280AI for F-Open

[Quickoz]

Gents,

I'm considering building a 280AI for the longs in F-Open. Have a few questions:

Is it a consistent performer day in, day out?
Why don't more people use it compared to the 284 family?
What's accuracy like compared to other F-Open 7mms?

Any pretty much just tell me anything you can about it. It's not used much here in Australia. In considering it because it shouldn't have the primer pocket issues of the 284, and is won't require a hell of a lot of case prep. i.e. turning, dealing with donuts, etc. And I should be able to run same MV as 284 but with less pressure.

 

[jr600yd]

Go for it! You can't go wrong with that caliber..

 

[kev77]

If you drive it at the speeds as the 284, 2820-2850 your brass will last a long time and should get 2000+ rounds on a barrel. I run my 280AI at 2950-3000fps and get about 1200 rounds on a barrel this is my 6th barrel. Its as good as the other bigger 7s in accuracy or better if there is a good driver.I went to a 280AI because i didnt want to be a 284 sheep!!! lol

 

[mac86951]

I'll post here instead of a new thread, with a 280AI what powder/bullet combos do you like?

I'm using Win Supreme 780 and a berger 180gr for my 7mmSAUM, but 780 is getting harder to find.

 

[jbhotrod]

You may also want to check out the .280 Sherman from Mr Rich aka "elkaholic" over on longrangehunting. Sweet, sweet round. Basically a .280 Gibbs but its off of a .270 case instead of .30-06 case. You end up with the same case capacity as a Gibbs cartridge but a longer neck. Performance is right there with a 7 WSM.

 

[Rtheurer]

If you drive it at the speeds as the 284, 2820-2850 your brass will last a long time and should get 2000+ rounds on a barrel. I run my 280AI at 2950-3000fps and get about 1200 rounds on a barrel this is my 6th barrel. Its as good as the other bigger 7s in accuracy or better if there is a good driver.I went to a 280AI because i didnt want to be a 284 sheep!!! lol

I m going to guess here that your shooting a 180 class bullet? Can you tell me a little about your ammo and Barrel length?
I have a 34" 7mm 1:8.7 twist barrel Blank sitting in the courner. Just have not had the time to dedicate to get it chambered and screwed on to something. I have a 280AI in a Long Range hunting Rig so I have Dies and some components around for it. I also have a 6.5X284 Match Rifle so I am having a hard time in choosing which way to go. 284 or 280AI.
Thanks for any help.
RussT

 

[kev77]

I use nosler 280ai brass 180 berger hybirds, 59.5-60.5gr of h-4831sc, cci br2 to get 2950-3000 fps on a 31'' barrel. I also shot lots of 180 jlk bullets but I lost 50 fps with the same load as the hybirds. Also the 180 hybird has a better real world bc than a jlk. I personaly like the 280AI and I think its easy to tune. I do believe most people lean towards the straight 284 because of the lapua brass.I bought 1000 pices of nosler brass and still have lots left 300pcs its good brass and i do aneal firafter 3-4 fireings. I get 10+realoads on this brass. Leave your barrel as long as you can. 1-9 twist is fine and is what I prefer as if am now running 2, 1-8 twist barrels and I find they are 50fps slower and no better accuracy than the 1-9s. Hope this helps a little

 

[Rtheurer]

Thanks Kev.

 

[wwbrown]

Going to shoot a 280 AI in F-Open this summer so I hope it works. I went with the original 280AI and will be using Lapua 30-06 brass for fireforming, I always like to start with Lapua brass for any competition, I know others do well with other flavors I just stick with Lapua.

 

[Rtheurer]

Kev77

Have you ever shot or tried Retumbo or H1000 in your 280AI. How about N160?

RussT

 

[Rtheurer]

Kev

Also if you get a chance can you measure the internal Capcity of your fired cases in H2O and whats your OAL with the hybrids. ( Just trying to run some Quick Load Models)

RussT

 

[kev77]

Will get back to you asap

 

[kev77]

Sorry I,m away from home. Yes i tried H-1000 could not get to 2950fps pressure out at 2850or so.Can't remeber about about retumbo will check notes when I get home.N-160 I think it will work well will try later on this year with the 180s. Also will check out N-165 but i dont think i can get enough in the case 62-64 grains. I will measure case capacity when get home in a week or so.

 

[Heman]

I run a straight 280 Rem and 61.5gr of H1000 with a 175gr SMK gets me to 2880fps safely pressure wise.

 

[lawrence97]

I competed last season with a straight 284 (.313 neck) and I ran it at 2870fps and 2890fps with 180 hybrids and accuracy was excellent with just under 51gns of H4350 and same velocities with 55-56gns of H4831sc. It is no slouch and very accurate.

I have just started testing a 280AI (.313). I just grabbed Nosler 280ai brass out of box, weight sorted, did a quick powder charge test followed by a quick seating depth test using 180 hybrids and h4831sc. I decided to run it at 2990fps. Just had a Palma course of fire match yesterday and it performed well given the quick development I did to get it ready for the match. I am sure with more time I can ring some more out of it but it definitely impressed! Prior to the match I had only shot at 100-200 yards so I just plugged into a ballistic calculator and went to the match. It shot a 148@800, 150@900 and 142@1000 with 22X's 13X's were at 900 yards…. I shot out the small spotter and my puller only had a spare large spotter which also suffered.

As to which is better, it depends on if you want more recoil and 100fps more velocity with less barrel life. The 284 is very accurate, I do spend more time prepping new brass and it uses less powder. The 280AI hits the shoulder a little more, uses more powder and will most likely burn the barrel quicker, uses brass right out of box and is more expensive.

Primer pockets in my 280AI go bad instantly at 3040fps, Maybe 2 firings at 3020fps and hopefully a few firings keeping it at 2990fps.

 

[expiper]

Larry,,,,that is good shootin on that 900yd spotter,,,,that is ~2.5" grouping,,,,,keep us posted,,,Roger

 

[lawrence97]

I really wish the other spotter could have been saved! I was stoked when I saw X after X at 900 for 13 shots in a row!

Now I just need to see how the throat wears and how it does in different temps….

 

[Rtheurer]

Oh Man... I didnt want to hear that about the Primer pockets openeing up after three firings..... Drats. What Powder was that load agian?

Looks like it will shoot plenty well though.

RussT

 

[lawrence97]

I just lost about 3-5 pieces of brass! my load was 60gns of H831SC and it was on the edge in 62-70 Deg weather but when I tested in 83 Deg weather it reached its limits. The barrel also picked up some extra speed that I was not expecting until the 300 rd mark like my 284 did. This barrel picked up speed at around 90rds so i had to drop my load from 60.5 down to 59.5 to stay ay 2990 fps. The barrel with less than 90rds averaged around 2990-3010 fps with 60.5gns and once the round count went up it suddenly shot around 3030-3040fps

I think if I keep it around 2990fps the brass should have a good life! You could run it at 284 speeds and get good brass life but to me it does not make sense to burn more powder than my 284 for the same performance. My 284 brass running from 2870-2900fps during its life is at 5 reloads and still doing good.

 

[Rtheurer]

Intresting. Thanks for sharing. My Plan was to run a slower powder than the H4831SC even though I have burned what seems like a half a truck full of it in the past with the 6.5X284.
Looking at some pressure curves via Quick Load and later on actual Pressure testing equipment im hoping to find somthing that isnt so hard on Brass but still performs well.

OK last question. Are you Jambing your bullets or Jumping them?

Again thanks for sharing.. Appreciate all your help in these silly questions.

RussT