Canadian Airgun Forum

I would imagine I am not alone in having problems casting small caliber hollowpoint bullets, and in particular skirted pellets.... particularly in regards to incomplete fillout…. I use a 10 lb. Lee Bottom Pour Pot (the drip-a-matic), and even running it way up at 900*F with 40:1 alloy (2.5% Tin) my reject rate is dismal.... :-[

I have been looking at the spectacular results that Wayne has been getting with a hooded dipper and pressure pouring, just a few rejects out of 500 skirted pellets.... …. and wondered if I could adapt my Lee for pressure pouring.... I had tried it stock, and the small rounded spout went so deep into the taper in the sprue plate, and sealed against it, so you couldn't tell when the cavity was full.... My solution was simple.... I got out a grinder, gathered up my courage, and ground the bottom of the spout off flat, just below where the taper on the spout transitioned into the rounded end.... I then filed a notch, facing forward, using the corner of a square file, to create a path for the lead to escape from the tapered hole in the sprue plate.... Here is a photo of the modified Lee spout....



When you cast, you lift the mould up so that the end of the (now shorter and flat) spout hits the inside of the tapered hole in the sprue plate, and lift the handle to pour the cavity.... You MUST start at the front cavity and work towards the rear, or the overflow, which happens quite quickly, runs into any hole forward of where you are pouring, and stops you from pouring that cavity on that pour.... Hold the mould at about a 45 deg. angle to the base of the pot, so that the overflow (which comes towards you) is easily visible.... Stop pouring before the lead runs over the edge of the sprue plate, of course.... You will see this....



If you hold the mould up against the spout too long, the lead will solidify and you will have to rock the mould a bit to break off the thin part of the sprue.... The trick is when you see that squirt of lead that indicates the mould is full, lower the handle to stop the lead flow, and then drop the mould down and move it to pour the next cavity, or cut the sprues.... I have only done a few bullets so far, I was so excited by how well this worked that I needed to share it immediately.... Here are some 60 gr. NOE .224 cal bullets, the first few from the mould…. I had 2 wrinkled bullets out of the first 4 (using a preheated mould), so even without getting the mould up to temperature the fillout was perfect....



After I do some more of these, I have some 24 gr. HPs to cast in .172 cal.... THAT should be a critical test.... I'll let you know how it goes....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Not toooo bad, Bob, but as you are well aware (others might not know) ANY defects in small

diameter bullets or pellets are disasters on target or game, accuracy wise.

I converted my current 2 - 20 pound Lee Pots to dipping pots. One for pure lead, one mixed for bullets.

Now, I get perfect bullets from .48gr. .22's to 525gr. .458's., perfect balls from .350" to .740"

virtually every time. I just checked my last casting of .22 cal. G/C bullets and they are all perfect as well.

A combination of temperature, pouring from the ladle technique gives this repeated success.

I drained my pots, dismantled the bottom pour parts, then ran a 5/8" self tapping #6 sheet metal screw into the hole from the inside

of the pot. In retrospect I should have run it up from the bottom, as there is the screw-head on the bottom of the pots, but it is not

a real problem.

Further - not in the picture of my pure lead pot, the position of the temperature dial.

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Best Wishes
Daryl

With hollow point or hollow base plugs, they MUST be HOT or defects will be there, virtually every cast.

I have, in the past, had a propane torch running beside the pot, to put the hollow nose plunger into the flame

to re-heat it, prior to reinstalling into the mould for the next cast, as when it is pulled from the mould, it instantly

starts to cool, not good as it then causes wrinkles. I also did that with the first HP NOE mould I bought for the Condor.

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Best Wishes
Daryl

Just took a picture of my plain as-cast and moly coated 51gr. bullets for the Condor.
I did not segregate these as they all looked pretty good. I can see 3 maybe 4
that should have gone back into the pot.
These were cast from my 4-cavity mould.

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Best Wishes
Daryl

These are from a DC Lyman mould and weigh 45gr. in .225".

With closer magnification, I see the bottom middle bullet and the bottom right

hand bullet need to go back into the pot. The middle bands are rounded and not

filled out with sharp corners.

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Best Wishes
Daryl

I think you're cooking the lead too hot. Lead starts melting around 620... 700 is a good temp. 900, you might have some zinc in the mix that will mess up some pours. Might be why you're having harder time filling the mold out.

Those are some great looking bullets, Daryl.... I also found that for small HP bullets, and in particular with the skirted pellets, I have to run the pot VERY hot.... I recently got a PID, and with the pellets I was running over 900*F and still getting 30-50% rejects where the skirts were not filled out properly.... This simple mod. so that I can pressure pour let me drop the temperature a LOT and still get complete fillout on the skirts and even tiny hollowpoints….

I cast some 25 gr. HPs today in .172 cal, and here is a photo of just a handful of random bullets I scooped out of the tray....



You have to see these little gems to appreciate them.... they are less than 1/2" long, and the HP is not much over 1/16" in diameter.... …. I also cast some of the NOE .217 cal Magnum Hunter pellets today.... This is a mixed batch of 24 & 26 gr. pellets…. The mould comes with 4 sets of base pins to produce 4 different weights of pellets.... These are the lighter two....



Here is a closeup of a random handful of them, you can see the two different skirt depths....



The 61 gr. .224 cal and the pellets were cast at 800*F, the tiny .172 cal HPs at 850*F.... For anyone who is having difficulty casting small, intricate shapes.... try modding the spout and pressure pouring.... I will NEVER go back....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

Oh yeah - those look a lot better.

Since I do not use a pressure fill, I run my lead, both alloyed and pure at a higher temp than actually needed.
With pure lead, I have to add 1/2" of 50/50 plumbers solder into the 20 pound pot, just to slow down the oxidation
meaning the scum that forms on the surface. This way, I can usually cast 50 or more balls or bullets before having to
re-flux the metal.
After going through your process a second time, Bob, I more fully understand your pressure filling & the change you made
to your pot's spout.
Needing to case heavy bullets for my buffalo rifles and 12 bore rifle was the primary reason for my plugging the bottom pour
and going with dipping, all the way.
Bottom pouring heavy bullets does not work well enough as if wanting accuracy out at 1,000yards or more, consistent bullet
weight is very important. With bottom pouring heavy bullets, that consistency is not there and dipping is the only way to get
it.
Just for interest's sake, here is a shot chart giving sizes.

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Best Wishes
Daryl

I am just tickled about this pressure pour mod. I came up with for my Lee pot....



I did 350 pellets today, with only 10% of them where the skirts were not 100% filled out.... and I was pretty picky, most of them probably would have shot just fine.... Really there was only a half dozen that were truly bad.... I did 120 of those tiny .172 bullets and only 1 was a reject.... The 61 gr. FN .224 cal. I rejected 5 out of 300....

I was pouring at 800*F today, and 850*F on the .172 cal.... but I'm thinking I can reduce the temperature further.... I have some of the heaviest pellets, and some flat base versions to cast yet, I'm going to try 750*F and see how they come out.... Considering I was rejecting 1/3 or more of my pellets using over 900*F without the pressure pour, this is pretty amazing....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

If you can stand it, add just a bit more tin and casting should improve. I wold expect 30:1 would work just about as well,
but fill out a bit better.

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Best Wishes
Daryl

Interesting.... When I started casting I was told by a couple of old timers on Cast Boolits that just 1% tin was all you needed to get good fillout…. I use 40:1 from Rotometals for consistency, I don't really want to go harder....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

With the thin skirts, 30:1 would be just fine, I'm sure, however the 40:1 obviously should be as well.
Just that the higher the tin content, the lower can be the casting temp and still give good fill-out, is all.
I get perfect fill-outs using just about any alloy, just by adjusting the casting temp, of course.
As I don't have a lead thermometer, I just go by what works with my pots. I have noticed, my older
pot that has the harder (high speed) alloy in it, needs the dial up higher than it used to require, just
to get the evenly frosted bullets, which I prefer.

_________________
Best Wishes
Daryl

wow...nice casting there Bob...

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"A candle loses nothing by lighting another candle"

I cast 280 of the NOE .25 cal. Hunter pellets today half were the lightest, 26.5 gr. and half were the medium weight 28.2 gr.... I only had TWO skirts that weren't 100% filled out....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal; Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!

This is a great idea Bob, I may also try this.
So why is it then, if I leave a generous molten glob of lead on the sprue plate that the weight of the glob doesn;t force the lead into the corner of the base and sprue plate ?

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