First AR purchase

[HKGuns]

Where exactly does that chart (Nice little guide BTW and thanks for posting it, even though I don't think its 100% accurate either.) say anything about accuracy there arguy? Or, are you simply trying to impress everyone with your AR knowledge and pick his post apart?

I too shoot mainly 55 grain bullets, they also continue to be the most prevalent rounds found on sale in most places.

 

[SSN Vet]

I'm not really into arguing these topics.... But a too fast twist barrel can present a problem with light bullets...over stabilization.

The AR platform can be set up to do a lot of things, but there's not a single configuration that can do them all. In my mind, pushing a 55 gr bullet 3,000 fps (flat trajectory and terminal ballistics that yaw, tumble and fragment) is one of the hallmarks that I wouldn't want to give up. And though I'm no expert, I've read over at AR15.com, that 1:7 barrels over stabilize 55 gr bullets.

"An over-stabilized bullet rotates too fast and its axis tends to keep its orientation in space. The bullet´s longitudional axis becomes uncapable to follow the bending path of the trajectory"

http://www.nennstiel-ruprecht.de/bullfly/fig15.htm

Some guys have lot's of opportunities to shoot serious long ranges and that's what they want to set up for. I don't have access to anything over 200 yds without spending quite a bit of money, and even then, I would have to travel pretty far to find a range that is longer than 300 yd. YMMV

 

[Eb1]

An over-stabilized bullet on a high-angle trajectory lands base first

I don't know about you, but I am not in a trench shooting volleys across European farm land.
Also your forgetting a key point, and that is velocity of the projectile. You cannot shoot a .223 fast enough out of a standard chamber with a 55 grain bullet out of a 1:7 twist to make your point valid IMO.

I am not arguing any point, but you cannot tell the difference of a 1:7 twist shooting a 55 grain bullet at distances in practical shooting to make a comparison between 1:9 and 1:7 twist barrels from an AR-15.
And like has been said before. Most people who want a 1:7 twist want the ability to shoot the longer/heavier bullets, and also shoot 55 grain bullets with great success.

And people who shoot distances of 600 meters are shooting the better match bullets which demands the stabilization of the 1:7 twist barrel.

especially when fired vertically

I don't shoot straight up either.

 

[SSN Vet]

The link shows an extreme example to illustrate the point, which is, that if the bullet spins too fast, it can't maintain it's alignment to the path of the trajectory (yes your going to see some pretty serious drop out at 600 yds). And if axis of the bullet isn't aligned to the path of the bullet, you will lose accuracy. Evidence of an over stabilized bullet can be keystone holes in the target (with larger than normal groups).

Regardless, I haven't heard that guys shooting in long range matches or popping prairie dogs favored 16" barrels. So that leaves the main advantage for 70+ gr bullets in carbine length barrels as penetration of cover.....which is not a driving concern for me.

Again, YMMV

 

[Eb1]

Anyway you look at it I guess, but I'd take a 600 yard shot with a 69 grain SMK out of my 1:7 16" barrel over shooting a 55 grain pill out of a 20" with a 1:9 twist to 600 yards.

 

[Brockak47]

go with PSA fit and finish on mine is superb havn't shot it yet, just got it yesterday
fits together like a glove real tight, all in all very happy with it. ( long as it shoots good )

 

[kwelz]

go with PSA fit and finish on mine is superb havn't shot it yet, just got it yesterday
fits together like a glove real tight, all in all very happy with it. ( long as it shoots good )

How can you make a determination of being happy with it when you haven't even shot it?

 

[WNTFW]

"How can you make a determination of being happy with it when you haven't even shot it?"

Perhaps in the spirit of the season he is not filled with bitterness & negativity. He did say as long as is shoots good. So I guess the rifle looks & feels fine.

Brockak47,
Hope is shoots perfectly for you. Do you have a link to that particular rifle? I did manage to snag a PSA BCG. Like you I have not shot it yet but maintain a level of bliss even though ignorance may be a factor. Being men sometimes we go by looks. BCG seems pretty nice.
Is this your first AR?
Enjoy!