Having had discussions with Charlie Dell on cast bullet composition the question is  always posed "does the composition of the cast bullet make any difference as long as the alloy is within a certain hardness range. Let me try to explain my question --suppose you are the rifle barrel, you know if the bullet was hard or soft but do you care what alloys were used to arrive at that hardness or softness.
        To any and all who care to respond--thanks in advance
      leadball

Leadball,

  Yes!  I think it does.

  Altho Lead/Tin alloys don't harden much over a period of time, those that contain Antimony will. I've never been able to prove that this natural hardening affects accuracy. But there are those who think it does and they will let their bullet "age" for two weeks to a month before using in order to normalize the hardness.

  The old timers felt that if you changed your Lead/Tin alloy by as little as 1 point..... i.e...... 1-20, 1-21, 1-22, etc. That it would affect accuracy.

  My own personal experience isn't quite that refined but I did find that when working with my .28/30 that going from 1-30 to 1-32 did make a noticeable difference in group size. About a 1/3rd less!

  I'd like to do some testing some day to see if this applies just to the small calibers, or applies to the larger ones as well. Usually when working up loads for the .40 & larger calibers I've just gone with 1-20, 1-25, or 1-30 and always got what I thought was good accuracy when one of those alloys was used. Using one of these three you will definitely notice the difference between them.

  To get into your question a little deeper. Instead of the barrel needing a certain alloy I tend to believe that the powder charge determines what hardness you need. If the powder charge is greater than the bullet designs ability to resist deformation of the nose; then the nose will slump. This slump will not be even around the bullet and will throw it off ever so slightly when it leaves the muzzle. This in turn will cause a slight oscillation, which will never damp down, and that will affect accuracy at the target. What you want is an alloy that's hard enuf so that it won't deform past the point where the ogive begins yet is still soft enuf to expand into any irregularities in the bore, and for the job you want it to do.

  To point this up a bit, the Sharps Rifle Co. made their PP bullets using a 1-16 Lead/Tin alloy. Seems rather a strange number to use but more than likely that's what they found worked the best in their guns.

PETE

Leadball 

I think that the compisition of the alloy is important to how well the bullet shoots. There is more that just hardness to consider. The ductility is an important factor also. Lead-tim alloys combine hardness with excelent ductility. The addition of antimony dramaticaly cuts down ductility. Where the break point is I don.t know, Stevens 52 60% wheel weights 40% lead could be the point. Personally I have always followed the advice to shoot as soft as I could and work up for accuracy. My experience is that you will get leading faster with a too hard alloy than a too soft one.

40 Rod

I agree when using WW only I get a slight amount of barrel leading, but when I get close to the 25/1  lead tin mix using WW and lead and a slight amount of tin of about 60/40  70/30--I cannot find any real accuracy differences and no leading.
         We can tell what our alloy is by casting a few bullets with our favorite mould, if the base of the bullet tears away it is WW--with a lead tin mix it is near impossible to make this happen.
          The bottom line is--I have a good supply of WW that I feel I must use because if it is mixed properly I can't tell any difference in accuracy.  I keep trying to prove myself wrong but so far I have not.   leadball

Paul;
I didn't understand your post regarding your preferred alloy using w/w's. Please clarify - percentage of w/w, lead, and tin.

Thank you.

FWIW, I am currently using pure lead and pure tin, 25/1 in my .32 Dell (.32/.357 or .32 Miller Short) with excellent results.

Dale53

We're basically doing the same thing. The basic 60/40 WW/lead mix gives a hardness comparable to 25-1 lead -tin. I find bullet weights to be very close also. I'm curious what noticeable difference you've found the addition of the tin to make?

I'd like to see a chemical analysis of one of the 60/40 bullets. It might fool us how "pure" our slugs really are. They can't be that far from "real" bullets. The low temp metals that would trash a pot like zinc or aluminum obviously aren't there and I do discard an occasional oddball wheelweight. Sure does keep the cost down...........

Leadball;
Thanks for the info. I have been using 25/1 for a long time with excellent results. I have more than a 1000 lbs of W/W so I might have to consider using up some of it.

Dale