High velocity chamberings known for having exceptional accuracy.

[Max Heat]

OK, what about this: I spotted something online a while back referring to 6.5RUM being a chamber option on something orderable. Can't remenber if it was a barrel or not

I AM willing to jump into wild cat territory on my next build, so long as brass and dies are available.

Is the 6.5RUM a WC that anyone actually does (or HAS done)?

Or does what I saw online HAVE to have been some sort of misprint?

Out of curiosity, can the 6.5-284AI case be wildcatted out beyond Ackley's improvement, to hold 80+ grains? That may have been what the guy was saying, because he WAS talking about having custom dies. I can say that it was downright nasty, handling the cuncussion of being next to him at the range when he would fire, with the muzzle brake he was using. It was enough to convert me right into being an anti-fan of the MBs. Not likely that any builds of mine will sport them. Cosmetically speaking, they definitely DO add to the "eye-candy" appeal of a rifle though.

 

[AZShooter]

The guy might have meant it was a 284 bore but got tongue tangled in explaining it.

Here is a reference of case capacity:

Case Capacities

They use water for the comparison and fill case to top of neck.

The 7 rem mag is really close to holding 80 gr of powder. Hodgdon lists 77 gr of US 869 with a 175 as the most powder this case holds.

The 7 Rem mag is 2.5" long while the 284 win case is 2.180" So we can conclude that the suggested 280 win improved will not hold 80 gr of powder!

 

[Max Heat]

So the 284 IS a W-based (winchester) case?

Does that mean the 6-284 IS the same as the 243W?

Meaning that, technically, there IS a 6-284AI, which IS the 243AI?

I have a 7RM which I regularly load 75gr into no problem.

So your saying if the guy WAS pushing 80+ grains powder into a 6.5 bore, the case had to AT LEAST be a wildcatted 7RM parent case ?

Is there a "known" 6.5RM, or preferrably for me, a 6RM wildcat round? I do have several hundred 7RM "base" cases to work with. And would dies for 6RM (aka 243RM, right?)be readily availabe?

Realistically, a 7RM cart necked-down to 6mm would effectively put the round into the "ultra" magnum category FOR THE BORE SIZE, would it not?

 

[Jud96]

So the 284 IS a W-based (winchester) case?

Does that mean the 6-284 IS the same as the 243W?

Meaning that, technically, there IS a 6-284AI, which IS the 243AI?

I have a 7RM which I regularly load 75gr into no problem.

So your saying if the guy WAS pushing 80+ grains powder into a 6.5 bore, the case had to AT LEAST be a wildcatted 7RM parent case ?

Is there a "known" 6.5RM, or preferrably for me, a 6RM wildcat round? I do have several hundred 7RM "base" cases to work with. And would dies for 6RM (aka 243RM, right?)be readily availabe?

Realistically, a 7RM cart necked-down to 6mm would effectively put the round into the "ultra" magnum category FOR THE BORE SIZE, would it not?

No the ,284 Winchester is a completely different case than the .243 Winchester. The .284 has a rebated rim that uses a standard bolt face, but its body is larger in diameter than a standard cartridge. The .264 Winchester is a 7mm Remington Mag necked down and a 6.5 Remington Mag is basically the short mag version of the .264 WIN. A 6mm Remington Mag would be terribly overbore and would burn barrels out in a heart beat. The .240 Weatherby burns 55grs of powder and is hard enough on barrels, now burning 70grs would burn one out in less than 700 rounds.

 

[AZShooter]

You beat me in the explanations Jud96,

Max Heat,

The 6mm-264 win mag is called the Mach IV or 240 incinerator. It would burn a barrel out by 700 or so rounds but man what a ride it would be! (thinking of top fuel drag engines that don't last long either) Imagine a 105 Berger hybrid at 3800 from a 28" barrel!!! Flat with minimal wind drift. Or over 3000 mph ( mach IV) with a 70 gr bullet!



I would suggest you bookmark this link and refer to it when you have questions on non wildcat cartridge sizes:

List of rifle cartridges - Wikipedia, the free encyclopedia

Then go to an individual cartridge listed and open up the hyperlink. Cartridge dimensions and case capacity is shown along with a plethora of other information.


1-Wildcats



[ame="http://www.youtube.com/watch?v=oZO-WCoAYdg"]Taming Wildcats: Custom Cartridge Design and Fabrication AGI 217 - YouTube[/ame]

 

[Max Heat]

What other HOT 6's are there (any above 55gr)?

I do like the name "incinerator", but unfortuately it [rightfully] implies "barrel" incinerator.

PS - I'm NOT looking for a FULLY wildcatted round, where reloading dies must be custom ordered. I preference is for an "already available" cartridge. Wildcat would be acceptable, IF it a common, off-the-shelf, wildcat round. What does THAT narrow it down to in 243/6cal?

 

[Jud96]

You meat me in the explanations Jud96,

Max Heat,

The 6mm-264 win mag is called the Mach IV or 240 incinerator. It would burn a barrel out by 700 or so rounds but man what a ride it would be! (thinking of top fuel drag engines that don't last long either) Imagine a 105 Berger hybrid at 3800 from a 28" barrel!!! Flat with minimal wind drift. Or over 3000 mph ( mach IV) with a 70 gr bullet!



I would suggest you bookmark this link and refer to it when you have questions on non wildcat cartridge sizes:

List of rifle cartridges - Wikipedia, the free encyclopedia

Then go to an individual cartridge listed and open up the hyperlink. Cartridge dimensions and case capacity is shown along with a plethora of other information.

A few links on wildcats:

Taming Wildcats: Custom Cartridge Design and Fabrication AGI 217 - YouTube

1-Wildcats

I'm confused by what you meant here haha.

 

[MudRunner2005]

OK, what about this: I spotted something online a while back referring to 6.5RUM being a chamber option on something orderable. Can't remenber if it was a barrel or not

I AM willing to jump into wild cat territory on my next build, so long as brass and dies are available.

Is the 6.5RUM a WC that anyone actually does (or HAS done)?

Or does what I saw online HAVE to have been some sort of misprint?

Out of curiosity, can the 6.5-284AI case be wildcatted out beyond Ackley's improvement, to hold 80 grains? That may have been what the guy was saying, because he WAS talking about having custom dies. I can say that it was downright nasty, handling the cuncussion of being next to him at the range when he would fire, with the muzzle brake he was using. It was enough to convert me right into being an anti-fan of the MBs. Not likely that any builds of mine will sport them.

No, there is no way the 6.5-284 case could ever hold 80 grains of powder.

 

[AZShooter]

I saw that and corrected the Meat to beat a few seconds later. You must be reading as I write it Jud96 ...sorry chalk it up to fast typing.....

Hmm other 6mms? The 6mm-284, 6mm-06, 6mm Catbird (270 win necked down) and
240 weatherby are very similar using approx. 55 gr of powder.

A 6mm/30-30 Ackley improved exists too. It has a rimmed case, would make sense but would be similar to the 243 for a lever gun

Larger? I have heard of:

6mm-WSM,
6mm-264 aka mach IV (or any related case like the 7 rem mag)
Bet someone used the 7 SAUM necked down.
6mm-6.5 Rem Mag, know someone who has one
244 H and H isn't a wildcat but produced by Holland and Holland in 1955

Who knows someone might have even tried the 338 RUM case for grins.

 

[Max Heat]

So there IS a 6-264, and it IS the mach IV? Can I get dies to neck down 7RM cases and reload them, right off-shelf?

Could it be that the 6.5 guy said wildcatted 6.5-264AI? He did show me a round, and I do remember thinking that it looked like it was big enough to hold 80gr. Don't recall if it was belted or not though.

 

[Jud96]

So there IS a 6-264? And I could get dies to neck down 7RM cases and reload them, right off-shelf?

Dies will have to be custom made.

 

[MudRunner2005]

So there IS a 6-264? And I could get dies to neck down 7RM cases and reload them, right off-shelf?

That's a WHOLE LOTTA powder behind a little bitty bullet. I don't think I'd go that far with it.

Why not just go with a .240 Wby or 6mm-06 if that's what you're after? Atleast brass will be easy to find, and you could neck down .25-06 brass in 1 step for 6mm-06.

 

[AZShooter]

6mm-284 is NOT the mach IV. Mach IV is a necked down 264 win mag!

I have a 6mm-284 and am very impressed with the 105 Berger match target hybrid sent out at 3445 fps from a 28" barrel.

I have actually considered making a 6mm-264. The reason is that Berger bullet. I have a magnum boltface LA rifle that has a tired 257 weatherby barrel. I could rebarrel to the 257 or make a 7 rem mag or some other hard kicking magnum but I thought wouldn't it be fun to try the 105s in a sporter weight with the 6mm-264! Low kick very flat trajectory and excellent deer/antelope killing power.

The die issue could be solved several ways.

A coordinated plan using Pacific Tool and Gauge for the reamer along with Whidden Gunworks for the FL/bushing die plus a seater would be the straightforward approach. It would cost approximately
$140 for reamer plus $270 for die set.


I have many dies on hand plus a lathe. I would order the reamer then make a forming die from an old barrel or pay PT&G $19 for a die body. I made a form die with my 6mm-284 which necks down 284 brass to 6mm wonderfully. A gunsmith could use the reamer to make the forming die.

A Redding 7 rem mag bushing/FL die can be used to size the fired brass. Just put in a smaller bushing. As for the seating I discovered that a Redding competition seating die for 284 works great for seating bullets for the 6mm-284. The body is what gets centered in these comp dies. The seater plug might have to be altered or switched out. A 7 rem mag comp seater die should work for the 6mm-264. Fortunately I have all these dies on hand.


The big hang up for me is the barrel. I have been machining Rem takeoff barrels for many of my projects. Saves a ton of money. To shoot the high BC 105 Berger requires a 1 in 8 twist. All 243 takeoffs are 1 in 9 1/4. Plus they are 24" long. There are plenty of 1 in 8 twist sporter weight barrels for sale by outfits like Bartlein but they cost over $300. Considering barrel life the rifle would have to be saved for hunting only. No load development past getting one bullet to shoot.

If you want a wildcat bad enough you do what is necessary to make it happen.

 

[MontanaRifleman]

First, IMO, there is no such thing as a "more accurate" case design/chambering than any other case design/chambering. The biggest factors in accuracy are quality/type of rifle components, quality of smithing and rifle build, and load quality/consistency.

That said, in theory, smaller case and lighter loads are less susceptible to barrel harmonics and this is probably why you see BR shooters with cases like the 6ppc and 6 BR. However, larger and higher BC bullets at higher velocities are less susceptible to environmental conditions. In a no wind situation, the 6 BR "might" out shoot a 300 WSM @ 1000 yds, but in a wind situation, especially variable, the 300 WSM will have the advantage. A lot of factors to consider when you are talking accuracy.

Anecdotal stories of my 257 Wby shoots bug holes, etc., don't mean that on average they all shoot bug holes better than any other rifle.

Next, in my 6-284, 61 gr of RL33 is about 100% capacity with a bullet seated near the bottom of the neck. There is very little room for that case to be improved and I don't see it gaining any more than maybe 3 gr of powder space. IMO, not worth the effort and you will end up shortening the neck which is already not long.