.44 Special Leading

[Storm_Shadow]

So I've been having a slight leading problem with my .44 special loads in my Ruger Super Blackhawk Hunter. I am using Missouri Bullets Cowboy #3 with Unique in .44 Special Starline brass with CCI 300 primers. I've started my loads at 5.7 grains and worked up to 6.5 grains. I'm getting some leading in the cylinder throats and the first inch of the barrel. It usually happens around 40-50 rounds in.

My question is does this happens with a .44 special in a .44 mag as the bullet won't obturate until the throats? Could the loads be under powered not being able to obturate fast enough? My plan was to keep working it up until the "Skeeter" load. No over pressure signs so far with primers or case extraction.

Any help is greatly appreciated.

 

[RealGun]

My understanding is that leading can occur above about 1100fps and the heat that it generates. That can be raised by using harder alloy bullets. I don't know but suspect COWBOY #3 is rather soft and intended for subsonic loads. I can't say what hardness to use, but you might want to research that. Note that a hard bullet does not obturate easily, You also may need a set of COWBOY or oversized dies. I am using Hornady Cowboy dies for .44 Spl/Magnum. I don't push the load too hard and don't shoot in a Magnum gun, but understand there are ways to increase performance.

 

[Sam1911]

First off, have you read Brad's technical write-up on pressure and hardness?

https://www.missouribullet.com/technical.php

Second, have you measured your cylinder throats and bore?

As a very preliminary seat-of-the-pants guess, I'd say you'll see that leading disappear as you bump up the charge, but you need to make sure your other ducks are in a row.

 

[MEHavey]

You're not going to like this, but here goes:

Ruger has a reputation of having cylinder throats significantly smaller that the barrel's groove diameter. [This problem is rampant on their 45s], and immediately negates all efforts to properly size cast bullets to groove +0.001" dimensions. Instead you find yourself with an undersize bullet entering the forcing cone and immediately starting to lead.

Slug the barrel, and then see if that slug can be pushed through all cylinder throats with just very minor pencil-eraser pressure. If it's tight -- or won't go through at all -- you need to ream the throats to that groove+0.001". [Brownells sells reamer just for this problem]

 

[Sam1911]

Yup. That was my supposition as well, but each gun is different, so he'll have to check it to know for sure.

I had the throats reamed on my .44 (629) and since have been shooting lead exclusively, with sometimes 1,000 rounds between cleanings and no significant leading. It's worth the effort if they're tight.

 

[Walkalong]

Yep, check the throats, then check the bullet diameter. When it leads in the throats and first inch of the barrel it is gas cutting from improper fit, improper hardness, or undersized throats.


Undersized bullets, unless they have enough pressure to bump up and fill the bore, will cause gas cutting and leading when the hot, high velocity gases "cut" lead off the bullet on its way between the bullet and the throat and/or barrel. Leading will be mostly at the throats and forcing cone, but will continue until it fills the whole barrel if you keep shooting the offending load.

Properly sized bullets (in the range of .001 to .002 over throat diameter) will not suffer from gas cutting unless they are too hard.

Bullets that are too hard will not bump up and seal the throats and barrel well, even when sized properly, causing leading.

Bullets that are too soft to hold the rifling at the velocity they are driven at, will break loose from the rifling and "skid", breaking the seal and causing leading galore all the way down the bore.

If the bullets are sized properly, you can get away with them being a little harder than needed.

If the bullets are soft enough to bump up easily with the pressure used, you can often get away with them being a hair undersized, as long as they are hard enough to hold the rifling for the trip down the bore.

Hmm....did I miss anything? Probably.

Oh yea. Bullets that do not have enough, or good enough, lube, will tend to lead towards the end of the barrel.

 

[MEHavey]

Bullets that do not have enough -- or good enough -- lube
will tend to lead towards the end of the barrel.

"Normally" [don't say it ] it's hard to run out of lube in a pistol-length barrel. But a nice lube star at the crown is always comforting to see after a few rounds.

Sidenote: I was shooting my 45-70 Sharps the other day with trapdoor-level loads of AA5744 pushing a Nice`n Soft/30:1/540gr Postells using butter-soft DGL blackpowder lube. After a dozen rounds I pulled the Oehler chronograph back in to find it looking as though someone had sprayed it with fake "snow" like used on Christmas trees. [Bullets spinning in excess of 100,000 RPM shed a lotta lube once out of the muzzle.]

But's hard to actually run out of lube inside the barrel -- even with one 32" long.

 

[Walkalong]

"Normally" [don't say it ] it's hard to run out of lube in a pistol-length barrel.

Agreed, and definitely not the problem here.

 

[Storm_Shadow]

Throats and bore was slugged. Throats were .431 and bore was .429 if memory serves me right. The Cowboy #3 is a 12 BHN. FWIW I've been using Brads 240 Keith 18 BHN in my magnum loads with H110 with great success. Absolutely no leading with that load.

 

[Jlr2267]

Yep, check the throats, then check the bullet diameter. When it leads in the throats and first inch of the barrel it is gas cutting from improper fit, improper hardness, or undersized throats.


Undersized bullets, unless they have enough pressure to bump up and fill the bore, will cause gas cutting and leading when the hot, high velocity gases "cut" lead off the bullet on its way between the bullet and the throat and/or barrel. Leading will be mostly at the throats and forcing cone, but will continue until it fills the whole barrel if you keep shooting the offending load.

Properly sized bullets (in the range of .001 to .002 over throat diameter) will not suffer from gas cutting unless they are too hard.

Bullets that are too hard will not bump up and seal the throats and barrel well, even when sized properly, causing leading.

Bullets that are too soft to hold the rifling at the velocity they are driven at, will break loose from the rifling and "skid", breaking the seal and causing leading galore all the way down the bore.

If the bullets are sized properly, you can get away with them being a little harder than needed.

If the bullets are soft enough to bump up easily with the pressure used, you can often get away with them being a hair undersized, as long as they are hard enough to hold the rifling for the trip down the bore.

Hmm....did I miss anything? Probably.

Oh yea. Bullets that do not have enough, or good enough, lube, will tend to lead towards the end of the barrel.

This is good stuff Walkalong. I thought I knew how to use lead bullets (did so for years), until I ran into recent problems with MBC hardcast bullets (which I have yet to solve).

I think my problem may be related to the FCD, but that is a topic for another thread.

 

[CraigC]

I honestly think that MBC's guide to bullet hardness/velocity is a little off. You do not need rock hard bullets for magnum loads. Let us remember that Keith's favorite bullet was only a BHN of 12 for his 1200fps loads. IMHO, swaged bullets and cast bullets with a BHN of ~8 work great at CAS velocities. That particular cast bullet should be fine to at least 1200fps. As Sam suggested, it'll probably respond well to a little more velocity.

 

[murf]

try working up a load using 44 magnum cases. your bullet may be handicapped by the long run through the chamber and up the lead into the throat. the longer case will get the bullet started in the throat right away.

murf

 

[Storm_Shadow]

try working up a load using 44 magnum cases. your bullet may be handicapped by the long run through the chamber and up the lead into the throat. the longer case will get the bullet started in the throat right away.

murf

This is basically what I was thinking. Is this a common problem when using specials in a magnum cylinder? If not then I would like to keep working on this so I don't get the full house rounds mixed up with the powder puff rounds.

 

[Sam1911]

I've fired something like 15,000 specials through my 629 and haven't had that problem. So I don't think that's a reasonable compromise to have to make.

 

[Storm_Shadow]

I've fired something like 15,000 specials through my 629 and haven't had that problem. So I don't think that's a reasonable compromise to have to make.

Awesome. Gives me hope. I'm working up some loads to do more testing.

 

[Storm_Shadow]

So just a little update. I have loaded 5 rounds in .1 grains from 6.5 to 7.5. I'm still getting leading and accuracy has been declining. I don't know what the maximum charge is for a 44 spaecial as all my manuals only go up to 6.9g. I may just load a few in a mag case with 10 grains of unique to start and see if the leading still occurs. If it does then I guess it's gas cutting. If it stops then I need to figure out a what's going on.

 

[fatcpa]

I load the same bullet over 7.5 gr Unique or Hodgdon Universal and get minimal leading in both my S&W Model 629 and Ruger Blackhawk 44 Special.

 

[PistolPete45]

Cast bullets

I use Missouri cast .44's as well the cowboy bullets are softer then some of the others so if your pushing them out fast that might be the leading problem . Back off just a bit on the powder load and see. A good excuse to go shooting .