6x45mm or 6mm-223

[tahoe2]

Both are the same cartridge(I know). My question; is anyone familiar with this cartridge? I have been inquiring about " black rifles" in another thread, and as I'm not sold on the the 223/5.56 NATO, the bolt face and magazines will remain true to the original production(6x45) with the exception of the barrel. If I embark on this mission (black rifle) I will probably use it for target/varmint applications. Just want to here yea or nea on the 6x45 or another varmint round (.250 Sav, .243 Win ) in the AR platform.

I am a reloader, so no problem with ammo; thats the fun in shooting? "Odd calibers don't scare me" !!

 

[snakeman]

I considered this cartridge but it's miniscule following lead me to choose the 6.8 and I don't regret a thing. I love 6.8 it's a great round easy to load for and buy factory ammo for.

 

[tahoe2]

snakeman

does the 6.8 require its own upper?

 

[snakeman]

With the 6.8 you need a new barrel, bolt, and mags

 

[LoonWulf]

Take a look at 1stmarines 6x45 project (he calls it something different but off hand i cant remember what it is). I have a 6x47 bolt gun, love this family of cartridges, It shoots great. Velocity with a given bullet weight is pretty much what id expect from the parrent case firing the same weight bullets,or a little faster.

 

[Shadow 7D]

um ok, but anything other than main line cartridges will end up costing MANY times more in ammo than any gun

PERIOD
if you want a specialty AR in a specialty ammo
RELOAD, or yer gonna be broke

NOW
here's a stupid question
what are you doing with it?

punching paper?
up to 400m (with the right ammo) and you are fine with a 5.56 AR or hell a 5.45, or even a 7.62x39
More than that, buy a AR10, why, ammo is MUCH cheaper than the custom stuff

if you have the money to spend, sure, get a gun that shoots ammo from 2?? makers

oh, ever think about how much ammo you go through at the range, shooting a 1000 rounds with an AR is a breeze, and might take you 3-4 hours if you are going slow.

 

[NCsmitty]

I was going to mention the 6x47, which is the 222 Rem Mag case necked to 6mm. And the 222 Rem Mag case is what the 204 Ruger is designed around. As LoonWulf mentioned, the 6x47 can give a slight boost over the 6x45.
These rounds are a reloading proposition, and if you don't reload, then forget about it.


NCsmitty

 

[tahoe2]

I do reload. Haven't shot factory ammo in over 2 decades, except for 22lr. And it would be used for paper & varmints to 300yds.

 

[gshipps]

I wish I could tell you how good mine is but UPS ran a forklift thru two boxes and broke a chunk out of the mag well. That was a a month ago. Still waiting on replacement. Anyway 6x45. What's not to like. Almost free brass, same bolt, wide selection of 6mm bullets. Dang I can't wait! It's killing me!

 

[Shadow 7D]

My point is, many people see the 'next big thing' in some caliber or
'special forces does it...'
tactical BS
without realizing that a good AR that takes advantage of the FULL capability of the accuracy (and that's why you are getting it, right?)
DOESN'T come off you LGS 'tactical' wall, and will cost you MANY times (Ok, i'll back off my cost point, as if you know where to look, you can find and get quality barrels/uppers for less than a junk run of the mill upper that sells more on name that performance)

you get my point, it's not a plinking gun or a 'for the house/sd/TEOTWAWKI'

is it true prairie dogs can see you from 200 meters away, and can come to associate you with death and hence duck in if they see someone off in the distance.

Also, if true, have you thought about a closer in, heavy sub-sonic 6.8 round with a good suppressor?

 

[LoonWulf]

LOL, Shadow you kinda sound up set Im just teasing

Tahoe, how much do you think youll shoot? Im with Shadow, if your going to be shooting in real volume. I handload for my mini on a single stage, and normaly run thru some 100-200rnds per range trip. Most of my goof off ammo i just buy. My "serious" (by what ever definition) i load, as it would be too expensive to purchase.

 

[Shadow 7D]

Not upset, just pointing out that you should have a reason for your choice
the tone, comes from listening to too many 'experts' tell me how tactical they are etc.

I was on my unit's CQB demonstration team, that meant I was taught by experts, who worked with the senior NCO's to help train and implement 'tactical' stuff

I hung with the snipers (was a medic, so I got around, was also top's drivers hence the above)

My point is, was, continues to be, have a reason for it
that's basically it, have a real use, and poking prairie dog eyes out at 200M is good, and many, some who will read this, will think 'wow, that's a cool round, maybe I should get one'

OK, now go look at the prices of the upper, the ammo etc, not what you go blow a bunch of ammo with

BUT, the coolness of the AR is you can just buy a .223 or 5.45 or even a .22 upper and use it.

Was reading up on the round, now I have another caliber to consider if I get an AR, but I really like 6.5 too.

 

[viking499]

To me, anything in a 6.5 is a sweet round.

 

[sixgunner455]

Tahoe, what are you not sold on about the .223/5.56 for your purposes? It is more than accurate enough (out of a truly accurate weapon) for serious target and varmint use. I don't see an advantage in the 6mm for either purpose out of this case size. The .223/5.56 will cost you a lot less money, time, and hassle to run as a high-volume tool.

I thought about building an upper for 6x45, but then I considered what I really wanted to do with it, and bought a bolt-action chambered in 6mm-08 instead (LOL), as the .243 is a standard production round (can buy it at wallyworld and any gun store), and has a lot more of the more that jumping up in bullet size gives you over the 6x45 or 6x47 due to being based on the 7.62x51mm case. I handload for it, and without even trying hard, I can go well over 2800fps with a 100gr bullet. Factory ammo is actually hotter than what I usually load for it, and I doubt the 6x45 will ever see that kind of velocity with that size bullet. And I'm still on my first set of 70 pieces of brass, since I've yet to see a situation that would prevent me from finding one, or wear one out.

If your unique situation has more to it than what you said in the OP, then 6x45 may be useful, but from what you said, I kind of think it's a whole lot more bother than I'd put up with.

 

[303tom]

I would rather have a 6x51...........

 

[helotaxi]

I'm working on a 6x45 AR upper as well. Black Hole Weaponry has that cartridge as one of its standard chamberings with a 1:9 twist. Uses standard mags and bolt.

The cartridge is an upgrade from the .223 because for a same-weight bullet it gives you an increase in velocity (same chamber pressure with a larger bullet base having pressure applied means more force accelerating the bullet) and a heavier range of varmint bullets available. Up to the 87gn VMax can be loaded to magazine length but you can also really sling the 55gn BT and 58gn VMax out there at well over 3000fps. Load data is available from most sources.

The .243 and .250Sav are more powerful cartridges but they require the larger (and heavier and significantly more expensive) AR-10 platform. The 6.8SPC is a great cartridge as well, but the selection of bullets that work at magazine length is considerable more limited. Additionally, brass is much harder to come by and good brass is quite expensive ($65ish per 100 for SSA which is the only stuff worth using IMO) not to mention the different bolt and mags. PRI and Barrett are about the only mags in current production that actually function well and they run in the $40+ range each. 6.5 Grendel is another cartridge that might get recommended, but it has the same limitations as the 6.8: uncommon, expensive brass; different bolt; different mags. There are more different bullets that will work but it lacks the energy up close of the 6.8 in favor of using heavier bullets for long range. It is probably the best long range target cartridge available in the AR-15 (because it was designed around using long, efficient bullets) but it isn't the best hunting cartridge because it lacks velocity and energy. The 6.8 is a lot more common at this point because it is very well suited to hunting at reasonable range.

If you're willing to go out on the fringes of wildcat land, there are the DTI series of cartridges from Dedicated Technology. They are based on a 6.8SPC case and use the same bolts and magazines as the 6.8 (which while not as common as .223/5.56 are becoming more commonly available). Currently he offers the .22, 6mm, .25 and 6.5mm DTI cartridges. All were designed with hunting in mind and offer pretty substantial velocity and energy. In addition to the 6x45, I'm working on a 6mm DTI rifle as well. With its slightly shorter case and increased case capacity, I can load longer bullets (compared to the 6x45) for longer shots or the occasional deer or pronghorn. I already have the 6.8 brass to convert and the mags as well. I'm not sure I would recommend this to someone if they didn't, but I'm just throwing the options out there.

If you're willing to go quite proprietary, but want the ultimate in power and performance from the AR-15 platform, the WSSM family of cartridges and wildcats based on them are it. They use a specially machined upper, a different bolt that requires a special barrel extension. The .243WSSM will actually outperform the .243 Win and the .25 WSSM will shoot right with the .25-06. Wildcats are available in 6.5mm, .270, 7mm, .30 and .325. DTech makes uppers for some of these as well. While certainly not needed for coyotes or punching paper, they certainly make the AR-15 a potent medium to large game rifle at decent range.

The popularity of the AR-15 in the last few years has really created a great market for innovation and for people to think outside the established norms and figure out what is really possible within the limitations of the platform. The 6x45 is certainly not a new proposition and has been done in the AR-15 for quite some time. It is the easiest non-.223/5.56 to do and offers some real benefits. No reason not to go that way if you want something different.

 

[tahoe2]

Min caliber for big game in washington is .24 cal and I like the xtra punch of a 6mm vs a 5.56, but still the same BCG and magazines. I know I said targets/varmints, but small game/big game seasons overlap and I wouldn't want to be caught by a said blacktail with a .223 in my hand. The 6x45 will launch a 90 grn pill @ 2800fps, that will dump a blacktail @ 200 yds no problem and Yotes out to 300 and pretty darned accurate to boot! I do have many, more powerful rifles designated for deer & elk & whatever, but to have a "varmint gun" that could take the occasional deer would not be a bad thing. As I stated before, I handload for all my firearms and have done so for many years. I could easily find a .243 bolt rifle with a scope for less than a black rifle without one, so there lies the rub.

 

[Kosh75287]

I keep hearing that the 6x45 is between the .25-35 and the .250 Savage in power, thus marginal for deer. On the other hand, I wonder how many deer probably have fallen to a good marksman with a .25-35, and this trepidation wanes.
It just seems to me that anything the 5.56x45 can do, the 6x45 can probably do better. You mention that it is mainly for target and varmints. If you ever must engage two-legged varmints (may God forbid), I would expect the heavier bullet mass and cross-sectional area to work in your favor.
As long as you are well and truly okay with reloading for it, I don't really see the harm.

 

[LoonWulf]

One of the neat things about the x45/47s is that at the lower velocity they operate great with the lighter varmint bullets. 70s from my x47 at 3100 punch 2" thru and thru on local goats.

 

[W.E.G.]

Anytime you wildcat the .223 to be used in an AR-15, you need to think first about magazines.

Does the 6x45 widen the "ammo stack" in the magazine?
Look at the neck-area ribs that guide the rounds.
Wider ammo-stack in the neck area means more friction there?

I have a 6x45 AR.
Always had trouble with necks of rounds binding in the magazine when more than a few rounds were loaded in an unmodified GI magazine.

Other than complying with silly laws that forbid "less than .23 caliber" for hunting, I don't see what the x45 case does with a 6mm bullet that it can't do with a 5.56mm bullet.

My nephew shot a doe with my rifle.
Doe dropped "like a light switch."

 

[68wj]

Also, if true, have you thought about a closer in, heavy sub-sonic 6.8 round with a good suppressor?

I started to respond to this when you posted that there really wasn't a good 6.8 sub option. Then Bison Armory announced their BSP project with a 200 gr. 6.8 SPC.

 

[68wj]

I have a 6x45 AR.
Always had trouble with necks of rounds binding in the magazine when more than a few rounds were loaded in an unmodified GI magazine.

If you haven't already, the simple fix is a polymer mag and shaving the rib. You can get Lancer mags pre-shaved from Wilson Combat due to their 7.62x40 WT cartridge.

 

[Leadbutt]

Have a bolt gun in the x47 version and it has turned out to be a great general use deer/goat/pig rifle. ammo for the most part has been hand loads off of my dad's paper work.

If I was going to look at a new one , I mite take a run at Baer's new 264 version, sounds like and reads like the x45 version under another name

 

[LoonWulf]

the Baer .264 is the Grendel. Baer also offered a 6x45 but they didnt rename the cartridge...ive still got the G&A issue talking about them.

 

[rc109a]

I have a 6x45 and never had any issues with magazines. The dimensions of the neck really do not change all that much from a fired 223 round. In most cases if you take a 6mm BTHP it will fit inside the the fired neck of a rifle chambered in 5.56. I tried this with our rifles while I was in the military and a few others while at the range. The difference is only .019 inches. In most cases you will have a really hard time telling the difference between the two cases (223 fired and 6x45 unfired) with just a casual glance.

It is a nice firing gun and the round lends itself to being pretty accurate in almost any barrel configuration. I have been loading 85g BTSP and 100g BTSP/BTHP with groups approx .5" at 100yrds bench. It is really easy to load and all you need to change is the barrel.

FYI: My main purpose on chambering for this round was to use for hunting when the law requires a round larger then .24 caliber. The 223 I feel is still better for varmints using the 55g rounds since they are cheaper.