...that previously kept me from owning a gun ... (Para.2)
previously: ad. before the present time
The ground was so dry that it was difficult to see where the river had been previously. 土太干燥了，很難看出原先河水流經的地方。
The land where the new buildings were built was previously a park. 正在建造新大樓的那塊地原先是個公園。
previous: a. coming or happening before or earlier
Sorry! We've passed the street. The previous one was the right one. 對不起，我們已走過了那條街了，前面我們走過的那條街才是對的。
My previous trip out of the country was to Europe. This time I went to Africa. 我上回出國旅行是到歐洲，這回我去了非洲。
He said that during the previous year the company suffered heavy losses. 他說在過去的一年中公司損失很大。