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All Springer/NP/PCP Air Gun Discussion General => Projectiles => Boolit and Pellet Casting => Topic started by: Lani52 on March 18, 2019, 11:45:18 AM
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For the last month or so I have been experimenting with ladle techniques to get consistent weights for pellets, full fills without the fins that like to appear with too much ladle pressure. Testing was interrupted when I came down with a Shingles infection, otherwise this would have been a week long test.
I tried full ladle, simply pouring, and half ladle pours at 850F and 900 F.
I am using a Lee 20lb pot converted to ladle pour by removing the bottom pou system. I cast at 850 F ,, fluxed just prior to casting. I tried unsucessfully 900 F, with 20-1 alloy. I am using the 22 caliber NOE hunter mold. I have used the pin that gives the largest base cavity, lightest weight, the optimun weight my MM barreled Prod seems to like is 19.9 and I weight sort to 19.9-20.00 grains. The mood is adjusted to leave no flared bases.
I cast 50 casts then sort, 100 pellets which makes it easy for a 70 year old to figure the percentage. Percentages from 30 % to 76% have been realized so far, but some were returned to melt early it was that bad.
Mold prep was to smoke the pins and cavities then heat on a hot plate on medium, then quickly heat the pins with a blow torch, then cast 50 pours on 850 F. 900 F was tried but almost all pellets had fins with ladle contact either half full or full.
If the pelleted weight gets up to 20.1 grains it indicated, with my mold, that I will have fins that I can feel with my fingers, accuracy suffers with those fins, ie., .75 of an inch at 12 yards, 19.9 to 20.00 yeilds .12 inch to .25 depending on My eye strength I hhave remaining at the time of testing.
A full oadle with spruce plate contacrt, turning the mold sideways for the first cavity, yielded 30 % with the pellets going over the targeted weight, a non contact pour yielded under weight pellets indicating skirts not filled and I did not keep track of the percentage or even finish the weighing it was that bad, same with 900 F.
A half ladle, spruce plate contact is the best so far with .76 % of the pellets in the 19.9 to 20.00 weight range.
Until learning more, the half ladle seems best and that is what I use now. This pellet mold has been a humbling experience, but in the end has proved, you can indeed “teach an old dog new tricks”.
Roachcreek
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NOE pellet mold/ladle pour update.
Just switched over to the Hawke sidewinder 4x16 ffp scope on the prod replacing the Simmons 3x9 a0 Target knob scope.
Way too top heavy, however perhaps the most accurate scope, rifle and pellet combination I have ever shot.
Really pleased with this pellet. I only hope the Skyhawk, which is in the possession of JSAR, shoots it as well When they are finished with it.
Roachcreek
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RC I haven't tried them in any rifles yet but I really like them in my pistols, very consistent and they seem to be winners for sure. I've got a new rifle coming soon that I try them out with. Supposedly it does over 30fpe according to a lot of people that have them so it'll be a good one for testing the .22 Hunters. The rifle also has a hi and lo power too which will make it really convenient for extended testing.
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Lani I went through basically the same steps , and conclusion with casting these pellets, to the point to where you are now or a little better, need more target time soon.
What I have been trying last was about 750 - 780 pot fluctuation with casting ladle, and direct pour hold for like a 2 count then seperate. Lower temp but pressure enough to fill the mold.
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James,
I will try dropping it down about 2040 degrees.
Thanks,
Roachcreek
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RC the temp is too high. One, it will be thinner and give more fins, and more importantly, the tin will be separating from the melt. GRRRRR!!!
I am looking forward to seeing what the new toy will do after JSAR does their magic with it. 8)
Mike
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Thanks all, I will lower the temp down into the 700’s today and cast some up.
Roachcreek
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I've got almost a full post of smelted lead ready to cast up more of the Hunters today, I started yesterday on it but got sidetracked by other things but did manage to get over a hundred good ones from it yesterday.
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Ran 100 pours in my brass 2 cavity mold at 760.
Only got 100 pellets in my plus or minus 1/10 grain range, with my mold, termoter and technique it appears. I need a tad more heat as most were under weight/fills. And yes the pins were heated up.
I will try just under 800 F next.
Still learning,
Roachcreek
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Did you get less fins in the process ? If so seems like you are getting close, just bump up the temp a hair at a time.
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I have the noe 25 mold in brass two cavity, I have found that with my mold the key was a very long mold preheat duration. Even when I was sure the pins were warm they weren't. Whenever I cast pellets now I always cast with another mold first while the pellet mold sits on a digital hot plate, I set the hot plate so that my mold temp gets up to 360 degrees and maintains that temp +/- a bit. For pour technique I use a very close ladle pour, but not ladle contact with the mould. A huge puddle and a slightly off center pour onto the sprue has been producing very consistent pellets with minimal finning. Ymmv
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Yes there were very few fins and very few over weight pellets, ie., 20.1-20.3, my targeted weight is 19.9-20.00, most rejects were 17.8-19.8, so yes as I wrote, I need to bump it up tp 790-800F.
Roachcreek
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My last run of the .22 hunters were mostly all about 19.6 grain and they shoot really good from my Airmax Master blaster, I tried one out on a fox squirrel at about 18 yards out by my wood pile, in behind her left ear and out her right eye. I do cast from pure lead though.
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I changed my weight parameters after measuring the difference of the dimensions of pellets weighing 19.9-20.1 grains and finding little difference with my Harbor freight adopters.
I then cast 300 pellets today, incorporating something that was a ah-ha moment at 3 am the other night the result of both changes was that the last 180 pellets cast had a reject percentage of .066%, or 12 remelt pellets out of 180 pellets.
So what was the insomniac moment at 3am? The fact that when I open my mold when cold, only one pin falls forward. So yesterday I weighed the average of 5 pellets from each cavity and found the culprit, the tight cavity weights were 19.9 to 20.00 and the loose one was 20.2 to 20.3.
So the first 70 casts today involved balancing the cavities, both are tight while cold now, both swing out when hot, and my percentage being well under 10% remelt.
These were cast at around 805 to 810 F, no fins present.
I know most of you probably knew about balancing the cavities, but as I have said before, 50 years of casting and I am still learning.
Roachcreek
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:-[ My bad for assuming that the pins were set ;)