GTA
All Springer/NP/PCP Air Gun Discussion General => Projectiles => Boolit and Pellet Casting => Topic started by: Madd Hatter on October 06, 2020, 11:20:43 PM
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Did some casting with my new 27 grain .25 cal alu mold. All I have to do is shake the the mold and the pellets just fall out. One thing that did surprise me was the weights that I'm getting. The first 10 I cast were right about 29.1 grains. If they were less than 29 there was a defect. So I went full production mode and cranked out around 100 pellets. After putting everything away I did some weighting and was getting 29 to 30.5 grains. 🤔 I know that alu expands 3.5 thousands at 350 degrees. The mold temp varied between about 320 to about 360. I did the casting with the shortest pin and that's why it's up in the 29 grain range but I didn't expect it to drop pellets in the 30.5 grain range.
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sounds about right. i have the brass variant of this one. i did a small run myself last night on the same pin. I'm seeing 29.2-29.4 gr on mine. Man do i love the consistency NOE molds produce.
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I have stuck with the longest pin myself, the pellets are devastating out of my Avenger.
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the long pin seems to be universally the most accurate across the board. NOE Produce< hoe you meant products. I know think Swede sells veggies. LOL! ;) ;D 8)
Heading out to shoot and then cast some of the NOE CC1's from the mold I HP'd right now. ;D WooHoo!!!
Last pic is my modded NOE .250 mold. The others are .2224 sized to .2227".
Knife/Mike
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the long pin seems to be universally the most accurate across the board. NOE Produce< hoe you meant products. I know think Swede sells veggies. LOL! ;) ;D 8)
Heading out to shoot and then cast some of the NOE CC1's from the mold I HP'd right now. ;D WooHoo!!!
Last pic is my modded NOE .250 mold. The others are .2224 sized to .2227".
Knife/Mike
So, you sized bigger or are you going dislecsic on us? 😁
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sounds about right. i have the brass variant of this one. i did a small run myself last night on the same pin. I'm seeing 29.2-29.4 gr on mine. Man do i love the consistency NOE molds produce.
I expected 29.1 to 29.3-4 but not 30.5.
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Here's what my Avenger is doing with my 26 grain, everytime I shoot the gun my thoughts are "Man this thing hits where the trigger breaks every time". I honestly doubt that I could do any better with the JSB 25.39's
(https://i.imgur.com/haM05Cj.jpg)
The gauge on the left is where my regulator is set, in reality it's probably 2100psi though.
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I'm going to be using mine in my Sumatra. That's why I'm going for the heavest pin. As it is right now, the Sumatra is pushing them to 1044 fps with the power wheel set on 6 of 16. I originally ordered the mag hunter but Al mistakenly sent me the hunter instead. I decided to just stick with the hunter instead of sending it back. I guess I will be needing to lower the power down to setting 4 which should give me a lot more shots per fill.
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Robert I've got a Xisico Sentry 25 cal prototype that I modified and it's doing about 50fpe with the magnum hunters, very accurate too. The ones that I use are 34.5 grain.
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That was the one I originally planned on using. My Sumatra is pushing between 62 and 70 fpe with the 29.2 grainners. I think I will go with the longest pin and turn down the power until I'm shooting them around 900 and call it good. Just can't figure out why my mold dropped pellets a full grain heaver than the first ones? Haven't really had the time to do any target work with them yet so will see what happens.
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Just a thought, but 320-360 degrees is a very big temp swing. Try to keep it +/- 5 and it will drop perfectly consistent weights
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You are probably a little cold as well, most small caliber low antimony casting likes 380 degrees plus temps. Ymmv, but mine varies little. Good luck
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Found out that the pellets that are in the 30 grain range are longer by.015 - .020 than the correct 29.2 grain pellets. That alu mold really grew in length at the higher temperatures. I ended up rejecting about 1/3 of the pellets I cast. If I were to do over I would get the brass mold for any pellet casting instead of the aluminum mold. The CTE difference between the steel of the pin and the aluminum mold requires much more even mold temps than the brass mold.
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Robert I try getting them all brass !!!
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Found out that the pellets that are in the 30 grain range are longer by.015 - .020 than the correct 29.2 grain pellets. That alu mold really grew in length at the higher temperatures. I ended up rejecting about 1/3 of the pellets I cast. If I were to do over I would get the brass mold for any pellet casting instead of the aluminum mold. The CTE difference between the steel of the pin and the aluminum mold requires much more even mold temps than the brass mold.
I have brass and aluminum molds. The brass is heavier to work, but stays hot better if not working steady. The brass is more prone to warp, so you have to watch its temp. The aluminum is lighter to work and will hold temps just fine when working steady. I heat mine up to ~350°-370° on a hot plate and then more by piling molten lead on top of the sprue plate while casting, and waiting a few extra seconds for the heat transfer. When the bases start to get frosty, I know I can back off on heating up the mold more. I cast between 750° and 800°.
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I have cast a lot with brass myself and as of yet I've never warped a mold yet and I came to the conclusion that's because doing the pressure pour method I've never been real concerned about temps or fill out either. I'm not a real speed demon when it comes to casting like some may be and when it seems that things are getting a little warm I'll take a little break open the mold and let it cool down before going back at it.
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I have cast a lot with brass myself and as of yet I've never warped a mold yet and I came to the conclusion that's because doing the pressure pour method I've never been real concerned about temps or fill out either. I'm not a real speed demon when it comes to casting like some may be and when it seems that things are getting a little warm I'll take a little break open the mold and let it cool down before going back at it.
NOE says to not go over 600° on the brass. I don't ever get the molds hotter than that either.
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Robert I try getting them all brass !!!
After casting with the 30 grain BBT aluminum slug mold I loved how easy it was to cast with so figured I'd go with alu for the.25 cal hunter pellets. Both of my.22 hunter and mag hunter are brass and are harder to cast with,at least for me.
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Robert there is a little more tweeking that you need to do with a pellet mold, main thing is getting the pins adjusted to where you want them. They are heavier and I only get them in 2 cavity because of that, it's less wear and tear on me when casting than a very heavy brass 4 gang mold is. Another thing I like about getting a 2 cavity mold is you only have two cavities to worry about getting right.
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The only one of the five molds I have in brass is for the .30 cal pellets in four cavity. I use a guide plate from NOE that fits my Lee Pro 4-20. That helps to alleviate some of the fatigue with that heavy beast. It is a nice mold for sure, but I prefer the aluminum molds personally.