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October 10th, 2021

Smart Advice for Reducing Run-Out with Standard Seating Dies

USAMU Handloading Hump Day Seating Die Adjustment Stem TIR Concentricity Run-out

The U.S. Army Marksmanship Unit (USAMU) regularly publishes reloading “how-to” articles on the USAMU Facebook page. This USAMU article, the second in a series on improving concentricity, has many useful tips. If you use standard (non-micrometer) seating dies when loading some cartridge types, this article is worth reading. And visit the USAMU Facebook page for other tips on handloading and marksmanship.

Once again, it’s time for USAMU’s “Handloading Hump-Day!” Last week, we addressed achieving very good loaded-cartridge concentricity (AKA “TIR”, or Total Indicator Runout) using standard, “hunting grade” reloading dies.

We explained how to set up the Full-Length Size die to float slightly when correctly adjusted for desired case headspace. We also cited a study in which this method loaded ammunition straighter than a set of [higher grade] match dies from the same maker. [One of the keys to reducing TIR with both sets of dies was using a rubber O-ring below the locking ring to allow the die to float slightly. READ Full-Length Sizing Die TIP HERE.]

Now, we’ll set up a standard seating die to minimize TIR — the other half of the two-die equation. As before, we’ll use a single-stage press since most new handloaders will have one. A high-quality runout gauge is essential for obtaining consistent, accurate results.

Having sized, primed and charged our brass, the next step is bullet seating. Many approaches are possible; one that works well follows. When setting up a standard seating die, insert a sized, trimmed case into the shell-holder and fully raise the press ram. Next, back the seating stem out and screw the die down until the internal crimping shoulder touches the case mouth.

Back the die out one-quarter turn from this setting to prevent cartridge crimping. Next, lower the press ram and remove the case. Place a piece of flat steel on the shellholder and carefully raise the ram. Place tension on the die bottom with the flat steel on the shellholder. This helps center the die in the press threads. Check this by gently moving the die until it is well-centered. Keeping light tension on the die via the press ram, secure the die lock ring.

USAMU Handloading Hump Day Seating Die Adjustment Stem TIR Concentricity Run-out

If one were using a micrometer-type seating die, the next step would be simple: run a charged case with bullet on top into the die and screw the seating stem down to obtain correct cartridge OAL.

However, with standard dies, an additional step can be helpful. When the die has a loosely-threaded seating stem, set the correct seating depth but don’t tighten the stem’s lock nut. Leave a loaded cartridge fully raised into the die to center the seating stem. Then, secure the stem’s lock nut. Next, load sample cartridges and check them to verify good concentricity.

One can also experiment with variations such as letting the seating stem float slightly in the die to self-center, while keeping correct OAL. The runout gauge will show any effects of changes upon concentricity. However, the first method has produced excellent, practical results as evidenced by the experiment cited previously. These results (TIR Study 2) will reproduced below for the reader’s convenience.

TIR Study 2: Standard vs. Match Seating Dies

50 rds of .308 Match Ammo loaded using carefully-adjusted standard dies, vs. 50 using expensive “Match” dies from the same maker.

Standard dies, TIR:
0.000” — 0.001” = 52%;
0.001”– 0.002” = 40%;
0.002”– 0.003” = 8%. None greater than 0.003”.

“Match” dies, TIR:
0.000”– 0.001” = 46%;
0.001” — 0.002” = 30%;
0.002” — 0.003” = 20%;
0.003” — 0.004” = 4%.

AccurateShooter Comment: This shows that, with careful adjustment, the cheaper, standard dies achieved results that were as good (or better) than the more expensive “Match” Dies.

These tips are intended to help shooters obtain the best results from inexpensive, standard loading dies. Especially when using cases previously fired in a concentric chamber, as was done above, top-quality match dies and brass can easily yield ammo with virtually *no* runout, given careful handloading.

Permalink - Articles, Bullets, Brass, Ammo, Reloading, Tech Tip No Comments »
June 4th, 2018

Precision Hand-Loading — Ten Steps Explained by Sinclair Int’l

Sinclair Precison Reloading summery tech tips

Sinclair International has created a series of helpful articles on rifle cartridge reloading. Today’s feature lists ten basic steps for precision hand-loading, with links to longer, detailed Sinclair Int’l technical articles providing more complete information. There’s a lot of helpful info here guys, if you click all the links to access the ten “long form” articles.

Tying It All Together: 10 Steps To Precision Handloads

Feature based on article by Roy Hill, Brownells/Sinclair Copywriter

Sinclair International offers a series of detailed articles on hand-loading precision rifle ammunition. The articles are included in Sinclair’s GunTech Articles Archive, but sorting through the index to find each article takes time. To help you access all these articles quickly, here’s a handy summary of ten key topics, with links to longer articles covering each subject in detail.

Part 1: The first step in making high-quality handloads is to carefully choose the best brass for your application. You need to know how to identify the different types of brass and how to choose the best kind for the ammo you want to load. CLICK HERE for Part 1.
Part 2: Even high-quality brass can have burrs around the flash hole that can interfere with the primer flame and cause inconsistent ignition – which can lead to shot groups opening up. Flash hole deburring is a critical step in making sure primers ignite powder consistently. CLICK HERE for Part 2.
Part 3: The next step is to make sure the primer pockets are square and uniform. Like flash hole deburring, primer pocket uniforming may reduce variations in primer ignition by ensuring more consistent primer seating. CLICK HERE for Part 3.
Part 4: Making sure all your cases are precisely the same length is crucial, especially when you use cases that have been fired before. Case trimming is the way to get there. CLICK HERE for Part 4.
Part 5: After trimming, cases still have to be resized. In order for them to work through the resizing die, they have to be lubricated. The case lube method you choose is crucial to making precision handloads. CLICK HERE for Part 5.
Part 6: Now it’s time to choose the dies that will resize your cases. There are several important options to consider in selecting the right sizing dies. CLICK HERE for Part 6.
Part 7: Wait! You’re not quite ready to start sizing yet. There’s yet more to consider before you start cranking cases through the press. Learn more about setting up and adjusting your sizing dies. CLICK HERE for Part 7.
Part 8: Once the cases are completely prepped, it’s time to start putting fresh components back into them. We start off by seating primers. CLICK HERE for Part 8.
Part 9: After the primers are seated, it’s time to drop in the powder. There are several tools that will help you handle powder for precision handloads. CLICK HERE for Part 9.
Sinclair Precison Reloading summery tech tips Part 10: The final step in the process is carefully seating the bullet to just the right depth. And then… you’re ready to try your loads at the range. CLICK HERE for Part 10.
Permalink - Articles, Bullets, Brass, Ammo, Reloading 2 Comments »
June 28th, 2011

Redding Add-On Micrometer Seating Stems Now Shipping

Well folks, the new Redding Micrometer Seating Stems for standard Redding seating dies are finally shipping. Robin Sharpless, Redding’s Executive VP, confirmed that “these Seating Stems started shipping this month, by the hundreds. MidwayUSA, Grafs, Midsouth — all the major vendors are getting inventory.” We confirmed that MidwayUSA now has, in stock, the Micrometer Seating Stems for .204 Ruger, .223 Rem, 22 PPC, 22-250 Rem, .243 Win, .308 Win, .284 Win, .30-06, and .338 Lapua Magnum, plus many other calibers. (One model Seating Stem can often work for multiple cartridge types of the same caliber.) MidwayUSA is charging $42.99 for both the regular and VLD-style seater stems.

Micrometer Seating Stems Retro-Fit to Redding’s Standard Seating Dies
The big advantage of these new Seating Stems is that you can get the additional control and precision of a micrometer top by simply upgrading your existing dies at about half the cost of a new, complete Competition Seater Die. NOTE: the Seating Stem assemblies are a component of the bullet seating die. These are not the dies themselves. It is the top portion of the die that contains the plunger, which pushes the bullet into the case. The micrometer is graduated in increments of 0.001″ to assure precise seating depth control. The Seating Stems feature a dead stop on the threads allowing full repeatability even if changed from one die to another. NOTE: These Micrometer seating stems are direct replacements for the original stems. To comfirm die compatibility,the stem numbers match the numbers stamped on the tops of the original seat plug which was shipped with your standard seating dies.

The new Redding Micro Precision Seating Stems are available for both standard bullet shapes as well as VLD Bullets. These allow the user to accurately seat the longer-nosed VLD-style projectiles.

Permalink New Product, Reloading 3 Comments »