6x55 A.I. questions

T

TG-5150

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I was raised shooting a Rem 788 in 6mm. I love that caliber and have had a few .243 wins since. I am fairly new to the wildcat arena and was thinking a .243 A.I. would be a pretty neat project. So the research began.
6mm A.I. is faster but some say more finiky to load for, and has a longer neck which will grab the longer bullets I want to shoot better. Barrel life is supposed to be better over the .243A.I. But not sure on this. Rem. brass might be a concern in the area of longevity in reloads but is very available for me. Don't know if I am ready to make it out of better 7x57 brass yet or not.
.243 brass in the top shelf varieties is very plentiful. In fact I have once fired brass for it now. It's supposed to be a cinch to load for in all bullet weights(243a.i.).
Next I read about the 6.5x55 being one of the top gainers to be improved. And that leads me to thinking why not neck that to 6mm then fire form. Some great brass is available
Would a 6mmx55 improved be a better round for what I want to do?
Rifle will be built on a M77 tang safety action get a 26" tube in light senders.
Twist should be between 7 or 8 ?
Will be shooting 105 gr.
Thanks for any help and I already know the wows of the M77 but it's what is going on this build :)
 
TG-5150 said:
I was raised shooting a Rem 788 in 6mm. I love that caliber and have had a few .243 wins since. I am fairly new to the wildcat arena and was thinking a .243 A.I. would be a pretty neat project. So the research began.
6mm A.I. is faster but some say more finiky to load for, and has a longer neck which will grab the longer bullets I want to shoot better. Barrel life is supposed to be better over the .243A.I. But not sure on this. Rem. brass might be a concern in the area of longevity in reloads but is very available for me. Don't know if I am ready to make it out of better 7x57 brass yet or not.
.243 brass in the top shelf varieties is very plentiful. In fact I have once fired brass for it now. It's supposed to be a cinch to load for in all bullet weights(243a.i.).
Next I read about the 6.5x55 being one of the top gainers to be improved. And that leads me to thinking why not neck that to 6mm then fire form. Some great brass is available
Would a 6mmx55 improved be a better round for what I want to do?
Rifle will be built on a M77 tang safety action get a 26" tube in light senders.
Twist should be between 7 or 8 ?
Will be shooting 105 gr.
Thanks for any help and I already know the wows of the M77 but it's what is going on this build :)
Click to expand...
I don't have all the answers to your questions, however something that I do when researching for a build is to research "factory" calibers that are close instead of reinventing the wheel! If you want that special, one of a kind rifle then keep going in the direction you're going in. As for the Ruger 77, tang safety build, I've got a whole safe full of them; 30-06, 35 Whelen, .270 Winchester (2)and.358 Winchester. Good strong action, that you're not too apt to break anytime soon. Good luck with your build .
 
I am really leaning on the 6mm A.I., I do want something unique. The 6mm Vias is an improved 6.5x55 from what I am reading. But harder on barrels. This is gonna be a deer and antelope rig and possibly a 'yote gun from time to time.
 
TG-5150 said:
I am really leaning on the 6mm A.I., I do want something unique. The 6mm Vias is an improved 6.5x55 from what I am reading. But harder on barrels. This is gonna be a deer and antelope rig and possibly a 'yote gun from time to time.
Click to expand...
I understand what you're talking about here. I've been kicking around building a custom,270
 
.270 is an amazing caliber that just got better in the last few years with all the hi b.c. Bullets. If you are stuck on the .270 take a look at the .270 Sherman if you haven't already.
 
Alibiiv said:
I understand what you're talking about here. I've been kicking around building a custom .270 now for a few months while considering all the variables. I have a .270 Winchester Ruger 77 and have thought about the.270AI, but then there's all the reteric about it isn't going to get you anything extra in performance, but it will be a really neat gun to have. Then I'm toying with a.270WSM, not sure if it will feed in the long action?? Then asking myself maybe a 6.5-06AI would be something worth looking at. Or the latest hot number.280AI?? I really like the felt recoil of the.270 Winchester and just might keep that caliber and put a really good 24-26 inch barrel and get the action blueprinted. How that for caliber anxiety!!?? Sounds like you've made up your mind, go for it!! This life isn't a dress rehearsal.
Click to expand...
 
You would have to have the bolt face reamed I believe, to fit the .270 WSM. I had one in a Tikka. I loved it.
The .280 A.I is really a great round and would be more conventional.
There are so many choices, it's worse than picking out a candy bar for sure
 
TG-5150 said:
6mm A.I. is faster but some say more finiky to load for
Click to expand...

After years of shooting various improved 6mm Remingtons, I can't say that I've found any version to be 'finicky'. This includes a 30 degree, 32 degree, 37 degree and 40 degree shoulders. My favorite is the 6mm Crusader which was developed by GA Precision on the 6mm Rem case. Dies are available as is the reamer. Easy to load for and easy to shoot. This is simply fireforming in the chamber with the fireforming loads being very accurate.

The other cases I find to be useful are:

6mm Creedmoor
6mm SLR
6mm-284
240 Weatherby

Don't forget about the 6mm Arch made from the 6.5x55 Swede.
 
The 6x55 Improved would be a great cartridge, but realistically it will not have much gain over the 243 Ackley. The things I look for are the availability of good components and dies. There's also a couple great sources of brass for the .243 from Lapua and Peterson. You can also pick up .243 Ackley dies through MidSouth Shooter supply and other online stores and not have to special order them.

The 6mm Remington AI is a potent cartridge, but unless you already have a good amount of brass for it, I wouldn't bother with it. It will have a longer O.A.L. with the 105gr bullets and brass availability can be hit or miss. I wouldn't worry about the difference in neck length either. If you get a chamber properly throated for the 105s you'll have plenty of neck gripping the bullet's bearing surface in the .243 AI.

I shoot a standard 243 with 70-87gr bullets for Varmints and it's very easy to load for and a fast round. I've had friends build customs with fast twists shooting 105-107s at 3100-3200fps with the standard .243 Winchester. The Ackley will add another 100-150fps on top of that. I'm more concerned with accuracy, brass life, and quality component availability than a little bit of speed gain.

There's also a lot of other great 6mm cartridges out there that are smaller like the 6x47 Lapua, 6mm Creedmoor, and 6XC. They will have performance equal or slightly better to the standard .243 but be more efficient. There's also bigger cartridges like the 6mm-06, .240 WBY, and 6mm-284 that are real hot rods. I think the good old .243 Ackley falls in the middle though and would fit what you're looking for perfectly.
 
I found a source for 6mm rem brass at $150ish for 250 ct. and dies and reamer for the A.I are very available. If I go with the .243 it will definitely be an A.I. . I am very open to opinions and more advanced knowledge for sure.
 
TG-5150 said:
I found a source for 6mm rem brass at $150ish for 250 ct. and dies and reamer for the A.I are very available. If I go with the .243 it will definitely be an A.I. . I am very open to opinions and more advanced knowledge for sure.
Click to expand...

I'm not very familiar with the old tang safety Rugers, so I'm not sure if they had a long action and short action or just a one size fits all type of action. I like to be able to use the box magazine on my hunting rifles. It makes me feel better to have a round or two on hand just in case it's needed. So for me, if I had a short action I would do the .243 Ackley and use an extended mag box if needed. If I had a long action I would either go up to 6.5 or settle for the 6mm AI if I really wanted one.

I am starting to really appreciate high quality, long lasting brass. That's why I really lean towards cartridges with Lapua, Peterson, ADG, Alpha, or Bertram brass available for them. Remington, Winchester, Federal, Hornady, and some others can be good, but often times the primer pockets just don't hold up to max or close to max loads for very long. I seem to find Remington to be some of the best though for holding up and lasting compared to the other more common manufacturers I listed. It's ultimately your decision and your rifle though. I would have to say the 6mm Ackley makes more sense than the 6x55 AI. The Swede case is really nice, but I would just worry about getting dies and a good reamer for it.

I almost forgot, my cousin has a standard 6mm Remington chambered for 105s on a Shilen barrel and it hammers with the old 105gr AMAXs with H1000. I believe he gets right at 3200fps with that bullet and prints sub 1/2 MOA groups all day with it. His brother also has a custom .240 WBY sending 105s at 3300fps. The Weatherby is a good round, but brass can be expensive for it.
 
After i found out how quick a barrel goes in the 6x55 A.I. it was a no brainer for me. How hard is it to make 6rem brass out of 7x57 ?
 
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