For those seeking compensation, the condition of the items was agreed upon before they were given to the destruction team.
Buy-back participants also provided their bank accounts for reimbursement in the next fortnight.
Murphy said the owners were "accepting" of the situation.
"It is a bit of the unknown. They don't know what to expect but I think once they see the system and the process they go through, it is fair and transparent and they leave pretty positive after having a relatively good experience."
He said the majority of attendees were hunters or sporting and competition shooters.
Murphy also said the attendance levels matched police expectations.
"Things have been fairly steady throughout the weekend and as I say, people ... understand the reasons behind it. There are still people that are obviously a bit upset about the whole law change, but they are accepting."
Leading up to the Rotorua event, Murphy helped run other events in Taupō, Ōhope, and Te Puke.
Police have released an extensive list of affected guns, each with a price for poor condition (25 per cent of the base price), average condition (70 per cent of the base price), and new or near-new condition (95 per cent of the base price).
The list also includes gun parts - including magazines, silencers, open sights, and custom triggers - with a different price setting: 70 per cent of the base price for new or used, and 25 per cent of the base price for poor condition.
Rotorua's next buy-back event will be on September 13 to 15, again at the Rotorua International Stadium between 9am and 2pm each day.
Visit the police website to check if your firearm is prohibited, or if it can be modified to make it non-prohibited, before attending a collection event.
The scheme ends on December 20.
Local buy-back collection points in the Bay of Plenty:
• Tokoroa Cricket Club, 56 Mossop Rd, 9am to 1pm, August 16 to 18.
• Kawerau Firmin Lodge, Waterhouse St, 9am to 1pm, August 23 to 25.
• Tauranga Stadium Lounge, Bay Park, 9am to 1pm, August 30 to September 1.
• Waiotahi Settlers Hall, 9 Waiotahi Valley Rd, Opotiki, 9am to 12pm, September 6 to 7.
• Rotorua International Stadium, Devon St, Rotorua, 9am to 2pm, September 13 to 15.
• Murupara Sports Pavilion Hall, 48 Pine St, 9am to 1pm, September 20 to 22.
• Tauranga Stadium Lounge, Bay Park, 9am to 1pm, September 27 to 29.
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More details about the buyback scheme are on the police website www.police.govt.nz