Hard cast bullet size question - trying to stay safe

R

robinny

New member
I'm still a fairly new reloader, so I just want to check if I am acting responsibly.

I have a box of Missouri Bullet Co. 158-grain SWC Action! bullets (BHN 18) that I intend to load for my 6.5" New Model Blackhawk. The bullets mike at 0.3585", the same diameter as the groove diameter of my barrel, but I slugged the chamber throats and the smallest of them is 0.3575" (largest matches groove dia). I have never loaded hard cast bullets before, and just want to be sure I'm still in Not Stupid Territory. I know the tighter throats may cause some accuracy issues and am trying to find a local smith who will ream them all to the same diameter, but right now I'm just trying to verify there are no safety issues with using these bullets in this gun.

Thanks for any reassurance or forewarning to be had.
 
Nothing to worry about safety wise. The lead bullets should be slightly larger than the cylinder throats. They will swage down easily enough.
 
Lead bullets, even the hard ones squeeze down and even bump up remarkably well without causing issues. IF your load pressure is not in the "stupid zone", the bullet's diameter being a small amount different from the bore won't be a problem and isn't a safety concern.

Standard advice (and practice) is to run cast bullets .001-.002" larger than groove diameter for best performance.

I, personally, would hold off on having the cylinder reamed, until you know IF you are going to have issues with accuracy because of chamber throat size. It can cause issues, but unless it does, (and it MAY NOT) you're spending money to fix what isn't broken, and assuming that the reaming will fix it in the first place.

The internet is full of good advice, and some not-so-good advice, and some advice that while it may be good, may not apply to your specific situation.

Shoot your gun, and with a number of things, and see what it does, before you have any work done on it.

Then, if you're not getting the results you want, figure out why. Might be the gun. Might be the ammo. Might be you, the shooter. All these things work together and problems can be in the individual factors, OR they can also be in the way the individual factors work together.

The way I see things, taking metal off a gun should be the last thing done when trying to solve a problem. One should be absolutely certain it needs to be done, and will solve the problem, because while removing metal is relatively easy, putting it back is not.
 
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that should be fine.

grab a bullet grab the gun. can you push the bullet through the cylinder throat? it should be a very snug fit requiring a little pressure, or just not quite fit into the throat.
 
First thing that comes to my mind is how are you measuring the throats? Are you using a calipers? Or are you doing it the right way with pin gauges? And how are you measuring your bore? Have you slugged it? Are you measuring the slug with a calipers or a micrometer? Until you have a true measurement using the right tools you really don’t know for sure what you’re dealing with.
 
Shadow9mm said:
that should be fine.

grab a bullet grab the gun. can you push the bullet through the cylinder throat? it should be a very snug fit requiring a little pressure, or just not quite fit into the throat.
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In the largest chamber, I can push a bullet through. In the smallest it is very difficult to do without a dowel and mallet.
 
jetinteriorguy said:
First thing that comes to my mind is how are you measuring the throats? Are you using a calipers? Or are you doing it the right way with pin gauges? And how are you measuring your bore? Have you slugged it? Are you measuring the slug with a calipers or a micrometer? Until you have a true measurement using the right tools you really don’t know for sure what you’re dealing with.
Click to expand...
Slugged the barrel and each chamber throat and measured with micrometer.
 
robinny said:
In the largest chamber, I can push a bullet through. In the smallest it is very difficult to do without a dowel and mallet.
Click to expand...
in theory, for best accuracy, the bullet should get sized down 3 times, going through the throat, into the forcing cone, and into the barrel. Generally if you have a tight fit in the throat your good to go.

some bullets, particularly jacketed, will be slightly under sized. lead bullets should be snug to prevent gas going around and cutting into the bullets and leaving lead deposits.

sounds like your bullets are a good fit. load em, shoot em.
 
the bullet should get sized down 3 times, going through the throat
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Not so.
The bullet should pass the throats with just finger pressure. If not (you would have to hammer them in), then the throat(s) need reamed. If they 'fall through' the bullet diameter needs to be increased... The cylinder throats should be at least 0.001 over the bore size to make a good seal when bullet is passing down the bore. The forcing cone doesn't squeeze anything but helps guide the bullet into the bore. That's the forcing cone's only purpose.

No safety issues. Load 'em up.
 
When revolvers were still king of the bull's-eye target shooting hill, there were a good number of accuracy revolver smiths serving the target shooting market. I've read articles about them over the years, and most would ream chambers to SAAMI max as one of the first steps in the process. IME, if your groove diameter is nominal and you want to use bullets sized one-thousandth over, you ream the chambers about 1.5 thousandths over groove diameter, unless the gun is to be used with speed loaders, in which case 2 thousandths over makes more sense, but won't be as free of leading just behind the throat.

Every revolver I've had with uneven cylinder throat diameters has had at least one chamber that threw shots to a slightly different POI than the others, though they would tolerate a good deal more difference with jacketed bullets than with lead.
 
You think 38s a funny, check 45 colt. In years past, cylinders and barrels were micked at .452-.455. today most cylinders and barrels mic at .451-.452. I have even seen some old bullets micked at .456, and were still used in 45 colts.
From what I have read, the change started sometime about 1910 or so. All these different sizes played havic with accuracy. Is good most of these were lead

I still love revolvers. have a Ruger security six, 357/38, Uberti EL PATRON 45 colt,
and Tauras .22/.22 mag.
Course I have 2 1911 45s, a 1911 38 super/9mm . Is funny I did not know all you had to do to change from 38 super to 9 mm was change the barrel/bushing and magazines. Works great, one Ed Brown barrel/bushing and magazines and pressto, 9 mm.
My 38 super was built in 1967.
 
All these different sizes played havic with accuracy. Is good most of these were lead
Click to expand...

There wasn't as much havoc as you might think, because nearly all the ammo was lead bullets.

The common nominal diameter for .45 Colt barrels, pre-WWII was .454". When the diameters were generally reduced to .451-.452" to get better accuracy from .45acp bullets the larger .45 Colt slugs, being lead squeezed down just fine.
 
The thing that played havoc was that a lot of old guns had rifling only 0.002" deep, so bullet stripping in the rifling was common. Keith claimed some old-timers preferred tumbling bullets in a gunfight, as they stopped a man faster. Needless to say, this assumes engagement at close range.
 
Unclenick said:
The thing that played havoc was that a lot of old guns had rifling only 0.002" deep, so bullet stripping in the rifling was common. Keith claimed some old-timers preferred tumbling bullets in a gunfight, as they stopped a man faster. Needless to say, this assumes engagement at close range.
Click to expand...
I have a .30-40 krag just like that. It shoots cast bullets pretty lousy. Out of desperation I tried jacketed bullets. It worked much better.

-TL

Sent from my SM-N960U using Tapatalk
 
"I have a .30-40 krag just like that. It shoots cast bullets pretty lousy. Out of desperation I tried jacketed bullets. It worked much better."

Interesting. I have to ask, what were your bullets sized to and what was the hardness level of your bullets? Did you slug the bore of the rifle? Which bullet design did you use? Knowing the answers to those questions might point to a solution for better accuracy.
Paul B.
 
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