Leading at forcing cone and frame

[johndays]

Hello Veral,

I have a new USFA single action army in .45 Colt. I ran 30 rounds of Lyman Keith 454424 over 7.5grs Unique. Minor leading in the cylinder chambers but the forcing cone had a lot of lead around it but not much in the barrel. THe slugs were 452.5 with the barrel going .449-50. I did have some lead on the frame just below the cylinder pin and to the right of it. I tried Lyman's 454190 and it really leaded the cylinder chambers and forcing cone and into the first inch of barrel with more splashes of lead on the frame. Bullet size was 452.5. Brinell is about 10 on both bullets. I used W231 on the 454190 and by the nature of the conical bullet it was deep seated. Accuracy at 25ft was one ragged hole, pretty decent but getting the gun clean of lead is a drag.

I plan on using bullets sized .453 and see if that helps with the leading of the chambers and cone. My thoughts is that the forcing cone is the culprit in that it might be to small for the job. Would your lapping procedure help with this? THanks

[Veral]

  Lapping is in order for any gun that hasn't already had it done, but I believe your lead is coming from the bullet bases expanding enough to spit lead out through the cylinder gap as it leaves the cylinder.  Try some harder bullets, and keep them as large as your chamber will accept or as large as the mold will drop, whichever.  Do you have a good lube?  Many so called waxes sold for bullet lube aren't lube in my opinion, and may be the problem if you are getting lead in the barrel too.

[johndays]

Veral, thank you for the reply. I will try a harder alloy. I have some 50/50 solder and will try and mix some Lyman #2. I am using your LBT soft blue. I have thought of melting down some Oregon Trail Silver Bullets and trying them in my moulds. Thanks again.

John

[Veral]

  Be sure to keep tin content slightly below that of antimony and you need a bit of arsenic to make your alloy heat treatable.  Wheel weight alloy, with not more than 2% tin is about as good as it gets so far as hardness  obtained when water quenching from a hot mold, and will yield something on the order of 20 bhn or higher.  That will be enough hardness to cure your problem.
  I've tested several Lazer Cast bullets sent in by customers and never found one harder than 16 bhn, so don't bother using their bullets as a richening alloy!  I don't know of any commercial casting alloy that contains arsenic either.  Best source for arsenic is lead shot, which is very high, and highest with the finer sizes, second choice is Wheel weight metal, which only has a trace.  But only a trace is needed, so 10% WW will normally be enough to make a good alloy heat treatable.   (Arsenic is used in shot to make it round up better when dropped from shot towers, during shot manufacture.)

[johndays]

Veral, I have ordered your pull thru slugs and lapping kit. I need to know the correct measurements of the cylinder and barrel of the USFA SAA. Hopefully I am using the wrong size bullets. With the design limitations of this model gun I am wondering if too hard of alloy won't work because I might not be able to get the correct pressure for the bullet to upset in the chambers. I did try 14 Brinell this weekend. It is still accurate but leaded the chambers (one chamber more pronounced with a ring of lead on the face of the cylinder than the other five) and forcing cone. No lead in the barrel. Lead on frame. No wheel weights here on the island, speed limit is just 30mph so no need for them. I have available to me lead, tin and I can get the shot from shotgun shells. Do you have a recipe of these items for a hard alloy? I was trying to stay with the original bullet design for the 45 Colt but maybe I should have you make a mould for me. Thanks for all your help Veral.

John

[Veral]

  Correct measurement for any revolver is a mute concern.  What your gun measures is what one has to deal with.  Cylinder throats must be at least as large as barrel groove for low pressure guns, a bit over for magnums, to allow a bit for throat erosion.   Your best approach to this problem is to email me direct as it appears that your questions aren't going to be of interest to the public.  If you think they are, post questions here.  But you will get a lot quicker response from me by emailing direct.
  Lean a bit heavy on the shot, as it has good antimony content.  Go with maybe half shot, half lead, and with 2% tin added.  Water quench your bullets if they up to size.  If undersize, you'll have to play with softer alloy and balance the powder charge to the bullets to make them upset and seal off the blowby.  YOu can get fair results this way, but a properly sized mold is mandatory for optimum acccuracy. 
My email address is    LBTisAccuracy@Imbris.net