INSANE Precision: 223 Loads using Forster Equipment

Knowing how accurate the 223 trainer rifle Gavin built is, especially when combined with Berger’s factory 77 grain OTM ammo and Travis’ handloads, it seemed natural to also build that same load using Forster’s unique Co-Ax press and associated equipment


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The 223 trainer rifle leaves nothing to be desired with a Bat TR action, Foundation Genesis 2 stock, Hawkins Precision Bottom Metal, MDT Poly 223 Magazine and a 1:8 heavy contour barrel from a Benchmark blank. It’s not only a fun rifle to shoot but an easy rifle to shoot well. On a Friday afternoon, all of the Ultimate Reloader staff took turns shooting three-shot groups with the rifle using a bipod and rear bag. I managed to barely beat out Gavin for the win with a group measuring 0.179″ using Berger’s factory 77 grain OTM ammo.

I’ve only had 19 shots through the trainer thus far, but others in the team have had much more time on the gun. Recently, Travis uncovered that we could achieve the same accuracy of the Berger factory 77 grain OTM ammunition but with a better standard deviation by recreating the load ourselves with Forster equipment.  


About the Forster Co-Ax Reloading Press

The Forster Co-Ax press has been in production for decades and is highly respected among the reloading community. It has several unique features which endear it to those who own it. Key among those are jaws which accept any number of different case rim sizes for sizing and seating operations and also for on-press priming if desired. Dies are simply inserted into the press rather than screwed in as they are on most other presses. With the case and the die “floating,” the jaws center the brass cartridge case during operation. This leads to to very uniform sizing. The leverage is excellent and the press is very easy to use. I greatly appreciated the spent primer trap which completely contained all of the primers in a small jar. 

From Forster’s web page: 

Co-Ax Press, supplied with “S” jaws. No need to complicate the reloading process. Our Co-Ax Press keeps it simple while still delivering famous Forster precision. The Forster Co-Ax Loading Press comes with several unique features that help make it truly one of a kind, including:

    • Snap-in and snap-out die changing. You can actually change from sizer die to seater die in two seconds!
    • A positive spent primer catcher system which passes all spent primers and dirty carbon through a tube and into a container. That helps keep all working parts free of dirt and abrasives.
    • Dual floating guide rods to help ensure perfect alignment.
    • Because there is absolutely no torque on the head of the Co-Ax Press, long life is the rule rather than the exception. Due to the design of the linkage and pivots, all forces are in equilibrium whether the press is at maximum work load or at rest.
    • Our Co-Ax Press has three times the mechanical advantage of an ordinary “C” press. It’s so effortless, full length sizing can actually be accomplished by operating the handle of the press with the little finger! There’s no pain but plenty of gain.
    • The Co-Ax Press delivers perfect alignment of the die and the case because the shell holder jaws are designed to float with the die, thereby permitting the case to center precisely in the die.
    • With no frame supports or swinging primer arms to interfere or cause an obstruction, the Co-Ax Press provides plenty of elbow room for both right handed or left handed operators.
    • The Co-Ax Press accepts any standard ⅞″ X 14 reloading die, some with existing locking rings. We recommend Forster Cross Bolt Locking Rings.
    • The unique top priming device seats primers to factory specifications. The seater is always at right angles to the case head. Primers will not flip or tip. They will be seated straight, level and at a uniform distance below the case head. Primers cannot be crushed, nor will they protrude from the case head and cause premature firing.
    • The top of the stroke provides a rock solid stop for consistency.


About the Forster honed sizing die

Forster offers several interesting custom services, including honing the sizing die to a customer-specified dimension! This allows the case neck dimension to be optimized for the brass being used and specific chamber size for increased precision. The Forster sizing die I used to build these precision 223 loads was one such die. I suspect this die contributes to the excellent accuracy we are seeing from the 223 trainer. 

From Forster’s Web Page: 


We custom-hone the inside neck diameter by using a diamond stoning process. We enlarge the inside diameter to your specification to prevent oversizing of the case neck due to thick neck walls. You may require this service for multiple reasons:

    1. If you use some brands of brass cases with thicker neck walls.
    2. If you do not intend to outside neck turn case necks that have thickened after repeated firings.
    3. Please send us your die along with the Custom Neck Honing Form, specifying the inside neck diameter. Note:
    1. No more than .008″ stock removal from your existing die neck diameter is possible.
    2. Honing is done in increments of one-half thousandth of an inch (.0005″), meaning that your specified inside diameter must be either .XXX0″ or .XXX5″.

$26.00, includes shipping within continental U.S. (lower 48 states). Please allow 1-3 weeks.

Calculating the proper dimensions just takes a little bit of math.

This will prevent the little rings that appear on your bullet when the seating stem is pushing too hard and the bullet sizes the brass. (You don’t want the bullet to have to do this!) A honed neck die is also all perfectly concentric — there is no bushing floating around. On the Sinclair Concentricity gauge, Guy’s loaded ammunition only had a total needle movement of just over a thousandth of an inch.

About the Forster Ultra Micrometer Seater Die

The Forster Ultra Micrometer Seater Die was an absolute pleasure to use. The micrometer makes small changes in seating depth easy and more precise. Forster can also polish the seating stem to perfectly fit the bullet! 

From Forster’s Web Page: 

The Ultra Micrometer Seater Die is a non-crimping style seater die (except for the 30-30) that holds the bullet and case in perfect alignment while the bullet is press-fit seated.

A handy micrometer fixes the bullet seating depth to your specifications. After you have seated your bullet close to the desired depth and measured it, simply adjust the Micrometer stem up or down to the desired depth and the cartridge will be exactly the length you need.

    • Includes all the popular straight line seating features of the original Bench Rest Seater Die plus an ultra-accurate Micrometer for adjusting bullet seating depth
    • Micrometer allows fine-tuning in either direction; easily adjustable to .0005″
    • Gradations at increments of .001″ are clearly marked
    • Eliminates much of the trial and error that was once associated with seating accurate rounds
    • Bright, white markings make micrometer easy to read
    • Available in 80 calibers

About the Forster Neck Tension Gage Kit

We had the ability to take a look at this kit at the SHOT Show before it was released. Inserting this gage into the case mouth tells you what the diameter is sized to within a thousandth of an inch.

From Forster’s Web Page: 

Use the Neck Tension Gage (NTG) as an inspection tool to quickly and accurately screen/sort a batch of brass before your bullet seating operation.

Each NTG provides reloaders with the information needed to create exacting neck tensions during the bullet seating operation.

  • Use after case neck sizing and before bullet seating to help determine optimal inside neck diameter for consistent release of a bullet from your reloaded rounds.
  • Allows for inspection of the inside diameters of case necks to be sure a “donut” has not formed at the neck-shoulder junction.

This kit includes all five calibers available. Each Neck Tension Gage (NTG) Inspection Tool consists of four stepped diameters that increase in size until reaching the handle. Each diameter is etched on the metal tool.

Simply insert the stepped end of the tool into the neck of your sized case, sliding it in until one of the diameters achieves a slip fit in the case neck. Use the resulting value to fine-tune your case preparation.

The gages are available individually or as a set.

About the Forster Co-Ax primer seater

We recently completed an article about this primer seater.

It features adjustable jaws to accept many different cartridge cases and works quite well. I quickly primed all of the Lapua brass used in this project with the Forster Co-Ax primer seater on my home loading bench. 

From Forster’s Web Page: 

It’s fast, it’s easy, and it seats primers perfectly – all with a level of quality you won’t find anywhere else. Set the jaws for a particular caliber, load the tube, and you’re ready to seat primers into multiple cases of that caliber.

    • Unique design allows the operator to eliminate all slop when working with a specific cartridge, translating into perfect seating, reliable ignition, and reduced misfires
    • Requires no additional shell holders; the jaws close to securely grip most modern rifle and pistol cases with a rim thickness of .045″ to .072″
    • Built-in primer flipper tray; tubes fill easily from tray
    • Large and small primer tubes have an open slot
    • Primers stack sideways for added measure of safety
    • Includes large and small primer tubes

About the Forster Bench Rest Powder Measure

As with other Forster products, this is not only a high quality measure, but features an interesting design. It’s quite different from other powder measures I’ve used, as the powder charge reservoir is actually in the measure’s arm. 

From Forster’s Product Page: 

The Bench Rest Powder Measure keeps your powder flowing evenly. Its long, narrow, powder-charge reservoir minimizes shearing. 

The charge arm meters the powder and dispenses a flow of consistent charges using your choice of gun powder. For example, it will measure from 2½ grains of Bullseye to 95 grains of IMR 4320 or Alliant Reloader 15.

The powder hopper is designed to eliminate variation in charges due to changes in the volume of powder contained in the hopper. The small outlet on the hopper serves as a built-in baffle, regulating the powder leaving the hopper and entering the measure in a uniform manner.

The Powder Measure comes with two large drop tubes for large and small capacity cases. The integral C-clamp fastens securely to a bench or shelf. An optional Stand is sold separately.

With the superior design of our Bench Rest Powder Measure you are able to achieve repeatability within 1/10th of one grain, along with throwing a charge every 4 seconds.

Forster advertises that the powder measure is accurate within 1/10 of a grain, and my limited work with Vihtavuori N140 showed that it indeed did throw consistent charges. It’s an easy unit to use, after taking a moment to understand how it works and how to adjust the powder charge. 

About the load

As early discussed, Travis recreated the OTM Berger 77 grain load with the following.

I actually loaded to 2.264” COL, but did not have to be worried about making the rounds fit a typical AR-15 magazine. 

Sinclair Concentricity Gauge revealed minimal runout, an indicator of how well the press and dies work together along with the quality of the Lapua brass and Berger bullets.

100 yard Groups

At the 100 yard UR rifle range I fired several groups using the ammo I’d built using the Forster CoAx press and the Forster dies. I’ve now fired a grand total of 19 rounds from the 223 Trainer, all from the bench using a bipod and rear bag. Gavin, Travis and I have all seen excellent accuracy from this rifle and load. 

Two three shot groups were particularly impressive from the bipod — 0.053” and 0.179” 

I have to admit that when I looked at that tiny 0.053” group, I thought it was only two bullets and wondered how I could have thrown the third completely off the paper. Then I watched the target camera video and saw all three bullets go into that tiny group! I don’t normally shoot such tight groups we’ve all been shooting well with this load from this rifle. 

Get the gear! 

With the current component shortages, availability of the components we used for this Precision 223 load can be spotty. MidSouth Shooters Supply shows the Forster Co-Ax press at $369.60 but is not available for purchase as of 5/22/2022. The other Forster primer seater and dies are all available.

Co-Ax Single Stage Press | Forster Reloading Press (

Forster Co-Ax Bench Priming Tool | Midsouth Shooters (

223 Remington Full Length Die & Bench Rest Seater Set by Forster (

The micrometer seating die may have to be ordered directly from Forster at this time. 

Bench Rest® Ultra Micrometer Seater Die – Forster Products

High quality Lapua brass is available from MidSouth: 

.223 Brass | .223 Remington Brass in Stock | Midsouth Shooters (

Midsouth also carries Vihtavuori powder and the Federal 205 primers. 

VihtaVuori N140 Smokeless Rifle Powder 1 Lb by Vihtavuori (

Small Rifle Primer #205 (1000 Count) by Federal (

Berger’s accurate 77 grain OTM bullet is carried by many major dealers, but given today’s component shortages, it may not be readily available. They’re worth searching for. 

Berger Bullets | 22 Caliber 77 Grain OTM Tactical


Guy Miner

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