I looked back through all the various 280 AI threads and wanted a more specific/concise load discussion. I've decided my 280 AI shoots ok with Re26 and Accubonds but not exactly what I'm looking for (1.5" at 100 yds for 5 shots). I'm exploring other loads with 160 Partitions. I have a whole range of powders in the 'slower' range but instead of shooting $2-300 in bullets thought I'd start here.

What specific loads are you guys running with 280 AI and 160 Partitions?

Thanks.

Cross-check 'cause this is from memory, but I believe I was shooting about 61 grains of IMR 7828 with the 160s. I was working with Nosler brass and Nosler data, not Hodgdon's data.

bwinters, after trying several powders with the 160gr. Nosler Partition, which is my favorite bullet, I have settled on IMR7828. My load is 60.5 of it which give me about 2940fps or so out of a 24" Krieger barrel. Accuracy is very good. I happen to have a three inch 100yd group that is essentially one hole. However, typical five shoot groups at a 100yds for me on windless days will be one inch +or -. Way better than is needed for any reasonable range.

Thanks for the loads. I used to shoot alot of IMR 7828 and Re22 in various 7mms. One or the other always shot well. Then I started chronographing them on cold days. Re 22 was the worst, lost ~ 100 ft/sec and groups opened up. I 7828 wasn't as bad. I'll try it again.

I also used 7828 in one 280AI with the Speer 160 Hotcor ( another even "cheaper" to shoot but great bullet!) I could not get good accuracy over about 2800fps in the rechambered Mod 700 Mtn Rifle, but it was an elk killer deluxe for my friend I loaded it for!

I've had such good luck with RL26 in my 7 SAUM, it'd be hard for me to not try it with the Partitions. IMR7828SSC was close in velocity and accuracy, but RL26 won out.

Good luck in your load development.

Did you mean 3/8 or 3/4, maybe?

Put me in the 7828 camp also. Fed Gold medal magnum match primer, Nosler brass, 160 Partition. Ill have to confirm the charge,but I'm thinking it was 60 grains. It has printed a couple 3 in 1 hole groups from a 24" Pac Nor barreled Remington.

You guys using IMR 7828 - ever shoot loads in cold weather? Velocity loss or major group changes?

I guess the real question for me is,do I ever shoot them in warm weather? I do very little load development in the heat of the summer. But more to the point. I've not noticed any changes in my groups within the temperature ranges I shoot in.

Reloader, thanks. I should edit my stuff more carefully. Should read a THREE SHOT group.

7828 has always been a very reliable powder for me. I do all my load work in the dead heat of the Texas summers. It always maintains its properties thru the most extreme temp. differences.

I shot Re 23 and IMR 7977 this AM with 160 Partitions. Temp was 28-30. 3-shot groups were good. I'll post more later but think I'm done............

Please do.

Glad it worked out for you.

Test results from yesterday.

Hornady brass, Fed 210 primers, seated 0.020 off

This is RE 23. I ran it from 57.0 to 59.0.

Velocities/Gross group size were:

57.0 - 2869 / 2.0
58.0 - 2933 / 0.97
59.0 - 2970 / 1.66




This is IMR 7977. I ran it from 61.5 to 63.5
Velocities / Gross group size were:
61.5 - 2794 avg / 1.20
62.5 - 2885 / 1.23
63.5 - 2958 / 1.08



I really like the IMR 7977 groups - 3 different charge weights but group size remained consistent. I'll play with 7977 a bit more.

I'm also going to try H1000 and re-run Re 26.

Anyone used H1000 under a 160? What was your charge weights? On the Hodgdon website, they list 61.0 for the 280 AI and 67.0 for the 7 SAUM. When I had my 7 SAUM, it ran at 2975 with 67.0 grains of H1000. My 280 AI cases hold 75 grains water, my 7 SAUM held 74. It would seem the 280 would hold more H1000 than the 61.0 listed by Hodgdon.

Thanks.

Don't use the Hodgdon data for .280AI. It was not developed to the the full SAAMI .280AI pressure standard, it was apparently developed prior to standardization and to a lower pressure limit. Go with Nosler's data on this one.

I'm with you - but Nosler doesn't use many Hodgdon powders. They have no H1000 data for the 280 AI.

I think H 1000 is too slow fir the little 280AI case.

I tried it with 150gn Ballistic Tips and even 65gn which is a heavy powder charge only generated 2730fps which is 300fps slower than my best loads using Rel 22 or Rel 17.
With the 154gn Hornady SP I tried to 63gn for only 2673fps which again, is 300fps too slow for that bullet weight.
160gn Accubonds and 62gn generated only 2593fps so it is clearly better suited to magnum volume case capacity.
John

That's curious, H-1000 is excellent with 140s in the same case but .264 caliber.

All the medium slow powders will work. I have had good results form R26, MRP, R22, VV165, H4831 with R26 being the velocity champ. Have not tried Ramshot Magnum or Hunter. Magnum should be good. All of them are you don't know until you have tried as all rifles will vary.

H-1000 works great in my 270 win with 140 TSX’s.