270 Ackley

[davkrat]

I am considering having my Rem 700 .270 WIn rebarreled wth a 24" barrel and am considering a 270 Ackley. How much of an increase can I expect from the standard to the improved version? Looking in the Nosler manual the difference between the 280 Rem and 280 Imp. are no that great. Does the larger case capacity allow lightly slower powders? What is the big attraction of the AI? I think they look cool which helps, besided different is usually better right /ubbthreads/images/graemlins/smirk.gif If I went the 270 AI route would the larger case allow me to use a slower powder that might better alunch the 169.5 ULD's?
Thanks

 

[royinidaho]

I launched some 169.5s in my 270 Win w/10" twist. I got good velocity but no accuracy. Rather than waste the rest I sent them to Budlight (on this forum) who has a 270AI. I don't really know how they turned out for him. Do a search on Butlight and PM him.....

However since I've discovered US 869 I'm thinking I'll try them again in the Win.

My test was done in a 27" Lija bbl. Velocity was really good, if I remember correctly exceeding 150gr published velocities.

I think twist will be more important than velocity.

 

[davkrat]

Thanks,
So the main benefit is that you can fit more of a slower powder in to launch bigger bullets. I would assume that 1:8" would be better than 1:10" for the longer bullets. Right now my rifle shoots 130 BTips very well with 58Gr of H4831, the Nosler manual shows this around 90% case capacity. In an Ackley case would I be able to increase this amount a few grains and maybe get an increase in velocity or would the real gain be that I would have enough room for something in the H1000 or H870 range?

 

[royinidaho]

58.6 RL-22 gets me 3200 w/140 Hor SPBTs and 3300 W/Nosler Ballistic tips. Both are very accurate.

4831 didn't do squat in mine. Good accuracy and maybe 2900 MV. Powder grains are too large. 60 grains of 4831 was well into the neck.

I think I charged the 169s w/7828. I doubt that success can be attained w/a 10" twist. The AMs have a 7" twist I think and are said to get good accuracy from 2900 to 3400 FPS MV with the 169s. The Win will push the 169 within that range.

Long story short. I gave the 270Win to my son and had Kirby craft a 270 AM on a REM 721 action that was my Dad's.

The 140 @ 3200 is sufficient for mulies out to 800 or so (see 7mmRHB thread) So if practical at the time, my son will take the short shots, I'll take the longer ones. We spot for each other....

 

[JD338]

I think the advantage of going to an AI will depend on the rifle, the action and the barrel.
I have a 700 blueprinted action with a Hart 24" #5 flutted barrel in 280AI.With the 160 gr AB,
I am averaging 3029 fps and with the 140 gr AB, average MV is 3225 fps.
I shot this group this afternoon.
[image]

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JD338

 

[davkrat]

JD338,
How much does your rifle weigh with the 24" #5 fluted barrel? That is exactly what I was planning on having put on my 700. Those numbers you are getting are pretty impressive. Do you have a picture of the rifle. I would deffinately be happy with three shots inside a dime!