Contemplating a 6X45 build

[Exocet]

I'm looking at building a walking varmint rifle in 6X45mm. I'm thinking a #5 contour barrel on a Rem 700 action.

What twist is best? Thinking at least 12 but maybe 10 or 9 to shoot some of the 100 grain bullets.

It should be pretty mild, what kind of barrel life can can I expect?

I'm also thinking a .270 neck reamer so that I don't have to turn necks. I would like to avoid that if possible just for the sake of ease.

Any thoughts?

 

[seattleray]

Why not a 6BR and avoid the hassle of a wildcat cartridge not standardized? r in w

 

[Kermit in Va.]

Go for it...
I had one built a month or so ago and love it. I had wanted one for 5-6 years and it finally worked out to get it built.
Its a 9 twist and seems to shoot everything I've put through it better than I was expection. 55 grs.---85 so far.


Kermit

 

[rickiesrevenge]

I had one in a 10 twist. It was a mini14 and I used the mag so nothing larger than 85 grains. I really want one in a xp-100 pistol. You'll likely get better barrel life than a .223 because of the larger bore and similar powder charges.

Aaron

 

[pdog2062]

I'll let you know more this evening,I'm heading to the range now to shoot mine for the first time.Savage model 10,26 inch mcgowen heavy barrel,stocky's thumbhole stock,1-8 twist.I'm trying 58,70,75 and 87 grain bullets.
Wish me luck.

 

[RJinTexas]

pdog why not lets us all know? Please post results. I'm currently awaiting a fellow Texan's reamer for my build on a XP.

Thanks
RJ.

 

[pdog2062]

just got back from the range and was the wind blowing!I tried several bullet and powder combinations.The 58 grain v-max was a flop,the 75 gr. sierra hp was a little better but the winner was 75 gr. v-max and 26 gr. of varget.Shot 5 in less than .5 in 25 mph wind with almost no up and down.The biggest surprise was the 87 gr.v-max at over 2 inches at 100 yards.I thought it would do better in my 1-8 twist.Guess I better stock up on 75 gr. v-max and get ready for my annual prairie dog trip in July.

 

[BoilerUP]

I've been SERIOUSLY considering a 24" 1:8 light varmint 6x45...105gr Hybrids @ 2600fps would do pretty darn well at intermediate and long range...

 

[GrocMax]

http://saami.org/PubResources/CC_Drawings/Rifle/6x45mm.pdf

SAAMI has standardized the 6x45/6mm223, but its a 'one-size-fits-all' type chamber with ~ .050" freebore and a 2.5 deg lead angle, .270" neck. If your focus is lighter or heavier bullets might wish to change it a little. SAAMI policy is short freebores are dangerous so you won't see a SAAMI std reamer with a short freebore.

Certainly has great potential to be the most economical 6mm plink/varmint round for several reasons, barrels will last, 223 based dies and gauges, brass availability and pricing, easy brass forming, use std 223 mags, 223 powders, etc. 3200-3300 FPS with 55-60g looks like the norm. That'll work.

 

[Exocet]

Are the heavy bullets >80 grains even worth trying in this case? If not, I'd probably specify a shorter freebore to maximize accuracy.

Also, I have buckets of good 223 brass. To make the case, am I correct in that it just has to be lubed and run into a standard sizer? I would suppose a trim would be in order next and then load and shoot.

I think .270 neck is the way to go with this for simplicity's sake.

Thanks.

 

[GrocMax]

Its possible to modify 223 dies, or buy a 6x45-6mm223 die set, the std non-bushing Redding 80312 set is reasonably priced and is the right neck size for the cases I use, but won't seat light bullets far enough down with the #6 seater plug. Just as with a 20 Practical, shoulder angle, case diameter and body taper stays the same, only changes are from past shoulder datum point to case mouth. With a barrel nut gun, 223 go/no-go gauges work.

 

[5spd]

6x45 1/10" twist will run the 55g - 95 gr bullets into small holes all the way to 700yds.
I built mine in 3/11 for coyote & antelope.
VERY accurate.
aa2015/exteraminator/h335 are you friends for all those bullets.
I have over 1500 rounds through mine.
http://forum.accurateshooter.com/index.php?topic=3806239.0

 

[jbarnwell]

I really like mine. I shoot a 12 twist Lilja barrel on a Stiller Action. I designed the reamer for 55-65 grain bullets. I have seen the best accuracy and speed out of AA2200 with the 55 Ballistic tips. Have reached 3,500 FPS with Accurate Arms reloading data for this powder and bullet, and I have not exceeded their published data. What's not to like about this cartridge, great barrel life, light recoil, excellent accuracy and usually plentiful reloading components.

 

[GrocMax]

jbarnwell- Have any idea how AA2200 compares to H335 or WC844?

I really like mine. I shoot a 12 twist Lilja barrel on a Stiller Action. I designed the reamer for 55-65 grain bullets. I have seen the best accuracy and speed out of AA2200 with the 55 Ballistic tips. Have reached 3,500 FPS with Accurate Arms reloading data for this powder and bullet, and I have not exceeded their published data. What's not to like about this cartridge, great barrel life, light recoil, excellent accuracy and usually plentiful reloading components.

 

[jbarnwell]

Grocmax, I can't answer that one as I have not tried either of those yet. I have shot AA2230, H322 and N133. I can't get the same speed out of any of these, but they are all pretty accurate. Honestly this rifle shoots about anything I've tried in it. I've been very impressed with it.

 

[Ian]

I chose a 21" 9-twist for mine. Even though its a light rifle (Sako Vixen w/a sporter stock) I was pleasently surprised at how precisely it places 95gr. Bergers over 23gr. of H322

 

[SantaFe66]

I am also building a 6x45 rifle from a 223 Howa hvy bbl I wasn't using. My gunsmith is rebarreling with a Douglas bbl, 24" long in 1:9 twist. I chose that twist because all the custom rifle builds I found had that twist rate. The Howa Short action came in other calibers so I will have to measure the box to make sure it will accommodate longer 6mm bullets should I want to shoot them. I'm building this to shoot varmints so planned to use primarily 58 - 65 gr bullets so those might fit fine. My rifle has the magazine optional floor plate but I kept the metal Howa one so I can switch back. I'm loading up some ammo now using FC cases, H335 powder and some Sierra 60gr HP bullets I have a bunch of. Other bullets I may use include the Barnes Varminator which is 58gr and there are some good Hornady bullets as well. The stock I'm using is a Stocky's Carbon Fiber second that I got a good deal on and will be having it camo dipped when the gunsmith finishes his inletting.

 

[Louisiana Shooter]

 

[NZ_Fclass]

I would seriously consider the 6ARC as an alternative - if there's any brass available!

 

[moorepower]

just got back from the range and was the wind blowing!I tried several bullet and powder combinations.The 58 grain v-max was a flop,the 75 gr. sierra hp was a little better but the winner was 75 gr. v-max and 26 gr. of varget.Shot 5 in less than .5 in 25 mph wind with almost no up and down.The biggest surprise was the 87 gr.v-max at over 2 inches at 100 yards.I thought it would do better in my 1-8 twist.Guess I better stock up on 75 gr. v-max and get ready for my annual prairie dog trip in July.

I had issues with the 87Vmax until I started jumping them .035 with my ARC. I need to try jumping more, because there was a notable improvement from .030 to .035.