44 magnum Super blackhawk leading.

[Bazoo]

I did a little reading, and im thinking that my alloy is not sufficient for the pressures im loading to. I settled on a starting load of unique as a test round, the books says its a smidge over 25k psi Or cup... cant remember. So... wheel weight alloy with or without tin added aint quite enough for this according to lasc webpage.

So I will try some 44 special loads with my made bullets, with no other change, and if that is acceptable, I will try water dropped ww for the magnum loads.

I am both enjoying and frustrated by the "problems" im experiencing. If I can get it figured out though, i'll have learned a heck of a lot about the gun and casting and bullet development. I appreciate everyones patience with me as I continue my reckon'n.

[DougGuy]

Bazoo, if you want to send the cylinder and get it measured really accurately, I have a brand new Starrett 82BZ Split Ball Bore Gauge coming. This is a $1350.00 dial bore gauge that reads in .0001" increments. This is even closer than the Z minus pin gages I use that are in .0005" increments.

Throughout this thread I don't think the boolits have yet been sized to fit the throats. This is generally what's required to stop leading, and it's pretty easy to keep lube from being blown out of the groove if powder gas can't get to it to begin with, so my suggestion is to mic the throats and get an accurate reading, hone the smaller throats to match the larger so they would all be even now, and then size .0005" under that diameter. I would hone out a sizing die to fit the throats if you want to send one.

The Uberti in my avatar is a 45 Colt with .451" barrel and .4565" throats! I size to .456" and use a 454190 boolit made up of 50/50+2% with SPG lube, the gun shoots lights out and only has a slight bit of powder residue in the barrel after a shooting session. It performs like a dream and never needs cleaning. I think I have hit on the combo this one likes.

My 7 1/2" SBH has 4325" throats, I size to .432" and use a Lee C430-310-RF with the gas check, again cast in 50/50+2% alloy, I can scratch it with a thumbnail, and I use either Felix or randyrat's TAC1 soft lube, exact same results as the Uberti. The 45 Colt really came to life with 9.0gr HS6, and the heavy boolit in the 44mag loves 17.0gr 2400 both guns get WLP primers.

What I have managed to arrive at, is the perfect COMBO that works the best in both guns. Dimensions are good, sized to just under throats, alloys are soft enough to scratch with a thumbnail, soft lube, forcing cones properly cut and polished, if I change one thing in the scheme of things, it begins to take away from the sum of the whole. Does that make any sense?

It's like taking a boat out on a lake, and you can feel it when it "planes out" and everything is working as one. Same way with your 44magnum. You just haven't gotten close enough yet.

[Silver Jack Hammer]

Take DougGuy's advice, he turned my SBH from an OK shooter into the most accurate pistol in my collection.

[Bazoo]

I slugged the cylinder throats and measured the slug to determine the measurements of .433 and .434. I also have made and fired a small batch of ammo with bullets sized to .433, which leaded worse.

[2 dogs]

In post #42, Doug gives precise information as to the correct size of the cast bullet you should be shooting. I'm quite sure both he and I would like to take a look at that cylinder and do some measuring for ourselves. I would also be interested to see if the barrel has restriction at the threads. You should consider sending it off to be carefully measured along with some of your cast bullets so an actual accurate measurement can be taken on them as well.

[DougGuy]

2 dogs I hope you are safe from the ravages of Harvey! I have good friends in the flood water now, but they are safe. So far.

Now.. I am "upping the bar" a notch with the tooling I use for cylinders and barrels, I have put into service a Starrett Split Ball Dial Bore Gauge and a stack of master ring gauges in all the pistol calibers.. This indicator reads in .0001" increments and let me tell you, NOTHING about a cylinder throat or a barrel throat will escape the telltale precision which it brings to the table! It finds oval cylinder throats in a New York INSTANT, it finds bell mouths, tapers, uneven throats and any small miniscule irregularity in the throat will immediately show itself. The thing is brutally honest in reporting measurements. I have been without one for too long!

[BHill]

Tool envy is not a pretty thing. That has abilities that make me drool and my wheel guns are shooting very well but i still want to play with it.

You loan that thing out?

You would be crazy!!!

[Bazoo]

I shelved this project for a while, but i've been pondering it, and researching it some. I have not tried anything else. But im convinced that the ww lead alloy is too soft for the pressures I was loading to. I will try some 44 special pressure loads next.

According to http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm I shouldnt get leading even with over sized cylinder throats, just less than ideal accuracy. I am also convinced that i'll get good results from fire lapping as it will smooth anything in the throats that needs it, and remove any restriction in the barrel as I believe I have a slight one but not excessive.

One thing at a time however.

Thanks for everyones suggestions and help. I work slow sometimes so it might take me a while to get it all going again. I needa fire it up and make some more bullets... .dagummit

~Bazoo

[Bazoo]

I sent the gun back to ruger with a note complaining of leading. I received the gun back with a note that they adjusted the timing. I've yet to shoot it as I dont have any bullets. I sold my bullet mold and am going to get another one.

After thinking it all over, I think the barrel constriction is the problem. I expect that after I fire lap it, I wont have any further issues with leading. I will report back as I get a mould and test more. I havent given up on it yet, but i've been working on other stuff so its been on the pondering shelf a while.

[El Bibliotecario]

I shoot what are probably undersize. 429 bullets with gas checks in a 44 magnum and 44 special revolvers and get no leading.

[Bazoo]

El Bibliotecario, I was getting leading the cylinder throats, forcing cone, and the first inch of barrel using plain base bullets. When I shot gas checked bullets, the leading was completely alleviated in the bore, but the forcing cone still was bad.

[DougGuy]

I sent the gun back to ruger with a note complaining of leading. I received the gun back with a note that they adjusted the timing. I've yet to shoot it as I dont have any bullets. I sold my bullet mold and am going to get another one.

After thinking it all over, I think the barrel constriction is the problem. I expect that after I fire lap it, I wont have any further issues with leading. I will report back as I get a mould and test more. I havent given up on it yet, but i've been working on other stuff so its been on the pondering shelf a while.

You may want to send the cylinder and get it checked, and corrected if needed. Firelapping will be much more effective if the throats are dimensionally corrected first.

You can rent the forcing cone cutter kit from 4D or one of the other rental places, 4D has a great video showing how to use the tool.

[Bazoo]

You may want to send the cylinder and get it checked, and corrected if needed. Firelapping will be much more effective if the throats are dimensionally corrected first.

You can rent the forcing cone cutter kit from 4D or one of the other rental places, 4D has a great video showing how to use the tool.

Other than with throats that are undersized, what would be the benefit of reaming them? Having slugged them and measured with calipers, I know it isnt the most accurate measurement, but its not completely useless right? I measured .433 x4 and .434 x2 when I slugged them. My goal is to rid myself of the leading. If I fire lap it with .430 bullets... they wouldnt do much of anything to the throats right?

[DougGuy]

You would want to firelap with the biggest boolits you can load and chamber.

Ultimately, the MOST important part of the cylinder throats isn't their diameter, it's how even they are in diameter. Uneven throats cause pressure variations which cause the gun to recoil differently in the shooter's hands, shot to shot. With the SBH, the boolit exits the muzzle as the muzzle is arcing upward in recoil. Variations in the position the muzzle is in from varying pressure, will cause groups to open. You can always size to fit the throats, but you cannot size to fit uneven throats.

I have a Uberti (avatar photo) with .4565" throats, I size to .456" to fill the throats to a light drag fit, and it shoots extremely well. At 10yds that gun is a fly's worst nightmare.

I suspect your larger throats are closer to .432" and the others smaller. The reason I say this is that Ruger used to ream cylinders on a Hitachi machine with 3 cutters, and as the cutters wore they cut smaller and smaller throats. Finally when the smallest and most worn of the reamers was replaced, they cut .432" holes, and since the others were not worn to the point of being unserviceable they were used until they wore out. They gang ream 3 throats, index the cylinder one hole and gang ream the other 3. Each cutter cut a pair of throats, adjacent to one another. I have not seen factory cylinders larger than .4325" although with Ruger, -anything- is possible. This is just my suspicion. And in the 1 1/2 years this thread has been up, no accurate measurements have been taken so all this discussion is based on measuring a slug with a caliper, which is probably the most "iffy" way to measure a cylinder.

[Bazoo]

That is really interesting info. I didnt know that they reamed the cylinders 3 then rotate and 3 more.

The difference in pressure from one chamber to the other causing difference in recoil is not something i've ever heard of, nor thought of. I can see how it would cause vertical stringing.

How will honing the cylinder throats to be consistent affect my leading problem?

[DougGuy]

By honing them all to match the largest throats, the smaller ones won't be downsizing the boolits as they are fired, that is, IF you size to a light drag fit in the largest throat(s). If you are shooting full power loads, and your alloy is somewhat malleable, BHN14 or softer, then boolits will obturate on firing to fill the throats. Now you have all the throats the same, you will be presenting a consistent and larger boolit to the bore.

Since no definite measurements have been taken and posted for this cylinder, there is speculation that the boolits/throats may be smaller than your calipers say they are, and if they are not bumping up in the throats as they are fired, then you are losing powder gas which is cutting the side of the boolits. You may have oval throats as well, this is common. Honing them would make them round. Awful hard to size a boolit so it will seal in a throat that is bigger on one part.

Then there is the thread choke. The larger you can shoot firelapping boolits, the better lap job they will do.

That is really interesting info. I didnt know that they reamed the cylinders 3 then rotate and 3 more.

The difference in pressure from one chamber to the other causing difference in recoil is not something i've ever heard of, nor thought of. I can see how it would cause vertical stringing.

It doesn't cause strictly vertical stringing, since the gun torques sideways as well when it fires, there is enough lateral deviation that groups just open up.

[Bazoo]

Hmm, let me think that over a while. Thank you.

[CJR]

I second what DG stated about re-cutting the barrel forcing cone. I routinely re-cut all 44 barrel forcing cones to clean them up and to insure the forcing cones are concentric to the bore/rifling axis. This helps center the CB, as it enters the barrel, and it also reduces the "lateral spitting", of shaved lead + unburned powder kernals, through the barrel/cylinder gap.

Best regards,

CJR

[white eagle]

powder coat and use gas checks
why size larger than the throats just to size to the throats when you fire

[W.R.Buchanan]

Bazoo: Have you warmed up to Powder Coating yet?

It would have solved all your leading problems a year ago.

Might want to look into it since you can be up and running with an old Toaster Oven and a Harbor Freight PC gun.

Might be a better way of fixing this problem than endless experimentation with lubes and bullet sizing and gun mods which so far don't appear to be working.

Just trying to help.

Randy