Thread: Forbes 280AI Load Development

Originally Posted by GWH

59gr of 2213sc for 2900 from 24" 280AI, near max so work up

Well over adi book max?

This isn't a 162 load but I finally sorted a load yesterday for mine with 150LRABs which are pretty slippery for their weight.

Despite what the ADI and Nosler load data suggest, I could get good vels and good accuracy with 2209. Although well above book max, vel is 3130 average (27" bbl) with no base expansion measurable at 1/2gr above what I settled on so that'll do me. No point wringing its neck any further.

I would suggest that if intending to load the 162gr for 60kPSI peak or over - as seems to be the practice in the endless quest to equal 7mmRM performance - then 2213sc may be the limit for burn rate as the case is not large enough for the slower ADI powders to generate this figure. N560 has also produced top velocities for me, followed by Re-22, but I wouldn't be dogmatic with any claim about best accuracy and in the 280AI prefer the ADI single-base powders in this regard along with the added benefit of better temperature stability.

Originally Posted by Puffin

I would suggest that if intending to load the 162gr for 60kPSI peak or over - as seems to be the practice in the endless quest to equal 7mmRM performance - then 2213sc may be the limit for burn rate as the case is not large enough for the slower ADI powders to generate this figure. N560 has also produced top velocities for me, followed by Re-22, but I wouldn't be dogmatic with any claim about best accuracy and in the 280AI prefer the ADI single-base powders in this regard along with the added benefit of better temperature stability.

Useful comment Puffin. I currnetly jam about as much 2217 in my 7x64 as will fit, but still a pretty moderate load. About to start playing with some bulk 4831 I acquired, to look for a little more speed.

I do wonder though, if people want 7mmRM performance it's probably safer to just start with one. I don't understand the fascination in trying to make cartridges something they're not. I wouldn't want to stand in front of my "slow" load (and it shoots better than I do)!

That's true, a .280AI will never truly reach 7RM performance even if you wring its neck.

Equally, no point buying a 300 WSM and loading it like a weak .308 as does one guy I know. "It boots too much if you don't back it off.."

Further to the previous post and some more info specifically for @Feebz' Forbes in case he is interested, putting his results into QuickLoad along with the other powders being mentioned. This identifies that the slower powders do produce more velocity at a fixed moderate peak pressure which may be what the book data was indicating. Predicted for 50kPSI peak:

2225, 66.5gr, 2850 ft/sec, 10% compressed (if achievable)
2217, 61gr, 2800 ft/sec, 2% compressed
2213sc, 58gr, 2725 ft/sec, 95% fill

If loading for 60kPSI peak then the following is predicted, the double-based N560 also included:

2217, 64gr, 2950 ft/sec, 7% compressed (if achievable)
2213sc, 61.5gr 2900 ft/sec, 1% compressed
N560, 62.5gr 2980 ft/sec 1% compressed

So if wanting to try for more velocity than the 61gr of 2217, then 2213sc, N560, or similar burn rate powders are recommended, bearing in mind that the above figures are from a simulation and come with no guarantees. If preferring to stay with 2217 and happy to work with heavily compressed loads and accuracy remains, then the prediction is that there is still quite a bit of room to move.

Thanks guys. I appreciate it all, even though I don't understand it all. Though the last paragraph seems to sum it all up & gives me something to move forward with. Thanks Quickload owners (esp @Puffin ) for sharing the paid-for info.

Definitely not trying for 7RM performance, just trying for higher 280AI performance.

I've used RL22 & 162 AMAX with really great results in my 280AI 24 in Truflite UM barrel. Up to 2950 fps before hitting pressure signs. But the accuracy sweet point (0.3 moa) was back at a more modest 2850 fps - still plenty for 800 yds which is what I built it for. Beyond that you really need to go to a magnum.

Hi Feebz,

Good post mate, and some really good info to read. Have a 280 AI as well. Was a Tikka 708 so barrel is 22". From memory running 55.5gr of 2209 on 150gr LRAB. This was 1gn over book max. Gives about 2835fps. Has claimed one victim at about 325yds and was good clean boom flop! Have some heavier projectiles and 2213sc loaded up to have a go with. Once have had time to do this will report back.

Cheers,

Hi All,

Just an add/ressurection of this post by Feebz. Finally got some 168gr LRAB's down range. 58.7gr 2213sc and gave 2750fps for sub moa.(note 1gn over book max).This on 22" barrel, 1:9.5 twist. Will do some verification in the next while.

Cheers

N560 in this Forbes with 162gn ELDMs:

59.0gn=2787fps
60.0gn=2955fps
61.0gn=3019fps
61.5gn=3051fps
62.0gn=3061fps
62.5gn=3099fps (hard extraction)

Cluster is 61.5, 62, 62.5 top to bottom. Water capacity is 75.3gn, OAL 3.333". Calibrating with QL I the last 2 twp are definitely over pressure. 61gn didn't group spectacularly (1") so will try 60.5gn and 61.5gn. Also 60.5gn in 168gnVLDs.

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Impressive velocities. Nice to see it's in good hands.

Originally Posted by Feebz

Impressive velocities. Nice to see it's in good hands.

N560 does well... not sure how temp stable it is...which is where ADI powders are good. Just carried this thread on to build on your good posts.

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Group is around 0.25MOA. Very cold morning. Easy bolt lift and sticky extraction...even with milder loads. Brass might be past use by?

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Haven't played with mine for awhile, settled on R22 with 150grn swift's around the 3100fps.