This is a very hard to find "square" O-ring rubber washer for the Remington 58 Sportsman 12ga, 20ga and 16ga shotgun fore-end. This rubber ring also fits Remington 878 forend assembly. This item fits inside the fore-end steel ring (part #30) which fits inside the wood fore-end. Without this rubber washer the cycling gases will escape and the gun will not cycle properly. Some people will use a "round" O-ring because they are unable to locate the original square type O-ring. The round style washer might work for awhile, but Remington designed their model 58 with a square washer for a reason. If you know the load dynamics for round vs square washers you know why it was designed with a square washer. If you care about your shotgun then - "Do it right the first time." Note: The Remington Model 58 was manufactured between 1956 and 1963. The earlier versions had a different style rubber washer and steel ring that holds the rubber washer in the wood forend. The earlier washers had a "ridge" on the washer and the steel ring was completely circular, not like the newer version. Remington re-engineered the washer and steel ring sometime in 1957-58 to the "square" washer and improved design ring. If you have any issues or questions please send me a message and I can help.

This is a very hard to find "square" O-ring rubber washer for the Remington 58 Sportsman 12ga, 20ga and 16ga shotgun fore-end. This rubber ring also fits Remington 878 forend assembly. This item fits inside the fore-end steel ring (part #30) which fits inside the wood fore-end. Without this rubber washer the cycling gases will escape and the gun will not cycle properly. Some people will use a "round" O-ring because they are unable to locate the original square type O-ring. The round style washer might work for awhile, but Remington designed their model 58 with a square washer for a reason. If you know the load dynamics for round vs square washers you know why it was designed with a square washer. If you care about your shotgun then - "Do it right the first time." Note: The Remington Model 58 was manufactured between 1956 and 1963. The earlier versions had a different style rubber washer and steel ring that holds the rubber washer in the wood forend. The earlier washers had a "ridge" on the washer and the steel ring was completely circular, not like the newer version. Remington re-engineered the washer and steel ring sometime in 1957-58 to the "square" washer and improved design ring. If you have any issues or questions please send me a message and I can help.