Home Forums Hunting & Shooting AR and Tactical Rifles Quick Question on Upper swapping?

It is ok to swap uppers with other lowers but not bolt carrier groups correct?


Also if I break a bolt, I can simply replace the bolt with or do I need to purchase an entire BCG?

Thanks.

Yes. You can swap complete uppers with lowers. You could probably get away with swapping bolts and BCG's also but not recommended and best to keep them with their own barrel. If you break a bolt, you can just replace the bolt. You can use the existing carrier.

Thanks for the clarification. Much appreciated.

The idea is the lugs on the bolt and barrel extension break in slightly to fit one another better as more rounds are fired. Sort of like lapping the lugs on a bolt gun they each will eventually carry equal pressure holding the case in the chamber.

When you swap to a different bolt (not carrier) this break in process basically has to start over. As minute as it might be.

Will it ever really be a problem? I guess it just depends on how long a bolt has been used with the barrel and how far off the new bolt is, or if the bolt has already been used.

Good explanation. Makes sense. Thanks for the help.

I've swapped BCG from upper to upper more than a few times in my life, for many thousands of rounds. A bit more concerned about headspace actually but thats never been an issue.

I'm a fair bit demanding on accuracy, that being said .5 moa for 10 shot groups from the AR does tend to keep me happy. At least at 300 yards it will.

I should add, as noted I'd be more worried about headspace and I don't suggest swapping them as best bet, but with known builds that I have and using same components and headspace etc.... its never bothered me.

Now take a factory BCG lets just say DPMS, and swap it with a nice well built custom White Oak Precision, precision upper... nah, I'll pass on that.

Gottcha! I was more worried about head space issues myself. Either way I think I will just keep the bolts with the same rifle to prevent "Murphy's Law" coming into play unless a necessity to do otherwise. Thanks.

If all bolts fall into milspec so to speak made, then its really not supposed to be an issue, though you may be overworking your brass. ANd not all handloads might work depending.

I prefer to have a complete upper for all mine, but at times, an extra 125 ish or so bucks ain't laying around and I want to shoot...

Lugs on AR bolts will eventually wear down if it doesn't crack. Some change bolts with every rebarrel and some just re-use and guage them. A friend told me one of the guys where he works AR started to malfunction. He figured out that the little ball on the gas tube was so worn it was leaking gas. He looked at the bore and the rifling was shot. He decided to just check the headspace and it would fire on the no-go guage.