questions about changing an upper...

[MDT]

guys,

Sorry for the question, it may be a dumb one, but.....

Let's say I wanted to change my upper on my AR. Right now I have a 16" DPMS. If I wanted to change to a varmit flat top or something else, can I:
1. Just swap the upper and use my old bolt? Will it be headspaced properly?
2. Swap with a NEW bolt and be good to go.

Also,

if I want ed to change calibers (say to 6.8mm, or whatever), same questions.


Thanks for your help.


MDT

[strazz]

It's a good idea to keep bolts and barrels together, just to be safe. You can use the same BC without a problem though.

A different caliber upper would require the correct bolt and possibly a different magazine, depending on the caliber.

[MrMurphy]

What he said for new calibers

And I would go with #2 for diff. uppers, just for safety.