User blog comment:DEathgod65/Battlefield 3 Patch Notes/@comment-4887100-20120407131312/@comment-4577090-20120407161146

I am not one hundred percent sure but the heavy barrel only increases first shot accuracy as the recoil kicks the weapon out of aim. The foregrip is supposed to increase the cone of fire meaning the bullet deviation increases. Combining the foregrip and the heavy barrel might nullify the accuracy increase and the accuracy decrease making the weapon as accurate as it was before either attachment was added, however the heavy barrel also increases vertical recoil while the foregrip only decreases horizontal recoil so that would be a problem. Either way, the G36C is a carbine so it does 14.3 damage at long range. It is far better suited for close range therefore the heavy barrel is not a good choice and the accuracy penalty is not a major problem if at all.