The inquest into Ranger Michael Maguire's death at Castlemartin range in Pembrokeshire also heard that a popular beach was in the direction of, and within range of, live machine gun fire.
The brother of Ranger Michael Maguire, who was killed on a range in Pembrokeshire, said "soldiers should not be killed in training, and we hope that lessons are learned army-wide to ensure that an incident like this will not happen again."
The jury at an inquest in Cardiff recorded a verdict of unlawful killing.
Jimmy Maguire described Ranger Maguire as "a dearly-loved son and brother, much missed by his family and everyone who knew him."
– Ministry of Defence spokesperson
Our thoughts are with Ranger Michael Maguire’s family and friends at this very difficult time.
We will look very closely at the Coroner’s comments to ensure that we make all the necessary changes to prevent an accident of this nature happening again.
There are still ongoing investigations into Ranger Michael Maguire’s death so it is not appropriate for us to comment further.
Ranger Michael Maguire was on his lunch break in a "safe area" at the range and had taken off his helmet when he was hit in the head by a bullet, an inquest into his death heard.
He had joined the Royal Irish Regiment in 2010, and survived a tour in Afghanistan.
The inquest in Cardiff heard shooting targets had been set up wrongly and were in "dangerous positions."
It was told the cause of death was a gunshot wound to the head.
The jury returned a verdict of unlawful killing.
Investigations by the military and the Health and Safety Executive are underway.
An inquest into the death of a soldier at a training range in Pembrokeshire has recorded a verdict of unlawful killing.
Ranger Michael Maguire, who was 21 and from County Cork in Ireland, died at the Castlemartin range last May.
The jury has been sent out to consider its verdict at the inquest into the death of a soldier during a live-firing exercise in Pembrokeshire.
Summing up, the coroner reminded the jury of the exercise taking place - described by a senior officer as "standard and simple."
When the incident happened, Ranger Maguire was on Range 10 at Castlemartin, which was split into two parts - he was on Part A, and there was live-firing on Part B.
The coroner referred to evidence from the pathologist who conducted the post-mortem, and said Ranger Maguire died from a gunshot wound to his forehead.
The coroner said that, if the jury was happy with this, it must then decide where the bullet came from.
She said that other ranges were in action, but most of the witnesses seemed to agree it was likely to have come from Range 10 Part B.
A tourist beach outside a popular seaside resort may have been sprayed with machine gun fire during training in which an Army ranger was shot dead.
An inquest into the death of a soldier at a range in west Wales heard that machine gun fire was directed towards Freshwater West Beach, near Tenby.
The beach, well known to surfers, is situated less than one and a half miles (2.4km) along the coast from Castlemartin Ranges where the Army trains recruits.
Civilians ran the risk of being shot and killed themselves on the day one soldier died after a fatal error.
The inquest is into the death of Michael Maguire in May who was hit in the temple by a single machine gun bullet probably fired from 0.6 miles (1km) away.
The jury heard evidence today suggesting that civilians who may have been relaxing at a nearby pleasure beach could also have been hit.
An inquest has heard that a soldier was killed when he was hit in the head by friendly fire during a training exercise at the Castlemartin range in Pembrokeshire.
Ranger Michael Maguire, 21, died when he was shot by a machine gun after returning from Afghanistan.
Cardiff Coroner's Court heard Ranger Maguire was not wearing a helmet and was waiting in a field a kilometre away from the action zone when he was hit.
Army medic Michael Gleeson told the inquest: "I was sat in the battlefield ambulance when we received a call to say someone had been hurt.
"As we arrived the people around him started grabbing kit and throwing it out of the way.
"They were making a work space for us - which made it clear we where dealing with a serious casualty.
"I ran over to him, they had applied an emergency bandage to Michael Maguire's wound, to the left side of his temple."I applied CPR to him until for 15 to 20 minutes until an air ambulance arrived - the whole time I was with him he was unconscious."
The inquest heard how Ranger Maguire was on army training exercise with the 1st battalion of The Royal Irish Regiment when he died. The soldiers were taking part in a training exercise firing machine guns and rifles series of static and pop-up targets when the accident happened.
Ranger Maguire was rushed by helicopter to the University Hospital in Wales suffering from head injuries but doctors were unable to save him.
His dad Michael Snr told the hearing: "I loved Michael dearly and will miss him terribly.
"He was a sporting, fit lad and very lovable and he was always very happy with army life."
Ranger Maguire was from Bantry, in County Cork, Ireland and went to school at nearby St Goban's College.
After school he joined the 1st Battalion, The Royal Irish Regiment on 10 May, 2010, and was sent to Afghanistan four months later.The inquest continues.