diff --git a/Core/Core.vcxproj b/Core/Core.vcxproj
index 366ae5b7..446e2de3 100644
--- a/Core/Core.vcxproj
+++ b/Core/Core.vcxproj
@@ -554,6 +554,7 @@
     <ClInclude Include="KeyManager.h" />
     <ClInclude Include="Lh51.h" />
     <ClInclude Include="Mapper116.h" />
+    <ClInclude Include="McAcc.h" />
     <ClInclude Include="MMC3_198.h" />
     <ClInclude Include="MMC3_208.h" />
     <ClInclude Include="MMC3_224.h" />
diff --git a/Core/Core.vcxproj.filters b/Core/Core.vcxproj.filters
index d5c2da20..c5dcf53a 100644
--- a/Core/Core.vcxproj.filters
+++ b/Core/Core.vcxproj.filters
@@ -1490,6 +1490,9 @@
     <ClInclude Include="TxcChip.h">
       <Filter>Nes\Mappers\Txc</Filter>
     </ClInclude>
+    <ClInclude Include="McAcc.h">
+      <Filter>Nes\Mappers\MMC</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="stdafx.cpp">
diff --git a/Core/MMC3.h b/Core/MMC3.h
index 42566e45..ac4e9a9d 100644
--- a/Core/MMC3.h
+++ b/Core/MMC3.h
@@ -27,7 +27,6 @@ class MMC3 : public BaseMapper
 		bool _wramWriteProtected;
 
 		A12Watcher _a12Watcher;
-		bool _needIrq;
 
 		bool _forceMmc3RevAIrqs;
 
@@ -37,11 +36,6 @@ class MMC3 : public BaseMapper
 			uint8_t RegA001;
 		} _state;
 
-		bool IsMcAcc()
-		{
-			return _romInfo.MapperID == 4 && _romInfo.SubMapperID == 3;
-		}
-
 	protected:
 		uint8_t _irqReloadValue;
 		uint8_t _irqCounter;
@@ -93,8 +87,6 @@ class MMC3 : public BaseMapper
 
 			_wramEnabled = GetPowerOnByte() & 0x01;
 			_wramWriteProtected = GetPowerOnByte() & 0x01;
-
-			_needIrq = false;
 		}
 
 		virtual bool ForceMmc3RevAIrqs() { return _forceMmc3RevAIrqs; }
@@ -192,7 +184,7 @@ class MMC3 : public BaseMapper
 			SnapshotInfo a12Watcher{ &_a12Watcher };
 			Stream(_state.Reg8000, _state.RegA000, _state.RegA001, _currentRegister, _chrMode, _prgMode,
 				_irqReloadValue, _irqCounter, _irqReload, _irqEnabled, a12Watcher,
-				_wramEnabled, _wramWriteProtected, registers, _needIrq);
+				_wramEnabled, _wramWriteProtected, registers);
 		}
 
 		virtual uint16_t GetPRGPageSize() override { return 0x2000; }
@@ -261,52 +253,31 @@ class MMC3 : public BaseMapper
 
 		virtual void TriggerIrq()
 		{
-			if(IsMcAcc()) {
-				//MC-ACC (Acclaim copy of the MMC3)
-				//IRQ will be triggered on the next falling edge of A12 instead of on the rising edge like normal MMC3 behavior
-				//This adds a 4 ppu cycle delay (until the PPU fetches the next garbage NT tile between sprites)
-				_needIrq = true;
-			} else {
-				_console->GetCpu()->SetIrqSource(IRQSource::External);
-			}
+			_console->GetCpu()->SetIrqSource(IRQSource::External);
 		}
 
-
 	public:
 		virtual void NotifyVRAMAddressChange(uint16_t addr) override
 		{
-			switch(_a12Watcher.UpdateVramAddress(addr, _console->GetPpu()->GetFrameCycle())) {
-				case A12StateChange::None:
-					break;
+			if(_a12Watcher.UpdateVramAddress(addr, _console->GetPpu()->GetFrameCycle()) == A12StateChange::Rise) {
+				uint32_t count = _irqCounter;
+				if(_irqCounter == 0 || _irqReload) {
+					_irqCounter = _irqReloadValue;
+				} else {
+					_irqCounter--;
+				}
 
-				case A12StateChange::Fall:
-					if(_needIrq) {
-						//Used by MC-ACC (Acclaim copy of the MMC3), see TriggerIrq above
-						_console->GetCpu()->SetIrqSource(IRQSource::External);
-						_needIrq = false;
+				if(ForceMmc3RevAIrqs() || _console->GetSettings()->CheckFlag(EmulationFlags::Mmc3IrqAltBehavior)) {
+					//MMC3 Revision A behavior
+					if((count > 0 || _irqReload) && _irqCounter == 0 && _irqEnabled) {
+						TriggerIrq();
 					}
-					break;
-				case A12StateChange::Rise:
-					uint32_t count = _irqCounter;
-					if(_irqCounter == 0 || _irqReload) {
-						_irqCounter = _irqReloadValue;
-					} else {
-						_irqCounter--;
+				} else {
+					if(_irqCounter == 0 && _irqEnabled) {
+						TriggerIrq();
 					}
-
-					//SubMapper 2 = MC-ACC (Acclaim MMC3 clone)
-					if(!IsMcAcc() && (ForceMmc3RevAIrqs() || _console->GetSettings()->CheckFlag(EmulationFlags::Mmc3IrqAltBehavior))) {
-						//MMC3 Revision A behavior
-						if((count > 0 || _irqReload) && _irqCounter == 0 && _irqEnabled) {
-							TriggerIrq();
-						}
-					} else {
-						if(_irqCounter == 0 && _irqEnabled) {
-							TriggerIrq();
-						}
-					}
-					_irqReload = false;
-					break;
+				}
+				_irqReload = false;
 			}
 		}
 };
\ No newline at end of file
diff --git a/Core/MapperFactory.cpp b/Core/MapperFactory.cpp
index 72e9fcbe..08dacf08 100644
--- a/Core/MapperFactory.cpp
+++ b/Core/MapperFactory.cpp
@@ -145,6 +145,7 @@
 #include "Mapper244.h"
 #include "Mapper246.h"
 #include "Mapper253.h"
+#include "McAcc.h"
 #include "MMC1.h"
 #include "MMC1_105.h"
 #include "MMC1_155.h"
@@ -306,7 +307,13 @@ BaseMapper* MapperFactory::GetMapperFromID(RomData &romData)
 		case 1: return new MMC1();
 		case 2: return new UNROM();
 		case 3: return new CNROM(false);
-		case 4: return new MMC3();
+		case 4: 
+			if(romData.Info.SubMapperID == 3) {
+				return new McAcc();
+			} else {
+				return new MMC3();
+			}
+
 		case 5: return new MMC5();
 		case 6: return new FrontFareast();
 		case 7: return new AXROM();
diff --git a/Core/McAcc.h b/Core/McAcc.h
new file mode 100644
index 00000000..5b0b6067
--- /dev/null
+++ b/Core/McAcc.h
@@ -0,0 +1,53 @@
+#pragma once
+
+#include "stdafx.h"
+#include "MMC3.h"
+
+//Based on krikzz's research: https://forums.nesdev.com/viewtopic.php?p=242427#p242427
+class McAcc : public MMC3
+{
+private:
+	uint32_t _counter = 0;
+	uint16_t _prevAddr = 0;
+
+protected:
+	void StreamState(bool saving) override
+	{
+		MMC3::StreamState(saving);
+		Stream(_counter, _prevAddr);
+	}
+
+	void WriteRegister(uint16_t addr, uint8_t value) override
+	{
+		if((addr & 0xE001) == 0xC001) {
+			//"Writing to $C001 resets pulse counter."
+			_counter = 0;
+		}
+		MMC3::WriteRegister(addr, value);
+	}
+
+	void NotifyVRAMAddressChange(uint16_t addr) override
+	{
+		if(!(addr & 0x1000) && (_prevAddr & 0x1000)) {
+			_counter++;
+
+			if(_counter == 1) {
+				//"Counter clocking happens once per 8 A12 cycles at first cycle"
+				if(_irqCounter == 0 || _irqReload) {
+					_irqCounter = _irqReloadValue;
+				} else {
+					_irqCounter--;
+				}
+
+				if(_irqCounter == 0 && _irqEnabled) {
+					_console->GetCpu()->SetIrqSource(IRQSource::External);
+				}
+
+				_irqReload = false;
+			} else if(_counter == 8) {
+				_counter = 0;
+			}
+		}
+		_prevAddr = addr;
+	}
+};
\ No newline at end of file