Hand Loading for Precision Rifle
So you have a pile of brass that you picked up from your last range session. First thing is to put them in a tumbler and run it for at least 30min - 1hour, 4-8 hours and the brass get really shiny. I use corn cob media with Iosso brass polish which really helps shine the brass. With fresh media or after you have run several batches though the tumbler you can add more Iosso to freshen the media up. I add about 2 tablespoons without brass in the tumbler for the Iosso to mix before adding your fired brass.
They come out looking like this.
Now the next step is going to be to apply lubrication to the cases so that they do not stick in die during the resizing process. If I only need to do a few cases I use sizing wax and just apply it with my fingers but usually I do several at a time and just spray them with Dillion Case Lubricant. I spray a few squirts then shake the cardboard box and spray one or two more squirts. Then let the alcohol evaporate for a few minutes before sizing.
Now we need to set up our sizing die properly. Most sizing dies are going to be run down all the way until they touch the shell holder with the ram raised. Then you lower the ram and screw the die in an additional 1/8 to 1/4 turn before securing the locking ring. This is how I set up my dies for *general* loading purposes.
However in loading for precision we want to control the amount of set back we do to the shoulder. I always FL or Full Length size my brass. I had a neck sizing die which will only size the neck and not size the body of the case but you can run into feeding issues and I want the round to chamber every time. I was not able to see any appreciable difference in accuracy using a neck die so I sold it.
I use Redding Dies and prefer there type S bushing dies. They allow you to vary the neck tension of the round. I will get into this in more detail later. As stated I use FL sizing dies and I HIGHLY recommend the precision micrometer seating die in order to vary the bullet seating depth. If you are going to load different bullet profiles or will have a need to vary the bullet seating depth, spend the extra coin and get this seating die.
Now to set up your FL sizing die.
For a bolt gun you are going to want to take a piece of brass that has been fired in your weapon and measure the distance from the base of the case to the shoulder. We will use this measurement to then set the shoulder back 0.0015" – 0.002". In order to measure this you are going to need a special tool. I use one made by Hornday. It has several different inserts for different calibers. The gray piece (the insert) can be removed from the holder (red) for measuring different calibers / shoulder dimensions.
So with the tool attached to your calipers and the calipers zeroed take a piece of fire formed brass and measure the length from the base to the shoulder. As you can see it measured 1.624" and for a bolt gun we want to set the shoulder of the case back 0.0015-0.002" with our sizing die. (For a semi-auto 0.004"-0.005" is recommended).
Now it is very difficult to adjust the die just a few thousandths at a time. It can be done with patience and VERY small adjustments but Redding makes a Competition Shell Holder set that makes this task very simple. The set consist of 5 shell holders that vary in thickness .002" at a time. The 5 holders are marked +0.010, +0.008, +0.006, +0.004, +0.002 respectively.
In order to set the FL sizing die correctly you place the +0.010 shell holder in the press and run the ram all the way up. Then you screw in the FL die until it touches the shell holder and lock the locking ring in place. There should be no need for an additional 1/8 to 1/4 turn.
Now take a piece of clean fire formed brass, place it in the shell holder and run the case all the way in the die until the handle and ram are bottomed out. Lower the ram and remove the brass and re-measure the case. The case again measured 1.624" so the shoulder was not setback at all. Next I removed the +0.010 shell holder and installed the +0.008 in the press.
Again run the brass all the way in the die until the ram and handle of the press are bottomed out and remove the brass and re-measure.
As you can see the shoulder has been set back 2 thousandths so we have found the correct shell holder.
Now more on neck tension:
If you do not have a bushing style FL or Neck sizing die then the amount the neck of the case is squeezed down will be fixed based on the dimension of the die itself. So the OD of the case neck will be the same no matter what manufacturer of brass you run through the die (neglecting any spring back). The issue is that different brass manufactures have different case wall thicknesses. Example: Winchester brass is thinner than Lapua brass, so this means that if the OD of the Winchester and Lapua were sized to the same dimension but the Lapua brass is thicker then the ID of the Lapua case neck will be smaller than the ID of the Winchester case. Thus the Lapua case will have more neck tension on the bullet. With a bushing style die you can change out the bushings which size the neck to get the desired neck tension on the bullet no matter what brass you have. In order to determine what bushing you are going to need you need to measure the OD of the neck of a loaded round.
As you can see the round measures 0.337". We want to select a bushing that is 0.002-0.003" under that measurement (Redding calls for 0.001" but most guys use 0.002"-0.003" under). So for this instance we would select a 0.335" bushing for the Lapua Brass (in comparison I use a 0.330" for Winchester).
So now that you have the dies / shell holder and the proper bushing installed in your FL die you are ready to size all of your fired brass casings.
One other note is that from the factory the Redding die comes with an expander ball installed in the die which is grey and a black piece which just holds the decapping pin in place is included in the box in a small Ziploc. You want to remove the silver expander ball and install the black piece. What the silver one does is as the fired piece of brass goes in the die the case mouth will be enlarged from firing and the silver expander ball will pass through the case neck without contacting it. At the top of the ram stroke the neck will be squeezed down by the bushingand as you lift the handle and lower the brass the expander ball which is now inside the case cannot pass freely though the now smaller ID neck. This will cause the expander ball to expand the neck on the way out of the case. Well this has just ruined your 0.002* of neck tension that was applied by the properly selected bushing. Here is a picture of the grey expander ball removed and placed in the bag that the black one comes in. The black one will not touch the case neck when exiting the case after the neck has been sized by the bushing.
The next step is to clean out the primer pockets. During the resizing process the decapping pin of the sizing die removes the spent primer. However, the primer pocket will have residue which is not easily removed during the second round in the vibratory tumbler which will come a little later. Also the primer pocket itself may become slightly deformed during firing. In order to have uniform primer pocket dimensions for both roundness and depth while simultaneously cleaning the primer pocket I use a primer pocket uniforming tool from Redding. I chuck this up in my drill for a quick cleaning. Here is a picture of the tool as well as a before and after.
Most brass manufactures use a punching / stamping process to create the flash hole. This can create a small burr that can remain inside the case attached to the flash hole. A flash hole deburring tool is needed to clean up this chip and ensure the hole is round. Lapua uses a drilling process to create the flash hole and thus round holes with no burrs exist. With Winchester brass I recommend cleaning up the flash hole to remove any burrs for precision ammo. This step is only necessary once to remove and uniform the flash holes. Again I do not perform this step with Lapua brass as it is not necessary nor for plinking ammo. But for precision rounds with brass manufactures who use the punch / stamping method I would perform this added step.
When a round is fired the case expands to take the shape of the chamber. During the resizing of the case the case is squeezed back down and the shoulder is pushed back toward the base. The case is enclosed on the bottom by the shell holder and on all sides by the die but not the top. So what happens is as the shoulder is bumped back you are taking what was a larger piece of brass and squeezing it down. Like if you put a partially filled balloon in your hand and squeezed it. The extra air and balloon have to go some place. Well the same holds true with the brass. The brass *flows* around the shoulder and the neck of the case elongates. So the OAL or Over All Length of the case will grow. This is the reason that it is necessary to trim brass back to length. This process may not be required after each and every firing as brass case lengths have a tolerance. IIRC for .308Win the range is 2.000" – 2.015" with a recommended trim length of 2.005".
There are a several different tools on the market to trim brass to length. I started out using a case trimmer by Possum Hollow which with a drill attachment chucks up in a drill and you insert the case and trim it to length.
After trimming you should have a shoulder that is square to the neck. The next step is to chamfer the inside of the case mouth. What this ensures is that during the bullet seating operation the bullet will slide into the case with minimal resistance and not scrape any jacket off the bullet. This can be done with a hand held tool. I recommend a VLD or Very Low Drag profile. The VLD tools cut the inside of the case mouth to a shallow angle which are usually 15 degrees. This removes any burrs left on the inside of the case mouth from the trimming process.
Next is called the deburring process where the outside of the case mouth is cleaned up from any burrs from the trimming process. This usually leaves a 45 degree bevel on the outside of the case mouth. Again this step can be performed using a hand held deburring tool.
I have a specialty tool made by Giraud Tool Company that trims, chamfers and deburrs all in one step. Here is some before and after pictures, notice the 15 degree chamfer on the inside of the case mouth and the 45 degree bevel on the outside.
At this point the brass has been fully prepped. I run them back through the tumbler one more time for about 5-10min to get the oil off of the cases from the sizing operating and remove any burrs or residue from the trimming and primer pocket operations. Once finished tumbling you need to inspect the flash holes for any media that may have become stuck in them. I just take a small screwdriver and knockout any media that has become lodged in the flash hole.
The next step is to prime the brass. I use a cheap Lee hand priming tool. (I now use an RCBS which is better). Fill the tray with primers and seat a new primer in the fully prepped and cleaned brass.
Congratulations you now have fully prepped and primed brass ready for loading.
Now for loading:
You will need to consult a loading manual for recommended charge weights and powder selection. You should always start at the lowest recommended charge and work up the load in increments from there. A rule of thumb is 1% at a time. For instance if the recommended amount of charge for a particular powder was 40.0 – 43.0 grains in your caliber then you would want to start at 40.0 grains of powder for your first loads. I would then work up in 1% or 0.4 grain increments at a time. 40.0, 40.4, 40.8, 41.2 ect. You should find the load with the best accuracy and stop there.
During load development you need to be wary of any signs of pressure that the gun or the brass may exhibit. Some signs to look for are flattened primers, ejector marks on the case head or a sticky bolt lift. These are the beginning signs of pressure. Worse signs would be primers that are blown out of the primer pocket, cracks in the case near the case head or case neck and cases where the head has separated. These indicate that you are WAY over pressure. At the first sign of ANY pressure STOP! Pull any remaining loads with that charge weight or higher and drop the charge weight of your load.
Next we will remove the FL sizing die and install a bullet seating die in the press. As stated earlier I highly recommend a micrometer seating die to be able to easily vary the seating depth of the bullet. To install the die back out the micrometer adjustment all the way then raise the ram of the press and screw in the die until it contacts the die body then back it out a 1/2 turn so that the numbers are facing you. Secure the die by tightening the locking ring. (Note there are setscrews on the locking rings so that once you set the die’s height the first time you can secure the set screw to that the ring will no longer turn. Now when you remove the die’s and reinstall them the locking ring and die are already set to the proper depth every time).
So we have consulted our loading manual and have a desired charge weight to begin with. I use a loading block to hold the primed cases upright and place a funnel on the case in order to dump the charge.
Next I fill my RCBS Charge Master 1500 with powder. This machine allows you to select a powder charge and it will throw the amount you selected then stop. This machine is a real time saver and if you shoot enough to justify it I highly recommend buying one. This machine as well as the Giraud trimmer significantly cuts down the time of hand loading by about half.
Next I dump the charge into the case and seat a bullet on top and place it in the press. Run the case and bullet all the way up in the die until the handle stops.
ow we will need to remove the loaded cartridge from the press and measure the length to see how much we need to adjust the die so that the bullet is seated to the proper depth. If you are just loading plinking ammo you may just measure the OAL or Over All Length of the loaded round as shown here.
The problem with going off of OAL for precision rifle rounds is that the length of bullets will vary slightly and thus the OAL of your loads will as well. I only use OAL to ensure that the loads will fit into a magazine. The whole key to accuracy is consistency. Consistency in your shooting position, ammo, trigger control, breathing, ect. What we really want is for the ogive of the bullet to be the exact distance away from the rifling each and every time. Varying the seating depth of the bullet can and will affect accuracy so we want this to be consistent. The ogive is the start of the bearing surface of the bullet. The bearing surface is what contacts the rifling which induces the spinning of the bullet which leads to its gyroscopic stability. So really what we want is a consistent measurement form the base of the case to the ogive of the bullet. This ensures that the distance from the ogive to the throat of the gun remains constant as well. In order to measure this you will need a bullet comparator tool. I use one from Sinclair but Hornady as well as other manufactures make them. They fit on your caliper and you can change out the insert for different size bullets just like the Hornady tool used for measuring how much we bumped back the shoulder during the resizing process.
So to reiterate the OAL of the rounds will vary. It will depend on the consistency of the bullet manufacturer. However the length from the base to the ogive should be the same each round with quality dies. This is the important measurement.
When I received my rifle I did my load development and found that the gun likes a 2.091" base to ogive length. I ran the bullet in the die and measured and it was 2.102". So I adjusted the die 0.011" as each tick mark on the die is a thousandth of an inch and fifty thousandths per turn. So after moving the die 11 tick marks I ran the bullet and case back in the die and re-measured.
As you can see it is VERY easy to PRECISELY vary bullet seating depth with a micrometer seating die. If you do not have a micrometer seating die then you have to try to adjust the die itself. With the very coarse threads of the die and having to keep loosening the locking ring and retightening it gets frustrating quickly.
During load development you are going to need a starting length for your rounds. A decent place to start your lengths is 0.010" – 0.020" off of the rifling. Then do what is called a ladder test where you start at the low end of recommended powder charge and increase the charge weight 1% at a time. Once you have determined the load that shoots the best groups you can then vary the seating depth 0.005" – 0.010" at a time in and out. This will fine tune the load and usually decrease the group size by either increasing or decreasing the length. Be careful loading longer as once the bullet touches the lands this can cause the pressure to increase and what was a safe load before can become an over pressured load. It is recommended if you increase the length to drop the powder charge to the original weight and work back up.
We end up with a loaded cartridge that is very consistent round to round for brass uniformity, neck tension, powder charge and length. This ammo is custom tailored to your rifle and is cheaper and in just about all cases better than factory ammo.
I hope this has been informative.