First, the OP is new here, and actually posted info on his gun in another section. That was where he learned this cylinder was wrong for his gun. He ASKED if he could sell here. I call that polite. He was informed he could, and also in buying a correct cylinder for his gun to be sure to check the OAL.
When he posted this cylinder for sale, an honest question about OAL was asked. The OP replied he wasn't able to get an accurate measurement. An honest answer, followed by an honest offer of a refund if it didn't work.
Yes, the OP is new, but he appears to be trying to be good here.
Meanwhile, another person posts an "I'll take it."
While we do not have a hard, fast rule about that, in general, a full price acceptance does override any low offers or inquiries that appear to the OP at the same time.
conder0289,,, you were offered a chance to buy it & check it, and he would hold your $$ until you were satisfied. Calling a sale "s***y" is first, poor language for our Forum. Second, you didn't say you would take it.
In a private PM, I had told the OP to bring it to the show this upcoming weekend for me to look at. IF IT DIDN'T SELL. I had ample opportunity to buy it. I do not feel slighted at all by having someone post an "I'll take it."
Kevin, you may have sent a PM with a lower offer than the OP wanted to accept, but gave you an option in case it didn't sell to the person who posted an "I'll take it." From what I can see, the OP sent you a SPF after he got an "I'll take it". While many of us send a PM with an offer, the seller does not have to accept it.
While the OP is a newbie HERE,,, it appears he was trying hard to sell an item, for an asking price, and took the first full priced offer of acceptance. He tried to make it easy for anybody who had questions to make sure they were happy with the purchase.
I think the OP is fine, and that all things considered, handled this as best he could have.