6MM ACKLEY OR 243 ACKLEY

[wildcat]

Hey guys, like I have mentioned before, my new project has begun. I am currently wanting to build a 6mm Ackley Improved, but I have some tell me that the 243 Ackley is just as good and the Brass selection is better. I know the 6mm Rem Ackley gives more velocity, but is it that much different. I have shot a 6mm Ackely Improved, and love it's performance. What do you guys think.

Thanks, Wildcat

 

[uncleB]

wildcat,
on your new project you have said your going with a 1-12"twist barrel for medium weight bullets,with this combo you give up very little going to the 243 Ackley and the 243 Lapua brass is better than the Rem or Win brass you would use on the 6mm Ackley.
UB

 

[James Jones]

I'm not 100% sure but I think that Lapua make bass for the 7x57 Mauser so if you wanted the trouble your could fome the 6mm Rem brass from that. Or at least the 30-06 brass from Lapua , it would be a pain in the PeePee to form them but it could be done

Me personaly I would use the 243Ai due to the brass already being out their and performance wise I doubt seriously that you would be giving up more that 100fps in normal length barrels. Burning less powder would give you longer barrel life and from folk I have talked to that have had both perfer the 243Ai , they say its less finiky with all loads
Also if you got in a bind you could use the quality brass for the 308 in the 243.

 

[Aussie]

If it's a short action Remington and you want to use the magazine you will be better off with the .243 .

 

[Ballistic64]

I think your right JD,Lapua doesnt make 7x57 but I'm pretty sure Norma does.
Ballistically these rounds are very close and your not giving up much one way or the other.It more boils down to preference and if theres what you feel is an advantage to one or the other.
Theres a good write up on the 243AI on 6mmBR this week.
http://www.6mmbr.com/243win.html

 

[wildcat]

UncleB, I am probably going to go with the 6MM Ackley. I can use 7x57 Norma brass if Winchester doesn't work for me. I am currently going with a 28" barrel, however, I am thinking about going to a 30" instead. Do you think a 30" barrel will be too long. I will be using either 75grn V-MAX and 87grn V-MAX. If I use the 87grn V-MAX, I should get around 3700 fps in the 28" barrel. But if I go with the 30", I could probably get around 3800 fps and that would be impressive. What do you think.

 

[TOM H]

[ QUOTE ]
UncleB, I am probably going to go with the 6MM Ackley. I can use 7x57 Norma brass if Winchester doesn't work for me. I am currently going with a 28" barrel, however, I am thinking about going to a 30" instead. Do you think a 30" barrel will be too long. I will be using either 75grn V-MAX and 87grn V-MAX. If I use the 87grn V-MAX, I should get around 3700 fps in the 28" barrel. But if I go with the 30", I could probably get around 3800 fps and that would be impressive. What do you think.

[/ QUOTE ] I shoot a 6mmAI and your not going to get near the velocity with the 87 gr bullets, you will be around 3300fps you may get 3400fps if you push it, my rifle has a 26" barrel. What you need to look at is the 6x284 or 6x06, I shoot the 6x284. Well good luck.

 

[wildcat]

Roper, what kind of powder are you using. My friend has a 6 Ackley, and he uses 52 GRNS of VV-N160 with a 87-V-Max. He is getting between 3600 and 3650 fps out of his 26" 1-12 twist barrel. That's why I think if I get a 30" barrel, I might be able to get around 3700 to 3750 fps.

Thanks, Wildcat

 

[Aussie]

One of my loading manuals lists the charge your friend is using as maximum in the .240 Weatherby , a case with considerably more capacity .
I can't find a load anywhere for any 6mm cartridge that will give an 87 gn V Max the sort of velocity that you are talking about .
Have tried several powders in my .243 AI with the 87 gn and find that 3350 is about all I can safely get in a 26 inch barrel . Add 100 FPS for the additional case capacity of the 6mm and maybe another 120 for the 30 inch barrel . Still a long way short of 3800 FPS .

 

[TOM H]

wildcat, I pull up Vihtavori site figuring I might learn something about N-160 it has the same burn rate as IMR-4831 alittle faster than H-4831 they didn't have any data for the 6Rem but 52.6gr/N-160 is a max load for the 240Wby using 90gr bullets velocity was 3327fps. I looked at Hornadys manaul max load for the 6mmRem was 46.7gr/N-160 with 87gr bullet velocity was 3100 and your friend is using in a 6remAI 52gr/N-160 with a 87gr bullet 3600/3650fps. I always figured the 6remAI was pretty close to the 240 Wby and my velocity using 87 gr bullets has always been about the same. I wish you luck with your project.

 

[hvyw8t]

You will not get 3800 fps with an 87 grain pill out of a 6mm AI, at least with out the worry of losing your face to flying chunks of metal. That is 257 weatherby class speed.

 

[budlight]

Wildcat - I'm building or should I say having built a 30 inch 1:8 twist 243 AI out of my 243 rem 700. I went with 243 because I have 500 some cases.

I was trying to find the article for you on the laws of barrel length diminishing returns. they start out the test with something like a 40 inch barrel and keep chopping it back down in inch increments and rechrono test.

What it really comes down to is: Lighter high speed bullets gain less speed from additional barrel length. The old assumption of 50 FPS per additional inch is not true. The greatest gains are going from 22 inches to say 26 inches. Going from 26 - 30 inches the gains are significatly less.

I'm using a 30 inch barrel because I plan on shooting the heaviest .243 bullets made 95% of the time and varmint lighter bullets 5% of the time.

 

[1doug]

[ QUOTE ]
I was trying to find the article for you on the laws of barrel length diminishing returns. they start out the test with something like a 40 inch barrel and keep chopping it back down in inch increments and rechrono test

[/ QUOTE ]

this one? http://www.riflebarrels.com/articles/bullets_ballastics/long_barrel_velocity.htm

 

[budlight]

Yes, that article is very simular to another one using a smaller caliber.