(CNN) A farmer in New Zealand packed up his semi-automatic firearm Monday and surrendered it to police.

The weight of the terror attacks on two mosques in New Zealand and the thought of what could happen if the gun fell into the wrong hands made John Hart voluntarily turn in his firearm, he said.

"I had had that gun since it was made. I was glad it had never harmed a person," Hart, 46, told CNN. "Now I can know that it never harmed a person, so I have some reassurance in that."

Friday's attacks killed 50 people in the nation which has had relatively few gun-related deaths . The shooter's weapons including two semi-automatic firearms and two shotguns, according to New Zealand officials.

Hart has been a gun owner for almost two decades, he said. He owns a 50-acre farm in Masterton, New Zealand, where he raises sheep and beef. He said he thought a lot before making his decision and ultimately, he felt a "bit of relief."

Until today I was one of the New Zealanders who owned a semi-automatic rifle. On the farm they are a useful tool in some circumstances, but my convenience doesn't outweigh the risk of misuse.



We don't need these in our country.



We have make sure it's #NeverAgain pic.twitter.com/crLCQrOuLc — John Hart (@farmgeek) March 18, 2019

He said he had purchased the semi-automatic firearm to help with killing goats and wild pigs to aid in pest control on the farm. Hart said he still has other guns on the farm for "chores and euthanizing animals."

"For me, the main reasoning was that these types of weapons are convenient for some types of tasks, but they aren't the only way to perform those tasks," Hart said.

"To my mind, the tradeoff of having the convenience of that weapon versus having it misused, it just wasn't worth it. I think that we should not have these in our country in the wake of what happened," he said. "It felt like the perfectly logical thing to do was to surrender mine."

Turning in his firearm was a simple, quick process, Hart said. He filled out an arms surrender form and notified police he would be bringing the gun to the station.

"In southern New Zealand, you are able to give up firearms with no questions asked," Hart said. "With the terror attack, we're on a heightened awareness, so I really didn't want to walk up to police station with a gun with armed guards outside."

He's not alone in voluntarily surrendering his firearm. Some gun owners in New Zealand turned to social media on Monday to post their stories of why they gave up their guns.

Twitter user Blackstone shared a redacted version of an arms surrender form Monday, stating the reason for return as "doesn't want it." The gun owner declined to speak with media, as posted on Twitter.

Since I first heard about the atrocity on Friday afternoon I have reflected and reserved my thoughts.

Monday morning - this is one of the easiest decisions I have ever made.

Have owned a firearm for 31 years. pic.twitter.com/fBFqfd0gTm — Blackstone (@SirWB) March 17, 2019

"Since I first heard about the atrocity on Friday afternoon I have reflected and reserved my thoughts," Blackstone wrote on Twitter. "Monday morning - this is one of the easiest decisions I have ever made. Have owned a firearm for 31 years."

A woman named Fey Hag also posted on Twitter about turning in her guns for destruction by police. She did not respond to CNN's request for an interview.

"When my husband died his guns were handed to family holding the requisite license," she wrote. "Daughter of crack shot food hunting parents, I have used guns from the age of 9. Today I requested that those guns be handed in for destruction."

When my husband died his guns were handed to family holding the requisite license. Daughter of crack shot food hunting parents, I have used guns from the age of 9. Today I requested that those guns be handed in for destruction. — Fey Hag (@FeyHag) March 18, 2019

Hart said he has been "overwhelmed" by the feedback he has received online after posting about surrendering his firearm. Many of the comments were positive, but there were a fair number of gun owners posting negative comments, he said.

"I'm fairly confident that we will have a positive outcome from this," Hart said in response to New Zealand saying it would reform laws. "[Jacinda Ardern] has already committed to changing the gun laws and we need to see how that plays out."