I have a Colt Match Target HBAR 6601 that I like a lot. However, it has a 1 in 7 twist. I would like to get another upper for it I guess in a 1 in 9 twist. Will any uppper fit it?  I changed the front pin for one from Brownells that just pushes in. Do you have any recommendations? How about twist rate? I would like to shoot some 55 grain bullets. My 1 in 7 really likes the 77 grain sierra hpbt bullets. My savage 1 in 9 likes the 69 grain sierra hpbt bullet. What is a good all around twist rate? Thanks, John

Quoted: I have a Colt Match Target HBAR 6601 that I like a lot. However, it has a 1 in 7 twist. I would like to get another upper for it I guess in a 1 in 9 twist. Will any uppper fit it?  I changed the front pin for one from Brownells that just pushes in. Do you have any recommendations? How about twist rate? I would like to shoot some 55 grain bullets. My 1 in 7 really likes the 77 grain sierra hpbt bullets. My savage 1 in 9 likes the 69 grain sierra hpbt bullet. What is a good all around twist rate? Thanks, John

Try it first. It's not like it'll blow up.

Try it first. It's not like it'll blow up.


OK, how can I try it before I buy it?

Quoted: Try it first. It's not like it'll blow up. OK, how can I try it before I buy it?

"You have a 1 in 7 twist. You want to shoot 55 grain. Thus you need a 1 in 9" is what I read.  Have you tried 55gr in your 1 in 7. It should do fine. You'd be better off with a 1 in 9 for accuracy, but you're then just spending money on another upper.

thanks, I had not considered that.

after considering the matter I have decided to get another complete ar15. I had shot the 55 grain and lighter bullets in my ar and did not like the accuracy. I will go with the 1 in 9 twist this time. Thanks for your help

Quoted: after considering the matter I have decided to get another complete ar15.

If you had just bought the 1/9 upper, you would eventually have bought another lower anyway.

That's how black rifle disease works.  Currently I've got two "unattached" uppers, and it gnaws at me.  I know I'm eventually going to get another couple of lowers.