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mrnkc130 · October 19, 2009, 03:35 AM

What calibers can I use with a regular milspec lower just changing magazine and complete upper?

I know 6.8spc (anyone have one? how do you like it?)

22lr (with or without dedicated upper)

5.7x28 with FN type magazine on top is all I have seen for this...

I found all these on DPMS but not sure which of them will work without a dedicated lower for that caliber.

.204 Ruger
.223 Remington
5.56x45mm
6.8mm Remington SPC
7.62x39mm
.243 Winchester
.260 Remington
.338 Federal
6.5 Creedmoor
.458 socom

Also most important question: is it legal to put what ever caliber upper I want on a m16 FA lower? Or do you have to stay with 5.56? Which calibers are compatible with FA m16 lower as opposed to SA(if legal to do so)?

I have the feeling it's just too good to be true that you could by a m16 FA and drop whatever upper in different calibers you want on it...

October 19, 2009, 03:35 AM	#1
mrnkc130 Senior Member Join Date: July 27, 2009 Location: Justin, TX Posts: 149	More m16 questions.... What calibers can I use with a regular milspec lower just changing magazine and complete upper? I know 6.8spc (anyone have one? how do you like it?) 22lr (with or without dedicated upper) 5.7x28 with FN type magazine on top is all I have seen for this... I found all these on DPMS but not sure which of them will work without a dedicated lower for that caliber. .204 Ruger .223 Remington 5.56x45mm 6.8mm Remington SPC 7.62x39mm .243 Winchester .260 Remington .338 Federal 6.5 Creedmoor .458 socom Also most important question: is it legal to put what ever caliber upper I want on a m16 FA lower? Or do you have to stay with 5.56? Which calibers are compatible with FA m16 lower as opposed to SA(if legal to do so)? I have the feeling it's just too good to be true that you could by a m16 FA and drop whatever upper in different calibers you want on it... __________________ Already long ago, from when we sold our vote to no man,the People have abdicated our duties; for the People who once upon a timehanded out military command, high civil office, legions — everything, now restrains itself and anxiously hopes for just two things:bread and circuses (Juvenal, Satire 10.77–81) Last edited by mrnkc130; October 19, 2009 at 03:46 AM.