Cessna 208 captain reported an near midair collision with aircraft not complying with normal pattern...

Narrative:

I was on a VFR approach runway xx into ZZZ. I called unicom at this time and announced I was planning for a straight in approach for runway xx. When I called again for a 5-6 mile final an aircraft came on the radio to announce his position it came in garbled and unreadable; so I announced on unicom 'last aircraft to call it was unreadable.' so aircraft X repeated and announced that he was doing a dog leg to downwind for runway xx. He was a light experimental aircraft and I am in a turboprop airplane on an about 5 mile final; so I continued my approach. After this; aircraft X didn't make any other calls so I assumed he was still on downwind. I announced that I was on a 3 mile final; then a short final and this aircraft did not make any more calls. When I was very short final; less than half a mile before runway xx something to my left caught my eye and I look over: aircraft X was 10 feet or less descending on to me and turning into me. I made quick and sharp evasive maneuvers to the right to avoid what would have been a sure midair collision. When I saw I was clear of him (because I am a faster aircraft) I continued my landing. He was unprofessional on the radio afterwards telling me that I didn't have the right away (I was lower and on final when he decided to do a short approach and descend on top of me). I cleared the runway and got my passengers safely into the terminal.

Original NASA ASRS Text

Title: Cessna 208 Captain reported an NMAC with aircraft not complying with normal pattern procedures; at non towered field.

Narrative: I was on a VFR approach Runway XX into ZZZ. I called Unicom at this time and announced I was planning for a straight in approach for Runway XX. When I called again for a 5-6 mile final an aircraft came on the radio to announce his position it came in garbled and unreadable; so I announced on Unicom 'last aircraft to call it was unreadable.' So Aircraft X repeated and announced that he was doing a dog leg to downwind for Runway XX. He was a light experimental aircraft and I am in a turboprop airplane on an about 5 mile final; so I continued my approach. After this; Aircraft X didn't make any other calls so I assumed he was still on downwind. I announced that I was on a 3 mile final; then a short final and this aircraft did not make any more calls. When I was very short final; less than half a mile before Runway XX something to my left caught my eye and I look over: Aircraft X was 10 feet or less descending on to me and turning into me. I made quick and sharp evasive maneuvers to the right to avoid what would have been a sure midair collision. When I saw I was clear of him (because I am a faster aircraft) I continued my landing. He was unprofessional on the radio afterwards telling me that I didn't have the right away (I was lower and on final when he decided to do a short approach and descend on top of me). I cleared the runway and got my passengers safely into the terminal.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1685880
Time
Date	201909
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Caravan 208A
Operating Under FAR Part	Part 135
Flight Phase	Landing
Route In Use	Visual Approach
Flight Plan	VFR
Aircraft 2
Make Model Name	Small Aircraft
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 150 Flight Crew Total 1350 Flight Crew Type 350
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 10

Cessna 208 captain reported an near midair collision with aircraft not complying with normal pattern procedures; at non towered field.