The Iver Johnson HP18 is a semi-automatic shotgun chambered in 20 gauge with an 18.5-inch barrel and a 3-inch chamber. It holds 5+1 rounds and comes with a pistol grip buttstock in black synthetic finish. The barrel carries a cylinder choke. 
 

Key Specifications 

• Brand: Iver Johnson Arms 
• Model: HP18 
• Caliber: 20 Gauge 
• Action: Semi Auto 
• Barrel Length: 18.5" 
• Capacity: 5+1 
• Color/Finish: Black 
   

Detailed Features 

• 18.5-inch barrel with cylinder choke 
• 3-inch chamber 
• Pistol grip buttstock in black synthetic 
• 5+1 round capacity 
• Blue/black metal finish

Owners of the Iver Johnson HP18 in 20 gauge often mention how the short barrel and pistol grip configuration makes the shotgun easy to maneuver in confined spaces. The lightweight 20 gauge chambering is a common point of appreciation for shooters who find 12 gauge recoil less manageable in a compact platform.

The HP18 trigger and cycling reliability get a range of opinions. Most users report reliable function with standard loads, but a subset notes that lighter target loads can cause short-cycling until the action breaks in. The pistol grip stock is polarizing: some owners prefer it for home defense handling, while others find it tiring during extended range sessions.

On value, the HP18 occupies a budget price tier and opinions reflect that. Buyers looking for a no-frills defensive 20 gauge tend to be satisfied, while those expecting competition-grade build quality walk away less impressed. Customer service feedback on Iver Johnson Arms is inconsistent in owner discussions.