Reloading: Brass Resizing

The resizing step does exactly what the name implies. Using a die like this Hornady .308 resizing die, you squish the fired case back into its original dimensions.

The resizing step does exactly what the name implies. Using a die like this Hornady .308 resizing die, you squish the fired case back into its original dimensions.


Part 1: Want to Reload Your Own Ammo? Basic Questions to Consider

Part 2: The Reloading Process
Part 3: The Gear You’ll Need and What It’ll Cost You

Part 4: Brass Cleaning and Preparation to Load

Part 5: Brass Resizing

Part 6: Trimming Cartridge Cases

Part 7: Repriming the Cartridge Case

Part 8: Powder, Propellants, and Pressure

Part 9: All About Primers

Part 10: Projectiles: Materials, Weights, and Styles

Part 11: Seating and Crimping Bullets

Part 12: To Crimp or not to Crimp

Part 13: Final Inspection and Packaging Tips

Last time, we discussed ways to clean used brass to get it ready for the actual reloading process. Now, it’s time to talk about actual brass processing – getting it ready for a new primer, propellant, and projectile. The steps you have to take depend on the source of your brass and whether it’s a straight wall or bottleneck cartridge.

Sources of Brass

Depending on where you get your brass for reloading, you may have to perform from zero to several steps to prepare it for reloading. You can certainly buy ready-to-load brass that’s never been fired. The first time you load it, you usually don’t have to do anything. The brass vendor should have delivered it clean and sized and shaped to proper specifications. Of course, after you load and fire this “new” brass, you’ll need to clean, inspect, resize and maybe trim to get it back to original specifications.

Speaking of buying brass, you can also buy once-fired brass. Enterprising folks out there collect, sort, and clean brass that’s been fired at places like police and military ranges. That brass came out of a new box of factory ammunition, was fired on the range, then collected for resale, so it’s in pretty good shape. If you start your process with once-fired brass, you’ll need to inspect each piece. There’s no telling if some were damaged during its initial use. Some once-fired brass may already have the primers removed and some may not. Most of it is at least cleaned, but most of what I’ve seen still needs to be resized and trimmed if it’s bottleneck rifle brass.


Even with factory new brass, it’s a good idea to look over each piece, even if you do so when picking it up to go into the loading press.

One of the first steps during inspection is to toss cases that are not made of brass. They're generally not reloadable.

One of the first steps during inspection is to toss cases that are not made of brass. They’re generally not reloadable.

Look for any signs of cracks or splits. If you see those, toss that case! A few cents isn’t worth the risk of a case rupture when you fire it later. I also like to look for for abnormal bulges anywhere in the brass. You might see these around the base. For example, .40 S&W cases fired from guns with partially unsupported chambers can create bulges near the cartridge case base. You can purchase push-through dies that reform brass like this, but just know that even when reshaped, that’s still a weak spot as the brass had been overworked. You’ll have to make your own call as to whether you use or toss these cases. I toss them as I prefer to operate with an overabundance of caution. I call out the .40 S&W example, but you might find bulges and significant indentations on any caliber for a variety of reasons.

If you plan to load your new cartridges to the maximum pressure and velocity range, you also might look for signs of previous overpressure situations. Does the spent primer look flattened around the edges or is the firing pin indentation all flattened around the edges? That might be a sign that the case has been subject to higher than normal pressure.

If you’re working with previously fired range brass, be picky. You don’t know the history of any given cartridge case. You’re not hooking up with just a piece of brass, but rather every previous conflagration that brass has had before. If you see signs of abuse, toss it.

Keep an eye out for brass with the "wrong" primer sizes like these two on the right. Even though they are .45 ACP cases, they have small pistol primer pockets. You can reload them, you just don't want to mix them in the same batch as regulars when adding new primers.

Keep an eye out for brass with the “wrong” primer sizes like these two on the right. Even though they are .45 ACP cases, they have small pistol primer pockets. You can reload them, you just don’t want to mix them in the same batch as regulars when adding new primers.

One more thing. I’m starting to find a lot more once-fired brass with the “wrong” primer sizes, so you’ll want to look out for that. For example, normal .45 ACP cases use a large pistol primer. Yet I see quite a few Blazer and Federal cases with small pistol primer pockets. I’ve also seen .308 Winchester cases that small instead of large rifle primer pockets. New ammo manufacturers will sometimes do runs like this so you have to look out for these anomalies. Trying to stuff a large primer into a small pocket will bring your process to a grinding halt, especially if you’re using a progressive reloading press. It’s easier to catch these flukes during the inspection step.

Should you sort your brass?

Depending on how you’re going to load, you may or may not want to sort your brass by headstamp. Different cartridge case manufacturers have slight differences in the way they make their brass. In theory, exterior dimensions and things like case mouth dimensions will always be the same. However, interior specs like wall and interior base thickness will vary. You can easily see differences by weighing a few random cartridge cases.

For example, I weighed these randomly picked .223 Remington empty cases and found the following:

Lake City: 97.0 grains
Winchester (plated): 96.9 grains
Winchester (brass): 97.2 grains
Winchester (5.56mm brass): 98.6 grains
Federal Cartridge: 95.8 grains
PMC: 96.2 grains
Hornady: 96.9 grains
Perfecta: 100.6 grains
PSD: 96.8 grains
Remington Peters: 94.8 grains

If there’s more brass material inside of one case, then the interior volume is going to be smaller. When fired, this cartridge will have higher pressure than one with a larger interior volume. If you’re loading at the maximum end of the scale, this could become an issue. Accuracy can also be affected by using different brass in any given lot. Don’t get too concerned about this for recreational shooting – the differences are usually pretty small. I did an informal test with .223 Remington a while back, using moderate loads, and didn’t see much practical difference. Certainly, if you’re shooting a precision bolt rifle, you will see a more significant variance.

For pistol brass, unless I’m trying to create some super accurate load, I don’t bother sorting by head stamp. Besides, I load most of my pistol cartridges to moderate pressure and velocity so I have safety margin when it comes to pressure.

The same rule of thumb can apply to rifle cartridges. If you’re making plinking ammo not loaded to extreme maximum pressure, there’s not much reason to sort by head stamp. If you need top end velocity or extreme accuracy, then consider loading for specific head stamps only.

Resizing and decapping

The process of resizing involves using the reloading press to jam a cartridge case into the interior of a resizing die. “Resizing die” is a fancy term for a hollow tube of metal where the inside is cut to the exact original shape of a new cartridge case. By jamming a used case, that’s probably stretched a bit, into the resizing die, the brass is forced back into its original size and shape.

This Hornady .308 Winchester resizing die also has a decapping pin that knocks out the old primer. The case on the right has already been resized.

This Hornady .308 Winchester resizing die also has a decapping pin that knocks out the old primer. The case on the right has already been resized.

Decapping means poking out the used primer from the cartridge case. A steel pin sticks out the bottom of most resizing dies. When you press the case into the die all the way, the pin pushes the spent primer out from the inside. You can buy a dedicated decapping die that does nothing but remove primers from virtually any type of case with a “boxer” (one-hole) primer pocket. There are reasons you may want to do that separately from resizing. We’ll get into that in a later article in this series.

Resizing straight wall pistol cartridges is easy. Most resizing dies have a carbide ring just inside the mouth. This steel is hard and slippery so the case won’t get stuck in the interior of the die. This is handy because you don’t need to lubricate these types of cases before resizing. Most straight wall case resizing dies also include a decapping pin, so the old primer is removed in the same step.

There is a second step to pistol case resizing we ought to mention here. A second case mouth belling die (or case mouth expansion die) opens the mouth every so slightly so there is room to insert a new bullet in the seating stage. The resizing die tends to close the mouth, so the case mouth expander opens up the lip just enough to allow a bullet to start the seating process. Less is better in this step as the bullet is held in place not by crimping, but by the case neck tension created during the seating step when the bullet is forced into the case. If you expand the mouth too much, the bullet will not be secure, not matter how much you crimp later. We’ll talk about this in detail in the “Seating and Crimping” article soon.

If you look carefully, you can see that the case on the right has a very slight expansion right at the mouth. It's already been through the case mouth expansion die.

If you look carefully, you can see that the case on the right has a very slight expansion right at the mouth. It’s already been through the case mouth expansion die.

Resizing bottleneck rifle cases like .30-06, .308 Winchester, or .223 Remington is a bit different.

First, due to the more complex shape of the resizing die, it’s hard and expensive to make a carbide insert. The bottom line? You need to lubricate your cases before resizing. If you don’t, the case will almost certainly get stuck inside of the die. And when I say “stuck” I really, really mean it. You’re not getting it out by tapping or with a pair of pliers. You’ll need to use a stuck case remover. That process involves drilling out and threading a hole in the stuck cartridge base, then using a bolt to slowly back it out. It’s almost like using a car jack, except your pulling the case out of the die with the “jack” as opposed to lifting something.

You need to lubricate bottleneck cases like these .308s before resizing. You can use a spray or roll them around on a grease pad like this.

You need to lubricate bottleneck cases like these .308s before resizing. You can use a spray or roll them around on a grease pad like this.

There are different ways to lubricate cases. If you use an oily spray or pad to distribute lubricant, then you’ll need to wipe that lubricant off after resizing. You don’t want oil getting inside the case where it can contaminate propellant. Also, brass cases and gun chambers are supposed to be dry. During the firing process, the brass expands and temporarily “sticks” to the inside of the chamber, thereby helping the bolt face keep the case in place while the bullet exits. Lubricant on the case tends to screw up this process. You can also use wax type lubes like Hornady One Shot. These aerosol sprays deliver a “drier” lubricant to the case while the carrier spray (alcohol or similar) evaporates. With these types of lubes, you have to wait until the cases dry before resizing. On the plus side, you don’t have to clean the lubricant off after. Do be patient. If you try to resize before the lube spray has dried, you’ll end up with a stuck case.

Another difference is that with most bottleneck rifle die sets, the case mouth is expanded by the resizing die. A “bell” on the decapping rod is pushed into the case body as the case is resized. As the case is withdrawn from the die, this bell is pulled back up through the case mouth, opening it back up to proper dimension.

I've removed the spindle on the Hornady .308 resizing die so you can see the decapping pin and the "ball" that opens up the case mouth as the case is pulled from the die.

I’ve removed the spindle on the Hornady .308 resizing die so you can see the decapping pin and the “ball” that opens up the case mouth as the case is pulled from the die.

For bottleneck rifle cartridges, you might hear of full length vs. neck resizing. That topic is too involved for now, so we’ll cover that in its own article at the end of the reloading process series. For now, know this. If you’re reloading ammo for use in multiple rifles or semi-automatic rifles, use a full-length resizing die. That shapes the entire cartridge. If you’re loading your own ammo, for use only in the same manual action rifle, you can resize the case neck only. From previous firings, the overall case will be sized perfectly for your chamber. Neck sizing only, when you can, might improve accuracy and increase the life of your brass.

Next up…

Next, we’ll get into case trimming. If you intend to reload bottleneck rifle of pistol cartridges, you’ll run into the need to trim your cases back to proper length after resizing. There are many ways to do this, and we’ll take a close look at several examples for both low and high-volume reloaders.

About the author: Tom McHale Literary assault dude writing guns & shooting books and articles. Personal accountability rocks!

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  • Jefferey Walters April 29, 2020, 11:27 pm

    I am brand new to reloading and chose to clean and then hand prime my 9mm brass… I am now ready to get on the AP press and load and am realizing that if I resize my brass isn’t it going to explode the new primers I have in my brass? Can I just remove the decapping pin from the resizing die? Or what do I do?

  • Rob Wurster January 20, 2020, 8:46 pm

    Great articles and comments. I’m in the middle of getting my 556 reloads to chamber properly. It seems that the first round that is racked gets stuck. Have tried to adjust some cases and am on the second day of troubleshooting. I was worried about dimples on the shoulder and after reading the advice from Boss I know now that I was using too much lube. Who knew? Tweedmus gave me some examples of resizing tricks like not extending the pin down too far in order to get a correctly sized shell. Overall, this was one heck of an article filled with a lot of sound fundamentals from everyone! Thanks for restoring my confidence in my abilities. I’ve been reloading pistol ammo for about a year and have almost got it down. Bottleneck reloading is a totally different ballgame.
    Thank you,

  • Frank McHutchison January 1, 2020, 8:44 am

    nice to see enthusiasts chewing the fat( Amicably !
    I learned quite a bit from this thread.
    Retired shooter in Western Australia 32 years Shooting and Loading .
    Thank you ,Happy new year to you all.

  • Larry September 4, 2017, 1:22 pm

    Can i take different range 223 brass and resize all at the same die setting without having to change resizing die for each different manufacturer? I have 10 different head stamped cases and want to resize all at the same time. I will load powder at less than max. Just for pinking with my ar-15’s. Thanks Larry

  • Zupglick April 3, 2017, 2:07 pm

    How about taking these articles and putting them together in a pdf and/or Kindle file?

  • Kent April 3, 2017, 11:51 am

    You failed to mention head space for bottle necked cartridges.

  • Pantexan April 18, 2016, 11:54 am

    Ensure you sort out the Berdan primed cases from Boxer primed cases. If you try to decap a Berdan primed case you will either break or bend your decapping pin or push it up into the resizing die. To differentiate the Berdan primed from Boxer primed look down into the case mouth Boxer primed cases have a single charge hole while Berdan primed cases have two charge holes. For straight walled pistol cases this is an easy task. For bottle necked cases you may need a flashlight to see to the bottom of the case. Usually the Berdan primed cases are European manufactured. I have picked up 7.65 Browning (.32 ACP), .380 ACP, 9mm, and .308 Winchester that are Berdan primed and broken a decapping pin or two.

  • tweedmus April 16, 2016, 10:57 pm

    Do not ever use any liquid lube on case necks; it is too easy to contaminate powder. Dry graphiteappliedwith a small brush is what’s needed, sold by everyone who supplies reloaders.

    • Alan April 17, 2016, 10:44 am

      Well, I’ve been reloading for 38 years, and have used liquid lube on necks without ANY issues.
      I load 11 different Rifle calibers, I have never had a failure to fire or “squib” load occur in thousands od rounds.
      I also record my velocities, and my pet loads are always consistent.
      I’m not sure what you mean by “easy to contaminate”, but I haven’t seen it.

    • Abby Normal April 18, 2016, 10:29 am

      I like to use Pam baking spray, decap/resize, then clean in an ultrasonic cleaner before polishing with walnut shells with a little NuFinish mixed in. When my brass is done it looks better than new. I’ve never had any bad rounds from my stuff but I have had 2 squib rounds from store bought stuff. Needless to say I don’t use store bought ammo anymore and I can reload my own for 1/2 the cost and mine is more consistent and more accurate. Not bragging but it’s easy to reload and you have all the control. Just do it with care, keep a clean work area, and don’t just throw it together. Do the research and buy a chronograph to measure your velocities for each recipe (powder, primer, bullet) for the speeds you want. I actually like reloading more than I do shooting and my ammo closet is proof. And ALWAYS wear goggles at the very least – especially during the priming stage.

  • Dan Schoenheider April 15, 2016, 11:41 pm

    I try to read all I can on reloading. I have been loading straight wall cases for my revolvers and just started a couple years ago with bottle neck rifle rounds. Maybe someone can tell me why I can cycle my loaded .223 reloads in my Savage bolt action but the same rounds will not even seat home enough in my Ruger SR 556 to fire. I know a bolt action has a cam action to push a round home but it should still be sized right for my Ruger. I inspect every piece of brass before reloading it. I clean them first, resize and deprime the cases in my Dillon dies and then trim them to factory length on my RCBS trimmer. I am frustrated and for now have decided not to mess with bottle neck cartridges. Can someone tell me what’s up with my Ruger, is the chamber smaller than the Savage or what?

    • walt April 16, 2016, 9:30 am

      any time you are reloading for an ar-15 you must full length resize the cases. not all chambers are the same size! if you use spent cases in the same bolt action rifle you can get away with neck sizing only but after a few loadings of that case in the same bolt action you will notice that the cartridge doesn’t chamber as easily as it did before–that is a sign that you must full length resize that case before using it again in that bolt action rifle. don’t give up on reloading bottle neck cases. it will provide inexpensive ammo for you and you may find the process enjoyable and a good way to spend time away from the tv or any other useless activities.

    • Boss April 16, 2016, 9:24 pm

      Good info from Walt.
      When reloading for a semi-auto rifle you should use Small base dies, usually designated by SB on the sizing die.
      But again, as Walt said chamber sizes vary from rifle to rifle and you may not need SBs for some semi-autos.
      Your rounds cycle in the bolt action with muscle pressure, sometimes you may be partially resizing the brass when you force the bolt home and lock it then when you fire it, it is fire formed to the chamber,
      With the semi-auto the recoil spring chambers the round so the brass must be sized to fit the chamber.
      You may want to separate the bolt action and semi-auto brass then neck size one and full length size the other thus extending the life of your bolt action brass.
      When sizing the brass do not use too much lube as this can cause dimples in the shoulder.
      Also be careful not to tighten the crimp die too deep this can cause a slight lip or bulge at the shoulder.
      If you want to check the AR chambering, remove the firing pin and cycle some of your loads thru.
      Ruger probably has a tight chamber so you may (most probably) will need a small base sizing die.
      If you don’t reload rifle your missing half the fun, so don’t give up!

      2/4 3rd MarDiv

    • tweedmus April 16, 2016, 10:49 pm

      Your problem is either insufficient resizing or over-crimping. This will not work with neck sizing dies,but will with full-length dies which you almost certainly have. Although generally a headspace gauge is used, your rifle can fulfill the same function with better accuracy. Run one case through your sizing die and see if it chambers in your rifle. If it won’t, turn the die in 1/4 turn, resize and retry and repeat until the case chambers, but no further. If the empty case will chamber, try backing off your bullet seating die several turns to prevent over crimping the case, insert empty case, then screw the seating die down until resistance is felt and tighten slightly further. These 2 steps will insure proper headspace and that the case is not overly crimped. In semi auto rifles a bullet with a cannelure is generally used and the case is crimped slightly into it as this prevents the bullet shifting either direction and causing jams or pressure problems. Insert a bullet (no primer or powder) and turn in the seating stem so that the case matches overall cartridge length as listed in the reloading manual. it should chamber OK, if not, tighten the seating stem further until it does. Once you establish that, you have made a dummy cartridge to use as a gauge should it be necessary to readjust the die for other bullet weights or shapes. One dummy like this should be made for every different bullet you use in that cartridge. If none of this works for some reason (that chance is infinitesimally small) you may need dies from a different manufacturer.

  • Mongo April 15, 2016, 7:28 pm

    Good article, just a few pointers I’ve learned over the years…
    –take your dies apart and clean every so often, especially around the ball. When bringing the brass back through the die, the bell collects gunk which builds up, and can contribute to a stuck shell as much as not lubing the case itself.
    — spray lube on a qtip and run it along the inside of the mouth of the die, and if you can squeeze it by the bell, even better. Trying to lube the inside of each case neck can get messy, but again, the bell needs to be able to be lubed to slide back/forth through the neck.
    –Lee make decapping pins that are very tough with no bell on it. When you get a case stuck, remind the top of the die and the pin will slide right down, tap it easy with a hammer and it’ll come right out.
    –make sure the de-capping pins don’t protrude too far out of the mouth of the die, it will prevent the case from being pushed as far into the die as it can be.
    Good luck, take your time and enjoy the hobby!!

  • Reggie Macamaux April 15, 2016, 2:36 pm

    After I have fired a box of ammo either new shells or bagged empties through my 6.5 x 55 Swede sporter it is much easier and faster after you clean them to use a collet die. The shell is already formed to your chamber after the first shooting. I just trim the case and the collet die resizes the neck only. It is a much faster, and I have found my cases last much longer.

  • John Deahl April 15, 2016, 11:52 am

    I reload 11 calibers. The hardest thing is to reload is 308 brass that was used in military machine guns. Most machine guns have larger chambers to feed well.

    These can be extremely hard to resize. The One Shot spray lube is great for smaller chambers, but I have had some 308 cases that were so out of spec that One Shot and two times through the full size die was still not enough.

    Although One Shot case lube is a spray, I sometimes have to resort to the best lube on the market. That is Lee case lube. It is a paste, actually a cream, and it really works for those stubborn cases.

    • Old Handloader April 15, 2016, 2:26 pm

      I’ve been wrong plenty before but it might be possible that the designated MG ammo is made a bit differently at the plant than good domestic ammo from your local gun shop. I tried using some surplus mil-spec brass case ammo once in my bolt action gun and I had to throw the empties away. Would not get up in the die.

  • Kimberpross April 15, 2016, 9:08 am

    I have been reloading for 40+ yrs. In the beginning, the reloading data was limited, as were the cartridge offerings. When I compare the reloading data in the 30 yr old reloading manuals to the new versions the charge weight has definitely been reduced vs. pressure in the new manuals. Probably for liability purposes. Using current reloading tables are conservative on max charge and will help keep you from over pressure. Not that the old manuals didn’t do that, but the new ones give more margin. Just an observation.. As for the article. I have experienced stuck .308 and .223 cases in small base sizing dies. I was able to remove the .223 on my own by drilling it out, not so with the 7.62 x51. I wanted you to know that RCBS will remove the stuck case, polish the internals of the die and return it for the cost of shipping. It was simple and easy, quick turnaround also. I have been told that if they cannot remove it, or the die is damaged, they will ship you a new one, no charge.

  • Don Harmon April 15, 2016, 8:23 am

    Very clear and logical explanation of good technique. Thanks for the fine tips and explanations.

  • Jay April 15, 2016, 8:04 am

    “You can certainly buy ready-to-load brass that’s never been fired. The first time you load it, you usually don’t have to do anything. The brass vendor should have delivered it clean and sized and shaped to proper specifications”
    Let me explain why this is an incorrect statement!
    1. Due to variances that are encountered in diameter of different bullet types, brands, etc…., it is a good practice to size the case, at least as far down as the bullet seating depth. The new brass has been banged and thrown around from machine to getting in the box, getting to your door and some will most likely be misshapen-ed! In my experience even full length sizing is required for new brass.
    2. Most reloading manuals generate their own trim-to-lengths from SAAMI maximum cartridge drawing specifications, they are not set in stone. They usually pick a number that comes in below the SAAMI maximum and then they state this as the recommended trim-to-length. Notice it will say recommended! Depending on what specific caliber, some cases will shrink and others will grow when fired and reloaded. When it comes to the trim-to-length recommendation its trying to impress upon you if the case is longer than trim-to-length recommendation, then trim back to this.
    It can be a mind boggler, especially to people new to reloading when they purchase new brass and want to trim it back to trim-to-length stated in the manual. Manufacturers of brass generally do not produce cases at maximum length and they need to have a reasonable tolerance to work with. Some will produce brass at a tolerance of say .005 below SAAMI maximum some at 010 below while other might pick .003 below, the brass will vary between manufacturers from .003 to .010. as an example. Unless you size and trim Even new brass, you have no way of knowing what this variance is! This is very important to get your equipment set up right for the proper crimp on each and every round. If you don’t do this you might have some get a crimp and others none at all, you need your brass to be all the same size.
    Take some advice from an old fart treat new brass as once fired and you’ll be the wiser for it!

  • Denis Bergeron April 15, 2016, 7:57 am

    Je suis du canada québec votre article est un plus à mon expérience du rechargement .Ont en veux d’autre article de cette qualitée

  • Joe S. April 15, 2016, 7:03 am

    Excellent info for both amateurs and pros. The key is taking your time with each step and DO NOT exceed max load.

  • Joe April 15, 2016, 6:12 am

    Excellent article

  • Roger V. Tranfaglia April 6, 2016, 6:34 pm

    Thank You Tom!!

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