# Technical Analysis: Fission Chamber

Suggest read: [Juno Mediblaster technical analysis](https://www.reddit.com/r/OverwatchUniversity/comments/1q3oa1v)

## TL;DR

While Fission Chamber is active, Juno fires at exactly **25 bullets/sec (187.5 DPS / 150 HPS)**. Attack speed item has no effect on this fire rate.

| Ring Touches | Duration | Bullets Fired | Overall DPS | Weapon Power Equiv. |
| --- | --- | --- | --- | --- |
| 0 | 2.75s | 68 | 111.5 | 7.8% |
| 1 | 5.75s | 143 | 130.6 | 26.2% |
| 2 | 8.75s | 218 | 150.0 | 45% (full clip) |
| 3 | 11.75s | 288 | 150.0 | 45% (full clip, Lux Loop required) |

---

## Mechanics

### Visualization

I build this tool to visualize the Mediblaster's attacking pattern.
You can use it to visualize Fission Chamber's fire rate.
<https://zero41120.github.io/mediblaster/#/>

### Activation

Casting Hyper Ring to activate Fission Chamber has a **0.55s cast time**, during which a 0.25s window overlaps with the buff before you can fire. The effective burst duration is therefore **2.75s**.

If you cast Hyper Ring **during reload**, you skip 0.3s of the cast lead-in. The 0.25s overlap still applies, so you cannot fire until that window passes.

### Fire Rate

During the buff, the gun fires at a fixed **2.4 frame interval** (25/sec), ignoring attack speed entirely. This is slower per-bullet than the normal 12-volley burst, which has a **1.8 frame interval**. If you have muscle memory built around the 19.8-frame volley window, you will only connect ~8.25 bullets in that same window instead of 12. Fission Chamber requires a fundamentally different aim style.

Because attack speed does not affect the fire rate, you should completely forgo building attack speed when running this power.

### Ring Refreshes

Touching Hyper Ring extends Fission Chamber by **+3s per touch**, up to 2 refreshes by default (+6s total). With **Lux Loop**, the Ring duration is extended by 25%, making a 3rd touch possible (+9s total, 11.75s total buff).

### Ammo Efficiency

| Touches needed | Bullets needed | Ammo item |
| --- | --- | --- |
| 2 | 218 | +20% ammo (216 bullets, 2 short, negligible) |
| 3 | 288 | +20% ammo, +40% ammo (Lux Loop route) |

The **+20% ammo item** is the highest value purchase for this power relative to its cost. At 2 touches you fire 218 bullets; a +20% clip gives 216, which is close enough that you run near-empty.

### Melee

After each 12-bullet volley, you have a recovery window. Using melee during this window adds +40 damage per kick, but melee recovery time is 0.55s instead of 0.45s. In situations where you can consistently land melee (e.g. Winston), this increases overall DPS by approximately 27.8%, which is more almost the same as touching ring once with this power. While using this power, you should not be kicking at all, so you have the opportunity cost of picking other power, if kicking is available in the first place for offensive use.


### Downtime Analysis

Hyper Ring has a 14s cooldown. In a 2-touch scenario:

| Phase | Time |
| --- | ---: |
| Ring cast lead-in | 0.55s |
| Firing (2-touch) | 7.20s |
| Reload | 1.50s |
| Down time | **4.75s** |

### Reducing Downtime with Medimaster

Medimaster reduces Ring cooldown by **0.2s per critical hit**. To eliminate the 4.75s downtime you need **24 critical hits** per cycle.

Estimating from top-500 open profiles: most Juno players run 35–45% accuracy. In Stadium specifically this is likely lower due to the mode's play style. Using 35% accuracy and a 10% crit chance:

> 180 bullets × 35% hit rate × 10% crit rate ≈ **6–7 crits per cycle**

Unless you have a consistently hittable headshot target (Zarya, Ashe), reaching 24 crits while Fission Chamber is active is not realistic. And I argue if you are hitting many headshots, you wouldn't need to care about the downtime as enemy is just dead.

### Reducing Downtime with CDR Items

| Downtime target | CDR required |
| --- | ---: |
| 0s (100% uptime) | ~34% |
| ~2s | ~20% |

Reaching 34% CDR requires stacking 4 items, which is inefficient. Even 20% CDR is a significant opportunity cost. Stadium generally favours burst output over sustained output, so CDR routes are usually not worth it.

---

## Item Synergies

| Item | Notes |
| --- | --- |
| **Lux Loop** | Extends Ring by 25%, enabling a 3rd touch (11.75s, ~288 bullets). Good if you can consistently refresh the Ring. |
| **+20% Ammo** | High value at low cost, brings clip close to the 218-bullet mark for a 2-touch run. |
| **Field Support** (Healing Station) | Place the station inside the Ring area; dance around it to maintain uptime while staying mobile. |
| **Long Range Blaster** | Enables a corner-camping play style where you selfishly sit inside your own Ring from a safer distance. |
| **Salvaged Slugs** | Shooting shield eliminates spread penalty. Combined with Fission Chamber, gives **~281 DPS against shields** (e.g. Reinhardt). Niche pick. |
| **Codebreaker** | Effectively ~72.5% weapon power against armour. High synergy if your primary target is a tank. |

---

## Power Synergies

| Power | Notes |
| --- | --- |
| **Heal Formation** | Ring grants 40% leech. Theoretical healing output reaches ~60 HPS if all shots land, which is more than Mercy's base beam at 55hps. But in practice requires the enemy to stand still. |
| **Medimaster** | 0.2s CD reduction per crit. Situationally useful with a stationary headshot target; rarely practical in most matchups. |
| **Hyper Healer** | Ring grants overhealth. In a Fission Chamber build you touch the Ring multiple times, meaning more frequent overhealth stacks. This is better survivability than in a Torpedoes build where Ring touches are infrequent. |

## My other technical breakdowns

* [Season 5 Defensive Item Guide](https://www.reddit.com/r/JunoMains/comments/1pn5ybh)
* [Reflex Coating/Divine Intervention deep dive](https://www.reddit.com/r/Overwatch/comments/1pj2x2o)
* [Three-Tap Tommy Gun deep dive](https://www.reddit.com/r/OverwatchUniversity/comments/1nmmu8u)
* [Armor mechanics deep dive](https://www.reddit.com/r/Overwatch/comments/1n4k71l)
* [Codebreaker (anti-armor) deep dive](https://www.reddit.com/r/JunoMains/comments/1kv2hoc)
* [Juno Ultimate deep dive](https://www.reddit.com/r/JunoMains/comments/1pw36b4)
* [Stadium Power Cosmic Coolant analysis](https://www.reddit.com/r/JunoMains/comments/1qdjczw/stadium_power_cosmic_coolant_analysis/)
* [Juno Anti-Winston Bulk Stadium Build](https://www.reddit.com/r/JunoMains/comments/1qh3etb/antiwinston_bulk_stadium_build/)
