280 AI w/ 160 gr AB

[JD338]

Guys,

I got my M700 in 280 AI back from the gunsmith. I had the action blueprinted and installed a Hart 24" #5 Flutted barrel 1-9 twist and Tubb recoil lug. For now I am using a Leupold VXIII 2.5x8 but will change to a VXIII 4.5x14.
Started load development with the 160 gr AccuBond and RL22. After 75 rounds, (50 fire forming) I have the following results:

60.0 grs RL22
GM210M
R-P Case
COL 3.495", .015" off the lands
3 shot groups of .295", 218"
moving up to 61.0 grs.

58.o grs RL22
GM215M
R-P Case
COL 3.495"
3 shot group of .575" ( first 2 shots were .161")


59.0 grs RL22
GM215M
R-P Case
COL 3.495"
3 shot group of .510" (first and third shots measure .153")

moving up to 60.0 grs and 61.0 grs.

So far, I am happy with the way this rifle is shooting. I may be pushing the limits of the 8x scope. My goal is to hit 3000 fps with the 160 gr AB. This should prove to be a decent long range deer, antelope, and caribou load that will buck the wind.

I will keep you posted with results if anyone is interested.

Regards,

JD338

 

[fredj338]

You might want to give IMR7828 a try. It is THE powder for my .280 w/ 150-175gr bullets. 57.5gr under a 160grNP or NAB gives me 2850fps from my 23: ultr lt. PacNor bbl. I have shot severl groups out @ 300yds that went under 2" for three shots.

 

[yeayow]

for what its worth quickload says 61 grs. will put you at 2940 fps at a little over 58000 psi

 

[JD338]

Guys,

Here is a update on my load development for the 280 AI w/ 160 gr AB bullets. COL is 3.495", .015" off the lands. R-P cases and Federal GM215M primers. Still no signs of high pressure.

61.5 grs RL22 resulted in a 3 shot group of .225" @ 100 yds.

62.5 grs RL22 gave me .218" for a 3 shot group.

I am going to duplicate these loads and retest.

Regards,

JD338

 

[rick smith]

60.0gr of IMR-7828 with a 160 in my 280AI gives almost 3000fps and a tight little cluster at 100 yards. Work up to this load.Rick.

 

[JD338]

Rick,

Thanks for the info.

Regards,

JD338

 

[Guest]

JD338,

From the looks of your post I'd say your off ot a great start on finding a load that works. Part of that I'm sure has to do with the quality of the work done by your gunsmith.

I haven't had quite as much success with my 280 Improved yet with but am getting loads to group between .75 & 1.125. I'm finding the groups are starting to tighten as I get towards the upper end of charge weights. But still not at the level of accuracy I had expected. I won't be happy until I get down to .625 or below.

I'm currenty at 62.5 gr. RL-22 with a 140 NBT and 61.5 with the 150 NBT. Still no signs of high pressure so I'm going up another grain next time at the range. My rifle has a long throat so I can't seat bullets out near the lands without exceding the magazine length. That may be part of my problem.

If anyone else has expeience with the 280 Improved and would care to share some load information, it would be greatly appreciated.

Harold

 

[JD338]

Harold,

Are you using Magnum primers? My gunsmith suggested this for better accuracy and he was right. A primer ppocket uniformer may also help.
I just bought one but have not had time to get back out to the range to retest the loads that I last posted. (Work, family oblagations, and weather have all been factors for not shooting).
You might also want to try the 160 gr AB. This bullet is extreamly accurate and will give great on game performance for deer to elk size game.
RL22 is a great powder for the 280 AI. You might also want to try RL19 for the 140 gr bullets.
Don't give up, I am sure that you you will find the right load for your rifle.

Tell me more about your rifle. What action, barrel make and size, ect.
Who did the work for you?

Regards,

JD338

 

[Guest]

JD338,

My 280 Ackley is a model 70 Win with a 24" Douglas Premium #3 barrel in a gray parkerized finish and fitted with an HS Precision stock. The original barrel work was completed by Pasadena Gun Center when I lived in Texas. I've since moved to Utah and have had some trigger work done by Ray Montgomery in Gunnison CO.

I have about 125 rounds through it fireforming and an additional 75 rounds working up loads. As previously mentioned, the groups are starting to tighten up as my loads near maximum charge weights at least according to the Nosler manual. I'm not sure where max is yet as I've seen no signs of high pressure so far.

I'm placing my trust in the Nosler manual as its the only printed source of load information I've found on the 280 improved. There are lots of suggested loads to be found on the internet but I'm a little leary in trying them since some of them seem to be pushing the pressure limits.

So far I've only used stardard large rifle primers. I've never had anyone tell me that magnum primers should be used for better accuracy, so I'll have to try them. I suppose I need to back off the charges a little when switching primers.

Who is your gun smith? Maybe I could give him a call and pick his brain a little about load development.

Thanks,

Harold

 

[JD338]

Harold,

I will send you a PM with the details.

Regards,

JD338