GTA
All Springer/NP/PCP Air Gun Discussion General => Projectiles => Boolit and Pellet Casting => Topic started by: Sbak on November 07, 2018, 10:26:13 PM
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Finally had a few minutes to spare before the daylight disappeared on me this evening to try out the NOE 25-27 mold I bought weeks ago. These were cast with the longest pins, pot temp of 710-720 and a mold temp of 395-405 degrees. Considering this was my first time casting pellets and the first time with this mold I am quite pleased with the way they turned out. I cast about 150 like a mad man before the light completely disappeared and didn't notice the amount of flash on the base of the skirt from one cavity. Because of that my reject rate ended up at about 50%. Once I get the pins set correctly these little buggers will not be any harder to cast than any comparable size bullet. I did weight all of the keeper pellets and they are dropping right at 27.00-27.06 grains. NOE sure do know how to make a beautiful mold.
Edit* forgot to mention these were cast in pure lead
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Excellent! Keep at it.
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Very nice !!! I really like my 25-27-RF mold also, I'm getting anxious for when the .22 hunters show up cause that's going to fill the niche for my lesser powerful .22's
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Adjusted the pins today and ran a quick casting. Despite the cold and wind I had only a few discards. Measured the head dia on a few and they are dropping at .2480+ with a mold temp of 395. I weighed all of them and they are dropping @ 27.00-27.18 Just for reference I weighed about 40 jsb Kings that ran from 25.1-25.8 grains with a little less than half weighing in at the advertised 25.4g. I'll hopefully be able to do some short range (25 yrd) accuracy testing this week with a green mountain (Mrod) barrel vs the jsbs
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Nice looking pellets, congrats!
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Nice work !!!!
Bob
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About a month and a half ago I was out on the state land shooting, I came across a small plastic butane bottle someone had discarded and figured I'd take about a 30 yard shot of it sitting on a log. I never did find it that day but about 2 weeks ago I did and it was probably 20 feet further out from where I had shot. It still had the pellet in it so I stuck it in my coat pocket to open it up later. I disected that pellet out a couple of days ago and it's been sitting here on my computer desk next to an unfired one, I seen this thread so I figured I'd take a picture of the two side by side ;D
These pellets were made with the middle size pin, most all of them weighed right about 27.5 grains.
(https://farm5.staticflickr.com/4814/45790791152_13d1ec9d93_b.jpg)
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Having a bit of trouble with the pellets. They are dropping very well formed with full skirts and very consistent weights, but it seems that regardless of mold temp I can't get them to drop with a head diameter greater than .248 Has anyone put a micrometer on their cast pellets yet? I also think it is a little odd that my pellets are dropping at 27.0 grains with the longest pins while others are 26. I did shoot some 25 yard groups the other day and they weren't bad, but not great either. About twice the group size as the jsb Kings, I'm wondering if the undersize head diameter are to blame
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Figured I'd post what I'm getting so far. Ignore the poi, the gun I used isn't sighted in yet. Top group is jsb 25gr lower group is the 27gr casts. Distance was 25 yrds five shot groups, and cold numb fingers
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It may be your measuring... what are you using... the reason is I do not think you would get good accuracy at .248..?
I have Two .25 Mrods and at the choke they are .249 and close to .2495... with the BBT 40g I get best accuracy when sized to .2495 and .250 with the .2495 barrel...
recover a pellet and take a look at it...
also could pull the shroud and check fit at the muzzle... I mean it could be choked that far but...
Have not checked My 34g BBT .25 pellets for head size yet... I use an inexpensive Fowler Micrometer...
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Using a micrometer. I've pushed pellets through and they never touch the Grove and just barely show land marks on the head. The pellets are essentially bore riders as cast.
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Using a micrometer. I've pushed pellets through and they never touch the Grove and just barely show land marks on the head. The pellets are essentially bore riders as cast.
well if the head is bore riding at the choke it might be just enough to be accurate... even if the head is bouncing down the rest of the barrels bore...
with No Sn or or Sb is when lead cast the smallest... with tin in the mix it flows better because it reduces surface tension...less surface tension less shrink...I have been told and read that lead without tin does not frost either...
I tried pouring with about .25 of 1% sb from crosman pellets in the mix and they grew a tiny amount with aging also... I pour with 1.5 Sn to 5% sn for my BBT and they fall as drawn to a touch large... unless I pour at 820 * pot temp and up...
for the 34g .250 I am using the brass mold so it will act a little different if you use aluminum... My other molds (boolits) are aluminum...
so this is a long winded way of saying try some tin in the mix and maybe even some antimony if necessary...The antimony grows because I think it fully crystallizes as it ages but do not quote me on that...
I do think it is possible that because the contact patches are small some hardness with pellets can work... Only one way to find out... this is pretty new stuff casting small caliber pellets... the pic below is my .250- 34 pellet cast with 1.5% tin cambered and pushed back out... 790* melt temp...slow pace... mold temp?
it just barely is bore riding the nose which has done well for me with many other pellets... in not choked barrels I want just a bit more engagement... also I will be experimenting with up to about 5-6% tin to get them to drop large just because I want to know how they do... and I have a XL725 Barrel that I need them to drop larger for...
So yep we get the fun of learning and blazing a bit of a trail not traveled much yet... and help by sharing our results... Now there are some similar trails that have been cut so we/I can read...
http://castboolits.gunloads.com/showthread.php?192192-How-does-alloy-mix-affect-casting-size (http://castboolits.gunloads.com/showthread.php?192192-How-does-alloy-mix-affect-casting-size)
http://www.lasc.us/castbulletnotes.htm (http://www.lasc.us/castbulletnotes.htm)
I searched google "does pure lead cast small" tho I already had done a lot of reading...
I grew up listening to guys that shot their own cast... black powder and modern... then in my late 20's was a mold core maker at an aluminum foundry...
I still do some searches and read...
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Thanks for the reply. My mold is brass as well and I've considered adding some tin, but I would rather not if I don't have too. I've tried mold temps from 350-430 and I've never had problems casting full diameaater bullets from .22-.357 in pure lead but hey, it is what it is. If I can still get them to shoot well I guess it doesn't really matter. Just FYI pure lead will slightly frost when cooking too hot, but it is very subtle and will mostly disappeared right after cooling. My brass mold is dropping the largest diameter and most round at 405 degrees +/- 10 degrees. I keep my pot temp under 720, no need to go higher with most of my casting done at 680-700 degrees. Sometimes lower if it's really cold out to limit the amount of oxidization
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Figured I should add an update. I finally got the chance to shoot some cast pellets at 50 yards the other day. The gun is a Nova freedom with a .25 Green mountain barrel (maurader barrel) at a six shot tune with jsb Kings @ 800fps. Groups are four shots apiece.
26gr are the longest pin with 1.75% tin, 27gr are the second pin with 1.75% tin and 28gr are pure lead. Any one of these will make a great hunting round for my intended distances
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Tin will indeed help. Try a tiny amount. Say 1 in 40. If your mod is well seasoned, you should get no tinning issues with the mold. The pellets will not get enough hardness from the small amount of tin to make any difference in velocity. But will hold the lands in the barrel better.
My Barrel is a L/W and slugs to .2495. so a little tight for a L/W, but shoots bullets and pellets well. (after the choke was removed). It had one TIGHT choke!
Knife
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When I first started casting I had a long conversation with a guy who casts bullet to sell, and had a lot of experience with using pure lead.... He ran his pot right at the top for temperature (well over 900*F) for pure lead, so hot that the bullets came out with a bluish tinge to them.... This produced excellent fill-out, of course, and the reason he used this method was the extremely low reject rate, important if you are selling them.... He advised me to add a small amount of tin if I wanted to use a lower temperature, as even 1% tin really made the lead flow better.... Unless he wanted harder bullets he never used more that 2.5% tin....
Just thought I would pass that along.... I started with 1% tin, went to 2%, and now just buy the Rotometals 40:1 alloy (2.5% tin) and use that for everything.... Pure lead goes dull in a hurry.... 1% tin will still goes dull after about a year.... but the 40:1 stays bright and shiny seemingly forever.... The 40:1 is harder than JSB pellets, but softer than Crosman, so is about in the middle of what we see in commercial pellet hardness....
Bob
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I am finding that in the 40-1 sead/tin, my HP perform very well. I started using the star bit method and could not be happier. 8)
Mike
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The tin flakes that I ordered came from Ohio and will be here today, I'll probably be out in the woods when they get here though, my postal carrier always sticks packages inside my screen door when they won't fit in my mailbox so I'll be relatively comfortable knowing they're there when I get back. Right now I have my F10 chugging away (love that compressor) to put the tank back up to 4.5K. ;)