6x45 AR barrel suggestions and twist recommendations.

[hades]

Hey all, I've just recently learned about this cartridge and apparently I'm about 10 years to late... The 6mm Arc has totally outclassed it and it's hard to even find a barrel in stock online for my next project build.

Before I get everyone telling me just to go after the Arc... I have a 6.5 grendel already. I really don't get to shoot long range and while I'd like to, its mostly 300 and less for me. So maybe an Arc someday but for now this cartridge is appealing with the dirt cheap brass availability over the 6.5 grendel/Arc..

The 6x45 is an interesting case that seems like a nice bump in performance over the 223 while being much cheaper to shoot than the grendel due to mostly the cases being dirty cheap for the 6x45 and bullets being considerably cheaper as well.


It'll mostly be a fun gun, and I would most definitely be interested in getting a mold/(s) for it and going after a cast load also.

Can anyone recommend a barrel? And then after that if I'm ordering a McGowen, Ritchie, X Caliber, Black Hole, ect, barrel which twist rate would be best for shooting cast without limiting me to the light varmint bullets? (1-12, 1/14?)

I was thinking maybe 1-9 or 1-10? I just want to make sure it will stabilize the 80-90gr pills yet give me the easiest road towards getting a solid cast load worked up as well.

Any and all comments and suggestions welcome as long as you're not telling me to get the Arc! I know what it is.. what its capable of... and already have its meaner, better looking big brother!


(This seemed like the appropriate room. If there's a better place to post I'm open for that suggestion as well!)

[Fitz]

You might also look at Mad Dog Weapons Systems they make a barrel for the AR platform called a 6mm mongoose uses 223 brass ,magazine and bolt so just a barrel swap , I have one with a 24 inch barrel and out to 300 yards does really well with 75 to 85 gr bullets and you use the 6x45 load data. Lot of info about it on the net

[BK7saum]

I just went down this road and purchased my 16 inch barrel from McGowen. Super pleased with mine. When I sighted it in at 100 yards with 58 Vmaxs, ended up with 3/8-1/2 inch group. Mine is a 1-10 twist because i do not plan on shooting over 80 grain bullets.

Currently my favorite AR. I don't shoot for groups once I got my load worked (first load I tried), and 1/2 moa for coyote hunting is plenty good enough for me.

If you want any additional info, pm me. happy to share what I have.

AR weighs less than 6lbs without optics.

Carbon Fiber Forend
Carbon Fiber receiver extension/stock
Aluminum lightweight castle nut
The rest is standard parts.

Nice light packing rifle for coyote calling.

[BK7saum]

Oh, and the attraction for me over the ARC was free brass and not worrying about losing $1 cases. I do run the caldwell picatinny rail brass catcher when I think about it.

[hades]

You might also look at Mad Dog Weapons Systems they make a barrel for the AR platform called a 6mm mongoose uses 223 brass ,magazine and bolt so just a barrel swap , I have one with a 24 inch barrel and out to 300 yards does really well with 75 to 85 gr bullets and you use the 6x45 load data. Lot of info about it on the net

I did run across the 6mm mongoose. It looked interesting but again no barrels in stock. Dies are out of stock too. Might be worth an email but at that point I'm already leaning back to the 6x45 just for die and barrel availability and option's.


What do you get for velocity numbers for some of your loads?

[hades]

I just went down this road and purchased my 16 inch barrel from McGowen. Super pleased with mine. When I sighted it in at 100 yards with 58 Vmaxs, ended up with 3/8-1/2 inch group. Mine is a 1-10 twist because i do not plan on shooting over 80 grain bullets.

Currently my favorite AR. I don't shoot for groups once I got my load worked (first load I tried), and 1/2 moa for coyote hunting is plenty good enough for me.

If you want any additional info, pm me. happy to share what I have.

AR weighs less than 6lbs without optics.

Carbon Fiber Forend
Carbon Fiber receiver extension/stock
Aluminum lightweight castle nut
The rest is standard parts.

Nice light packing rifle for coyote calling.

Awesome report to hear! I've never ordered a barrel before from scratch so just want to make sure I get what I want.


What profile barrel did you get? I'll almost certainly go after a 20", maybe an 18".

Probably the light weight? or the modified HBAR?

do you remember or did you weigh your barrel?


Lastly, 1/10 wont be enough to stabilize 80+ gr bullets?

Looks like 1-9 or 1-8 even then for me.

[hades]

Ohh, what kinds of velocities are you getting with a 16" and the lighter varmint bullets?

[BK7saum]

I haven't chrono'd them but book velocity was 3300-3400 fps from 24" barrel. I figure somewhere in the 3200fps from the 16". I have been pleased with how flat it shoots out to 250 or so.

[Outpost75]

The 6x45 has been around since the 1970s, first being used as a benchrest cartridge by Jim Stekl at Remington. American Rifleman published pressure tested load data in the early 1980s. Test barrel they used was a 1:9" twist and got 2640 fps with 85 grain BTHP bullet with 25.5 grains of IMR4895 from 20-inch barrel.

[hades]

The 6x45 has been around since the 1970s, first being used as a benchrest cartridge by Jim Stekl at Remington. American Rifleman published pressure tested load data in the early 1980s. Test barrel they used was a 1:9" twist and got 2640 fps with 85 grain BTHP bullet with 25.5 grains of IMR4895 from 20-inch barrel.

Are you recommending the 1/9 twist for what I'm looking to do?

[Outpost75]

Are you recommending the 1/9 twist for what I'm looking to do?

Yes.

[hades]

Yes.

Think that would stabilize 95-100gr bullets as well?

I've never really had to pick a twist rate before outside 1/7 or 1/9 for a 223/5.56 AR. And then I just got the one that was on sale with the profile I wanted.

[Outpost75]

Think that would stabilize 95-100gr bullets as well?

I've never really had to pick a twist rate before outside 1/7 or 1/9 for a 223/5.56 AR. And then I just got the one that was on sale with the profile I wanted.

I shot 105 Speer and 100 Hornady in mine, about 2400 fps. Still shot the 70-75 grain bullets well, but if you favor the heavier bullets a 1:8" twist would be a good choice.

[hades]

I shot 105 Speer and 100 Hornady in mine, about 2400 fps. Still shot the 70-75 grain bullets well, but if you favor the heavier bullets a 1:8" twist would be a good choice.

I don't know what I'd favor. Probably 70-80gr and whatever is cheapest. I'll definitely get some lighter 55-65gr varmint bullets as well but just don't want to needlessly limit my upper bullet weight if I can have options and have it all!


Thanks for the supporting data, this is part of exactly what I was looking for.


(Now just need that guy to chime in about his cast loads and success story!)

[BK7saum]

When I looked at the ballistics of the 90 and 100 grain bullets, I realized I didn't need a faster twist as the velocities/ballistics were not what I wanted to compromise by using bullets that heavy. I have other calibers and choices for heavier 6mm bullets and better overall ballistics.

[hades]

When I looked at the ballistics of the 90 and 100 grain bullets, I realized I didn't need a faster twist as the velocities/ballistics were not what I wanted to compromise by using bullets that heavy. I have other calibers and choices for heavier 6mm bullets and better overall ballistics.

For sure I get that if it's a varmint slayer. I'm just wanting to keep my options open since I'm not specifically building it for that. Sounds like 1/9 would treat me nicely.

I appreciate the feedback though!

I'd be curious how 80-85gr bullets shoot in your 1/10 if you ever wanted to load some and let me know.

[DDriller]

I would go with the 1:8 twist if you plan on shooting 105gr bullets. My 6mmBRX with a 1:8 shot 80-105 bullets well

[hades]

I would go with the 1:8 twist if you plan on shooting 105gr bullets. My 6mmBRX with a 1:8 shot 80-105 bullets well

90-100 would be my max and from what I've read is kind of the max anyways for a 6x45?

I'd imagine most of my shooting would be in the 70-90gr with some varmint bullets thrown in so I'll have some loaded in hand.


Actually just ordered a 1/9 so I'll have a painful 10ish week wait to find out!


I do appreciate the input though.
(Where were you anywhere from 4 days up to just a few hours ago!??? )

[exile]

Do you mind if I ask which barrel you bought?

[hades]

Do you mind if I ask which barrel you bought?

I ordered a 20" Xcaliber.