Case Annealing- What's it all about?

[Petey308]

Annealing for Precision Reloading: Torch vs Induction​

Preface:
This write-up is not meant to tell anyone what they “must” buy. Annealing can be done successfully with several methods, and many shooters are very satisfied with torches or salt baths. My intent here is to break down the differences, share my own progression through the options, and reference research (including AMP’s published studies: https://www.ampannealing.com/articles/) to explain why results may vary. The “best” method depends on your goals, volume, budget, and what level of repeatability you want.

My Progression Through Annealing Methods​

- Socket, Drill, and Torch – Tedious, inconsistent, and hard to verify results.
- Annealeez (Torch System) – Much easier for volume but still sensitive to gas pressure, nozzle position, and brass lot changes.
- Induction Annealing – No flame, no fuel pressure issues, and much easier to repeat settings. Safer to use, especially around kids.

Induction Annealers I’ve Used​

- Fluxeon Annie – Affordable, effective, can be automated with third-party kits.
- AMP Mk II – Industry gold standard. Uses “Aztec Mode” to calibrate to each brass type. Produces repeatable hardness results of ~98 HV ± 2 HV (https://www.ampannealing.com/articles/46/annealing-under-the-microscope/). Many brass makers now publish AMP codes.

DIY options like the “GinaErick” can also perform well.

The Science of Cartridge Brass​

Cartridge brass (C26000, 70/30 copper-zinc) doesn’t behave like steel.

- Quenching: Brass does not harden when quenched.
- Glow ≠ ruined: Brass begins glowing at ~950°F. Brief flash annealing achieves recrystallization without over-softening.
- Stages of annealing: Recovery → Recrystallization (goal) → Grain Growth (dead soft, undesirable).

Reference: https://www.ampannealing.com/articles/40/annealing-under-the-microscope/

Comparing Methods​

- Torch/Flame – Works if carefully calibrated. Tempilaq is subjective; AMP found torch methods often vary ±10 HV, which can show up on target.
- Salt Bath – Only achieves “recovery” stage, not full anneal. See AMP’s article: https://www.ampannealing.com/articles/
- Induction (Annie, DIY) – Safer and more repeatable. My HV testing showed ~97 HV anneals, right where it should be.
- AMP Mk II – Removes guesswork with Aztec calibration, achieving ±2 HV repeatability. Backed by AMP’s published studies.

Annealing Methods Comparison Table​

Method	Pros	Cons	Consistency	Safety	Cost / Setup	Best Use Case
Torch (socket/drill, Annealeez, etc.)	Affordable entry point, proven effective when done correctly, Tempilaq usable as a guide	Setup can be tedious, sensitive to flame pressure, nozzle alignment, and tank consistency; high chance of under/over-annealing	Variable (±10 HV or more), heavily dependent on operator skill	Open flame hazard, requires fuel	Low cost; ~$50 DIY to ~$300 Annealeez	Hobby/entry-level, reloaders doing small batches with patience
Salt Bath	Simple setup, relatively cheap, no flame	Only achieves “recovery” stage (not full recrystallization); doesn’t truly reset brass	Poor – not a full anneal, inconsistent	Safer than flame but still messy; hot salts can spill	Low to moderate cost (~$150–250)	Not recommended for cartridge brass (doesn’t achieve full anneal)
Induction (Fluxeon Annie, GinaErick DIY)	Very repeatable, no flame/fuel, quick setup, safer for kids/indoors	Requires experimenting with timing/coil height, not fully automated without mods	Good to very good (HV within correct range if tuned)	Very safe; no open flame	Moderate (~$500–700 DIY/Annie)	Precision reloaders who want safer, consistent annealing at home
Induction (AMP Mk II w/ AZTEC)	Industry gold standard; true scientific calibration (98 HV ± 2 HV); brass-specific codes; repeatable and validated	High initial cost, sacrificial case required if no code available	Excellent – lab-grade repeatability	Very safe	High ($1,400–1,600)	Competitive shooters, long-range hunters, anyone demanding maximum consistency

Choosing by Scenario​

- Budget-focused / small batches → Torch or Annealeez can work well if carefully calibrated.
- Tinkerers / moderate volume → DIY or Annie induction units offer safer, repeatable results without a flame.
- Maximum repeatability / competition → AMP Mk II with Aztec calibration offers lab-validated consistency.

My Practice​

- I anneal after every firing.
- Always anneal before sizing.
- Torch systems can and do work — I was happy with my Annealeez for years — but induction is easier, safer, and more repeatable.

Final Thoughts​

This isn’t about saying torch or salt bath users are wrong. Plenty of reloaders are happy with those setups. Annealing is valuable no matter the method.

The important point is that different methods come with trade-offs. Induction (especially AMP) offers the most consistency backed by metallurgy and data, but flame and Annie units can still produce good results when used properly. It’s not about how much you spend — it’s about choosing the system that fits your workflow, budget, and accuracy goals.