Crafting of some types of ammo are made more difficult than others (via "unsafe places"), perhaps, to make it more rare and valueble. However, if you compare all types of ammo and weapons that use them you will see that 7.62 are not on the top. Ridiculous, .223 caliber far more powerfull in fallout universe, as well as some of the best weapons (sniper rifle, .223 pistol, light support weapon) use it as ammo.
I suggest to make .223 ammo craft available only in sierra army deport/raiders base, remove special requiments for 7.62 ammo that it can be craft on a regular workbench.
I dont want to say that .223-weapons imbalased or something like that, i just think that more powerfull weapons must be more difficult to maintance. For an example - minigans, they consume realy huge amounts of ammo, so there no need to nerf them in such way. .223 weapons is less expencive, so making .223 ammo a little more hard for crafting, will not affect game to much. While 7.62 weapons will become a "newbie choose", for those who don't want to risk in sierra, or don't know how to join the raiders 

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Caliber    .223  AC modifier    -20 
DR modifier    -20 
Damage adj    1/1 
Weight    18 grams 
Base price    18 caps
.223 weapons:.223 PistolDamage    20 - 30 
Single    AP: 5, Range: 30.
Hunting RifleDamage    8 - 20 
Single    AP: 5, Range: 40.
Scoped Hunting RifleDamage    8 - 20 
Single    AP: 5, Range: 40.
Sniper RifleDamage    14 - 34 
Single    AP: 6, Range: 50.
Light Support WeaponDamage    20 - 30 
Burst    AP: 7, Range: 40, Rounds: 10. 
Caliber    7.62mm  AC modifier    -5 
DR modifier    -10 
Damage adj    1/1 
Weight    22 grams 
Base price    16 caps
7.62 weapons:FN FALDamage    9 - 18 
Single    AP: 5, Range: 35. 
Burst    AP: 6, Range: 30, Rounds: 10
FN FAL HPFADamage    11 - 22 
Single    AP: 5, Range: 35. 
Burst    AP: 6, Range: 30, Rounds: 10
M60Damage    18 - 26 
Burst    AP: 7, Range: 35, Rounds: 10