6x45 in an AR, barrel length and twist?

[GoWyo]

Howdy Hide,

I've come to the realization that I need a 6x45. I have a RRA nm lower,and a .223 BF BCG needing company.

I'm leaning towards an 18" stainless tube with a 1/10 twist but would like some RKI input. I have a huge amount of varmint weight bullets and .223 brass available, so I'm thinking a slower twist, or should I go 1/8 and not worry about the lighter bullets as this round isn't that fast?

This will be a coyote/close range whitetail rig. I've got a .17 rem 18 inch set up and like that length of barrel, it should still get enough velocity in 6x45 to do the job.

Again any input would be appreciated? Recommended builders?
Thanks,

Gary

 

[Scottmilk9]

Re: 6x45 in an AR, barrel length and twist?

Gary I would recommend a 1-10 twist. I shoot a 20" one and use several bullets also, but my favorite ones lately have been the 75gr Sierra Boat tail HP with IMR 8208XBR powder. Getting excellent groups.

I've built quite a few of these and would go with 18 or 20 inch.

just my .02 cents.

 

[BERTMAN77MK2]

Re: 6x45 in an AR, barrel length and twist?

Ha--was gonna recommend Scott but see you have already found him!
would rec 20" minimum but that is just personal preference--Les Baer promoting this also but few choices on build options

 

[MPFD]

Re: 6x45 in an AR, barrel length and twist?

I've got a 16" and an 18" 6x45, they both shoot the same ammo into small groups, Both are 1-10 twist.
http://i152.photobucket.com/albums/s177/MPFD/SDC11111.jpg[/img]]photobucket http://i152.photobucket.com/albums/s177/MPFD/SDC11110.jpg[/img]]photobucket
These are groups from the 16" (not chrono'd)

 

[GoWyo]

Re: 6x45 in an AR, barrel length and twist?

Thanks Scott, all, great info. Nice product Scott, I may be calling.

 

[RyanE]

Re: 6x45 in an AR, barrel length and twist?

Gary I would recommend a 1-10 twist. I shoot a 20" one and use several bullets also, but my favorite ones lately have been the 75gr Sierra Boat tail HP with IMR 8208XBR powder. Getting excellent groups.

I've built quite a few of these and would go with 18 or 20 inch.

just my .02 cents.

Hi Scott, I'm new here. This chambering is the reason why. I am in the process of building one of these for prairie dog shooting. Need something that will buck wind better than my 204 and 223. What other info do you have on twist rates and what grain weight will stabilize in them?

 

[Scottmilk9]

Hi Scott, I'm new here. This chambering is the reason why. I am in the process of building one of these for prairie dog shooting. Need something that will buck wind better than my 204 and 223. What other info do you have on twist rates and what grain weight will stabilize in them?

This thread is 12 years old, but same holds true. Lighter the bullet, the slower the twist(1:10), if you were to run a heavy bullet, the faster the twist(1:8/1:9) If you're dead set on the 6x45, i'd look at the 65gr vmax, 70 BT from Nosler(which is unobtanium) and i'd run a 1:9 twist, which IMO would be more versatile with bullet selection.

 

[RyanE]

This thread is 12 years old, but same holds true. Lighter the bullet, the slower the twist(1:10), if you were to run a heavy bullet, the faster the twist(1:8/1:9) If you're dead set on the 6x45, i'd look at the 65gr vmax, 70 BT from Nosler(which is unobtanium) and i'd run a 1:9 twist, which IMO would be more versatile with bullet selection.

I saw it was an old thread, but it seemed relevant to answer my question......and to show how late to the party I am. I had a good conversation with Matt at Dedicated Technology in Bemidji, MN this morning. He said he is personally running 1:10 and having very good results shooting 70gr blitzkings. And it has proven to handle weights a bit on either side of it. I'm pretty set on this. The load data we are finding is looking promising for what it will be used for. Prairie Dogs and Varmints from 400ish and closer in the wind. Myself and a few other guys have been evaluating this and compared to the 6 arc we know we are leaving a little zoom and flat on the table, but I have heard enough negatives about 6arc tearing up bolt lugs from the higher pressures and the fact that from what I am seeing your typical grendel bolt is just not as strong as a standard 5.56 bolt.

On top of that..... a virtual endless supply on once fired Lake City 5.56 brass off the military range makes reloading affordable. Whereas, the 6 arc is somewhat cost prohibitive for slinging pills at PDogs.

Thanks for the insight!!!!! I'll report back to this old thread and let everyone know how this thing works!