6x45

[AJC1]

I am curious if anyone is loading and shooting this. My interest is based on having 1200 87 grain a-maxes. It's like the cartridge using what I have on hand and seemingly a good cartridge. No bolt issues with pressure like Grendel or arc.

 

[W.E.G.]

I had one some years ago.

Olympic Arms built one for me on an A1 type AR-15 in the 90's/
I handloaded the ammo with RCBS dies.

It was plenty accurate, although I think the limited case capacity pushes the 6mm bullets kind of slow. My nephew killed a deer with it. Shot the deer in the neck. Deer fell over like a switch had been turned off. No exit wound. One drop of blood at the entrance wound. We paid to have a processor pack the deer, so never saw the bullet.

I got rid of the gun because of one reason. Magazines.
The "fat stack" of ammo in the .223 magazine caused the necks of the 6x45 rounds to drag on the splines of the GI mags I was using. That drag caused the ass-ends of the rounds to splay outward, causing MORE DRAG IN THE MAGAZINE. I eventually altered the splines on one magazine with a file, and I could reliably get it to fire six shots from the magazine. More rounds than that in the magazine and it would start having bolt-over-base malfunctions.

THAT SAID,...

We now have dedicated 300 Blackout magazines. And THOSE MAGAZINES have a shorter spline in the front. So I think if you use 300 Blackout mags with a 6x45, you eliminate that problem I described.

If you don't mind questionable bullet-expansion, the 6x45 is a perfectly decent round for recreational use.
I'll say its highly unlikely the 87-grain A-max or V-max or whatever-max will expand much at 6x45 velocity.

 

[AJC1]

I had one some years ago.

Olympic Arms built one for me on an A1 type AR-15 in the 90's/
I handloaded the ammo with RCBS dies.

It was plenty accurate, although I think the limited case capacity pushes the 6mm bullets kind of slow. My nephew killed a deer with it. Shot the deer in the neck. Deer fell over like a switch had been turned off. No exit wound. One drop of blood at the entrance wound. We paid to have a processor pack the deer, so never saw the bullet.

I got rid of the gun because of one reason. Magazines.
The "fat stack" of ammo in the .223 magazine caused the necks of the 6x45 rounds to drag on the splines of the GI mags I was using. That drag caused the ass-ends of the rounds to splay outward, causing MORE DRAG IN THE MAGAZINE. I eventually altered the splines on one magazine with a file, and I could reliably get it to fire six shots from the magazine. More rounds than that in the magazine and it would start having bolt-over-base malfunctions.

THAT SAID,...

We now have dedicated 300 Blackout magazines. And THOSE MAGAZINES have a shorter spline in the front. So I think if you use 300 Blackout mags with a 6x45, you eliminate that problem I described.

If you don't mind questionable bullet-expansion, the 6x45 is a perfectly decent round for recreational use.
I'll say its highly unlikely the 87-grain A-max or V-max or whatever-max will expand much at 6x45 velocity.

View attachment 1187332

Why limit it to 55k not 62k?

 

[adcoch1]

I shot an early Olympic arms 20" 6x45 that my uncle built when he worked there. It was a close range deer hammer for him and plenty accurate on the targets I got to shoot it at. Most 243 bullets are designed for significantly faster velocities than the 6x45 can throw them though, so make sure you use the right bullets on game. Just like the 300 blk, a varmint bullet is usually acceptable for deer in 6x45. I'd like to have one to play with.

 

[adcoch1]

Why limit it to 55k not 62k?

It was based on 223 loads, and not 5.56. it is a great candidate for some hot loads, just don't go crazy...

 

[AJC1]

I shot an early Olympic arms 20" 6x45 that my uncle built when he worked there. It was a close range deer hammer for him and plenty accurate on the targets I got to shoot it at. Most 243 bullets are designed for significantly faster velocities than the 6x45 can throw them though, so make sure you use the right bullets on game. Just like the 300 blk, a varmint bullet is usually acceptable for deer in 6x45. I'd like to have one to play with.

I'm killing paper no more dead than a fmj... just having fun with what's on hand. The 300hmr seems a better option than a 300bo but all three recycle brass and that's gooder.

 

[AJC1]

I had one some years ago.

Olympic Arms built one for me on an A1 type AR-15 in the 90's/
I handloaded the ammo with RCBS dies.

It was plenty accurate, although I think the limited case capacity pushes the 6mm bullets kind of slow. My nephew killed a deer with it. Shot the deer in the neck. Deer fell over like a switch had been turned off. No exit wound. One drop of blood at the entrance wound. We paid to have a processor pack the deer, so never saw the bullet.

I got rid of the gun because of one reason. Magazines.
The "fat stack" of ammo in the .223 magazine caused the necks of the 6x45 rounds to drag on the splines of the GI mags I was using. That drag caused the ass-ends of the rounds to splay outward, causing MORE DRAG IN THE MAGAZINE. I eventually altered the splines on one magazine with a file, and I could reliably get it to fire six shots from the magazine. More rounds than that in the magazine and it would start having bolt-over-base malfunctions.

THAT SAID,...

We now have dedicated 300 Blackout magazines. And THOSE MAGAZINES have a shorter spline in the front. So I think if you use 300 Blackout mags with a 6x45, you eliminate that problem I described.

If you don't mind questionable bullet-expansion, the 6x45 is a perfectly decent round for recreational use.
I'll say its highly unlikely the 87-grain A-max or V-max or whatever-max will expand much at 6x45 velocity.

View attachment 1187332

2500 fps at 47k. What does it look like at 55k leaving the 556 62k on the table for "saftey" the 20" barrel being likely.

 

[W.E.G.]

Note that the Quickload screen I posted is 100% loading density of TAC with that 87 and still be piddling velocity.

Its not possible to add more powder. Ball powder won't compress.

The only way you're getting more velocity out of a 6x45 is to go to something that borders on pistol powder. I don't recommend that.

 

[AJC1]

Note that the Quickload screen I posted is 100% loading density of TAC with that 87 and still be piddling velocity.

Its not possible to add more powder. Ball powder won't compress.

The only way you're getting more velocity out of a 6x45 is to go to something that borders on pistol powder. I don't recommend that.


View attachment 1187351

How about imr 4227 or 4198

 

[W.E.G.]

How about imr 4227 or 4198

 

[W.E.G.]

At minimum, when you go to those fast powders at 55K+, you can expect primers to start doing weird ****.

Semi-auto is probably gonna be puking primers under your trigger.

I wouldn't want to go to those pressures unless I were using virgin brass, with a crimped primer. And then, that brass would have to be condemned for further reloading. Because the primer pocket won't be right after that.

So, if you want to pull bullets from crimped 193, and then form 6x45 from it, and keep up with the drama all for an extra 200 fps, whatever happens is on you. Its definitely not PRACTICAL to do all that, and if you're unlucky, it will be UNSAFE.

If you want to kill deer, there are a lot of rounds out there that you can just buy that have bullet-construction matched to the velocity, all without you having to try to un-screw a puked-primer issue, or a case-head-rupture on the range or in the field.

 

[AJC1]

At minimum, when you go to those fast powders at 55K+, you can expect primers to start doing weird ****.

Semi-auto is probably gonna be puking primers under your trigger.

I wouldn't want to go to those pressures unless I were using virgin brass, with a crimped primer. And then, that brass would have to be condemned for further reloading. Because the primer pocket won't be right after that.

So, if you want to pull bullets from crimped 193, and then form 6x45 from it, and keep up with the drama all for an extra 200 fps, whatever happens is on you. Its definitely not PRACTICAL to do all that, and if you're unlucky, it will be UNSAFE.

If you want to kill deer, there are a lot of rounds out there that you can just buy that have bullet-construction matched to the velocity, all without you having to try to un-screw a puked-primer issue, or a case-head-rupture on the range or in the field.

Looks like 2550 is reasonable inside reasonable pressure. That's respectable and hot but but not insane.... the bigger picture is what the accuracy is doing. If it's dead nuts at 57k ish that's perfection.

 

[W.E.G.]

A good bullet through a good barrel will be accurate if you don't over-drive it.

 

[Varminterror]

Why limit it to 55k not 62k?

Be mindful, the C.I.P. 62k standard is their PROOFING load, not their MAP.

SAAMI is actually a tougher standard to pass, higher pressure standards are used for Proof loads in SAAMI than CIP - 223rem is proofed to at least 73,400psi, same for 6x45, but also equal for both are the SAAMI MAP of 55kpsi, or 58kpsi if you extend to 5.56 NATO epvat standard (which really isn’t significantly different than the 55kpsi SAAMI standard when corrected for measurement position).




I appreciate that it can be argued that a rifle action and barrel tenon which withstands 65kpsi in other cartridges can logically be extended to use the same high pressure expectation by a handloader - especially considering the fact the barrel tenon is thicker for a .380” nominal cartridge head than for a .532” magnum or .480” nominal standard boltface cartridge operating at 65kpsi, but of course this relies upon faith that the smaller, weaker 5.56/223 brass can withstand the same forces as the larger cartridge brass (hint: a lot of us lay on 5.56/223 based cases in bolt guns and the brass doesn’t hold up). Considering an AR platform rifle, naturally, bolt thrust for loads above 55kpsi also exceed the design parameters of the firearm, so the increased risk of metal fatigue and bolt lug failures are a liability the handloader is free to accept for themselves - but in this case, why are they really talking about any pressure standards at all?

And for what it’s worth 87 Vmax’s open just fine in coyotes out of 6x45’s - even without exceeding 55kpsi SAAMI MAP.

 

[AJC1]

Be mindful, the C.I.P. 62k standard is their PROOFING load, not their MAP.

SAAMI is actually a tougher standard to pass, higher pressure standards are used for Proof loads in SAAMI than CIP - 223rem is proofed to at least 73,400psi, same for 6x45, but also equal for both are the SAAMI MAP of 55kpsi, or 58kpsi if you extend to 5.56 NATO epvat standard (which really isn’t significantly different than the 55kpsi SAAMI standard when corrected for measurement position).

View attachment 1187406


I appreciate that it can be argued that a rifle action and barrel tenon which withstands 65kpsi in other cartridges can logically be extended to use the same high pressure expectation by a handloader - especially considering the fact the barrel tenon is thicker for a .380” nominal cartridge head than for a .532” magnum or .480” nominal standard boltface cartridge operating at 65kpsi, but of course this relies upon faith that the smaller, weaker 5.56/223 brass can withstand the same forces as the larger cartridge brass (hint: a lot of us lay on 5.56/223 based cases in bolt guns and the brass doesn’t hold up). Considering an AR platform rifle, naturally, bolt thrust for loads above 55kpsi also exceed the design parameters of the firearm, so the increased risk of metal fatigue and bolt lug failures are a liability the handloader is free to accept for themselves - but in this case, why are they really talking about any pressure standards at all?

And for what it’s worth 87 Vmax’s open just fine in coyotes out of 6x45’s - even without exceeding 55kpsi SAAMI MAP.

Thanks for your contribution. I definitely don't need to lean in on the loading. 47k just seemed a little anemic. Full pressure 223 will be ideal and extra strength used as a saftey factor as designed.... looking for a 200 yard range load ideally.

Do you recommend an AR barrel you've had good experience with?

 

[Varminterror]

H4895 and 8208 are great for the 6x45. It’ll reach a lot farther than 200, but for STANAG mags, we can’t use the slippery ones, so we can find ourselves transonic really early. But it’s a fun little round, and stupid simple. Fantastic Coyote calling round, especially if you’re playing with 10-14” barrels.

 

[AJC1]

Seems like some are using an 80 grain ttsx for deer and pig in areas that don't allow 22 caliber. Seems like it's a great setup for 250 yards.... so that's very intriguing. I'm not having a good time finding barrels.

 

[LoonWulf]

Seems like some are using an 80 grain ttsx for deer and pig in areas that don't allow 22 caliber. Seems like it's a great setup for 250 yards.... so that's very intriguing. I'm not having a good time finding barrels.

I had a 24" then 20" 6x47 built on a 700 action. I used it on sheep, goats, and pigs with no issues. The 6x45/47 are good solid little rounds. I consider building an AR in 6x45 (shaw sometimes lists barrels).

 

[AJC1]

I had a 24" then 20" 6x47 built on a 700 action. I used it on sheep, goats, and pigs with no issues. The 6x45/47 are good solid little rounds. I consider building an AR in 6x45 (shaw sometimes lists barrels).

Thanks for the barrel recommendation. I have emailed them to see if they have one on the back shelf or are willing to chamber a 6mm arc blank...

 

[Varminterror]

For those playing the home game, remember, the 6x45 and 6x47 are VERY different rounds. The 6x45 is 2mm smaller in both directions - the 6x47 is based on the 6.5x47 case, nearly equivalent to a 6.5 Creedmoor, whereas 6x45 is a necked up 223rem. The larger will push a 100grn class bullet as fast or faster than the smaller can propel an 80grn class bullet.

 

[dfish1247]

Never played with it in an AR. Have an xp100 remage and kimber super predator chambered in 6x45. I wouldn’t hesitate having one.

My two are not overly picky on powder. Any of the usual powders for heavy 223 work just fine here. It’s not a speed demon, but its not a slouch either.

 

[AJC1]

So I was looking at the 20" barrels at xtreme. For 400 is that better or worse than another vendor. No luck at shilen or krieger. What is the optimum barrel length for this loading. Considering letting the boy shoot a pig with an 80 ttsx and the bulk being target work with the 87vmax.

 

[Varminterror]

hat is the optimum barrel length for this loading.

No such thing.

If you're pig hunting to 200 yards, anything over about 7" makes sense, and anything over 20" probably doesn't. I'd personally build it either at 10.5"-12" to use on an SBR lower, or 16"-18" with midlength gas.

Kinda odd that Shilen isn't selling the 6x45's anymore for AR's. They still show the chambering for their bolt gun barrel options.

 

[AJC1]

No such thing.

If you're pig hunting to 200 yards, anything over about 7" makes sense, and anything over 20" probably doesn't. I'd personally build it either at 10.5"-12" to use on an SBR lower, or 16"-18" with midlength gas.

Kinda odd that Shilen isn't selling the 6x45's anymore for AR's. They still show the chambering for their bolt gun barrel options.

Why mid length gas? Not AR smart...

 

[LoonWulf]

For those playing the home game, remember, the 6x45 and 6x47 are VERY different rounds. The 6x45 is 2mm smaller in both directions - the 6x47 is based on the 6.5x47 case, nearly equivalent to a 6.5 Creedmoor, whereas 6x45 is a necked up 223rem. The larger will push a 100grn class bullet as fast or faster than the smaller can propel an 80grn class bullet.

Yeah i should have been more clear 6x47Rem based on the .222 Rem Mag case....i used 204 ruger cases to make them towards the end of owning that rifle.
Slight capacity advantage over thr x45 version, but not enough to really matter......

Huh..... On the off chance anybody wants them, I still have a bunch of cases and the dies for that gun.