.308 Jackets From .223 Brass Using Corbin 9mm to .308 Dies

.308 Jackets From .223 Brass Using Corbin 9mm to .308 Dies


223 brass is plentiful and can usually be picked up from leave-behinds of .223/5.56 shooters at many ranges. This has resulted many to ask the question: “Can I make .308 jackets from .223 cases similar to making .223 bullets from 22LR? “ BT Sniper did some work several years ago on this issue, but seems to be in the backwater now. This thread will be dedicated to how I make .308 jackets from .223 Brass for HEAVY bullets.

I make most of my 175 grain .308 bullets from 5/16 inch copper tubing using a set of dies that BT Sniper made for me a few years ago. The cost of copper tubing has incrementally increased since then from about 5 cents per jacket then; to a current 10 cents per jacket based on 50 foot 5/16 ACR Refrigerator copper tubing prices. Reduction of material costs for 175 grain .308 jackets can be achieved by using 5.7 x 28 once fired brass compared to 5/16 ACR copper tubing (once again – thanks to BT Sniper for his past efforts in this area). At times I find a few of these abandoned at the ranges I use every once in a while; so I collect them and make .308 jackets when I accumulate enough. Prices for these have also risen over the last two years going from 3 cents per case 2 years ago, to an average of 10 cents per case from various sources on the Internet currently.

My copper tubing jacket maker is optimized for 175 grain jackets. I could make heavier .308 bullets using these jackets; but I would then have an exposed lead nose – whereas the current jackets have the core coming to a really nice point with the lead just below the closed opening.
I will need to have BT Sniper make up some additional punches so I can also make jackets for lighter fully jacketed bullets (147/150 grain) and heavier fully jacketed bullets 180 to 210 grains.

Step One - .308 Jackets from .223 Brass

As is the case with almost all reloading and swaging operations, Cleaning the Brass is the first step. I use a Harbor Freight ultrasonic cleaner with Dawn Detergent and Lemi-Shine to clean my brass, then air dry.

Next operation is to de-prime the .223 brass. De-priming is CRITICAL for making jackets from .223 cases. When we size the case down; the large amount of brass at the base has to go somewhere, and the empty primer pocket allows it to flow inward. If one fails to de-prime the brass; a substantial tip will be created at the base of the bullet jacket when the primer is squeezed and flows backwards out of the primer pocket. Learned this when I tried making jackets from some Berdan Primed .223 brass. NO BUENO.

Step Two - .308 Jackets from .223 Brass

Some will cut the case down at this point, but I find that problematic. The .223 case is tapered from the rim to the shoulder; cutting the case down at this time with either a saw or a tubing cutter will usually result in a mouth on the jacket that is not fully 90 degrees to the side of the jacket.

Neck expansion for the .223 cases is required in my process. Expanding the neck as much as necessary will result in a split mouth unless the mouth is annealed first. I use a 1lb propane bottle and propane torch to heat the mouth until it is glowing red. Only heat the mouth at this time, not the whole case as we DO NOT want to affect the rim which will be required to function in a shell holder later.

Attachment 263839

Step Three - .308 Jackets from .223 Brass

I had Corbin make me a punch that is .250 in diameter to open the mouth after annealing. This punch fits into the “Top Punch Holder”. The Corbin Shell holder adapter fits into the Corbin Press Ram, which in turn holds a .223 Shell Holder. First we apply a light coat of swage lube on the point and sides of the punch using our thumb and finger so that there is lube between the punch and .223 case neck, this will allow a smooth expansion of the neck. Place a mouth annealed .223 case into the Shell holder, cycle the ram until there is a slight expansion of the neck, lift the ram and then cycle the ram again expanding the neck a little at a time 4 or 5 times until the neck is fully expanded to .250 inside diameter.

Attachment 263841


WARNING – If one gets too aggressive and trys to expand the neck in a single pass it will probably result in either a collapsed neck into the case – or a splt neck. A split neck will not ruin the case for making a jacket; but it and a collpased mouth make recovering and using the case in subsequent steps more difficult. A neck collapse can be seen in the case to the right and a neck split in the case to the left below.

Attachment 263840

That small metal piece to the right of the brass cases (previous picture) will come into play a little bit later. The next step “IS CRITICAL”; that being annealing the entire .223 case after expanding the mouth. There is a lot of brass in the base of the .223 case. Unless the case is adequatly annealed, it will be exceptionally difficult to size the .223 case from 0.378 at the rim to a uniform 0.307 or 0.3075 the length of the Jacket Blank. Failure to adequately anneal the .223 case could result in a Stuck case in the sizing die; or worse a damaged die in the sizing step or damage to other dies in later steps.

Many who are making .308 Jackets from 9mm, .223, or other brass requiring dramatic reduction are performing several stages of reduction in size – with an annealing in between each stage. I am only doing ONE full case annealing; and sizing step in my process. I am using a swaging press (Corbin CSP-1) so there is an advantage in machinery, and some steps are tailored to the specific size and set up of the Corbin CSP-1 press; but those using other presses should be able to determine similar operation capabilities.

The annealing must be particulalrly at the base of the .223 case; but also the entire length. The goal is to get the case Cherry Red. Fumes may be generated, so this should be an outdoor effort if possible. One draw back is that it will be very difficult to judge the case coler when heat treated if in a sunny area or on a bright sunny day.

I use a 2 Inch sheet rock screw and insert it into the case mouth; holding the screw with a pair of needle nose pliers. I used to use a 16 pennu nail; but found that the case would wobble on the nail. I found the ridges of the screw allows more control in holding the .223 case in the flame, and moving it to get a uniform heating of the .223 case during annealing.

Step Five - .308 Jackets from .223 Brass




Once again it’s time for a cleaning in the Harbor Freight Ultrasonic Cleaner with Dawn Dish Detergent and Lemi-Shine.

Step Six - .308 Jackets from .223 Brass
It’s now time to reduce that .223 case down to .307 or .3075 across it’s entire length. I use the Corbin 9mm Cartridge to Jacket convertor die to accomplish this. http://www.swagedies.com/mm5/merchan...ry_Code=jmkits
Remember that little piece I mentioned previously (to the left of the .223 cases in the picture)? It is a ¼ collet for a Dremel type tool. It fits over the vertical punch with the die set, and allows me to better align the case with the sizing die. I found that without it I would get some cases that would go in skewed off center; resulting in a jacket base that was not square with the sides of the jacket. This has reduced the numbers of reject jackets and helped with consistency of production of cases. Home Depot is one source for these collets. https://www.homedepot.com/p/Rotozip-...-CN1/203077224

The collet is slid up to touch the mouth as the .223 case is pushed up until the base of the case touches and enters the mouth of the die – while cycling the ram up. The Corbin 9mm to .308 die is only screwed into the press 3 to 4 full turns. Then when it is all aligned, the handle is pushed fully down cyclng the ram, resulting in the case base being reduced and the case being firmly squeezed into the die mouth.

Attachment 263851

The press arm is pulled up all the way; then the die is turned into the press 1 and ½ to 2 full turns, the press handle and ram are cycled again. Followed by repeating this process multiple times – each time turning the die down 1 and ½ to 2 full turns. This process allows incremental sizing of the .223 case using the greatest leverage (when the handle is closest to the bottom stroke) to size the case. This is how I am able to reduce the case dimension from 0.378 inches down to 0.307 inches in a single pass (although it requires numerous cycles of the press from each case sized. The following three pictures show the incremental screwing in of the Die into the Press as described.

Attachment 263848
Attachment 263849
Attachment 263850

The case is going to grow considerably in length during this process, and we are almost to the limits of the ability of the CSP-1 press to function in doing so.

We now have a condition where most of the .223 case/jacket is still in the die. If this were a 22LR die set for making .223 bullets, we would simply place another 22LR case in the press and push the previous one through. This DOES NOT WORK when making .308 jackets from .223 cases. Trying to do so will result in a case telescoping into the previous case and making it next to impossible to get the two damaged .223 cases/jackets out of the die.

The way I avoid this is by using a “Pusher Punch” that I made. The rod is a steel rod approximately 0.188 to 0.190 in diameter; and about 2.3 inches long. To use the rod to complete the sizing cycle on the .223 case/jacket we lift the handle all the way up lowering the ram. We then unscrew the die until it is 3 to 4 full turns in the press (or until we can insert the “Pusher Punch” into the jacket from underneath.

After inserting the “Pusher Pin” into the bottom of the jacket, we then lower the handle until the Ram Punch touches the “Pusher Punch”.

Attachment 263846

Push the handle down, causing the ram to rise and the “Pusher Punch” will push the formed jacket up through the die. Lower the ram, screw the die in and repeat until the “Pusher Punch” fully ejects the formed jacket.

Attachment 263852

Repeat Step Six for all .223 cases/Jackets.

Step Seven - .308 Jackets from .223 Brass

We now have a group of .308 jackets we have formed from .223 brass cases. These new jacket blanks are 0.307 to 0.3075 in diameter and about 2 inches long. A 210 Grain bullet is about the MAXIMUM that I can make in my Corbin Rebated Boat Tail 8s Ogive Swage die set. So this means that a 1.27 inch long Jacket is the most I can use in my dies for making the 210 Grain bullets.

I cut the jackets to 1.27 inches long using a tubing cutter. I have a Harbor Freight mini chop saw that I have used for cutting jackets in the past; but prefer the tubing cutter. I prefer the Home Flex Tubing Cutter for this job as it has a wide support roller on each side of the cutter. This helps in getting a square cut at the mouth. Also; given it’s size I find it comfortable to use, and ease of set up for each Jacket Blank to be cut.

In the following picture from top bottom to top there is a 2 Inch long jacket blank. A 1.27 inch long cut .308 jacket, and the scrap end (May be able to make some 80 to 100 grain .308 bullets out of these some day). Then a finished 210 grain .308 Boat Tail Bullet I quickly made up for this posting.

Attachment 263847