As a long-time shooter and reloader, I’ve spent countless hours chasing the holy grail of accuracy. And let me tell you, it’s often the little things that make the biggest difference. One of those “little things” – and a surprisingly impactful one – is bullet concentricity. That’s where a sinclair concentricity gauge, or a similar bullet concentricity gauge, comes into play. This article will break down everything you need to know about these essential tools, from understanding how to measure concentricity to choosing the best concentricity gauge for your needs, including options like the RCBS concentricity gauge and the Accuracy One concentricity gauge. We’ll also cover how to check concentricity and why it matters for your shooting.
Simply put, bullet concentricity refers to how well the bullet’s axis aligns with its overall length. Ideally, the bullet should be perfectly centered within the cartridge case. When a bullet isn’t concentric – meaning it’s off-center – it introduces several problems. As the bullet travels down the barrel, this misalignment causes it to wobble, increasing drag and reducing accuracy. This effect is magnified at longer ranges, where even minor imperfections can lead to significant deviations. Think of it like spinning a football; a perfectly thrown spiral travels further and more accurately than one that’s wobbling.
While factors like powder consistency, case preparation, and barrel quality are crucial, a non-concentric bullet can negate even the best efforts in these areas. For precision rifle shooters, competitive marksmen, and anyone striving for the highest possible accuracy, checking and addressing bullet concentricity is non-negotiable.
Several types of reloading concentricity gauges are available, each with its strengths and weaknesses. Here’s a breakdown of the most popular options:
The Sinclair concentricity gauge is a widely respected and often considered the “gold standard” by many reloaders. It utilizes a V-block and indicator to measure runout (the amount of wobble) as you rotate the cartridge. Sinclair offers gauges for various calibers. It’s known for its precision and repeatability. However, it can be a bit more expensive than some other options.
The RCBS concentricity gauge provides a more affordable entry point into concentricity measurement. Like the Sinclair, it uses a V-block and indicator. While generally accurate, some users report it may not be quite as precise as the Sinclair, but it’s still a significant improvement over not checking at all. RCBS is a well-established name in reloading, known for its durable and reliable tools.
The Accuracy One concentricity gauge is another high-quality option, often praised for its ease of use and clear readings. It’s designed to be very user-friendly, making it a good choice for reloaders who are new to concentricity measurement. It’s generally priced similarly to the Sinclair gauge.
There are also simpler, less expensive gauges available, but their accuracy can be questionable. Investing in a reputable gauge from Sinclair, RCBS, or Accuracy One is generally recommended if you’re serious about accuracy. Consider the calibers you reload most frequently when choosing a gauge, as you’ll need a specific gauge for each.
| Gauge | Price (Approximate) | Accuracy | Ease of Use |
|---|---|---|---|
| Sinclair | $150 - $250 | Excellent | Moderate |
| RCBS | $80 - $150 | Good | Good |
| Accuracy One | $180 - $280 | Excellent | Excellent |
Now that you have a concentricity gauge reloading tool, let’s walk through the process of how to check concentricity. I’ll use the general principles applicable to most gauges, but always refer to the manufacturer’s instructions for your specific model.
What constitutes an acceptable runout? This is a debated topic. Generally, for target shooting, a runout of 0.001 inch or less is considered excellent. 0.002 inch is acceptable, but anything above that may negatively impact accuracy, especially at longer ranges. Reloading Data provides a good overview of acceptable tolerances.
Understanding the causes of poor concentricity can help you prevent it in the first place. Here are some common culprits:
If you’re consistently finding high runout values, here are some troubleshooting steps:
Even when focusing on precision, it’s vital to remember responsible outdoor practices. Leave No Trace principles apply to reloading as well. Properly dispose of spent primers and case debris. Be mindful of your surroundings and avoid creating unnecessary waste. Furthermore, always consult reputable reloading manuals and follow safe reloading practices. The NRA offers excellent resources on safe reloading procedures.
Investing in a sinclair concentricity gauge or another quality bullet concentricity gauge is a worthwhile investment for any serious reloader. While it adds another step to the process, the potential gains in accuracy are significant. By understanding how to measure concentricity and addressing any issues you find, you can elevate your reloading and shooting to the next level. Remember, accuracy is a journey, and paying attention to these details will help you consistently achieve pinpoint results.