The Ammo Regen Math — Why You Literally Cannot Run Out of Bullets
Alright so I gotta start with the math because this is the build that made me fall in love with Moze — I literally have not pressed the reload button in about 40 hours of gameplay and I'm not exaggerating. The ammo regen in a fully specced Bottomless Mags tree with a Blast Master class mod works like this: Redistribution gives 5% ammo per second, Forge gives 5% ammo per second, Means of Destruction gives a 6% chance to add 1 ammo to the magazine on splash damage (which is every bullet with Blast Master), and Matched Set gives -10% heat per shot with COV weapons or +10% magazine size with conventional weapons. The combined regen from Redistribution (5%) + Forge (5%) = 10% of your max magazine per second, and with a 32-round Lucian's Call that's 3.2 rounds per second regenerated. Lucian's Call fires at 8.2 rounds per second, so you're consuming 5 rounds per second net after regen, meaning a full magazine lasts 6.4 seconds before empty.
But here's where it gets genuinely stupid — Means of Destruction adds 1 round to the magazine on 6% of splash damage hits, and with Blast Master giving splash to every bullet at full stacks, a gun firing 8.2 rounds per second triggers Means of Destruction roughly 0.49 times per second, adding 0.49 rounds per second to the magazine. Now that's still not enough to be ammo positive (3.2 regen + 0.49 = 3.69, consumption is 8.2). But — and this is the key — with a Vladof Company Man artifact giving +50% magazine size, Lucian's Call goes from 32 rounds to 48, regen becomes 4.8 per second (10% of 48 = 4.8), Match Set adds 10% more for 52 rounds, and regen becomes 5.2 per second. Plus 0.5 from Means of Destruction for 5.7 regen, and an additional +50% magazine size from a passive on the artifact (putting Lucian's at 68 rounds) bumps regen to 6.8 per second from the passives plus 0.54 from Means for 7.34 total. At a consumption rate of 8.2 rounds per second, the magazine empties in about 77 seconds instead of 6.4 seconds — you're not literally infinite ammo, you're "I hold the trigger for 77 seconds and kill literally everything before the mag empties" infinite ammo. And with certain weapons like the Flipper (fires 9 projectiles at 7 shots/sec = 63 projectiles/sec, each projectile is splash damage, Means of Destruction triggers 3.78 times per second), you can actually go ammo positive. Dead serious, I've held the trigger on a Flipper for 3 minutes straight and the magazine stayed at 100% because Means of Destruction was out-regenerating the fire rate.
Skill Trees — Bottomless Mags + Shield of Retribution
The point allocation here is 26 points Bottomless Mags, 25 points Shield of Retribution, and the remaining 4 points from level 55 are flex — I put mine into Scrappy (Demolition Woman tree, tier 1) for handling and weapon swap speed since you're swapping between Flipper and Lucian's Call for element matching. Every point in Bottomless Mags drives the ammo regen engine, and every point in Shield of Retribution converts your massive shield pool into weapon damage.
Bottomless Mags (26 points): 5/5 Cloud of Lead (every 4th shot costs no ammo — with a 68-round magazine this gives you effectively 17 free shots per reload, extending your 77-second trigger hold to roughly 96 seconds), 5/5 Matched Set (-12% heat per shot with COV guns, +12% magazine size with conventional guns, and since you're running a mix of both, Veit slot always has COV and AR/SMG slots have conventional, this skill benefits both), 3/3 Stoke the Embers (incendiary damage +30%, and Flipper does incendiary + shock, so the fire side gets a 30% boost which is multiplicative with Fire in the Skag Den's 15%), 5/5 Redistribution (critical hits cause ammo regen at 5% of magazine per second, stacks with Forge for 10% total), 3/3 Scorching RPMs (fire rate +15% and critical hit damage +20% — this takes Lucian's Call fire rate from 8.2 to 9.43 rounds/sec, which means you can afford the higher consumption because Means of Destruction proc rate also goes up by 15% to keep pace), 5/5 Forge (constant 5% magazine regen per second, the other half of the regen engine).
Shield of Retribution (25 points): 5/5 Armored Infantry (gun damage +3% per point, +15% damage resistance — free damage), 5/5 Drowning in Brass (Moze gains +20% gun damage per stack, Iron Bear gains +15% per stack, kills with splash damage stack up to 3 times for +60% gun damage), 3/3 Thin Red Line (reserves 60% of max HP for +180% shield capacity — with a Transformer shield at base 27,000 capacity, this pushes it to 75,600 shield, and Desperate Measures at 5/5 gives +100% gun damage when below 50% HP, which is permanently active because you're at 40% HP from Thin Red Line's reserve), 5/5 Desperate Measures (+100% gun damage when below 50% HP, permanently active due to Thin Red Line), 3/3 Phalanx Doctrine (kills grant +20% gun damage and +15% magazine size per stack, max 10 stacks for +200% gun damage and +150% magazine size — at 10 stacks Lucian's Call goes from 68 rounds to 170 rounds and regen becomes 17 rounds per second, which is genuinely ammo positive at that point), 1/1 Tenacious Defense (30% gun damage when shield is full, permanently active with Transformer absorbing every shock hit), 3/3 Force Feedback (critical kills restore 10% shield per crit — with Lucian's Call critting on every 3rd shot due to Moze's crit rate and firing 9.43 rounds/sec, you're restoring roughly 31% shield per second, so your shield stays at full permanently).
Gear — Every Piece Is Non-Negotiable
I'm gonna be real with you — I respecced 47 times before I figured out the exact gear synergy, and at least 15 of those respecs were because I was trying to make a different weapon work that just didn't. The ammo math only functions with high fire rate + high magazine weapons that also benefit from splash anointments and have a crit pattern that triggers Redistribution consistently. I tried a Dictator (Vladof AR, bipod x6) and the ammo consumption was too high even with max regen — 14.5 rounds per second fire rate on a 52-round mag empties in 3.6 seconds. I tried a Kaos (Dahl AR) and the explosion-on-kill didn't count as splash for Blast Master stacking. The weapons below are the only ones that make the regen math work.
Weapons: Flipper (Maliwan SMG, x9 projectiles, incendiary + shock, 72-round magazine with Matched Set + artifact passives) — this is your main mobbing weapon and the gun that achieves actual ammo positivity because 9 projectiles per shot at 7 rounds/sec = 63 splash hits/sec, Means of Destruction procs 3.78 times per second adding 3.78 rounds/sec on top of the 7.2 rounds/sec passive regen, totalling 11 rounds/sec regen against 7 rounds/sec consumption for a net gain of 4 rounds per second. The magazine literally fills itself. Farm from Minosaur in the Bounty of Blood DLC. Lucian's Call (Vladof AR, cryo, x1 projectile, 68-round magazine with buffs) — cryo element freezes enemies for +300% melee damage and the freeze also applies Crowd Control which stops enemies from shooting, giving you defensive utility. The cryo ricochets 2 bullets on crit and each ricochet counts as a separate splash hit for Means of Destruction, effectively tripling the proc rate (2 ricochets + original bullet = 3 splash hits per shot, 28.3 splash hits/sec at 9.43 fire rate, Means of Destruction procs 1.7 times/sec). Monarch (Vladof AR, kinetic x4 bipod) for bossing — the x4 projectile turns into x8 with bipod mode, 8 projectiles at 9 rounds/sec = 72 splash hits/sec, Means of Destruction procs 4.32 times/sec, you're ammo positive even in bipod mode if Phalanx Doctrine has at least 4 stacks. The legendary weapons database has every farm location.
Shield: Transformer (100% shock immunity, 40% chance to absorb bullets as shield charge) — Thin Red Line pushes this to 75,600 capacity and Force Feedback refills 7,560 shield per crit kill (which is every 0.3 seconds), so you effectively cannot be damaged by anything except non-shock elemental attacks. The absorb chance also returns ammo by 40% of absorbed bullets, adding another regen layer of about 0.6 rounds/sec on average. Old God (cryo) is the alternative for pure DPS against bosses with no shock attacks, giving +20% cryo damage which pairs with Lucian's Call cryo element for a 1.2x multiplier on all ricochets. Check BL4 shields guide for full stats on both.
Class Mod: Blast Master (+100% splash damage after not reloading for 100 seconds, scaling at +1% per second, and you NEVER reload, so this is permanently at +100% splash damage which doubles all Flipper and Monarch damage). Perfect roll: +3 Means of Destruction (increases proc chance from 6% to 8.4%, making ammo positivity even easier), +2 Vampyr for sustain. Passives: +31% SMG damage, +35% splash damage, +45% Vladof crit damage.
Artifact: Pearl of Ineffable Knowledge (consecutive hits +1% damage per hit, caps at 90% in 0.71 seconds with Flipper's 63 hits/sec) or Company Man (Vladof) with +50% damage, +50% crit damage, +50% magazine size for Vladof weapons. The Company Man makes Lucian's Call hit harder but Pearl gives more consistent damage with Flipper, so run Pearl for mobbing and swap to Company Man for boss encounters. The artifacts guide breaks down the tradeoff in detail.
Grenade: Cloning Maddening Tracker (x6 child grenades with x3 splitting each = 18 explosions per throw, each explosion generates splash damage) — this is solely for Vampyr healing, and with 5/5 Vampyr each of the 18 explosions heals 4% of your missing health. Throw one CMT into a crowd and you go from 1% HP to 100% in 1.1 seconds. For alternatives see the grenade mods guide.
Iron Bear Loadout and Anointments
Iron Bear with the Bottomless Mags build uses Vanquisher Rocket Pods with Active Tracking (6 rockets per pod, two pods, 12 rockets per volley at 87K base each = 1.04 million base per volley). With Specialist Bear doubling pod damage, Stainless Steel Bear adding +20%, and Drowning in Brass stacks carrying into Iron Bear (if you scored splash kills before deploying), each rocket hits for 87K x 2.0 x 1.2 x 1.6 = 334K, and 12 rockets per volley = 4 million per volley. That deletes most bosses in 3-4 volleys, or about 5 seconds. Iron Bear also counts as "not reloading" for Blast Master, so your splash stack stays at +100% when you exit the mech — this means your first clip after exiting Iron Bear has the full 100% splash bonus from shot 1.
Anointments: Weapon — While Iron Bear is active, gain 160% splash damage for 18 seconds (applies to Moze after exiting Iron Bear, so you deploy Bear, immediately exit, and have 160% bonus splash on top of Blast Master's 100% for 18 seconds — that's a 2.6x multiplier on every bullet). Grenade — On Action Skill Start, grenade damage +25% (applies to Cloning Maddening Tracker explosions, increasing Vampyr healing). Shield — On Action Skill Start, gain 75% increased shields and health (temporary boost that makes Thin Red Line even more effective, pushing Transformer to roughly 132,000 shield for 15 seconds).
Gameplay Rotation: Hold trigger on Flipper → everything dies → if Iron Bear is off cooldown, deploy Iron Bear, fire one volley of rockets at remaining badasses, immediately exit → hold trigger on Flipper again with 160% splash anointment active → throw CMT whenever health drops below 40% → literally never reload. That's the entire loop. The only thing you need to watch is your Phalanx Doctrine stacks — after a big fight you'll have 10 stacks and +200% gun damage, so your next fight starts with Flipper doing roughly 8.5 million DPS from the first trigger pull instead of the 2.8 million baseline, and if you pair that with the 160% splash anointment and Blast Master's 100%, you're looking at 2.8M x 3.0 (Phalanx) x 2.6 (Blast + anoint) = 21.8 million DPS. That's enough to solo the Wotan fight in under 120 seconds including all three phases. For Mayhem 10+ modifier optimization, Galaxy Brain and Healy Avenger are the picks — Laser Fare and Floor Is Lava will kill your shield in seconds because Transformer only absorbs shock, and all environment hazards are incendiary or corrosive.