Weight a minute!
Gary Chillingworth is now working on his spring gun’s balance
As I am writing this, there is good news; I survived and I still have most of my fingers and thumbs. Last month, we finished the TX200 stock – or as my friends have started to call it, the Frankenstock. We put on an adjustable cheek piece made from Kydex, a hamster made from an old umbrella shaft and some 2x1 scrap timber attached with some M6 bolts and rubber tap washers, and finally, a very nice adjustable 3D-printed butt plate from Brian Samson.
The thing is though, the stock needed a bit more weight at the back, so instead of going to my old reliable, self-adhesive wheel weights, I thought that I would cast a specific weight to fit between the top of the cheek comb and the top of the adjustable cheek piece.
Before we start, I promised that I would tell you how I got on with the stock at the Essex Open. Well, the stock worked very well. The adjustable cheek piece helped me to make sure that my eye was always central to the scope, and considering we were shooting out to 55 yards, this was very important; the hamster enabled me to rest my hand on the ground and then the rifle on my hand so this helped to maximise stability, and the Brian Samson Butt pad was a revelation. It helped the gun to lock into my shoulder and I am considering attaching one to my CS1000.
TWO POINTS IN IT
There were 70 people at the shoot and 20 of those were HFT shooters. In the Spring class, I managed to take the win, but more importantly, I was only two points behind the overall winner, Anwar Ghazi, who was using a top- of-the line PCP. This showed that a fairly standard TX200HC with a bogstandard stock and £ 50 worth of extras can take on a £ 3000 Steyr and scope set.
Enough of that, it’s time to start forging, but before we go any further I have to give some advice and words of warning. Molten metal is dangerous, very dangerous. When I told my friend, Alex, what I was going to do, he did that thing where he sucked air in through his teeth and said to me, “Are you sure you want to do that?”
Alex is a fireman and he also knows that I am not great with tools. My wife also told me, “Do it somewhere that you won’t burn the house down.” The faith these people have in me is amazing.
The thing is, what I am going to do is quite dangerous and I have to take some precautions. The advice I got was; wear safety goggles, thick gloves and cotton or leather clothing – no polyester or plastic because this will melt if hit by molten lead – and a hat or preferably a full face mask. Also, molten lead does gives off toxic fumes, so DO NOT do this inside! It must be done in
a well-ventilated area. The final thing is, a big bucket of water. If you do get burned, the NHS recommend that you keep the area submerged for at least 20 minutes and as lead melts at 327°C, if it burns you, it will hurt. I would also recommend a person to help, and check out where the local A& E department is. Well, that’s enough caveats and warnings, so I hope that, Phill, the editor is now happy that we won’t get sued.
To cast a lead weight, we will need a few things – firstly, some lead! I purchased 100 8g olive shaped fishing sinkers from eBay for £11. Next, some masking tape, a clay flowerpot or bucket, and some kids’ play sand. We will also need a heat source that can be used outside. I am using a gas cooking stove and finally, a saucepan that you are happy to destroy.
The first thing that we need to do is make a mould. As I look at the back of the stock, there is a nice gap between the top of the inside of the riser and the top of the comb. This is perfect because the weight will be almost in line with the spring.
My rifle riser was formed over a cylindrical tube that was used to hold vitamin C tablets. This tube slides into the gap between the top of the riser and the top of the comb, so I can use the same tube to make my mould. The tube is what is known as ‘a positive’. You could fill the void with children’s plasticine or air-drying clay and use this to make a perfect cast of the top of the comb, but this is quite advanced and for now, I will use the cylinder and keep it simple.
THE SCIENCE BIT
So, how much lead you will need? Take a large glass and fill it to the very top, then gently push the positive into the glass until it has just submerged. You will notice that a large amount of the water will have spilt over the edge. Remove the positive and start to fill the glass with your lead. When the water level has reached the top of the glass again, you have the exact 75% of lead that you will need. There will always be some lead and slag left in your pan, so add 25%. You can then raise a glass to Mr Archimedes, his bathtub, and his theory on displacement.
The next step is to take a large clay, or terracotta, flowerpot and fill it with play sand; this type of sand is finer then sharp sand and will give a better finish – it’s also only £ 5 a bag from B& Q. Half fill the pot and place the positive into it. Start to fill the pot with more sand and keep taping it down. You want it to be as compact as possible. When the pot is full and the
sand is at the same level as the top of the positive, you will need to remove the positive from the sand. Pull the positive out slowly and what should be left is a void in the sand that looks exactly like the positive, but in reverse. This is called ‘a negative’.
If the sand collapses, you can try wetting the sand a little, but not too much because molten metal and water creates steam, and steam will burn. If you have a good negative, it’s time to melt the lead.
Place the lead in a pan and start to heat it – use a long stick to stir it every now and then – and after about 10 minutes, the lead will start to turn into a liquid. Whenever you are near this stuff, you must wear the full safety gear because a spit of lead in the eye will blind you.
Take the lead and pour it very slowly into the mould, and when all of it is in, let it cool for a few hours. You will now have a weight that will fit perfectly to the top of your comb and also the inside of your riser.
As you can see from the picture, the lead weight fits between the top of the comb and the top of the riser. To keep it in place, I placed some epoxy on the inside of the riser and stuck the weight there. There is also a piece of tape on the comb and some material to cushion any movement, although I’m going to replace this with foam.
This weight makes the rifle feel well balanced, and it certainly helps to deaden the recoil. If you have a stock like the CS1000, you could cast a weight that sits just below the cheek piece, or you could drill a hole into the riser and fill it with lead, but I’m not even going to attempt this because I will break my stock.
Casting a lead weight was a lot of fun and I know that it looks a bit rough, but this was my first attempt and I want you to see my successes and my mistakes. With more practice I will improve, but part of the fun of these articles is the fact that I am ambitious, but rubbish. The information that I have passed on to you is all correct; it’s just the application that’s a bit lacking. Please be careful. If you want to have a go and let me know how you got on, you can contact me at garychilling[email protected] gmail. com and good luck. Next month, we will be making pellets from depleted uranium. That is if my North Korean contact, Kim, comes through with the goods.
You now have a lead core
Remove the positive and you will have a perfect negative into which to pour the lead
The water level is now back at the top of the glass, this is 75% of the lead you need
A perfect void to hold a weight
Heat the lead in a pan you are happy to ruin
Play- pit sand is cheap and effective for casting
“I managed to take the win, but more importantly, I was only two points behind the overall winner”
Pour the lead very slowly
A perfect fit and the rough exterior will help the epoxy to stick