You can try to sneak through an astral barrier with a Magic + Charisma [Astral] vs. Force x2 Opposed Test. This gets progressively more difficult as you try to bring sustained spells, active foci, and spirit companions with you, since you need a net hit for each.
"If you want to break through a mana barrier, you need to deal with its Armor and Structure Ratings, just as you would with any other barrier. A mana barrier has Armor and Structure ratings equal to its Force." (Getting Around Mana Barriers, SR5, p.316).
You can try to smash it with Astral Combat + Willpower [Astral], DV = Charisma + net hits, or use a weapon focus (same test, except using the weapon's Accuracy limit and Charisma-based DV). (Astral Combat, p.315). You can also attack it directly with mana combat spells. The attack test is unopposed, but it can generate extra hits for added damage. The barrier gets a damage resistance test, rolling Force + Force instead of Armor + Structure. If the remaining damage to the barrier is greater than its Structure (Force), the attack opens a hole in the barrier.
SR5 isn't entirely clear what happens at this point. Is the mana barrier destroyed? Or does the attack just create a hole in the mana barrier, as it would with a physical one? (Destroying Barriers, p.197). If it makes a hole, does the hole close up when the mana barrier regenerates its full Structure rating at the end of the Combat Turn? (Getting Around Mana Barriers, p.316). I think option A: When a mana barrier takes damage above its Force in a single Combat Turn, it pops like a soap bubble.
Leaving the question: Why attack the barrier? Depending on circumstances, breaking it might be easier than squeezing through it. Maybe you're carrying a lot of quickened and sustained spells. Maybe you want to intimidate the magician who created it, or send a message that his defenses are weak. It could be a way of throwing down a gauntlet, daring him to come and defend his barrier. Maybe you just feel like breaking something, or flexing your astral muscles.
