should a bolt charging group be kept with the original upper it was sold with? or could i use my bcgroup with another rifle?

usually best to keep the bolt itself with the bbl.

thanks for the info

Milspec means that parts are interchangeable.

While it's best to keep a BC/B with an upper, they can be interchanged without concern.

They are interchangeable, and fresh out of the box it wouldnt make a difference.
After 1000's of rounds (even just hundreds actually) the bolt will 'mate' with the reciever and wear in a way that reciprocates with the action around it. You could remove it and use it in another upper, but the wear wont perfectly match the second upper reciever. Will it work....yes. Is it the preferred way to go...not really, but I guess it comes down to personal opinion. I choose to get a new bolt carrier and bolt for each upper. I wont say that you will 'damage' anything by using the same bolt in multiple uppers, it just isnt....optimal lets say.

Quoted: They are interchangeable, and fresh out of the box it wouldnt make a difference. After 1000's of rounds (even just hundreds actually) the bolt will 'mate' with the reciever and wear in a way that reciprocates with the action around it. You could remove it and use it in another upper, but the wear wont perfectly match the second upper reciever. Will it work....yes. Is it the preferred way to go...not really, but I guess it comes down to personal opinion. I choose to get a new bolt carrier and bolt for each upper. I wont say that you will 'damage' anything by using the same bolt in multiple uppers, it just isnt....optimal lets say.

I had a bolt break on an upper after about 800 rounds and replaced it with a MP mil-spec bolt without headspacing, I didnt harm anything by doing so correct?

Quoted: Quoted: They are interchangeable, and fresh out of the box it wouldnt make a difference. After 1000's of rounds (even just hundreds actually) the bolt will 'mate' with the reciever and wear in a way that reciprocates with the action around it. You could remove it and use it in another upper, but the wear wont perfectly match the second upper reciever. Will it work....yes. Is it the preferred way to go...not really, but I guess it comes down to personal opinion. I choose to get a new bolt carrier and bolt for each upper. I wont say that you will 'damage' anything by using the same bolt in multiple uppers, it just isnt....optimal lets say. I had a bolt break on an upper after about 800 rounds and replaced it with a MP mil-spec bolt without headspacing, I didnt harm anything by doing so correct?

Not at all.....and more to the point...you didnt really have a choice. (the part broke)
Its more of a purist view to have the bolt carrier match up with the wear on the receiver...but it certainly isnt a requirement. The only real noticable effect 'might' be a looser fit...but it would have taken more than 800 rounds to create any significant wear to have started any major wear to begin with. If you have 10000 rounds through it when the old carrier broke, then you replaced it and went anoth 10000, it 'might' be a bit more loose than the same rifle with an original carrier that had 20000 rounds on it. But that is a 'might'....and a 'bit' loose, not a problem, just sub-optimal. You have nothing to worry about whatsoever.

Quoted: Quoted: Quoted: They are interchangeable, and fresh out of the box it wouldnt make a difference. After 1000's of rounds (even just hundreds actually) the bolt will 'mate' with the reciever and wear in a way that reciprocates with the action around it. You could remove it and use it in another upper, but the wear wont perfectly match the second upper reciever. Will it work....yes. Is it the preferred way to go...not really, but I guess it comes down to personal opinion. I choose to get a new bolt carrier and bolt for each upper. I wont say that you will 'damage' anything by using the same bolt in multiple uppers, it just isnt....optimal lets say. I had a bolt break on an upper after about 800 rounds and replaced it with a MP mil-spec bolt without headspacing, I didnt harm anything by doing so correct? Not at all.....and more to the point...you didnt really have a choice. (the part broke) Its more of a purist view to have the bolt carrier match up with the wear on the receiver...but it certainly isnt a requirement. The only real noticable effect 'might' be a looser fit...but it would have taken more than 800 rounds to create any significant wear to have started any major wear to begin with. If you have 10000 rounds through it when the old carrier broke, then you replaced it and went anoth 10000, it 'might' be a bit more loose than the same rifle with an original carrier that had 20000 rounds on it. But that is a 'might'....and a 'bit' loose, not a problem, just sub-optimal. You have nothing to worry about whatsoever.

Figured so, but thanks for the explanation!