Published: May 2026 | Last updated: May 2026
Disclaimer: Specifications and pricing in this article are drawn from manufacturer and retailer sources current at time of publication. Always verify current pricing before purchasing.
The Dillon SL900 is a progressive shotshell reloader designed for the serious clay target shooter who loads significant volumes – thousands of shells per month rather than a few boxes for a weekend. The Powder Measure Assembly is the component of the SL900 that handles the powder charge drop: a case-activated volumetric measure with separate charge bars for powder and shot, dropped in sequence as the shell progresses through the press stations. It is not a standalone bench tool – it is a press-integrated component, and understanding it requires understanding the SL900 workflow it is built into.
Dillon built the SL900 powder and shot measure around the same engineering principles that underpin their centerfire progressive presses: case-activation, consistent charge delivery at production speed, and aluminum construction that holds its tolerances over millions of press cycles. The measure assembly uses a reciprocating charge bar – a sliding bar with precisely bored cavities for both the powder charge and the shot charge – that is actuated by the shell carrier movement on each press stroke. One press stroke drops one powder charge and advances the shell toward the shot drop station.
This review covers the SL900 Powder Measure Assembly as both a standalone replacement/upgrade component and as the defining performance element of the SL900 press system. The primary audience is the SL900 owner who wants to understand the measure’s design, optimize its performance, troubleshoot inconsistencies, or evaluate whether a replacement assembly is needed. Secondary readers are prospective SL900 buyers evaluating the system’s powder charging capabilities against competing shotshell presses.
Key Specifications
| Feature | Detail |
|---|---|
| Manufacturer | Dillon Precision Products |
| Model | Powder Measure Assembly for SL900 |
| SKU | Not available at time of publication |
| UPC | Not available at time of publication |
| Actuation | Case-activated via shell carrier movement |
| Metering System | Reciprocating charge bar with fixed-cavity bores |
| Powder Charge Adjustment | Interchangeable charge bar bushings; adjustable powder bar |
| Shot Charge Adjustment | Separate shot bar with interchangeable bushings |
| Construction | Aluminum charge bar; aluminum housing |
| Gauge Compatibility | 12 gauge native; 20 gauge with conversion kit |
| Powder Type Suitability | Flake and ball shotgun powders |
| User Rating | Not available at time of publication |
| MSRP | Approximately $89.99-$119.99 (assembly) |
| Approx. Street Price | $85-$120 depending on configuration and retailer |
The Reciprocating Charge Bar System
The SL900 powder measure uses a reciprocating charge bar rather than the rotating drum design found in most centerfire powder measures. The charge bar is a flat aluminum bar with two precision-bored cylindrical cavities – one for powder, one for shot – that slides back and forth in a housing as the press cycles. As the bar reciprocates, each cavity alternately aligns with the supply column above and the drop tube below. The powder cavity fills from the powder hopper above, then slides to the drop position and empties into the wad below. The shot cavity does the same on its own timing in the sequence.
This design has specific advantages for shotshell loading. Shotshell powder charges are small and consistent – a 12-gauge target load with Hodgdon Clays might use 17-19 grains, and shot charges are in the 400-500 grain range for a 1-1/8 oz load. The reciprocating bar’s fixed-cavity geometry produces extremely consistent charges once the correct bushing is installed, because the cavity is completely filled on every cycle and completely emptied on every cycle – there is no partial fill variation from a micrometer setting between extremes.
The charge bar bushings are the adjustment mechanism. Rather than a micrometer ring that varies cavity volume continuously, the SL900 uses interchangeable bushings with specific bore diameters that produce calibrated charge volumes. Dillon publishes a bushing chart correlating bushing number to charge weight for the major shotshell powders. To change charge weight, the operator changes the bushing – a 30-second operation with a bushing wrench. This is the same fixed-cavity philosophy as the Lee drum insert system applied to a more precisely manufactured aluminum component.
The bushing-based system has real advantages for the shotshell loader. Shotshell recipes are fixed by published load data – you do not dial in 18.3 grains of Alliant Red Dot by trial and error; you follow a published recipe from a current shotshell manual with a specific bushing number. The Dillon bushing chart provides the lookup. Once a recipe’s bushing is identified and verified by weighing, it stays in the charge bar for all shells of that recipe. Production loading proceeds at press speed without any adjustment between shells.
Build Quality and Design
The SL900 charge bar is machined aluminum – not polymer. This matters for a production-grade shotshell loader in the same way it matters for any powder measure: polymer charge bars wear at the cavity edges over time, eventually producing inconsistent charges as the cavity walls round off. An aluminum charge bar with precision-bored cavities maintains its geometry through the tens of thousands of cycles a serious clay target shooter logs in a single season.
The charge bar housing is also aluminum, and the bar slides in machined channels with controlled clearance. The fit between bar and housing determines whether powder and shot leak around the bar during the fill cycle. Dillon machines this to tight tolerances; the clearance is close enough that flow past the bar is negligible, while still loose enough that powder residue does not cause the bar to bind.
The powder hopper on the SL900 is a separate, oversized container that holds several pounds of powder – adequate for a long loading session without refilling. The shot hopper is similarly sized. Both are clear or translucent, allowing the operator to monitor fill levels. The hoppers connect to the charge bar housing through a baffle assembly that maintains consistent column pressure on the bar cavity during fill. Consistent column pressure is critical for ball and flake shotgun powders like Hodgdon Titewad, Hodgdon 700-X, and Winchester WST – without a baffle, charge weight drifts as the hopper empties.
The integration with the SL900 press carrier is tight and purposeful. The charge bar actuating arm is directly connected to the shell carrier’s reciprocating movement. There is no separate linkage rod to adjust or lose, no ratchet arm to wear out – the carrier movement is the bar movement. This direct coupling is one of the SL900’s durability advantages over progressive shotshell presses that use separate linkage systems between the carrier and the measure.
Setup and Operation
The powder measure assembly comes pre-installed on the SL900 press. Replacement assembly installation follows Dillon’s service procedure: remove the old assembly from the press carrier mounting points, install the new assembly, confirm the charge bar seats fully in its housing before the carrier is raised, and verify bar clearance through several dry cycles.
Bushing selection begins with a current shotshell reloading manual. Identify the recipe: gauge, hull type, primer, wad, shot charge weight, powder type, and powder charge weight. Consult the Dillon bushing chart for the powder type and charge weight combination to identify the appropriate bushing number. Install the bushing in the powder side of the charge bar. Do the same for the shot charge with the appropriate shot bushing.
Before loading shells, verify both charges with a scale. For powder, remove the charge bar assembly from the housing, actuate the bar several times over a powder pan to throw test charges, and weigh on a calibrated scale. Target weight should be within ±0.2 grains of the published recipe charge. For shot, weigh the shot charge from several throws – acceptable variation for shot is slightly wider, as individual pellet size variation is the dominant factor rather than bar fill consistency.
Common shotshell powders that meter cleanly through the SL900 charge bar include Hodgdon Clays, Hodgdon International, Hodgdon Titewad, Hodgdon 700-X, Alliant Red Dot, Alliant Green Dot, Alliant Clay Dot, Alliant E3, Alliant Extra Lite, Winchester Super-Field, Winchester WST, and Winchester Super Handicap. Steel shot applications require the steel shot bushing set and a powder charge bar appropriate for the typically heavier powder charges used in steel shot recipes. Alliant Steel and Hodgdon High Gun are common steel shot powder choices that work through the charge bar with steel-specific bushings.
Maintain consistent press stroke cadence during production loading. Shotshell presses produce more consistent charges when operated at a steady rhythm rather than with variable pause times between strokes. The charge bar fill cycle benefits from consistent timing – erratic pauses allow powder column pressure to equalize differently on each fill, producing slight charge variation.
Where It Fits – Use Cases
High-volume clay target shooting is the SL900’s core application and the context for which this measure assembly was designed. A competitive sporting clays, skeet, or trap shooter who fires 500-1,000 rounds per week loads those shells on a press that can keep up with consumption. The SL900 at its rated speed – up to 1,200 shells per hour under ideal conditions, realistically 700-900 for a careful operator – is one of the few shotshell presses that can genuinely supply a serious competitive shooter’s weekly consumption in a single session.
12-gauge target loads – 1 oz and 1-1/8 oz loads with Hodgdon Clays, Hodgdon International, Alliant Red Dot, or Alliant Clay Dot – represent the overwhelming majority of SL900 production. The measure assembly is calibrated and optimized for this application. Trap handicap loads, sporting clays mid-range loads, and skeet loads all fall within this category.
20-gauge loading with the conversion kit extends the SL900’s utility to the second most popular clay target gauge. The measure assembly’s charge bar and bushing system is gauge-agnostic in principle – the bushings calibrate the cavity volume regardless of gauge – but the hull handling and wad seating components require the 20-gauge conversion.
Steel shot waterfowl loads are within the SL900’s capability with appropriate steel shot components, though this is a secondary use case. Steel shot charges require different bushings and charge bar settings than lead shot, and the powder charges for steel shot recipes are typically heavier than target load charges. Verify that the powder and shot bushing combination for a specific steel shot recipe is available in the Dillon bushing chart before committing to the SL900 for waterfowl loading.
Premium hunting and game loads with heavier shot charges or specialty powders are less commonly loaded on the SL900, which is designed around the production consistency requirements of target ammunition rather than the variety of hunting load specifications.
Competitive Analysis
Dillon SL900 Powder Measure vs. MEC 9000 Series Powder Measure: MEC’s 9000-series progressive shotshell presses use a powder bushing system that is philosophically similar to the Dillon approach – interchangeable bushings for fixed-cavity charge drops. MEC has been in the shotshell press business longer than Dillon and has an extensive bushing inventory. The SL900 is generally regarded as more durable at high production rates and provides more consistent case-activation integration, while MEC presses offer a wider available selection of aftermarket bushings and a larger installed user base for practical support knowledge. The SL900’s aluminum charge bar construction is a build quality advantage over MEC’s lighter-duty plastic charge bar components in older MEC models. Choose the Dillon SL900 system for maximum production rate durability. Consider MEC alternatives if the larger MEC bushing ecosystem and established user community matter more than peak production rate.
Dillon SL900 Powder Measure vs. Ponsness-Warren Du-O-Matic / Size-O-Matic Series: Ponsness-Warren shotshell presses use a different charge mechanism – a powder bushing system with a rotary rather than reciprocating mechanism in some models. The P-W presses occupy a similar production-tier market position to the SL900 and have a loyal following among high-volume clay target shooters. The SL900’s direct carrier-to-charge-bar coupling provides more consistent case-activation timing than some P-W designs. Choose the Dillon SL900 if production speed and Dillon’s service infrastructure are priorities. Consider Ponsness-Warren if their specific gauge options or hull compatibility range better fits your loading requirements.
Dillon SL900 Powder Measure Assembly vs. Replacement with Factory Dillon Service: Dillon’s customer service policy is one of the best in the reloading industry – “No BS Warranty” covers parts replacement with minimal friction. An SL900 owner whose measure assembly has worn or failed has two paths: purchase a replacement assembly or contact Dillon customer service, which often provides replacement parts under warranty or at minimal cost for established customers. Before purchasing a replacement assembly, contact Dillon’s service line to determine whether the worn component qualifies for no-cost replacement.
Comparison Table
| Feature | Dillon SL900 Powder Measure | MEC 9000 Series Measure | Ponsness-Warren Measure | Standard Progressive Centerfire Measure |
|---|---|---|---|---|
| Application | Shotshell only | Shotshell only | Shotshell only | Centerfire pistol/rifle |
| Metering System | Reciprocating charge bar | Rotary bushing | Rotary or reciprocating (varies) | Rotating drum (micrometer) |
| Adjustment Method | Interchangeable bushings | Interchangeable bushings | Interchangeable bushings | Micrometer ring |
| Powder and Shot in One Bar | Yes | Yes (most models) | Yes (most models) | N/A – powder only |
| Construction | Machined aluminum | Plastic/aluminum (varies by model) | Aluminum | Aluminum or polymer |
| Case Activation | Direct carrier-coupled | Press-linked | Press-linked | Ram or carrier-linked |
| Production Rate (shells/hr) | Up to 1,200 | Up to 900 | Up to 800 | N/A |
| Steel Shot Compatibility | Yes (with bushings) | Yes (with bushings) | Yes (with bushings) | N/A |
| User Rating | ~4.5/5 | ~4.3/5 | ~4.4/5 | Varies |
| Price Range (assembly) | $85-$120 | $40-$80 | $50-$90 | $45-$130 |
Troubleshooting
Powder charge varies more than ±0.3 grains between shells. First verify that the charge bar is completing a full reciprocating cycle on every press stroke – watch the bar movement through several dry cycles without powder to confirm it travels to both end positions cleanly. If the bar is not reaching full travel, check for powder debris impacted at the end stops and clear with a dry brush. If travel is complete, check hopper fill level – the powder column pressure changes as the hopper empties, which can shift charge weight with some fine-grain powders. Keep the hopper at least one-quarter full. If the problem persists across a full hopper, the bushing bore may have worn – measure the bore diameter against a new bushing and replace if worn.
Shot charge varies significantly – more than ±5 pellets per shell. Individual pellet variation is inherent to shot charges and represents normal variation within an appropriate range. Significant charge weight variation – more than ±2% of the nominal shot weight – suggests the shot bushing bore is worn or the shot hopper column is producing uneven pressure. Check the shot bushing for visible wear at the bore entry edge and replace if rounded. Verify the shot baffle is correctly seated in the shot hopper.
Charge bar sticks or binds during press cycle. Powder residue has packed between the charge bar and the housing channel. Disassemble the charge bar from the housing – Dillon’s assembly procedure provides the steps – and clean all surfaces with a dry brush and compressed air. Shotgun powders, particularly fine-grained flake powders like Hodgdon Titewad and Alliant Extra Lite, produce fine dust that accumulates in tight clearances more rapidly than coarser pistol powders. A cleaning interval of every 1,000-2,000 shells is appropriate for these powders.
Powder leaks past the charge bar into the shell below the powder drop position. The charge bar clearance in the housing has widened from wear. This is a sign the measure assembly needs service or replacement. Contact Dillon customer service before purchasing a replacement – this type of wear is often covered under the No BS Warranty.
Bushing drops out of the charge bar during operation. The bushing retention is loose. Dillon charge bar bushings use a friction or snap fit; if a bushing is loose, check that the correct diameter bushing was installed and that no powder residue is acting as a lubricant that reduces retention friction. Clean the bushing seat in the charge bar and reinstall. If the bushing continues to drop out, the charge bar bushing seat has worn – replace the charge bar.
Frequently Asked Questions
Can I use the SL900 powder measure assembly on the original Dillon RL550 or XL750 for shotshell loading? No. The SL900 is a dedicated shotshell press and its measure assembly is designed specifically for the SL900’s shell carrier geometry, hull handling, and station sequence. The SL900 assembly is not interchangeable with the centerfire progressive measure assemblies designed for the Dillon RL550C or other Dillon centerfire presses.
What is the most accurate way to verify the powder charge on an SL900? Remove the charge bar from the housing, actuate it over a clean powder pan ten times, and weigh the total on a calibrated scale. Divide by ten for the average per-shell charge. This is more accurate than trying to catch individual shells’ powder charges because the small charge weights – often 17-22 grains – require a scale with 0.1-grain resolution and freedom from vibration during loading to read reliably. Verify at the start of each session, after any bushing change, and after opening a new powder container.
Which shotshell powders work best in the SL900 for target loads? The most consistently metered powders through the reciprocating charge bar are fine flake and small ball powders: Hodgdon Clays, Hodgdon International, Hodgdon Titewad, Hodgdon 700-X, Alliant Red Dot, Alliant Clay Dot, and Winchester WST. These powders flow freely into the bushing bore and shear cleanly as the bar reciprocates. Coarser flake powders like Alliant Promo and Alliant Green Dot work adequately but produce slightly higher charge variation. Verify with test weighing whenever switching powder types.
Does Dillon offer different bushing sets for different shot sizes? Yes. Dillon sells separate bushing sets for lead shot, steel shot, and bismuth/tungsten shot. The different materials have different densities, so the same cavity volume produces different shot weights depending on the material. Always use the bushing chart calibrated for the specific shot material and size being loaded.
How does the SL900 powder measure compare to weighing every charge individually? For target ammunition, the SL900’s charge bar consistency – typically ±0.2-0.3 grains for clean-metering powders in a well-maintained assembly – is entirely adequate. Competitive clay target shooters do not weigh every charge; they verify the bushing selection at the start of each session and trust the production consistency of the charge bar. The SL900’s production rate would be irrelevant if every charge required individual scale verification. For premium hunting loads where maximum consistency per shell matters, individual scale verification is appropriate – but that application is typically handled on a single-stage press rather than a production progressive.
What is Dillon’s warranty policy for the SL900 measure assembly? Dillon’s “No Bull” warranty is one of the more generous policies in the reloading industry. Parts that fail under normal use are typically replaced at no charge, and Dillon’s customer service has a strong reputation for resolving issues without friction. Wear from normal production use over extended time is handled on a case-by-case basis. Contact Dillon directly for current warranty terms and service procedures before purchasing a replacement assembly – in many cases, service or replacement parts are available at no cost.
Conclusion
The Dillon Precision Powder Measure Assembly SL900 is a production-grade shotshell charging system that represents the best integration of powder measure, shot measure, and case-activation in the progressive shotshell reloader category. Its machined aluminum charge bar, direct carrier-to-bar coupling, and interchangeable bushing system produce consistent charges at production speed for the serious clay target shooter who loads in volume. The reciprocating bar’s fixed-cavity geometry – the same philosophy as any bushing-based measure – delivers charge consistency that matches the needs of competitive target ammunition without requiring per-shell scale verification.
The bushing-based adjustment system is a constraint as well as a feature. Charge weight changes require bushing swaps rather than ring adjustments, which makes the measure less suited to exploratory load development where charge weight is being varied incrementally. Shotshell loading is primarily recipe-based rather than load-development-based; the bushing system aligns well with that workflow. A handloader who loads fixed recipes for a fixed set of target guns will set bushings once per recipe and load at production speed for the life of those components.
For the SL900 owner whose measure assembly has worn, the calculus is straightforward: verify with Dillon’s customer service whether a warranty replacement applies before purchasing an assembly. For the prospective SL900 buyer evaluating the system’s powder charging capabilities, the measure assembly is one of the strongest components in the package.
Choose the Dillon SL900 Powder Measure Assembly if you own an SL900 and need a replacement assembly, or are evaluating the SL900 system and want to understand how the powder and shot charging components perform at production speed for high-volume 12-gauge or 20-gauge clay target loading.
Consider MEC alternatives if the MEC bushing ecosystem’s wider selection and large user community are priorities, or if production rate requirements are moderate enough that MEC’s lower entry cost makes the system more economical.
Consider Ponsness-Warren alternatives if specific gauge availability or hull compatibility for non-standard loads drives the press selection decision.
Contact Dillon customer service before purchasing a replacement assembly – Dillon’s warranty and service policy frequently resolves worn component issues at no cost to established customers.
Disclaimer: Specifications and pricing in this article are drawn from manufacturer and retailer sources current at time of publication. Always verify current pricing before purchasing.
Editorial note: Originally published May 2026. Initial publication. The article covers the Dillon SL900 Powder Measure Assembly’s reciprocating charge bar mechanism, interchangeable bushing system, carrier-to-bar coupling, powder and shot charge consistency for target shotshell production, setup and bushing selection procedure, and competitive positioning against MEC and Ponsness-Warren shotshell press powder measure systems.
