Leading in 44 mag

[glockky]

I just picked up a ruger super blackhawk hunter bisley in 44 magnum. After getting it I took some of my .431 sized 255gr gas checked bullets and tested them in the throats. The bullets would just barely go in, they fit very tightly in each hole of the cylinder. At this point I thought well thats good I shouldnt have any leading problems.

Today after shooting several rounds loaded with Unique and 2400 I am still getting slight leading all through the barrel. I am casting bullets of straight COWW and using gas checks. Anyone have an idea what I am doing wrong here? I would think with the gas check and the bullets not being sized down in the throats I would not have this problem.

I also tried different amount of case expansion and crimp when loading.

[randyrat]

Well I don't know where to start except one thing for now. Is this brand new gun, maybe you have a rough barrel or bore and it needs to be broke in a bit.

[paul h]

It could be something simple, did the barrel have any jacket fouling before shooting cast? What type of lube are you using?

The issue may be thread choke in the barrel and not the cylinder. Clean the barell down to bear metal and then run a soft lead ball through from the muzzle to see if you have a choked barrel. If it is choked, I'm a big fan of Taylor throating to cure that issue.

If you're able to push the 0.431" bullets though the throats with resistance, they should be right at 0.431". My idea of the ideal dimensions for a revolver are bullets sized 0.001" over bore dia, and throats 0.0005-0.001" over bullet dia

[Oreo]

Slug the bore? Even if the cylinder throats fit the boolits the bore might be over-sized or have a constriction where the barrel threads to the frame.

[Larry Gibson]

Straight COWWs.......might add 2% tin to those as what you think is leading my be antimonal wash.

What lube?

Larry Gibson

[glockky]

Could you please explain to me antimonial wash?

['74 sharps]

Check the LASC website for an excellent explanation of pressure and obturation for prevention of leading.

[Bullshop Junior]

What kind of lube are you using? A good lube can make a whole world of difforance.

[glockky]

The revolver had 50 rds through it from the previous owner. I am using BAC lube. After cleaning it last night there is what feels like a rough spot about half way town the bore. It doesn't feel tighter just rough.
I am thinking a out taking some lights abrasive compound and working on the bore a little just to smooth it up

[kevmc]

My guess is it's a patch of lead.....

Choreboy or brush and patches....

[cylinderman]

The term slight leading can be vague. A cast load that is considered to not lead will still leave evidence that lead went down the barrel. To me the main factor is no build up developed, the ammount after 5 rounds is the same as that after say 100 rounds. I have found that new to me barrels will show more evidence of lead with a few rounds and after several hundred it becomes less, I guess kind of seasoned. This is one reason I don't scrub my bores clean very often, just run a tight dry patch to clear anything loose

[glockky]

I had the same amount of leading after 12rds as I did after 40. Accuracy was not bad except for me not being use to the trigger yet. I just figured with the gas checks I wouldn't get the amount of leading I have. I plan to hunt with 50/50 COWW/pure lead and am afraid that will make my problems worse. Heres my first 25 yd target keep in mind this was my first time shooting this revolver. 8" target

[glockky]

The term slight leading can be vague. A cast load that is considered to not lead will still leave evidence that lead went down the barrel. To me the main factor is no build up developed, the ammount after 5 rounds is the same as that after say 100 rounds. I have found that new to me barrels will show more evidence of lead with a few rounds and after several hundred it becomes less, I guess kind of seasoned. This is one reason I don't scrub my bores clean very often, just run a tight dry patch to clear anything loose

So you don't worry about leaving leading in the bore? Maybe I am just over thinking it. I am use to having a shiny bore in my other pistols with no leading at all.

[captaint]

It's the actual lead buildup we don't want. Using 50/50 COWW and soft lead may actually improve the barrel situation. A little softer boolit can expand some and fill the bore more completely. Do consider adding some tin. Just 1 or 2 % is all we need. Mike

[glockky]

I just bought 5 pounds of pewter. I tried to skimp on tin when I first started casting and am learning its not optional lol

[paul h]

I've shot over 200# s of lead through my 480 @1000-1200 fps and 90% of those were plain based bullets and all of them COWW. I've never had significant leading in the gun. Ww's are fine for hanguns with. no additives, you just need the right dimensions in the gun and the bullet sized to fit those dimensions. Bac is good stuff. A good bore scrubbing might be all you need., but slugging the bore to check for thread choke and slugging the cylinder throats will give you the dimensions you need to know if you should tweak them or leave them be

[cylinderman]

So you don't worry about leaving leading in the bore? Maybe I am just over thinking it. I am use to having a shiny bore in my other pistols with no leading at all.

What is a concern is the rough build up looking more like torn or galled metal or the filling of the rifling grooves. Little greyish silver streeking or thin lines I don't worry. Some barrels just like to keep a little lead. Another note, I have two superblackhawks and I will get more leading from lighter loads than full house loads of H110. 90% of the boolits are 240gr plain base SWC. I will also confirm that at handgun velocity 1000 to 1500 fps a harder alloy is more likely to lead than softer provided the correct size.

Do clean and carefully inspect the bore, my cleaning preference is a piece of copper chor-boy wrapped around an old bore brush. It will scrub it out quickly just make sure it is 100% copper no weird plated stuff.

[Larry Gibson]

Could you please explain to me antimonial wash?

Antimonal wash is a light gray colored deposit seen in the bore. It most often is fairly even distributed and does not "build up" after multiple rounds (as in " had the same amount of leading after 12rds as I did after 40"). Leading builds up and is often seen as in "rough build up looking more like torn or galled metal or the filling of the rifling grooves". Antimonal wash is cause from a ternary alloy having a higher content of antimony with little tin. The antimony crystalizes separately from the lead and does not go into solution with it. The addition of ti mixes with the antimony (up to about 3 - 3.5 % of each) and it then goes into solution with the lead.

I have shot thousands of pounds of COWWs over the years and used to shoot straight COWW alloy in my handguns and rifles. Back in the day there was more tin in COWWs. Not so these days and where you live make a big difference as all COWWs we scrounge these days are not created equally. I still have a 5 gal bucket of old COWWs and a couple buckets of newer COWWs. Big difference between them; adding 2% tin to the newer COWWs makes them the equal of the older COWWs.

BAC lube is good and shouldn't be the problem.

Larry Gibson