Old dog needs help learning new trick

[VaRandy]

I have been in the shooting world for some time and am not known for efficient wildcats!

I have acquired a 6/284 set up for 70 grains in 14 twist and am not interested in shooting fast little pills with sucky BC's. I have an 8 twist three land 29 inch Lilja that has been a Joe Nailer shooting 105s at 3300 fps. i want to replace the case with one that requires a lot less forming and hopefully one more efficient. I considered the 243 Ackley which I am familiar with and it was suggested that I look into the 6mmTurbo 40 degree. It looks like a strong contender and I have the following concerns: Apparently I cant get my favorite brass, Lapua and in fact I don't know all the choices for this little used case nowadays.

Secondly, I know it was designed for an AR and I have a bolt with a much longer barrel than AR's. Will I have trouble finding a powder slower for the additional length. Has anyone built one with a long barrel and what was the result.

I need to be able to throw 105 to 108s at 3300. Can I do it efficiently with this cartridge? If not, what then?

thanx to all

 

[dmoran]

I need to be able to throw 105 to 108s at 3300. Can I do it efficiently with this cartridge?
No, not even close (more like 2800 - 2900)

If not, what then?
For 3300 Mv's from 105 class bullets, going to have to stick with longer/bigger cartridges to achieve those kind of speeds. Look at cartridges with no less then 50-grain capacity.

My 2-Cents
Donovan

 

[Carolina Man]

You might take a look at the 6 Creedmore. Probably pretty close. A 6 Turbo will not with 105s. Dont understand your problam with forming 6x284. Just neck down Lapua 6.5 x284. I step down and fire form. I shoot mine with 115s at 3400.

George

 

[VaRandy]

You might take a look at the 6 Creedmore. Probably pretty close. A 6 Turbo will not with 105s. Dont understand your problam with forming 6x284. Just neck down Lapua 6.5 x284. I step down and fire form. I shoot mine with 115s at 3400.

George

No problem forming 6/284. Was talking about my previous wildcat that was a 7.5/55 throwing the 6 105. It took 53.5 grains of RL 22 and I was wondering if a more efficient case was capable of the speed I want the 6 to go.

 

[VaRandy]

You might take a look at the 6 Creedmore. Probably pretty close. A 6 Turbo will not with 105s. Dont understand your problam with forming 6x284. Just neck down Lapua 6.5 x284. I step down and fire form. I shoot mine with 115s at 3400.

George

Carolina Man ...is your 6/284 running an 8 twist barrel?

 

[B_Thomas]

.243 OR .243AI.

 

[Ledd Slinger]

No way with the 6mm T40. It's just a 6 PPC case with the shoulder blown forward and set to 40 degrees. I built one on a 722 with a 27" barrel. 2900-3000 fps with 105s? Sure, but no way in heck would I ever see 3300. Plus if your bolt isnt designed to take .473 and PPC cases, you would have to buy a different bolt.

Lapua 'sort of' makes brass for the 6mm T40. Use 6.5 Grendel or 6 PPC. 6.5 Grendel is less fireforming. Gotta blow the shoulder forward either way. Im running 6 PPC Norma brass in mine. Have a bunch of Hornady 6.5 Grendel brass im gonna use for varmint loads. You can load test while fire forming, just don't test hot loads.

243 AI or 6/284 will get you in those high speeds with the right barrel length. I would form the 243 brass out of Lapua 308 Palma small rifle primer brass so you can push pressures for top speeds.

Don't expect your barrel to last much more than 1K rounds using any cartridge that pushes 105s at 3300+ fps, especially if you're running strings and getting it hot.

 

[spclark]

Forget anything with a 0.440" case head diameter. You have a 0.475" bolt face, right?

Look into RCWIII's 6SLR, I think you'll find what you want. 3,200's within its capacity (3,300 maybe but I'm doubtful) with 105's - 108's & compared to a 6-284 your barrels might just last a little longer.

 

[VaRandy]

Forget anything with a 0.440" case head diameter. You have a 0.475" bolt face, right?

Look into RCWIII's 6SLR, I think you'll find what you want. 3,200's within its capacity (3,300 maybe but I'm doubtful) with 105's - 108's & compared to a 6-284 your barrels might just last a little longer.

Link failed to the RCWIII's 65SLR......

 

[VaRandy]

Carolina Man ...is your 6/284 running an 8 twist barrel?

My newly acquired 6/284 has a 14 twist so it could throw 70 grains. I have an almost new 8 twist Lilja is will have to chamber and change from a BAT action to Rem.

 

[billlarson]

When you think on it, the 284 case is just about the size of a .30/06.

The 6mm/06 and 6mm/284 have a number of wins at 1,000 yards. One step down is a 6 Ackely (6/7x57 improved). I had a 6/284 (actually, a 6 on a7.5x55 Swiss case) with the reamer held back .200. It had exactly the capacity of a 6 Ackley, which I also have. 106 Clinch rivers at 3,500 shot quite nice. The guys shooting 107 Sierras with a 6/.30-06 (old days) could get 3,600 with maybe a "plus."

I can make an argument for it to use at 1,000 yards. Not much of one, but an argument. Even Shehane backed down in case size, I believe his last 6mm was based on the 6.5x47 Lapua case.

For 600 yards, it would be a bit much. One thing to think about: with the smaller 6mms, you can shoot free recoil, without a muzzle brake. Harder to shoot free recoil without a brake with anything much bigger, though I did do this with my 6 Ackley.

FWIW, and that's not much.

Edit; BTW, that 3,500 was with Rel-22; I had a bit better accuracy with 4831, around 3,300. And the speed dropped before the throat washed out.
Last edited by C

copied and pasted out of archives..... not at all uncommon for a 6-284 with 105`s to go mid 3000`s ft/sec.
bill

 

[DOGCAPPER]

Pressure on the small head is a problem with the 284 case. A reamer is available with straighter wall taking some of the pressure by gripping the chamber sides. The name escapes me.

 

[swd]

The 6 Competion Match, 243 Ackley or the 6 Crusader which is an improved 6MM Remington will all be in the ball park.

 

[spclark]

Link failed to the RCWIII's 65SLR......

Huh... weird. Just worked on my iPhone, here's the full URL:

http://6mmar.com/Super_LR.html

 

[onelastshot]

A 6mmAI is the answer to your questions. You can throw 105 to 108s at 3300-3400. Richard Franklin of Richard Custom Rifles has been building 6mmAI rigs for the last couple of decades and uses these rigs on groundhogs out to 600-900 yards. His favorite combination is a 6mm AI, a BAT-actioned 14-twist that drives a 75-grain V-Max at a blistering 3860 fps. He's moved from Virginia to Montana but is still building rifles on his custom laminate stocks.

 

[spclark]

onelastshot may have a point...

http://www.angelfire.com/sd/6mmackley/

http://forum.accurateshooter.com/threads/6mm-rem-vs-6mm-rem-ai.3773296/

Seems few employ bullets over 95 grains though.

The 7mm wildcat I've been playing with since last year (284INCH by name) has a 6.5mm brethren but I'm thinking maybe the concept could be stretched (shrunk?) even to 6mm?

Case uses standard 308WIN brass; the inspiration was to see how well Lapua's small primer Palma brass could withstand the extra case capacity. Shoulder gets blown forward 3.5 mm otherwise the 7mm variant's a 7-08.

If it weren't for the "unmodified 308WIN case" restriction for Palma I think I'd be game to try the idea on a 30 cal too, put another 150-200 fps behind a 155 or 168?

No reason to think a 6mm wouldn't work either once you get past the minimal neck these cartridges feature! Reamer design puts throats @ 0.0005" over bore so what neck there is is there just to hold the bullet in the case until firing.

 

[JLT]

I'll echo the recommendations for the 6mm AI and the .243 AI. I've been able to exceed 3,300 easily with 105 grainers and RL-26 in my 26" .243 AI and I'm sure the 6mm AI will tack some more on top of that. Forming AI brass doesn't get much easier.

 

[VaRandy]

I'll echo the recommendations for the 6mm AI and the .243 AI. I've been able to exceed 3,300 easily with 105 grainers and RL-26 in my 26" .243 AI and I'm sure the 6mm AI will tack some more on top of that. Forming AI brass doesn't get much easier.

To make sure I read you wrong. I should have no trouble getting 3300 with a .243 AI and my 29 inch 3 land Lilja barrel shooting 105's. That sounds like the most efficient platform to get me there so I will probably go with that. Choice two was to go 6/284 so I could throw 115's at same speeds. I know how accurate the.243 AI is and have an unbelievable .260 Ackley to boot. Thanks.

 

[JLT]

To make sure I read you wrong. I should have no trouble getting 3300 with a .243 AI and my 29 inch 3 land Lilja barrel shooting 105's. That sounds like the most efficient platform to get me there so I will probably go with that. Choice two was to go 6/284 so I could throw 115's at same speeds. I know how accurate the.243 AI is and have an unbelievable .260 Ackley to boot. Thanks.

With 29" of tube you should have no problem getting 3,300+ with comfortable chamber pressures. As I mentioned, I get over 3,300 out of a 26" with 48.8 gr of RL-26 behind a 105. I use Lapua brass and S&B or CCI LRM primers. There's room for more, but that load gives me the accuracy that I'm looking for.

 

[dkhunt14]

I would bet running 3300 with an Ackley 243 will not get a good round count. Especially if shot fast. The TP point on an 6mm Rem IMP would get the speed easily and would give much better barrel life. Matt