Look up the Swiss Schmidt-Rubin military rifle, or the Blaser sporting rifle for examples. It is a bolt action rifle in which the shooter manipulates the bolt by pulling straight back instead of up and back.
Bolt action. A few are Fortner (straight pull) bolt actions.
This was a straight pull bolt action .303 rifle issued to the Canadian military starting in 1903. It had some problems. See the link below for an article on the Ross.
Pull and hold the trigger, then pull the bolt back and it should release.
Straight pull
The straight pull bolt action rifles haven't been inherently successful. The Canadian Ross Rifle, in particular, was especially problematic, and the Canadians ended up going with the Lee-Enfield, instead. Since the turn bolt rifles remained a military standard, they ended up becoming a civilian standard, as well.
Retract the bolt action to it's furthest open position. Pull the trigger which will release the bolt retaining latch, allowing the bolt to be removed from the rifle.
There is a button at the beginning of the breach that you pusy in and the bolt will pull straight back out of the breach.
Press the release tab on the left side of the receiver and pull the bolt rearward
Start by unloading the rifle, and operate the action several times to be sure it is empty. Point rifle in a safe direction, release safety, pull trigger to drop the striker. Unfasten the takedown screw on the underside of the stock, and remove action from the stock. Unscrew the receiver plug at the rear of the action (careful- under some spring pressure). Pull bolt handle back, sliding action spring and bolt out. Draw bolt handle straight out to the side, and draw bolt out of the action. STOP. Do NOT attempt to disassemble the trigger group. No, really- DON'T. It can be cleaned with spray gun cleaner. Barrel can be cleaned, and bolt and inside receiver can be cleaned. Contact Remington for an owner's manual for your rifle.
It should come apart like any other bolt action rifle pull up and back
The biathlete carries a small bore rifle, which weighs at least 3.5 kilograms (7.7 lb), including ammunition in magazines on her/his back during the race. The rifles use .22 LR ammunition and are bolt action or Fortner (straight-pull bolt) action.
It really depends on the exact rifle. Most bolt action rifles used a non-detachable box magazine. So, typically, you would pull the bolt to the rear, and feed the cartridges through the top into the magazine. When the magazine is loaded, you push the bolt forward to chamber the first round.