OK we’ve finished our first casting session and 5.5 of the 10 lbs. of lead we melted is sitting on our bench in the form of about 236 or so 165 Grain 30 Cal heads, and 4.5 lbs. or so is sitting in bars left over from the pot. Where do we go from here?
Feel free to go ahead and lube these suckers up and stuff ‘em into cartridges and go forth and make a joyful noise, but don’t expect the greatest sub MOA results. It’s your first batch, so I understand if you want to go that route. But if you would like to wring the most accuracy you can from these little buggers, read on.
The first thing you’ll be doing is to visually inspect the fruits of your labors. Bullets with badly wrinkled contours, and/or rounded bases are to be culled. The key to consistent accuracy is consistent components. Therefor any obviously deformed non-uniform castings need to go back into the scrap pot.
Next, if you have a scale you will want to take about 20 bullets and weigh them, taking note of the weights and recording them.
Surprise surprise, your moulds say that these are supposed to be 165 grain .308 heads and they’re weighing in at 159.4 average. What’s up with that? Perhaps it’s your alloy, don’t sweat it though, what we are looking for here is the average weight of our sample. Next we have to decide what our acceptable range of weight will be with this bullet mould, I typically use a range of one percent, sometimes less, total weight spread. With a 160 grain (nominal) projectile that’s a weight variation of about 1.6 grains. Match bullets are held to a higher standard but we’re not there yet!
So our heads are theoretically going to fall within the range of from 159.4 grains +/-.8 gr (158.6 ~ 160.2). Those higher we will put to one side those lower to the other. If we note that there is a larger group forming at one end or the other as we continue weighing, we may want to consider adjusting our mid point toward that more numerously weighted end of our range. If so, then simply reweigh our batches and make the adjustment.
For a lark, or as a result of my obsessive compulsive disorder, I decided to graph up the weights as I weighed up this batch, discarding any truly obvious outliers, of which there were 6. The results are posted here, surprise, surprise, a bell shaped curve with some missing teeth.
I have noticed that I get more rejects out of the cavity closer to the handles, and that, that cavity does not draw down quite as noticeable a dimple, so we might actually be looking at two intersecting bell curves… I guess that’s what keeps this interesting, figuring this random stuff out. But we digress.
Variations can result from several factors. Large variations may indicate voids inside the casting, incomplete fills or possibly inclusions of dross. Variations that are light but very close to acceptable will in most cases show slightly rounded base edges, indicating inadequate fill, or poor flow of the molten alloy within the mould.
As is the case with most of the surface anomalies, rounded bases can typically be attributed to too cool a melt, or a too cold/dirty a mould in which the air escapement channels are clogged. One last possibility is that there is not enough tin in our alloy. If you are using purchased alloy and not home brewed, look to the temperature.
Temperature of the lead will also affect finished cast weights but less so and will probably fall within our 1 grain total weight variation. The last potential variation in weight will derive from the consistency of the closure force applied to the moulds. Loosely held mould handles can cause slightly oversized projectiles which will weigh to the high end of the acceptable range.
Before you can use any of these cast beauties you will have to lube them up in one form or another. Lube serves to seal the bore against gas bypass as well as providing lubrication for the passage of the round down the bore. You can do this in several fashions, tray lubing, tumble lubing, or lube sizing. Assuming that you have done some form of lube, before you load up all these nice new bullets into cartridges, load up a couple of dummy rounds and check them for chambering. It is possible that some cast bullets can be slightly oversized resulting in difficult chambering. If so, you will have to size the bullets before loading the rest of them. You should also check COL and make certain that the issue is not seating depth. Cast bullets can have a different ogive and may well require a different seating depth than the loads you worked up for Jacketed rounds. If they chamber nicely and you are happy, you can again call it a day and load up the rest.
Here’s the thing though. If you’re into getting the most accuracy you can out of these little silvery beauties, you may want to take it to the next level. Of course you can bag the entire process, run out and buy some Match Kings and be done with it! But, if you insist on going down the rabbit hole, then sizing is a not bad idea. In any case, it leads to a more consistent product.
So, we’ll take an aside here, for tumble lubed sized bullets.
Lee Sizing kits include everything required to size and lube on your existing press. But this process is pretty much limited to pistol, and lower velocity, flat nose rifle bullets and only with bullet designs specifically for tumble lube process.
If you are using a tumble lube bullet design, once you are finished weighing your lot, you can lube them up by taking a “take out food” plastic tray and placing the bullets in the tray.
Dribble some liquid lube (such as Liquid Alox) on them and shake the tray, rolling the bullets around until all the bullets are equally coated with the lube.
Next take a nice old cookie tray or similar device and line it with some waxed paper. Dump the bullets onto the paper, spread them out nicely to dry over night and call it a day.
The next day, it’s time to size these beauties up. The Lee system is very easy and I use it exclusively for my pistol loadings. Simply screw the die body into your press, snap the ram into the spot where a shell holder would normally go, slide the catch basin on top, line up your first bullet and raise the ram. Continue raising and lowering the ram until your bullet supply is exhausted
The next slug you insert will finish forcing the first through the die, and for this reason, flat points are in order.
But with all going well, you will eventually wind up with all your lubed and sized bullets in the top plastic catch basin, which is also the storage container for the die set.
I have found that I have less leading issues when I re-lube pistol bullets after running them through the Lee system. It is not listed as being necessary or even mentioned as a possibility, but it just seems to keep my bores cleaner, so I do it. if we look closely at the finished batch, you can see lots of clean lead exposed. This would be analogous to the driving bands on rifle bullets, but like I said, my bores stay cleaner so..
That’s great for pistol loads, but since we are loading up rifle bullets we’ll need a sizing press and sizing dies. And, since we are loading for accuracy, we’ll want to be driving these babies faster than plinking rounds, so we’ll also be gas checking them.
We will take a small break here to discuss an issue common to cast bullets but one which can be avoided. Leading! Leading is a condition in which the lead from the bullet plates itself to the edges of the juncture of the lands and grooves, following the rifling. This condition arises from any combination of the following factors, a rough bore, a too soft lead alloy for the velocity of the round, inadequate or inappropriate lube, or attempting to drive a lead bullet at jacketed velocities. We will discuss these issues in depth at another time, but for the purposes of this discussion, we are presuming that the alloy we are using, the lube that we are applying, and the velocities at which we will be driving these bullets will require a gas check. The gas check serves three purposes. It protects the base of the bullet from the heat of the burning powder, it helps seal the bore from gas bypass, and it helps remove fouling (if any) from the previous round. All three of these are hugely helpful in reducing the potential for any leading to occur, and permit the driving of the projectile at higher velocities.
Cast bullet designs are designated as being appropriate for gas checks or not. Gas check design bullets CAN BE used without gas checks (at appropriate velocities) but designs that are NOT DESIGNED for gas checks CAN NOT be gas checked. So, what are gas checks? Quite simply, little gilding metal (same stuff used for bullet jackets) cups designed to be fitted over the reduced base of projectiles designed to accept them. Gas checks can be applied by hand or outside of the sizing die, but we will be illustrating the lube/size/gascheck process in a single operation.
Sizing dies are available in specific calibers and bore diameters. The literature suggests that you slug the bore of your rifle and order the die appropriate to the measured bore diameter. I have had decent success simply using the die described as “typical” for the caliber I am loading. Lead, in all but the hardest of alloys, will obturate (squish) under the acceleration of firing the round and engage the rifling, but hey, if you want to go over the top, slug your bore and order the custom die.
We will be using the Lyman 4500 Lube Sizer with heater and Lyman Sizing dies. We will be using the RCBS top punch appropriate for the bullet casting die design we used to cast our projectiles. After following the manufacturer’s instructions for setting up the sizing press and inserting the die into the press, we begin the process by inserting a lube stick into the reservoir and heating up the press and lube. While the press and lube are warming up, let’s take a look at our die and the bullet we will be lube/sizing. Seen from the “outside” we can take note of the holes through which the lube passes and by eyeball get an idea of how far we have to drive the projectile into the die for effective lube application. It is important to remember that we are only sizing the driving bands of our projectile, so as soon as we have inserted the bullet far enough to achieve that, the only other consideration is effective lube application.
Lubes come in various hardnesses and some require heating to become soft enough to pass through the press, others are useable at room temps. Typically higher velocity rifle lubes require heating, that is the case here. The lube is designed to stick to the grooves in the bullet and to adhere to the bore during the explosion that propels the round down the barrel. The stuff is sticky, messy and generally a pain in the butt, but a leaded up bore is more troublesome, so get over it. I have actually come to like the smell of warm lube in the morning, but then I am sitting here writing a blog that no one will ever read, so I guess liking the smell is the least of my issues.
OK our press and lube are warm enough, so we start by turning the handle on the lube reservoir until it encounters resistance. Next, we take up a gas check and slip it into the hole in our sizing die open end up. If this is the first time you are using the die, or if you have cleaned it and it does not have lube in the channels, pre-lube your first bullet by wiping some lube on it by hand. Otherwise the first bullet you size may be the last.
Take a projectile line it up with the cup and hole and guide it into the top punch as you lower the press handle.
Lower the handle fully and raise the handle again. The bullet should pop out of the die. Inspect it to see if the lube channels are filled with lube and that the gas check has seated flush on the base.
No lube? OK there can be several reasons. One, the lube has not yet passed through all the channels into the die holes. Look to see if there is lube squishing into your die. Another reason is that the bullet may not have gone deep enough into the dies to align with the holes through which the lube passes to fill the channels. So check the lube dispensing handle for pressure on the lube reservoir, and eyeball the depth of the bullet in the die. Adjust if necessary. Yeah, go ahead and keep using the same bullet until you get it set up right.
Your finished bullet should have a pretty well filled lube groove(s) and your gas check should be fully and squarely seated on the base of the bullet. Place another gas check, line up another bullet run the ram down and up and check the channels and base. Chances are this one will be fine too, but every bullet, or every other bullet will require a little turn on the reservoir handle. Ok, lets do it again, and again, and again etc.
Well that wasn’t so bad was it? Oh you had a lube explosion? the stuff started oozing out around the rams and got all over your bench and floor? Two reasons, one you left the press idle without backing off the pressure on the lube reservoir, and two your lube got too warm. When this starts happening, unplug your heater and back off the pressure on your reservoir. This is a very messy process especially at first, but with a little practice and perseverance you will get better at it and make less of a mess each time. This is one process where I actually wear latex gloves, you might want to think about it too.
Well you now have what, about 225 lubed gas checked sized bullets ready to load up. Feel free to throw the rejects, the ones with the crooked gas checks, or buggered tips, where you forgot to line up the tip with the punch, into the scrap lead pile and recycle the lead. The lube will act as a “helper” flux anyway.
I make it a practice to wipe excess lube off the base of the bullet, the gas check really. If nothing else this gives me a chance to check the overall integrity of the bullet one more time. The last note here is that I base my loading and record the projectile weights as the weight of the FINISHED bullet, after application of the gas check and the lube. Again the process of reading this will probably take longer than it will take to actually complete 200 or so projectiles once you get a decent rhythm and procedure in place, so have fun!