6x45 (6mm223) - Remington 700

[dwalker]

I have a Black Hole Weaponry barrel on my AR. Very accurate- think cloverleafs- and a great range gun. Mine is the heavy barrel with target crown. I thought about one in a bolt gun but I have a .223 for that

[Switchbarrel]

Chris (Savageguy) sells a bunch of barrels, good guy from my two dealings with him. Bought a Jewell trigger at one of the best prices also.

http://forum.accurateshooter.com/index.php?topic=3877606.0

From the above link:



-Rick

[russ69]

Bartlein 6mm 5R 1:8 twist and finished at 26" (for use/testing with 75gr to 105 gr)...

I tried to suggest that the 6X45 doesn't have enough powder capacity for heavy bullets but it looks like that is the way you are going so I'm going to recommend you ditch the 6X45 and go to a 6mmBR that is much better for a long range 6mm. The 6X45 makes sense if you shoot light bullets in magazine length AR15s and I guess it works well as a repeater because the 6mmBR is harder to feed (harder not impossible). In every aspect of 6mm performance the 6BR is the cartridge of choice (unless you blow the shoulder our a tad more, then it's perfect).

[ExtremeX]

I tried to suggest that the 6X45 doesn't have enough powder capacity for heavy bullets but it looks like that is the way you are going so I'm going to recommend you ditch the 6X45 and go to a 6mmBR that is much better for a long range 6mm. The 6X45 makes sense if you shoot light bullets in magazine length AR15s and I guess it works well as a repeater because the 6mmBR is harder to feed (harder not impossible). In every aspect of 6mm performance the 6BR is the cartridge of choice (unless you blow the shoulder our a tad more, then it's perfect).

I do have a .243 and .308 bolt action rifle, and plans to build up a 6.5 Creedmoor or 260 in the future. I do take my hand-loading bit more seriously for those rifles and don’t do it in large volumes.

The entire motivation behind this project was an alternate to the 223 Remington, which is my volume ammo “fun gun”… I currently bulk load my 223 ammo for this on a progressive but with a match bullet, and I don’t really do any match prep to the brass aside from sorting by head stamp. I would envision doing the same with the 6x45.

If it wasn’t for the 223 brass availability and the ease of necking up to 6mm I probably wouldn’t even be looking at doing this. I figured it would just be an easy benefit to take advantage of because I do reload.

That said, I am still researching ballistics so I have realistic expectations from my load/bullet/powder combos.

[russ69]

I fully understand, that is why Mike Walker came up with the 222 Rem Mag case size because even the 223 needed a bit more powder capacity but then the powder column got a bit too long and there were problems with consistency. The 6X45(223) is winding the clock back even further, really going back to the 222, which was 1950! I loved shooting my neck turned 6X47(222mag) bench gun, it's a fun little cartridge but it's time has passed and it was replaced by the 6mmPPC in the benchrest world.
The 6BR has taken over the world, it does it all, light bullets or heavy bullets, it is an American version of the 6PPC but with long range potential with the right twist barrel. It uses the 308 bolt head so that makes it easy also. It is the best thing going in 6mm.
One more thing, be very careful with a 6X45 and keep all 6mm ammo away from 223 ammo. you don't want to mix up those rounds.

[dwalker]

It IS a fun round to shoot and I shoot a lot of them. My reasons for it was that the 6mm is legal on deer sized game and .223 isnt. The 6x45 is an antelope bandit! Mine is as I mentioned an AR and not bolt platform, but that was because it was easy. My only regret was not opting for the threaded barrel to work with a can.
Mine shoots .5MOA groups with medium weight bullets, but get around 90-95gr and the groups start to really open up.

[dfletcher]

As much as I like my 6X45/223 Rem 700 and 6X47/222RM T/C barrel, I don't think of either as much more than a "maybe 250 yd" rifle. I'm not much on calculating ballistics, but my thinking is that on lighter bullets with good fps they're not particularly aerodynamic. And on longer, heavier (aerodynamic) bullets, the small case capacity doesn't give you enough fps.

Great accuracy, but not much legs.

[LynnJr]

Sell the 223 bolt on e-bay and buy a bolt from Pacific Tool and Gage. Get it with the 0.704 body a 0.062 firing pin and a coned bolt in 0.473 for the 6BR case.
It will match the ballistics of a 30 caliber 190 grain bullet in a 300 Win mag but it will use 45 grains less powder to do it.
Recoil is non existent barrel life is tremendous and it is considered buy some as the most accurate cartridge ever made. Brass lasts 25+ firings you get 1800 rounds to a jug of powder.
The 6/223 is a fun cartridge but the 6BR is in the same league as the 6 PPC.

[buffybuster]

As much as I like my 6X45/223 Rem 700 and 6X47/222RM T/C barrel, I don't think of either as much more than a "maybe 250 yd" rifle. I'm not much on calculating ballistics, but my thinking is that on lighter bullets with good fps they're not particularly aerodynamic. And on longer, heavier (aerodynamic) bullets, the small case capacity doesn't give you enough fps.

Great accuracy, but not much legs.

Do you consider the .308Win a "maybe 250 yd rifle"?
The reason I ask, is a 8-twist 6x45mm shooting 105's@2600fps loaded to 2.5" OAL, has the same trajectory as a .308Win shooting 175's.

The 6x45mm is not the equal to the 6BR, but they are apples & oranges.

[dwalker]

I have no trouble hitting out to 400 and beyond with the 6x45,

[Guardian Mode]

I've been thinking about 6x45 lately. But out of an AR.
So far, it seems like that $210 barrel on midway could get me about 2650fps from a 105 amax?
I don't know anything about the chamber on that AR Stoner barrel, but I'm will to cut a window in some steel mags to get a coal of 2.30ish for about 5 rds in a 10rd mag.
I looked at the ballistics and it compares really well with a 6.5 Grendel shooting 123 amax's from a 24" barrel.
Both calibers doing much better against the wind compared to my 75gn bthp 223 from a 18".
Seems awesome. I'm gonna keep my eye on this thread.

[ar15barrels]

I've been thinking about 6x45 lately. But out of an AR.
So far, it seems like that $210 barrel on midway could get me about 2650fps from a 105 amax?

You are unlikely to be able to get 105's to 2650fps at 2.3" OAL in a 20" barrel.
Even 2500fps will be pushing it pretty hard with all but a few powder choices.

[Guardian Mode]

You are unlikely to be able to get 105's to 2650fps at 2.3" OAL in a 20" barrel.
Even 2500fps will be pushing it pretty hard with all but a few powder choices.

I think you're right. It didn't make sense when I read it or after I posted it. 2650fps is more likely what I'm getting from 75 bthp's from my 18".

I guess there really is no way around it. Only way to get those long bullets hustling is to launch them from a great big stainless telephone pole of a barrel.

[buffybuster]

I've been thinking about 6x45 lately. But out of an AR.
So far, it seems like that $210 barrel on midway could get me about 2650fps from a 105 amax?
I don't know anything about the chamber on that AR Stoner barrel, but I'm will to cut a window in some steel mags to get a coal of 2.30ish for about 5 rds in a 10rd mag.
I looked at the ballistics and it compares really well with a 6.5 Grendel shooting 123 amax's from a 24" barrel.
Both calibers doing much better against the wind compared to my 75gn bthp 223 from a 18".
Seems awesome. I'm gonna keep my eye on this thread.

Not out of an AR. The limited COAL of ~2.250" means you really have to seat the bullets deep which eats up a lot of case capacity. A 6x45mm from an AR is limited to about 87gr bullets.

[khw9mm]

Randall built me my 6mm-223 (6x45mm) out of a bolt action gun. Shooting 107 smk's and getting about 2600 fps out of a Bartlein 1:8 5R 26in barrel. Using 26gr of R17.