Alloy as a Variable to Cast Accuracy

  • 763 Views
  • Last Post 14 February 2024
Wm Cook posted this 01 January 2024

Messing with (or even understanding) alloy was not in the top ten things I dealt with when I started working on cast accuracy. In the first 25 years of casting I only used #2 Lyman.  In the past 2 - 2 1/2 years I started to focus on accuracy and I've been using Linotype 99% of the time. 

With the off the shelf availability of #2 Lyman and Linotype from RotoMetal I knew I was working with a consistently stable material and that allowed me to focus on what I though was critical to achieving cast accuracy.  For me, things like bullet to bore fit, casting methods, figuring out if a custom mold is needed trumped whether 20 to 1 was better than #2 Lyman. 

In my mind I picture understand cast accuracy as going up a ladder and so far I think I've gotten past the first couple rungs of that ladder.  Right now I'm trying to figure out if and how the various blends of alloy are controlled or can be controlled to improve cast accuracy.

What brought this up on my "I need to have a better understanding of this" radar screen when I started to work closely with bullet to bore fit on a bore rider and how much bullet bump I was getting with #2 Lyman versus Linotype.  I was surprised that I could effect nose diameter (depending how ham handed I was in the sizing, lube gas check process. 

Here's the knowledge base I'm starting with.  I understand the PBB shooters all shooting 20/30 to 1 running velocities <1450fps.  I rationalize that as a need for a soft alloy to assist breech seating.  Since there's no gas check I'm guessing that they can do a very minimum sizing to lube the bullet without bumping the bullet size.

And I think I understand why everyone running over 1950fps are shooting Linotype. Harder metal, less leading.  But many of the "in between" shooters (mostly those in Factory and Production class) with velocities running between 1500 and 1900fps are using alloy blends that I don't understand.  So here goes a couple questions.

1) As a general rule do you/would you consider fussing with the type of bullet alloy you're using and what's the reasoning behind behind the effort.  What are you trying to adjust for.

2) What does it mean when someone list they are using "Linotype / #2" or "Linotype / Lead".  Does that actually mean they are running RotoMetals Linotype one to one with either lead or #2.  I'd need to dig out my old abacus to figure out that ratio.  Not sure what the hardness would be either.

3) How long do you wait to size your cast bullets.  Or is that another variable that you control.  Size same day if you need a bigger bullet or wait a couple weeks to keep it close. 

I can hear the grey beards out there groaning at the questions but there's a lot I don't know and I'd appreciate someone explaining the use of alloy as a variable.  Isn't the bottom line to get the proper bullet to freebore/leade/land fit and then to fill the bore, maximize bearing surface and sealing the gas? 

The more I look at bullet to bore fit the more I think I may have underestimated the impact alloy plays in the role of cast accuracy.

I can't speak for others but in my case don't assume I know anything other than the basics such as what Pb, Sn and Sb stands for.  I have about 90lbs of scrap bullets I've saved to smelt down some time in the future but haven't bit the bullet on that project yet.

All of my cast accuracy shooting is in the area of 1550 to 1800 fps with a ..308.  I/m not picky about what I shoot in my .22's, 7.62's and 9MM's.

So is it even worth the effort to tinker with alloys when working towards small groups or is it just another polarizing variable where you either fall on one side of the fence or the other.  Thanks, Bill Cook.

Patience isn’t a virtue, it’s a delay tactic.

Attached Files

Order By: Standard | Newest | Votes
RicinYakima posted this 01 January 2024

This is my story, but I don't know how relevant it is to your questions.

When I started CBA matches 30 years ago, I had access to 500 pounds of linotype. I cast all of my match bullets from linotype. I was shooting 1903 Springfields in military classes using Lyman 311284 because it was the most accurate in my rifles. For me it always shot better than any of the bore riding designs. Velocity was always about 1450 f/s. For me, the advantage was I could cast 95% match grade visually perfect bullets that weighed within .5 grains. 

Practice bullets were scrap plus WWs plus dabs of linotype with 2% tin added to the pot. Hardness was usually around 15 BhN. They were visually inspected, but not weighed. 

My records from 2007 showed the linotype bullets shot 1.5 MOA and the practice bullets shot 1.7 MOA. Different alloy made the difference? Powder and sizing and everything else was the same.

FWIW

Attached Files

  • Liked by
  • mashburn
  • Bud Hyett
Bud Hyett posted this 02 January 2024

So here goes a couple questions.

  • As a general rule do you/would you consider fussing with the type of bullet alloy you're using and what's the reasoning behind behind the effort. - I've shot cast bullets in the CBA competition for over three decades and this is the thought of the alloy factor in these years. 
  • What are you trying to adjust for. - A soft enough bullet that conforms to the rifling at the onset of passage and still strong enough to resist the rifling as it goes through the bore. In Illinois, I bought an alloy that was 92 Pb / 6 Sb / 2 Sn that shot very well. At the Windhill Range, we built a bullet catching box to see what was happening during the passage down the bore. The results were interesting as you can see the skid marks from the bullet entering and passing through the rifling plus the base of the bullet after firing. I'm thinking of doing this again as the records are lost after the passing of Ed Doonan. 
  • What does it mean when someone list they are using "Linotype / #2" or "Linotype / Lead". - That is up to the person writing as there is no standard. To me this means a fifty/fifty ratio. 
  • Does that actually mean they are running RotoMetals Linotype one to one with either lead or #2.  - Possibly. Shooters will buy Linotype that is labeled as "used"; this "used" Linotype could have been refreshed several times before being sold. The only time you know the value is to cast a few bullets and run them in a hardness tester. 
  • I'd need to dig out my old abacus to figure out that ratio. - I figure out the ratio from the scrap lead I have and smelt a large number of ingots. Then I cast a sample of bullets to test hardness and the shoot sample groups.
  • Not sure what the hardness would be either. - If you're not buying lead from a known supplier, you can only test with a hardness tester.
  • How long do you wait to size your cast bullets. - I size the bullets after casting while waiting for the pot to cool down. I have a RCBS Easy-Melt pot that requires the cooling fan to run until the pot is 140 degrees Fahrenheit. I use this time to sort and size. 
  • Or is that another variable that you control. - I size soon after casting since I've seen water-dropped bullets continue to harden for a week after casting. 
  • Size same day if you need a bigger bullet or wait a couple weeks to keep it close. - See immediately above. 
  • The more I look at bullet to bore fit the more I think I may have underestimated the impact alloy plays in the role of cast accuracy. - My years of empirical research have lead me to believe this is a factor. To control this factor, I choose to have a lead alloy close to the 92 Pb / 6 Sb / 2 Sn alloy that I used thirty years ago. Last year we were using Monotype alloy that did not shoot as well. The exception with the Monotype alloy is my 6mm casting that shot best above 2,000 feet-per-second. 
  • So is it even worth the effort to tinker with alloys when working towards small groups or is it just another polarizing variable where you either fall on one side of the fence or the other. - The way to control this variable is to smelt enough alloy to last a season or two. 

Keep immaculate records for the study, it's the best way to avoid repeating failure.

Farm boy from Illinois, living in the magical Pacific Northwest

Attached Files

Wm Cook posted this 02 January 2024

Thanks for the detail Bud, its appreciated.

I've shot cast bullets in the CBA competition for over three decades and this is the thought of the alloy factor in these years.

For competition do you work with the materials you have to smelt then checking the hardness or do you buy off the shelf certified alloys.

It seems that your alloy choice is based on experience and to that end you lean toward a middle of the road hardness (~16) that'll allow the alloy to "resist" the leading effect as the bullet passes through the lands while still allowing the bullet to readily marry the lands as it passes the leade?  Did I say that right?

If that description is accurate is there any justification for casting with Linotype since velocities are in the 1650 to 1725fps range?  At that velocity there's less chance of leading and the hardness of the Linotype would resist the bullet entering the lands.  I find that fascinating.

Could you tell me how long it takes for 95/5/5 that's not water quenched to fully harden?  With my #2 Lyman If I size same or next day after being cast it goes through my sizer like butter but its bumping the nose up in diameter.   Thanks again, Bill.

Patience isn’t a virtue, it’s a delay tactic.

Attached Files

  • Liked by
  • mashburn
MarkinEllensburg posted this 02 January 2024

I have found nearly always lynotype shoots the best in my rifles regardless of velocity. However I'm not setting any records. My lynotype is from scrap type of unknown age and I do not test for hardness. Recently I have been preparing for Spokane's annual lever gun match and cast a passel of 311041 from what I believed to be COWW. Was not happy with the groups I was getting. Found in my bullet cabinet some lyno bullets from last years efforts. Right away groups became smaller on average. This from a Winchester 94AE in .30/30.Velocity is moderate @ 1700fps. After Saturday we will see if I choose correctly. It could just be me, it could just be this rifle. Just for S&G's I also loaded up two other bullets and they also gave good groups, well at least they grouped, kept them all in the scoring rings at 100 yards. 

I generally cast on a weekend before a match. Size 1-2 days later and load 1-2 days before match. However when i have cast far in advance of matches I have not noticed any trends to show a difference in results. 

In Puyallup, WA there is a shooter, Doug Shellenberger that casts and sizes the day before a match from what he has told me. He often as not wins his class. IIRC he shoots production and hunter. Am not sure of alloy or any other details. What I do recall is that he is very consistent in results. 

I believe that alloy matters but I also believe that there are more variables that matter far more. Shooter ability is by far the most important once you have a solid foundation of rifle and load with accuracy potential. 

Attached Files

Bud Hyett posted this 02 January 2024

For competition do you work with the materials you have to smelt then checking the hardness or do you buy off the shelf certified alloys. – Three answers:

  • 1.     For Plain Base, I have been using off-the-shelf alloys because I bought four hundred pounds of alloy when Roto-Metal had barn-burner sale years ago. However, in the future I’ll be using the 20:1 lead alloy I smelted this past month.
  • 2.     For all other competitions, I use Monotype alloy I bought years ago mixed one part Monotype to two parts wheelweight alloy in 120 to 140 pound lots. This approximates the 92/6/2 alloy and is done in large batches for batch uniformity.
  • 3.     I’ve learned to smelt a large poundage to assure consistency. For a time, I was not testing the alloy and suddenly decided to test hardness because I was not getting the accuracy of previous years when I was using the foundry-bought alloy. I was simply adding “hard” blocks to the pot without measuring the hardness of each block. I have now procured a cast iron pot that holds 120 to 140 pounds. Going to a large smelt at one time solved the uniformity problem. Not so much the value of the hardness as the uniformity of hardness.

It seems that your alloy choice is based on experience and to that end you lean toward a middle of the road hardness (~16) that'll allow the alloy to "resist" the leading effect as the bullet passes through the lands while still allowing the bullet to readily marry the lands as it passes the leade? Did I say that right? – Yes. This was a certified alloy we would buy a ton and share. These 92/6/2 bullets shot very well. Using a bullet recovery box, the markings on the on the bullet from the lands showed the same with this alloy as the Linotype alloy. I think the slightly softer alloy squished into the leade and started straighter but was still hard enough to not strip in the lands as it passed through the bore. After I moved to California, one of the Windhill shooters wrote to me wanting to know where I got the alloy. He got his best accuracy with this alloy for both Military and Production competition.

Note: There is a qualification to the above statement that I want to experiment with this coming year. The 6mm BR grouped better with a harder alloy at velocities above 2100 feet-per-second. I want to set up several 6mm rifles with varying hardness to see if this is a truism with smaller diameter bullets or the experience with this one firearm.

If that description is accurate is there any justification for casting with Linotype since velocities are in the 1650 to 1725fps range? At that velocity there's less chance of leading and the hardness of the Linotype would resist the bullet entering the lands. I find that fascinating. – Going back to the Illinois days, the 92/6/2 alloy worked well. I think the fit of the bullet in the leade and the initial movement of the bullet down the barrel are key factors to accuracy. Initially experimenting with Trapdoor rifles, soft alloy (20 Pb / 1 Sn) with black powder and the harder alloy with smokeless seemed to be the correct combinations. These are separate physical/chemical scenarios. The explosive effect of black powder swells the base to fit the leade and the bore whereas the smokeless needed a harder alloy to do the same thing. The harder alloy fitted to the leade is key. Plain Base shooters use the same thought of seating the bullet into the bore at not greater than 1475 feet-per-second traveling down the bore, therefore there is less pressure to strip. The best use of Linotype is the higher velocities above common target velocities.

Could you tell me how long it takes for 95/5/5 (92/6/2?) that's not water quenched to fully harden? With my #2 Lyman If I size same or next day after being cast it goes through my sizer like butter but its bumping the nose up in diameter. – A week to ten days. The alloy is 90% of the hardness coming from the mold and only gains a slight harness in weeks to come. This is an empirical observation based on years past. I now dedicate an entire day to casting and sizing to assure uniformity. To assure a square base, I size through a slightly oversize (.001 inch) NOE nose-first die and then lubricate in a correct diameter conventional lubri-sizer thus there is little pressure on the nose.

Farm boy from Illinois, living in the magical Pacific Northwest

Attached Files

  • Liked by
  • Wm Cook
99 Strajght posted this 02 January 2024

I shoot about 3000 124 gr. cast bullets every year at USPSA and find that some lots of cast bullets do make a difference. I cast 20# of wheelweight  with 8 oz. of tin in each batch for over 1000 bullets. Sometime they shoot spot on and sometime the group moves right , left, up, or down. I always adjust for that batch. I have even seen larger and smaller group sizes between batches. Seeing I don't shoot for group size most of the time it is ok with me. For rifle shooting it is another matter.

Glenn

Attached Files

  • Liked by
  • mashburn
  • Bud Hyett
Tom Acheson posted this 02 January 2024

I will abstain from getting too long here.

This question about alloy is an age-old subject. What works best in what, for what, by who, involves a multitude of variables. For me, I focus on bench set-up and technique. Because as much I try to convince myself that I'm very consistent, I'm not.

Tom

Attached Files

Glenn R. Latham posted this 02 January 2024

Bill, all good replies here.  I have found some bullet/cartridge combinations are rather picky about bullet hardness and others not so much.  In my little 6mm CB rifle I found the bullets shot best at 15 BHN at 2000 fps.  Since I was casting almost exclusively with WWs, I heat treated them, then put them back in a cooler oven a few days later to "draw them back" to 15 BHN.  Takes a lot of experimenting and a hardness tester.  Fully heat treated bullets didn't shoot as well, and neither did linotype.  I have found the 22s and the 6mm to not require as hard bullets for a given velocity as the 30s.  It's all part of the fun!

Glenn

Attached Files

John Alexander posted this 03 January 2024

I agree with Glenn about small bore CB needing softer alloy.  I often see the opposite spoken with authority that small bores require hard bullets.

I only shoot factory rifles in competition.  I expect that with bullets swagged in a die cut with the same reamer as cut the chamber harder alloys have advantages especially with high velocities and all such folks seem to shoot linotype or heat treated alloys.

With the less perfect bullet fit possible in factory throats my experience is that the softer alloys are usually more forgiving.  Softer brings other things to watch for such as bullet upsetting (bulging under axial compression) while sizing (use Lee push through dies) and no sizing when lubing.  Even seating can upset the nose and disappoint when shot.

Newer shooters seem to have a fetish about harder must be better and I think that leads to a lot of  frustration and it ain't just with revolvers.

John

Attached Files

Wm Cook posted this 03 January 2024

Bud, thanks for the detailed response.  Its much appreciated. 

To Ric, Glen, Mark, John, Bud and others I want to thank you for the assist.  I know it must be hard for those that have spent decades working with cast bullets to fully understand how big of a boost you give "new to cast accuracy" buffs when you share what you know in these threads. 

You guys must chuckle when you see the naivete of some casters.  Or maybe cry when you see the lack of effort some put into it.  I encourage you to keep feeding those that are willing to put in the time and effort to get better. 

Tom you're right that there's a 101 things that can go south and cause big groups before you even think of fussing with the alloy.  But I had side stepped my understanding of alloy and its effect on accuracy because I had other cast related land mine I had to navigate through. 

But understanding a bit more about alloy and the why and why not's came at along at this point in my education.  Its only been a week ago that I compared Linotype versus #2 Lyman bullet nose dimensional changes coming out of my sizer.  So the information you all shared with me came at the right time. 

There's no golden BB that'll make you a better cast shooter.  Just a continued push to ask questions, keep details of what you're doing and keep working at it.  That's the fun thing about bullet accuracy.  You always have the challenge to improve. Thanks again, Bill Cook.        

 

 

Patience isn’t a virtue, it’s a delay tactic.

Attached Files

Bud Hyett posted this 03 January 2024

Andy Barniskis four (plus) decades ago published an article in the Fouling Shot estimating there is an interplay of 1,400,00 attributes that can go wrong when shooting cast. 

How do we ever get the accuracy we get? 

Farm boy from Illinois, living in the magical Pacific Northwest

Attached Files

4060may posted this 03 January 2024

we keep having the same things go wrong at the same time

Attached Files

  • Liked by
  • pat i.
John Alexander posted this 04 January 2024

Just remembered, one of the most interesting cast bullet articles I have ever read in TFS was by Dan Lynch (The Mountain Mold guy).  He discussed the Lee type approach to alloy selection. (in the Lee reloading manual) Seems like it was 4 or 5 years ago but I have found that things in the past are usually further back -- unlike what you see in the rearview mirror.  If somebody tracks it down please post the location here so others can look it up.

Dan also published the best, by far, set of reports on his experiments with polymer coating for high speed cast bullets with and without gas checks. He seemed to be closing in on the precision needed to win in CBA heavy or unrestricted class when I think his business or life interfered.  I certainly hope he gets back to that work.  His work also could serve as the proper way to experiment.

John

Attached Files

RicinYakima posted this 04 January 2024

John, 

Dick Lee published his chapter in 2003, taken from Veral Smith's book, 3rd edition, published in 1990. 

Ric

Attached Files

  • Liked by
  • John Alexander
Glenn R. Latham posted this 04 January 2024

John,

   I think you'll find Dan Lynch's articles in issues 242, 247, 248, 249, 256 and 257.

Glenn

Attached Files

  • Liked by
  • RicinYakima
  • John Alexander
John Alexander posted this 04 January 2024

Glenn,

Thanks, I really want to read them again.

John

Attached Files

Sevenfan posted this 09 January 2024

I have found nearly always lynotype shoots the best in my rifles regardless of velocity. However I'm not setting any records. My lynotype is from scrap type of unknown age and I do not test for hardness. Recently I have been preparing for Spokane's annual lever gun match and cast a passel of 311041 from what I believed to be COWW. Was not happy with the groups I was getting. Found in my bullet cabinet some lyno bullets from last years efforts. Right away groups became smaller on average. This from a Winchester 94AE in .30/30.Velocity is moderate @ 1700fps. After Saturday we will see if I choose correctly. It could just be me, it could just be this rifle. Just for S&G's I also loaded up two other bullets and they also gave good groups, well at least they grouped, kept them all in the scoring rings at 100 yards.

Saw the match results so I think you were pleased! Like you, also shooting a 94AE the past 2yrs, I found excellent accuracy with PC'd & air cooled Lyman #2 from Rotometals at around 1700fps (would have to check my notes for actual chrono'd velocity) using Shuz's RCBS 30-150-FN. It just works. "Bum"med I had to "sit" out Saturday's match, it was the right decision so I could heal.

Attached Files

  • Liked by
  • Bud Hyett
  • MarkinEllensburg
MarkinEllensburg posted this 10 January 2024

@Sevenfan, yes I was pleased. The day started good with a peak of the first group target. 1.019" a cluster of 4 and a flier! It kinda went down hill from there but still in the "good group" range. Score was reasonable. Of the lever guns I think I was on top in spite of using the red target and the iron sight crowd using the military target. The difference in scoring ring sizes between the two different targets seems to me to be a fair leveling of the field. If anything it actually favors the iron sights. For a run of the mill 94AE I think I made a lucky pick. The only thing I have done to it is shimmed the butt stock to fill gaps in wood to metal fit and checkered it. My forend barrel band is as loose as I dare have it to still retain the stock in place. A Leupold 3x9 scope mounted in weaver rings and bases works in spite of having to shim the base, and the bases are skewed so windage is off. I have a new wallet group to show off. Amazing what a Winchester 94 can do with cast bullets!

Attached Files

  • Liked by
  • Bud Hyett
  • Sevenfan
Sevenfan posted this 13 January 2024

Yes it is Mark!

I saw the numbers, my groups last year were pretty close to yours this year. Know we chatted about that some last year as well. Mine is bone stock save for letting barrel bands wiggle a bit and same with the forearm. Only other thing I did was mount the Balvar 8B I purchased new in '75, struggle too much with open sights. Whether or not those those made a difference I'll never know, it simply shot well right out the gate.

I'm looking forward to next year, heck, I might even shoot it in Hunter class at a regular match!

Attached Files

MarkinEllensburg posted this 13 January 2024

good group

.30-30 1.019" lyman 311041, 19grains imr4198, mixed brass. Lynotype

Attached Files

  • Liked by
  • muley
shootcast posted this 21 January 2024

Attached Files

shootcast posted this 21 January 2024

30-30 Win. IMR 4198- 19.0 grs. Lyman 041 100 yards, w/ wts & tin

i’ve gone back and forth with alloys. Usually w/wts aren’t consistent for me. Sweeten them with tin / Lino . Still couldn’t tell you the exact mix. What works one day doesn’t the next. I haven’t found alloy or hardness that works all the time. I do feel that pressure and alloy does have some effect. But in two different barrels of same chambering might not work the same.

 

Attached Files

2frogs posted this 14 February 2024

Rather hard or softer are you referring to plain base or gas checks. 223 here. I just had the gas check removed from my mold. Thinking maybe a softer alloy (bhn of 8) may shoot better. Waiting for a little warmer weather here in Pennsylvania.. thanks john

Attached Files

Close