280AI Load Development

[Creedmore]

I received my barreled action from McGowen last month, and put her together.

Stainless 26" #4 contour, fluted 1:9 twist
Holland's recoil lug
B&C M40 stock

I did my fire-forming and barrel break-in, and some abbreviated load development with 140 Accubonds and RL-22 powder. Started at 62 grains and worked up to 64. 63.3gr is my ceiling for pressure - and these clocked 3415fps on my Oehler 35. The group size really opened up, too. Anything above 63.3 and my primer pockets started getting loose.

the load I settled on with the best group was:
140gr AccuBond
62.0gr RL-22
Federal Large Match primer
Seating depth 3.340" - I measured the lands at 3.350"
This produced 1" groups at 3330fps

Managed to take 3 deer before Thanksgiving with this load.

I know the group size will shrink after more shooting. So, it's time to work on some load development over the next few months while we still have some cold weather. For the 280AI gurus on here, what would you recommend?

I think I will play with seating depth first on the load above and see if I can't find the magic depth that it really likes. Then, I'm thinking that I might go back and start over, maybe 60 or 61gr and do the work-up again at this seating depth. Also with H4831 to have a comparison load. I'm getting good velocity with a 140, don't really have plans to shoot anything larger than a whitetail, but I'm considering going up to a 160 AccuBond just to see what I get.

Thanks for any suggestons.

 

[sask boy]

It sounds like u have the start of a great combo there.
I do not have a load but was wondering what was the twist?
Is it a 9 or 9.5 if so it should have no trouble with the 160 or the new long distance coming out 168.

Blessings,
Dan

 

[Creedmore]

I'm certainly interested in the new 150 AB-LRs, can't wait to try them.

The barrel is 1:9 twist.

Thanks,
-Gene

 

[JD338]

Gene,

You are well on your way. You may want to give the GM215M magnum primers a try. My gunsmith suggested I go this way and the groups shrunk!

JD338

 

[Creedmore]

Gene,

You are well on your way. You may want to give the GM215M magnum primers a try. My gunsmith suggested I go this way and the groups shrunk!

JD338

Thanks for the feedback on the primers. Considering my pressure max is 63.3gr, and best group so far is at 62gr how far would you reduce the powder charge to start a workup with 215Ms?

Also, I plan to test H4831SC - start low and use 215Ms as well?

 

[tim629]

dragging up an old post but my 280ai should maybe hopefully be here end of the week.

Creedmore- did you ever try out the 160 accubonds? or the H4831?


i have the nosler manual here but figure any extra advice is always welcome

 

[vodekzz]

H4831 was good with 140 Ab, Rl-22 works with 160AB.
Vodekz

 

[FOTIS]

Nice combo. So far i am loving the LRAB's

 

[nvbroncrider]

7828SSC and 160's rock!

 

[Creedmore]

dragging up an old post but my 280ai should maybe hopefully be here end of the week.

Creedmore- did you ever try out the 160 accubonds? or the H4831?


i have the nosler manual here but figure any extra advice is always welcome

Tim,

I pulled parts of a post I made from earlier in the year with data, pics, etc. My rifle really likes the 140AB and the 168 Custom Competitions with H4831. The results were so good that I stopped working with RL22.

Haven't tried the 160AB or 168ABLR yet.

I ran a 500yd ladder test with H4831 and 140AB this spring, and the node that it liked centered on 61.6gr, which was 0.4 grains under book max. I went 1.5 grains over max without pressure during the test, but 61.6 was the sweet spot for accuracy. This is my last 200yd target, sure would like to have that flyer out of the group lol.



Nosler .280 brass
140gr AccuBond
GM215M large magnum match primer
61.6gr H4831
26" 1:9 McGowen barrel
3200fps over my Oehler 35.

Also, I found that my particular chamber likes a 0.015 jump to the lands with the 140 AccuBond.

-Gene

 

[tim629]

maybe this should be a new thread so all of us new reloaders catch it:

but how do you decide when to use a regular large rifle primer vs a large magnum primer?

 

[DrMike]

The rule of thumb is to use the coolest (least brisance) primer that will ensure complete ignition. For cartridges holding over sixty grains of powder, generally that will mean use of a magnum primer. The exception to this would be short magnum cartridges, for which a large rifle primer is sufficient due to the shorter powder column. Another exception is ball powders, which generally ignite better with magnum primers. A final caveat to the general rules is to use magnum primers if firing in cold temperatures. Cold is relative, but I generally would not apply this exception until temperatures reach -15 C (5 F).

 

[jmad_81]

I have had great luck with RL-17 with the 140 BT (3220 and .3 MOA all day long), and some great potential shown with the 150 ABLR and RL-17. I would have played with it more but I ran out of RL-17.

Other than that you really don't need anything other than RL-22 or 7828. 7828 just nudges out RL-22 in my gun as far as accuracy goes. It usually runs the same speed or a little better, but both powders are easily shoot .5 MOA or better.

I'm currently shooting the 150 ABLR with 61 gr 7828 and getting right at 3,000 fps and .5 MOA groups. I have room to go up, but I ran out of load development time.

I'm running a 24" Pac Nor three groove.