Originally Posted by JonM
My opinion is why gimp yourself with using pistol ammo in a rifle. Pistol are personal defense firearms and you dont need to carry a ton of ammo.
The xdm in 9mm holds 19+1 add in two spare mags at 19 each thats a decent ammo loadout. Then an ar15 chambered in 556/223 with 7 mags thats 210 roumds.
If you cant get it done with that load out no ammount of ammo is going to help you.
Using a pistol round in a rifle max range with even a 44mag is right at 100yds much less for 9mm or 45acp or 357mag
Same round for both doesnt make sense in a modern world. The reason the settlers liked it was cuz you could only get one or two types in most places.
I agree with Jon on this one. No reason to limit yourself to a 100 yard rifle for the sake of interchangeable ammo.
If the AR platform floats your boat then get it in 5.56 mm. Back that up with a service caliber handgun in 9 mm, .40 S&W, or .45 ACP.
These 4 calibers are prefered simply because should the SHTF, they will be the most available rounds to scavenge.
Now if your interested in a carbine and ammo compatibility is a must then look at platforms like the Kel Tech 2000, Barreta Storm or any of the other sub semi's on the market. These will run $300 tp $500 less than an AR and most accept common pistol mags so you can interchange your ammo AND your feeding device.
Good luck and welcome to club.