On a cold winters Saturday morning here in South Africa, in 2019, I decided that I'm fed up losing a handful of 30-06 rifle brass cases due to necks cracking every time I reload. I started reading up on annealing. It was clear that you get better accuracy when you anneal consistently, and that some rifle shooters report over 40 reloads from their brass cases when they anneal after every shot.
Then I built my first gas annealer, and ordered some Tempilstik. I didn't want to paint Tempilaq on the inside of my case necks, and Tempilstik has a slightly longer (but still too short for its price) shelf life. I started annealing every 3 shots, and like magic my case necks stopped cracking! I was hooked!
As time progressed, setting up my gas annealing flame temperature every time became a tedious task, and my Tempilstik crumbled as it expired. It was also a bit of a guessing game on measuring the actual temperature reached, and the consistency I was looking for was not really there. I almost burned down my garage once with the flame being too close to nearby stuff. I looked at induction annealing machines, but it was just too expensive.
One day I decided to start building my own induction annealer. Coming from an engineering and software background, I thought it'd be easy and affordable! Boy, was I surprised. The ZVS kits you can buy come with design flaws, and coil winding is a science of its own. The kits dont come with water cooling systems. The power supplies cost a pretty penny if you don't buy in bulk. I even accidetally shocked with 230V one time, and It's very likely to cost you more in the end than just buying an annealer. If you build one, it's not safety tested, and you still need a timing mechanism. After several months of playing around on weekends, you may have something working by hook or by crook, but you still don't really know how long to anneal.
Anneal time is dependent on how close the case is to your induction coil, and how well the coil couples with the case neck. It's also dependent on the current that passes through the coil, which depends on the repeatability of the oscillating voltage and the frequency. It depends on placement depth of the case neck, how much brass (weight) needs to be heated up, and how well the brass conducts into the bottom of the case, slowing the heating process. Power (heat) transfer also changes as your induction coil gets hot over time. All this needs to be taken into account to heat a brass case neck to a repeatable temperature over a repeatable duration for consistency. So how do you know the right temperature?
The right temperature over time is what gives you a consistent neck tention and hardness of around 100HV. HV stands for Hardness Vickers, a process where the material hardness is measured by measuring the size of a microscopic repeatable diamond indentation made into the case neck. Many brass manufacturers anneal their new cases to between 100HV and 110HV. However, I recently sent a brand new 7mm PRC case to be tested and it turned out it was never annealed and had a hardness of near 200HV. I did this after getting cracked necks after 3 reloads without annealing, and getting poor shot grouping, wasting countless hours before finding the issue.
Every time brass expands or contracts, such as by sizing or firing the cartridge, it hardens. A hardness of around 150HV or higher is more prone to cracking. A hardness much lower than 90HV might not be sufficient to grip a bullet for rugged hunting conditions driving on gravel roads with bumps and vibration. Measuring Hardness Vickers is expensive and time consuming. On some forums people say that you can anneal until the case gets dull red, but I found that this could soften the case neck down to 70HV, too soft for hunting purposes. There are other cheaper methods for measuring hardness, but they destroy your brass cases, and are not as accurate. So calibration of annealing setups remains a significantly overlooked problem for individual reloaders who strive for consistency.
On January 2025, the South African manufactured FNX Tech induction annealer was born, and we launched it at Huntex in April 2026. The annealer uses an infrared sensor in an enclosed controlled environment to detect when a repeatable temperature is reached (in most cases long before the case neck visibly starts glowing). Each unit is calibrated for a representative range of large/small calibres to produce a neck hardness of around 100HV. A tolerance is allowed around this calibration, because consistency is the primary concern. For most of us it should not really matter whether you anneal to 90HV or 110HV, as long as it's consistent over time. For professional target shooters, the FNX Tech annealer also allows you to configure the device over Wifi to anneal slightly longer for even less neck tension. Wifi connectivity also allows for firmware updates.
The benefits of using a sensor to anneal, and inserting cases into a controlled environment until the neck is pressed against a stopper, is that you can mix cases from different manufacturers and different calibers, it will not impact repeatability. This leaves the user with ease of mind, no burden to manually guess anneal time, and no need to sacrifice cases or setup the device .
FNX Tech's mission with our induction annealer is to bring cost effective annealing accuracy to every reloading bench, remove the guesswork, and get rid of the endless tinkering that takes up so much of our valuable time. Yes, there are lots of other annealer options available out there, but as it stands today they don't yet fit the budget of the majority of reloaders, as well as remove all the guesswork at the same time. Otherwise I would have just gone and bought one! With FNX Tech, you get a calibrated induction annealer that works out of the box for most calibers, no setup required, and you don't have to take out a second mortgage to afford accurate annealing. We stand by our products and will support you even after the warrantee expires.
After starting to anneal my 7mm PRC cases, I noticed better groupings and could feel the bullets seating more consistently. I had the pleasure in May 2026 of watching my 11 year old son hit a 1x1m plate 1km away in the Karoo, with his first shot, right after I tweaked my Arken scope turrets for him. That's just the kind of consistency we as reloaders should all strive for, it's just way more fun that way!
Francois du Plessis - CEO, FNX Tech.
3 comments
FNX Annealer is a standout—highly advanced, scientifically precise, and clearly engineered beyond typical standards. Temperature measurements rather than guessing the temp of your case. It outperforms gas annealers while being significantly more affordable than typical expensive induction anneal equivalents, which makes it exceptional value.
Testing was successful across all my different calibers (243Win; 6.5Creedmoor; 300PRC & 9.3×62mm), and it consistently exceeded expectations with accurate, reliable performance. Once you’ve used FNX annealer, other alternatives feel inefficient and outdated.
Bottom line: accurate, quick, and unbeatable for the price.
I had the pleasure of testing one of the first units, unsupervised at my own reloading desk. Initially I was a little skeptical about the unit, but boy was I pleasantly surprised. My 300 WM cases were perfectly annealed every one consistently and repeatable. The process is easy. The machine is manually fed, but the process is quick and you can do a relatively large batch is a short time. Well done FNX Tech – you have a fan for life.
Sal graag meer wil uitvind kontak my asb. Lyk netjies soek al lank vir so iets.