Continuing work on 280473 for 270 WIN

[Jal5]

I am on my second batch of boolits using this mold and have worked out the problems I posted about earlier. Using range scrap which is a little on the soft side being mostly jacketed bullets recovered.

This second batch of 60 is more consistent as far as weight, most were 121-122g and the band dimension was approx. .280-.281 and no wrinkles at all. The bases were consistently showing a little bit of lead scooped out, but I think I was concentrating on consistency in time to sprue hardness and I cut the sprue a little bit early. Will GC solve this problem?

The problem is the Handirifle seems to like the heavier boolit in the 130g range for accuracy and I thought that this mold would drop closer to that weight. Should I try to mix the alloy with WW 50/50 or add some tin for better fill out and weight closer to 130? I have been shooting this boolit in the lighter weights over Unique- should I change powder to achieve a better accuracy with the lighter boolit?

Thanks.
Joe

[Jal5]

pictures of this batch of boolits.

[Larry Gibson]

Add 2% tin.

Larry Gibson

[Marlin Junky]

Sorry Larry, I wouldn't add tin for a couple reasons. 1) He wants a heavier boolit. 2) It's expensive and not necessary for this application.

Jal5,

Since you're using range scrap and your boolits are coming out lighter than expected, a hardness tester can help. You have built-in hardness testers at the end of your thumbs. Allow the boolits to age for a couple weeks and in the meantime, do some research here on sprue plate lubes. The best I've found so far is Bullpate but I think the vendor has gone huntin'. I can't really tell the condition of your bases from the picture, but they look unnecessarily rough and should cut smoothly with a small divot in the center if everything is working properly. Regarding the boolit hardness... after a couple weeks, see if you can put a scratch into the ogive with your thumbnail. If not, decide how fast you want to shoot these things. If your H-R barrel is anything like I think it is, go down in burn rate as you approach 2000 fps and/or increase boolit weight. Unique should be fine up to about 1600 fps assuming your shooting about BHN 15-16 alloy.

Are the boolits dropping easily from the mold? Sometimes when the mold is on the cool side, boolits will hang up a bit and you'll actually get less boolit weight when the mold temp rises. If this is the case, and your boolits are plenty hard, stay away from adding anything with the possible exception of more Pb. Experiment with casting rates but I recommend an alloy temp with your Lyman mold of about 700F. Start with a 400F mold that is properly lubricated.


MJ

[runfiverun]

i'd just pour a bigger sprue and get a puddle of lead on the sprue plate,
you just need a bit more heat in the base area.
if that don't sharpen things up, then a bit looser sprue plate will help your venting.
a gas check will square your base up for you but you will have an air pocket there.

work on your casting cadence, some molds i open as soon as i see the sprue suck in, some its when they flash change color and others it's before the sprue puddle is fully solidified.

[Marlin Junky]

i'd just pour a bigger sprue and get a puddle of lead on the sprue plate,
you just need a bit more heat in the base area.


Jal5,

There ya go... there's some good advice. Also, I'd get a new thicker Lyman sprue plate for that out of production mold (assuming it has the thin plate). The thick plates should be available as part of Lyman's mold rebuild kit.

MJ

[Jal5]

thanks guys for all the advice.
I think halfway through the run one boolit would hang up needing a tap but that was only a slight tap and it fell out. I counted to 5 then cut the sprue and tried to keep about the same amount of lead in the puddle each time. The sprue seemed to be fully solidified at that rate. I thought I had the mold lubed sufficiently from the last time I put Bullplate on it, but maybe not. I didn't relube the plate this time.

Is it worth loading these and trying them given the divots and lower weight than I want?

[Marlin Junky]

thanks guys for all the advice.
I think halfway through the run one boolit would hang up needing a tap but that was only a slight tap and it fell out. I counted to 5 then cut the sprue and tried to keep about the same amount of lead in the puddle each time. The sprue seemed to be fully solidified at that rate. I thought I had the mold lubed sufficiently from the last time I put Bullplate on it, but maybe not. I didn't relube the plate this time.

Is it worth loading these and trying them given the divots and lower weight than I want?

I'd remelt the imperfect boolits but that's just me. I'm more concerned that the mold is below its optimum operating temp. The sprue is cut right after it solidifies. If your mold is properly lubed, you'll know if you're cutting too soon by smearing the base. There is a color change that occurs when the sprue is hard enough to cut. Watch for that change and swing the sprue open just after that color change takes place. Drop the boolits and repeat. Casting at this rate will enable even an aluminum mold to maintain proper operating temp with 700F metal and no carbon in the cavities. I'm glad you're using Bullplate... that way if you do smear a base by cutting too early, the alloy won't stick to the mold block; i.e., disaster avoided. :bigsmyl2:

Keep a Q-tip with just a trace of Bullplate handy and check the underside of the sprue plate frequently. When alloy starts to show up on the plate, wipe it off with the Q-tip.

MJ

[Larry Gibson]

jal5

I add tin to most all of my range lead which has been almost 2,000 lbs over the last 15 years. I didn't note where expense was an issue and to me the cost of tin to make the no cost alloy better is negligeable. Most range lead, even that mostly from j bullets, is a lead/antimony binary alloy. The lighter than expected weight is also an indication the antimony content is too high. The maximum amount of antimony that that can be in a soluable state is 3 - 3 1/2%. More than that and the antimony crystalized seperately from the lead. It is the excess antimony content that is causing the uneven bases.

The addition of tin makes the alloy a ternary alloy with more malleable features including cleaner cut sprues. It makes the antimony mix into a better soluable solution with the lead. That's why ternary alloys of lead/tin/antimony are the best and most common used for cast bullets. You might also add pure lead. With my current batch of range lead (about 750 lbs left) I mix the alloy at 7 lbs range lead to 3 lbs lead + 2% tin. It makes for a very good malleable alloy with a BH of 10-12. That alloy is excellent for all my pistol/revolver practice cast bullets and most all of my low velocity (under 1600 fps ) rifle cast bullets. A test of 10 lbs alloy would require 3 lbs of pure lead and only 3.2 oz of tin, worth trying in my opinion.

Larry Gibson

[Jal5]

Larry and MJ both are good suggestions.
I think I will try the alloy Larry suggests and see what happens. Will let you know. Thanks.
Joe

[geargnasher]

jal5

I add tin to most all of my range lead which has been almost 2,000 lbs over the last 15 years. I didn't note where expense was an issue and to me the cost of tin to make the no cost alloy better is negligeable. Most range lead, even that mostly from j bullets, is a lead/antimony binary alloy. The lighter than expected weight is also an indication the antimony content is too high. The maximum amount of antimony that that can be in a soluable state is 3 - 3 1/2%. More than that and the antimony crystalized seperately from the lead. It is the excess antimony content that is causing the uneven bases.

The addition of tin makes the alloy a ternary alloy with more malleable features including cleaner cut sprues. It makes the antimony mix into a better soluable solution with the lead. That's why ternary alloys of lead/tin/antimony are the best and most common used for cast bullets. You might also add pure lead. With my current batch of range lead (about 750 lbs left) I mix the alloy at 7 lbs range lead to 3 lbs lead + 2% tin. It makes for a very good malleable alloy with a BH of 10-12. That alloy is excellent for all my pistol/revolver practice cast bullets and most all of my low velocity (under 1600 fps ) rifle cast bullets. A test of 10 lbs alloy would require 3 lbs of pure lead and only 3.2 oz of tin, worth trying in my opinion.

Larry Gibson

Yes, exactly. Beyond a few percent concentration in lead alloy, antimony needs to be "tempered" with tin to form the intermetallic compound Sb/Sn. Without some tin in there, the antimony tries to come out of solution when cooling due to being on the primary field of crystallization.

Basically, tin acts like an emulsifier between lead and antimony, allowing higher concentrations of antimony to be blended with lead, and making a tougher, less brittle alloy than lead/antimony binary alone.

Gear

[JohnH]

Yes, exactly. Beyond a few percent concentration in lead alloy, antimony needs to be "tempered" with tin to form the intermetallic compound Sb/Sn. Without some tin in there, the antimony tries to come out of solution when cooling due to being on the primary field of crystallization.

Basically, tin acts like an emulsifier between lead and antimony, allowing higher concentrations of antimony to be blended with lead, and making a tougher, less brittle alloy than lead/antimony binary alone.

Gear

Best simple explaination I ever heard of that relationship, and I been listenin' for 30+ years!

[Marlin Junky]

Has anyone had a chance to purchase some of this stuff:

http://www.rotometals.com/product-p/antimonial_lead.htm

MJ

[Jal5]

"The addition of tin makes the alloy a ternary alloy with more malleable features including cleaner cut sprues. It makes the antimony mix into a better soluable solution with the lead. That's why ternary alloys of lead/tin/antimony are the best and most common used for cast bullets. You might also add pure lead. With my current batch of range lead (about 750 lbs left) I mix the alloy at 7 lbs range lead to 3 lbs lead + 2% tin. It makes for a very good malleable alloy with a BH of 10-12. That alloy is excellent for all my pistol/revolver practice cast bullets and most all of my low velocity (under 1600 fps ) rifle cast bullets. A test of 10 lbs alloy would require 3 lbs of pure lead and only 3.2 oz of tin, worth trying in my opinion.
Larry Gibson"

I tried to cast using more tin in the mix, 24" piece of solder to about 5# Range scrap, but didn't have enough pure lead on hand to add. The result was better fillout of bands and good crisp bases. I also slowed down my cadence a little so that there was more time for the sprue to harden up. The result was nicer looking boolits but still on the light side, 121-122g weight.

I will need to come up with sufficient pure lead to try a batch and see if that makes the difference or maybe mixing the range scrap 50/50 to WW?

Joe

[Jal5]

I followed the recipe given by Larry, 70/30 + 2% tin solder and melted a half pot that way, 5#.
Boolits poured nice and good fill out and everything but still only 121-122 gr weight. Any ideas?

Joe

[HORNET]

Don't worry about the weight, it almost NEVER comes out to what the manufacturer claims. My mold for that boolit runs about 127 grains at about .283 diameter out of my alloy (WW+2% Tin).

[Jal5]

I will try some of the recent casting and see how the accuracy does with Unique. I may change to a slower burn rate powder with the lighter boolit- is that the right theory? Joe

[Larry Gibson]

Jal5

Add the GC and lube to that bullet and it will come up close to the 125 grs my list shows for it. As mentioned, don't sweat the weight. If the bullets are good load'em up and test'em.

Larry GIbson

[Jal5]

I tested two trials yesterday with this boolit. First pic shows 50 yd target, rest using sandbags on the bench, Lyman 280473 over 14.9 Unique. 10 rounds, .280 sized, 70/30+2%tin, wgt. 125-126 with lube and GC. Nice fillout of boolits and good bases. 3.125 OAL, no leading at all.
Disappointing results.

Second pic is same boolit same powder, etc., 50 yds. only difference sized .279, 7 rounds total. No leading. Only marginally better results.

Since with my range scrap alloy 70/30 I only can get the weight up to 125-126 do I try a different powder with a different burn rate? I never did understand how this dynamic works- lighter boolit means use a slower burning powder?

Lyman 4th ed. suggests for a 140 gr. boolit Unique range should be 12-19 max. Using a 129-130 gr wgt boolit, same type boolit and same powder I got a 3 shot group of 1.07" and using a 130-131gr boolit I got a 1.6" 4 shot group. those were the best two trials I have had to date.

I am open to all ideas, and thanks! Joe

[P.K.]

If you ever think of selling that mold I'd like it for my 6.8. ;-)

[Marlin Junky]

I am open to all ideas, and thanks! Joe

Start with 22-24 grains of Re7, or 4198 (doesn't matter which) and an alloy around BHN 15-16.

MJ

[Marlin Junky]

I never did understand how this dynamic works- lighter boolit means use a slower burning powder?


Reverse it. Heavier boolit means more pressure. More pressure bad, less pressure, good. Therefore, slower powder is good. 8-) Don't go nuts and start loading everything with H870 though. Powder deposits bad too... especially for shallow rifling.

MJ

[Jal5]

MJ thanks for clarifying that point. I will give RE7 a try. But that is a slower burn rate than Unique so how does that fit the heavier boolit>slower powder principle? Will let you know.
Joe

[Marlin Junky]

MJ thanks for clarifying that point. I will give RE7 a try. But that is a slower burn rate than Unique so how does that fit the heavier boolit>slower powder principle?
Joe

Don't confuse the issue, we've only been talking about one boolit, Lyman 280473. Plus or minus a few percent in boolit weight due to alloy variation is not going to make a significant difference in group size unless you're on the threshold of accuracy. Judging by your groups, you're no where near an acceptable level of accuracy and a slower (within reason) powder can only help unless you've got fit/boolit-quality related issues.

MJ

[P.K.]

If you ever think of selling that mold I'd like it for my 6.8. ;-)

X2. I will buy this mold.

[rollingblock]

Back in 68 I got a lyman mold of around 135gr for my BSA .270. I knew nothing at all about casting except I had heard that small charges of fast powder were the way to go. I loaded straight out of the mold, no lube or gas check over minimal charges(5 or less grs) of 700x. I would guess the velocity was around 6-800fps. Those boolits would cut holes at 50mtrs but the killing power on rabbits was far less than a .22rf. Of course when I tried to up the velocity a bit I think I had molten blobs exiting the barrel leaving severe leading with non existant accuracy. I left casting 35yrs or so and am now enjoying trying to equal the accuracy of those 270 cat sneeze loads with an 8mm and 308. Not sure this will be any help to anyone but reading about 270 cast brings back memeries.