I was wondering whether anyone thinks 1:7 is too high a rate of twist for 55gr. 5.56 ammo. Will this cause over stabilization? Most of the old Colt Sporters seem to be 1:7. Also, do any Colts have chrome lined bores? Like older prebans with A1 sights? That's kind of what I'm looking for. And a 5.56 chamber, but most Colts seem to be .223...unless they're just marked that way and actually all have a 5.56 chamber, I don't know..

As you can see, I need lots of help and any is appreciated!

most new civilian colts have a 1:9 twist and a 5.56 chamber, and I think colt is only croming the chamber.

the top of the barrel will be marked with the twist and chamber.

the lower will usually  say 223/5.56 go by the barrel marking for the chamber.

1:7 will work for 55gr but it is not ideal.

Quoted: I was wondering whether anyone thinks 1:7 is too high a rate of twist for 55gr. 5.56 ammo. not necessarylyWill this cause over stabilization?what exactly is overstabilization? Most of the old Colt Sporters seem to be 1:7. Also, do any Colts have chrome lined bores?some do and some don't Like older prebans with A1 sights? That's kind of what I'm looking for. And a 5.56 chamber, but most Colts seem to be .223...unless they're just marked that way and actually all have a 5.56 chambermy guess would be that all chromelined colts have 5.56 chambers, I don't know.. As you can see, I need lots of help and any is appreciated!

No difference using 1/7 or 1/9 with 55 grain ammo at all in real life.

Read the Ammo-Oracle.

Quoted: Read the Ammo-Oracle.

Have done so many times, but thank you for the suggestion.