooting gas check bullets .... Nada.  Expansion after passing thru cylinder throats ..... only with dead soft bullets.

Shooting undersize bullets and expecting the bullets to "bump up" is a fools errand.  Also, at no point in research could I find any reference to indicate unlimited obturation.  The ONLY effective method for best performance is to shoot bullets sized correctly to the bore (Groove Diameter).

Those knowledge laden folks that toss the "fact" that lead bullets will "Bump Up" are only partly correct and only for an absurdly small number of CAS shooters.

[Cholla Hill Tirador]

SO.  Contrary to popular belief, Old Dogs can learn new stuff.  Rather than continue my belief about the possibility of cast lead bullets expanding upon firing, I went researching.

It is true that cast lead bullets can expand upon firing.  CAVIAT: This phenomenon requires the lead alloy be carefully for Brinnell Hardness to the pressure level of the cartridge.  If one is shooting common commercial cast lead bullets the probability of those bullets obdurating at the pressure levels we shoot at is ....... Nil.  If one is shooting Bevel Base bullets the probability of obturation is ..... zip.  Likewise, shooting gas check bullets .... Nada.  Expansion after passing thru cylinder throats ..... only with dead soft bullets.

Shooting undersize bullets and expecting the bullets to "bump up" is a fools errand.  Also, at no point in research could I find any reference to indicate unlimited obturation.  The ONLY effective method for best performance is to shoot bullets sized correctly to the bore (Groove Diameter).

Those knowledge laden folks that toss the "fact" that lead bullets will "Bump Up" are only partly correct and only for an absurdly small number of CAS shooters.

  Your text in red has already been addressed in a previous post. I researched the formula I mentioned and it is 1422 x Bhn of the bullet = the pressure required to begin obturation. That explains why the nearly pure lead bullets of ~6-7 Bhn used in cartridges 140+ years ago worked in (slightly) oversize barrels.

  I don't why a bevel base bullet wouldn't obturate, maybe not a much as a flat base bullet due to the smaller surface area of the bullet, but the forces of physics would still be at work.

  Sorry friend, like it or not, cast bullets can and do bump up, under the prescribed conditions. I don't recall anyone saying anything about "unlimited obturation". You can place a lead ball on an anvil and beat it with a hammer and it will only "obturate" so far. I'm not sure when/where/ and why that came into the discussion.

  Of course the best course of action is to size the bullet properly. I personally size for throat diameter, or even a thousandth or two over. Sizing to groove diameter works well only if and when the cylinder throats diameters are close to the diameter of the barrels grooves. This has been demonstrated repeatedly with Ruger SA's whose cylinder throats are very typically of less diameter than the grooves of the barrel. This makes for horrid accuracy and is why 'smith's offer the services of opening cylinder throats. I had a New Vaquero in 45 Colt with this very issue. At the other end of the spectrum are Colt SA's in 45 Colt flavor. Their throats are likewise notorious for being grossly oversized. The last 3rd Generation 45 Colt I owned had cylinder throats as large as .457". THAT is the very situation in which one must use a soft bullet that will bump up to fill the throats.

 You are exactly correct regarding CAS shooters who need a projectile capable of hitting a large target at short range. Few concern themselves with accuracy, but you must remember that there are those of us at the opposite end of the spectrum who enjoy shooting revolvers at longer ranges, and to do so effectively the bullets must behave properly.

 If you care to research the subject further, Dave Scoville, Brian Pearce, Mike Ventrino and the Cast Boolit website are great sources of information and learning.

 CHT

 

[Roscoe]

Hey all, i have decided to get chancey and go with a 44WCF revolver and Rifle combo. That being said ill obviously be reloading. The info i have found for the Cimarron Frontier is that its a .429 bore. I cant find any info on the bore size of the Short Rifle they sell. Regardless .429 has been near impossible to find online for a bullet, with .428 being the closest. Will .428 be okay for both revolver and rifle until i get to where i cast my own? Any potential problems? Thanks.

It is .430 bullets you need for a .429 bore, since you want to ensure a good bore seal on firing. My Uberti 1875 Remington Outlaw is the same, and its throats are too large for the .428 bullets I tried. I wound up with RCBS Cowboy dies (which are not carbide and require lubing cases). I had to get the expander plug for 44 Russian, Special, Magnum at .430. The chambers required that I trim brass to 1.290 or less and seat to a COL of 1.582. These passed both the cartridge gauge and the pistol chambers, so a rifle should accept them based on being in spec with the gauge. The bullets I use are the same profile and hardness that I use for 44 Special, and which others might use in 44 Russian. The bullets have to be flat nose in order to be shared for the rifle ammo.

Note that I do not size new brass, because the 44-40 dies would size it too small, expecting .428 bullets. The virgin Starline brass fits both the case gauge and the gun chambers, while taking on more of a necked shape after firing. The gun is remarkably accurate with these loads, so something is working.