Depends of what you nee.d, the swift training rifle had a range of 2-3inches but did it’s job very well.
I remember being told once that the Bren gun was initially too accurate & you didn’t get the spread of suppressing fire needed for a machine gun.
End of Broadcast!
Strictly speaking as those are smoothbore they can’t be counted as rifles but must be classed as guns which is a different topic.
Allegedly. Not in my hands it wasn’t.
Understatement. 
SLR……
For cadets, the Scorpion wins hands down for accuracy & ease of use. It’s noticeable that cadets who shot the air rifle first, progress very well on the L98.
L81 - basic tgt rifle, newer model needed.
Another vote for the Scorpion
Assume you mean the .177 not the 76mm one
Never fired That Rifle though. It’s something I’d like to have done.
Or Muskets.
Our local Sqn has a range & the safety sign up says it’s for musketry use only……which is a classic just update the sign but don’t change the wording.
When civilian tgt rifle moved from .303" to 7.62mm, I gifted my brand new (out of the greased wrapping paper) .303 rifle to my old ATC sqn. It had beautiful honey-coloured beech woodwork.
Wish I had kept it (new), would be worth a few £££ now.
Loved shooting .303’s as a cadet, got 3 x Cadet 100 badges too.
I only have a couple problems with the scorpion. It seems it’s always failing to fire . I had 6 failures to fire in a 2 groupings of 5 . When I handed it to the staff when i finished they tried shooting - trying to prove I was doing something wrong . And it failed to fire for him
Very unusual - have the rifles been serviced as they should be?
That fault is normally related to the bolt not being pushed hme & the bolt hand all the way down.
Similar thing to me on a BCC shoot.
Deliberate fire in at 150m, rifle to repetition, the guy two lanes down shot a burst off. Absolutely 
himself, not two minutes after the reg made a big deal about you being the problem if something happened.
Low and behold, rifle had a part that was defective that allowed automatic in repitition. It happens.
Happened on an L98 not long back, armourer had put the safety sear on wrong.
That rifle has an issue and should be inspected by an armourer, they are usually quite robust bits of kit.
Possibly not correctly pressurised? I’ve seen it also where seals need replacing (not on the Scorpion but similar kit)
Needs checking by an armourer as others have said.
The No8 .22in training rifle with a Parker-Hale M53 foresight to hold ring aperture discs is my answer for basic marksmanship training and competitions…or a BSA Martini action target rifle - keep it British made! 
After that the current service rifle: British service rifles have always had a good standard of accuracy which makes them suitable for challenging competitive practices, which any soldier can be trained for, as a basis for the better markspeople going on to use specialised weapons.
It will be a civilian gun shop for air rifles (or direct to BSA), not a military armourer. Normally, there are good signs of dropping pressure in the cylinder - group elevation dropping & erratic penetration of pellets through the tgt.
True, as ATC ones are private purchase.