My kids don't shoot with a brake but do shoot suppressed. If they are shooting prone, stay away from radial brakes. The apa tank was a good recoil reducer for it's time. I think they changed the name but it works.
APA FB- A lot of recoil reduction but terribly loud
Area 419 hellfire or sidewinder is a better balance of recoil reduction and noise at the shooter but ultimately a suppressor would fit the bill the best especially for kids
Shameless plug here. I used a Piercision muscle brake on my Tikka 300wsm. Tamed it down considerably to where it was very pleasant to shoot. The rear most port is 90 degrees so you don't slapped in the face. Rebarrelled that rifle and I have no use for it now. I'd make you a deal if interested.
I just put the Terminator brake on my 30-06. I went to the range yesterday and put 80 rounds through it - wearing a tee shirt - and it was like shooting a.22.
I could have shot all day with it. The Terminator outperforms them all. Pricey but worth it IMHO.