If I want to continue using my 10mm I can't because I ran out of ammo. So I'm forced to use my .38 pipe pistol which has 1,000 ammo and has terrible damage. Normally I would just deconstruct all .38 ammo to create 10mm.
So I'm carrying all these damn heavy guns not for strategic purposes but in case if my main gun runs out of bullets.
Again, you need to get better at the game. You're really crap at it.
Choose your perks wisely.
You only need Luck of 2 in order to find significantly more ammunition in the game.
You only need Charisma of 1 in order to significantly improve your bartering skills to purchase ammo at a cheaper price.
These are low-level low-special perks for a reason.
Furthermore, improve your combat perks so that you make better use of each bullet. Then you won't go through so much to take out the same enemies.