What do need to do to get this done? When my dividend comes (Oct 13) I'm morphing my Bushy 20in to a 16in M4gery. I have already decided on bushmaster's M4 upper stretched to 16in so I can use different muzzle attachments, and i have also decided on the 6 position fiberlite collapsible stock from bushmaster also.

Now , a few questions.

Can I use the bolt carrier and charging handle from my 20in, the whole kit and kabloodle, in the new 16in M4 upper and save $150?

and what does the collapsible stock bushmaster sells come with? Does it need a different buffer tube or can I use the one from my A2 stock? and if it does need a different one, does the stock bushmaster sells came with it?

Any help you can give me will be appreciated. Thanks

Quoted: What do need to do to get this done? When my dividend comes (Oct 13) I'm morphing my Bushy 20in to a 16in M4gery. I have already decided on bushmaster's M4 upper stretched to 16in so I can use different muzzle attachments, and i have also decided on the 6 position fiberlite collapsible stock from bushmaster also. Now , a few questions. Can I use the bolt carrier and charging handle from my 20in, the whole kit and kabloodle, in the new 16in M4 upper and save $150? and what does the collapsible stock bushmaster sells come with? Does it need a different buffer tube or can I use the one from my A2 stock? and if it does need a different one, does the stock bushmaster sells came with it? Any help you can give me will be appreciated. Thanks

The bolt and charging handle are fine to use with your new carbine.  I'm not sure what the stock comes with from bushmaster, but, you will need a new bufffer tube, & buffer. Without them , your new carbine won't be able to cycle the bolt!

P.S. I would check out vltor or magpul stocks if you are converting from A2 to collapsible

bump.

Quoted: Can I use the bolt carrier and charging handle from my 20in, the whole kit and kabloodle, in the new 16in M4 upper and save $150?

you should be able to. Are you rebarreling the upper, or just buying a new upper w/barrel?

and what does the collapsible stock bushmaster sells come with? Does it need a different buffer tube or can I use the one from my A2 stock? and if it does need a different one, does the stock bushmaster sells came with it?

You don't have to buy Bushy's, but obviously it's up to you. Cavalry Arms sells complete kits for around $70 or so. The rifle stock and carbine stock buffer tubes (receiver extensions) and the buffers themselves are of different lengths.  You cannot mix and match these, so buy complete if you can.

If you buy BMs M4 Buttstock complete, it will have everything you need.
I would headspace the bolt to the new barrel before firing- 99.99% of the time it will work fine but if it does not on that first shot.........Kaboom.
A gunsmith should be able to inspect headspace for next to nothing if you do not want to buy the gauges. The bolt carrier  and charging handle will interchange.
Don't forget, you will need a CAR wrench for the buttstock.