How to select a Redding bushing

Redding Bushing Dies: How to Select the Proper Bushing


Looking for a simple explanation of why we use bushing dies, or how to select the proper bushing for your Redding Type S, or Redding Competition Neck Sizing die? Here’s my take on it.

The advantage a bushing die has over a standard die is the amount of stress placed on the case neck as it’s sized. A standard full-length sizing die is machined to size a case to standard dimensions, regardless of case thickness. As far as the main body of the case goes, that’s no big deal. Once it’s fired to fit the chamber, the main dimensions of the case don’t change much in a die, even a full-length non-custom die. The problem is the neck.

To accommodate a wide range of varying brass thickness from brand to brand, and end up providing an inside diameter that will securely grip a bullet, a standard die uses two steps. First, the case is forced into the neck portion of the die and sized down, then it’s pulled back over an expander to set the final diameter.

In order to work with cases that are relatively thin, the interior dimension of the neck portion of the die is on the small side of neck diameter specs. That can be tough on brass, especially if it’s thick brass, like Lapua. It tends to cause concentricity problems, hardening of the brass, and muzzle velocity inconsistencies.

The bushing die eliminates the second step, and allows us to size the outside diameter of the neck to precisely where we want it. I prefer and recommend the Redding Type S FL sizing die. Click HERE to see why.

What diameter should the neck be sized to? I’ve had consistent success with brass that is sized .001” to .003” smaller than the loaded round’s outside diameter. This is commonly known as neck tension.

I now aim for .001” neck tension when working up a load. It provides enough grip to securely hold a bullet, is easy on brass, and doesn’t induce runout on a sized neck. Some of my older recipes still use bushings that squeeze the necks .002” or .003”. They work well, too.

I’ve tested different tensions within the same load, and even neck-turned some 260 Remington brass to see what difference it made.

I’ve found that as long as I don’t go over .001” of neck tension disparity, I can’t measure the difference. For example, .001” to .002” doesn’t affect anything, but .001” to .003” does. Neck turning has made no difference. I sort new cases for .002” or less thickness runout, but don’t turn them as a rule. I’ve since tested that process on a 7 WSM and 300 WM with similar results.

I concluded that the overall thickness of the brass was more important than small thickness variations when choosing a bushing.

Redding Die Bushing

To determine which bushing to use, you need to know what brass you’re going to use and how thick it is.

This is important. Brass can vary as much as .003” across different brands of the same cartridge case. The difference in thickness between Lapua and Remington 260 Remington brass is .002”.

The easiest way to measure for a bushing is to load a bullet in the brass you’re using and measure the outside diameter with a digital caliper. Subtract .001 and order that number bushing. For example, if my loaded round’s neck diameter is .294”, I’ll order a .293 bushing.

Measuring Loaded Round Mitutoyo Caliper

If you don’t have a loaded round, you can measure the case neck thickness, multiply it by two, then add the bullet diameter. For the round we just measured, it would look like this:

Neck thickness= 0.015”
Bullet Diameter= 0.264”

Neck Thickness (x2) + Bullet Diameter = Loaded Round Diameter

0.015”(x2) + 0.264” = 0.294”

To get an accurate thickness value, a ball micrometer works best. You can use a caliper, but because you’re measuring a curved surface with a flat anvil, it won’t be accurate. Mine come out .0015-.002” thicker when using calipers.

Measuring Case Thickness Mitutoyo Ball Micrometer

For reference, here are some of the cartridges I loaded last year, the brass I used, and the Redding bushing number:
  • 260 Remington/ Remington brass/ .288 bushing
  • 260 Remington & 260 Terminator/ Lapua brass/ .293 bushing
  • 300 Winchester Magnum/ Winchester brass/ .333 bushing
  • 7 WSM/ Winchester brass/ .312 bushing
  • 338 Edge/ Remington brass/ .364 bushing

I’ve only had one Redding bushing not match the dimension it was marked for. It was off by .001”. I ordered another one of the same size that was spot on. There are tolerances in everything, I guess. Don’t try to measure the bushing with your internal caliper jaws—it’ll be inaccurate because of the radius. Just size a case with it and see where you end up. These numbers are all relative anyway, and results on target are the ultimate measurements!

Check out this short video demonstrating how to measure for the proper bushings:

Here are some other things I do and have learned while using Redding bushing dies:
  • I use the plain steel bushings and lube the cases with Hornady One-Shot Case Lube before sizing.
  • I remove the decapping rod and expander from the Type S dies. An expander IS NOT needed when using a bushing die.
  • Don’t get wrapped around the axle about the exact amount of neck tension. Pick a value between .001” and .003” and run with it.
  • I’ve tried the bushings number up, and number down in the die. I insert the bushings with the numerical marking facing up. That makes it easy to look down in the die with a light to check which one is in it.
  • I clean my sizing dies before starting a big batch. I squirt a little One-Shot into the clean die before the first case gets sized, then leave it alone.
  • Keep notes on all bushing/die/brass combinations used, and always check the bushing number before sizing.
  • A Redding bushing die will not size the entire neck. Because of how the die is machined, it’s impossible. There will be a portion of the neck close to the shoulder that never gets sized. It’s normal. I set mine up so the bushing just barely self-centers in the die before locking the nut down.
  • Brass thickness dimensions vary from brand to brand, but calibers stay the same. If you’re using Lapua brass, you can use one bushing for 260 Remington, 6.5 Creedmoor, and 6.5-284.
  • I’ve ordered most of my bushings from Sinclair or Midway.
I think that’s all I have to say about using Redding bushing dies and choosing the proper bushing. As usual, I probably missed something important. Send me an email if you find something or have a question. Remember, results on target are all that matter to me. This is how I do it, but I won’t hold it against someone who does it differently. Question everything and try different methods until you get the results you want!

 

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Sam

As an Idaho native, avid hunter, and long range shooter, Sam has written numerous articles and gear reviews for various online publications. Specializing in long range hunting in the mountains of northern Idaho, Sam founded Panhandle Precision as a way to continue sharing his passions.

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12 Comments

  • Todd B
    January 29, 2017 at 16:25

    At this time I use the Redding neck bushing die approach on the 260 Rem only. It sure reduces the amount of work being done to the brass and lets us use the brass longer (neck/shoulder annealing is an important factor too)

    One thing I wanted to mention that I had to go through for my situation is to neck size down in two steps. Apparently my chamber is a little on the larger side in the neck area so when the cartridge is fired the neck diameter opens up to fill the space. Then when I use the neck sizing bushing I think I need, it reduce the neck diameter more than the bushing size. If I do a two step approach and only reduce the neck diameter 0.002 to 0.003 at a time then the neck diameter ends up right where I want it.

  • Brandon
    May 11, 2017 at 10:30

    Another excellent article! I have reloaded ammo for 12 years and I have learned a lot from your articles and your youtube videos. I have Redding bushing dies for my 20 Tactical and they produce accurate ammo. I have adopted some of your reloading techniques and will be buying Redding Match S Bushing dies for my 223 and 243 Remington 700 bolt action rifles.

  • Darwin
    July 2, 2017 at 06:28

    I was very pleased to find your youtube videos – they are the best I have seen period. Full of how-to info plus insights from a very experienced shooter/reloader. CC is an added bonus. I have reloaded for several years (but still a novice in many ways) starting with handgun ammo and now spend most of my time trying to find the right combo for my 22-250. I shoot targets @ 100 yds and am seeking the elusive bug hole. I am still a little confused about the sequence you follow for reloading – I don’t see if/when you neck size other than with a fl die is used. You use fl each time for hunting rounds but what about for target shooting. If you could list the steps and the equipment you use for each, I think many of us would benefit. If you have covered this previously in a video or you website, then I haven’t looked hard enough and apologize. Thanks.

  • David Swoboda
    February 8, 2018 at 14:34

    Thanks for all the information you share on your site! I live not far from you, just down the road in Post Falls, Idaho. In one of your articles, you talk about squaring up the dies in the press to help with concentricity issues. I’ve been chasing down potentially different causes of non-concentric rounds (now using Redding Type S dies) and squaring the dies in the press is something I’m not quite sure how to do. Any recommendations on how to solve this?

    • Sam
      Sam Millard
      February 8, 2018 at 15:04

      I use a small chunk of tool steel as a shim to force the bottom of the die parallel to the top of the shellholder. Just set the die up for the bump you want, and finger tighten the locknut. Then put the shim between the die and shellholder, apply pressure with the ram, and tighten the locknut. If the die and shellholder are square, the case should come out square. Any perfectly flat piece of steel should work. I’ve only had one die that didn’t square up, but the ammo shot as well as anything else I put together!

      • David Swoboda
        February 8, 2018 at 15:35

        Thanks for your speedy reply! Where can tool steel like this be found?

        • Sam
          Sam Millard
          February 8, 2018 at 20:32

          I got mine from a friend who used to work in a machine shop. I would look at machine shops, metal shops, or online. Another thing that would probably work fine is a plain steel ruler.

          • Todd B
            February 9, 2018 at 08:03

            If you have access to an old disk drive take one of the disks out and use it for a precision shim. The thickness is very parallel.

          • Sam
            Sam Millard
            February 9, 2018 at 12:29

            Good info. Thanks!

  • Mike
    February 10, 2018 at 10:19

    I have read about using expander mandrels to smooth out the inside of the case neck after running it through the bushing die. Do you an expander mandrel since the expander ball was removed?

    • Sam
      Sam Millard
      February 10, 2018 at 10:44

      I don’t use anything on the inside of the neck after sizing with a bushing die.

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