Thanks for the info! I'm looking more for accuracy than speed. I shot 58 rounds through it today breaking the barrel/ fire forming brass.
260 Remington AI Build
- Thread starter Rhino55
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codyadams
Well-Known Member
In my .260 AI (40°) H4831sc and the 140 vld was stupid accurate at 2930 fps with 47.9 grains, and with rl 26 I got the 147's to 3100, though I have a 30" barrel. I shoot them at 3040 normally, but one could drop it down, there was another very good node around 2950. Also, mine are HBN coated. I'm using 51 grains of rl26 with a 6" drop tube. Without HBN, I was at 49.7 grains. With yours, I would start at 44 or so and work up. With H4831sc, I would do as another stated, start around a mid book load for a .260 and work up.
J E Custom
Well-Known Member
We have some smart guys on this site !! I am a big fan of PO Ackley And I have most of his books but didn't know that there was only a 40o Ackley in 260 Remington. When he started testing different shoulder angles, he started trying 28o shoulder angles. Then he went to 30o shoulders. next he tried 32o angled shoulders. Then he followed up with 35o shoulders. still trying to find the optimum shoulder angels he went to 40o degrees. he found that 40 degrees was optimum even though he tried up to 50o.
I found that up to 30 cal he had tried 3 or 4 different 28o degree shouldered cases,about 6 different cartridges with 30o degrees, one or two with 35o degrees and 35 to 40 with 40o shoulders that you can still find dies for (He was a busy man) the only 260 Remington he tested was 40o degrees. all others would be called Improved.
There are many other wildcatters that have included these shoulder angles in their design and these are considered "Improved" but don't wear the Ackley name. The 30 and 35o degree shoulders have been very popular in some shooting circles and are widely used by others wanting to get optimum capacity with good feeding consistency. I have never found the Ackley's to be lacking in performance.
There is very little difference that I have found between the 30o and the 40o shoulder except a little better case life.
For those that are interested in a little Ackley history.
J E CUSTOM
I found that up to 30 cal he had tried 3 or 4 different 28o degree shouldered cases,about 6 different cartridges with 30o degrees, one or two with 35o degrees and 35 to 40 with 40o shoulders that you can still find dies for (He was a busy man) the only 260 Remington he tested was 40o degrees. all others would be called Improved.
There are many other wildcatters that have included these shoulder angles in their design and these are considered "Improved" but don't wear the Ackley name. The 30 and 35o degree shoulders have been very popular in some shooting circles and are widely used by others wanting to get optimum capacity with good feeding consistency. I have never found the Ackley's to be lacking in performance.
There is very little difference that I have found between the 30o and the 40o shoulder except a little better case life.
For those that are interested in a little Ackley history.
J E CUSTOM
LongBomber
Well-Known Member
It was what I would call a fluke, but you shoot enough groups and you have to get lucky. The rifle is consistently better than half moa, which for an 8 pound gun is not too shabby
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MudRunner2005
Well-Known Member
I see this posted up continuously, but yet I've never had any issues with any of my 40º Ackleys in 6+ years since building my first AI.
cjl2010
Well-Known Member
I have found a noticeable difference on ease of feeding from 30° to 40°.
J E Custom
Well-Known Member
I think you have a winner !
Any time I can get groups below .100 I consider it a success.
Good shooting
J E CUSTOM
J E Custom
Well-Known Member
I have found that If I install a center feed mag/box they all feed the same. So on 40o shouldered cartridges I always try to use a center feed.
J E CUSTOM
codyadams
Well-Known Member
Never once had an issue with my 40° .260 AI. Then again, it's a center feed AICS mag. Then again, so are most rigs set up for PRS. So I still wonder why people talk about running a 30° vs 40° for PRS guns. Never seen it have any issues in my first hand experience.
cjl2010
Well-Known Member
I use a center feed dbm mag. When fire forming 6.5ss rounds I could run the bolt significantly slower with the 30° shoulder vs the 40°. Not saying it feeds poorly but there is definitely a difference.
BallisticsGuy
Well-Known Member
Running 40deg shoulder .243AI from steel AI mags in a LSS chassis with a savage 10 action and comparing to the new barrel in 6XC which has a less steeply shouldered case, the feeding was definitely rougher with the .243AI than the 6XC. AI case took way more effort on the bolt and was subject to all kinds of hangups from running the bolt too quick or too slow. The 6XC is generally insensitive to bolt speed and never hangs up.
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