Home Forums Hunting & Shooting Custom Rifles & Wildcats about to wring out a new .280 AI

I've had this sitting in the closet for the last year and a half. It's a standard 700, with a 22" Mclennan 1-9" rem mountain rifle contour sitting in a mcmillan mountian rifle stock. 2.5-8 sitting in talley. Old .280 AI chamber. This is the year it's going to get it's chance. I have 120 ttsx, and 140 tsx- both molied. N165, h4350, R17, R22, H4831SC are all on the shelf. I have both virgin hulls, and some hulls formed in another rifle, but a good in the chamber.

My problem is where do I start? All of the above will work, but time is very limited with family demands, so I'm trying to figure out how best to cut to the chase.

I'm thinking N165 is my best chance for the best load with the least amount of trouble. I think 63-ish is a pretty standard charge in formed cases, but what about fire forming?

I would start with the 140 tsx and an appropriate dose of RL22.

I am using IMR 7828ssc only because I cannot find any RL22 to purchase.

Many people like to seat the bullets touching the lands and then use a light load of something like IMR 4895. Me, I simply load a standard case with what would be a max load for the standard 280. NOTE: This only works if you have a proper AI chamber which will be .004" shorter than a std chamber. This ensures a nice little crush fit on the unimproved shoulder thus emliminating any case stretch. I have found accuracy to be generally very good with this method and use it all all my AI chamberings.

If you are uncertain about your chamber, seating to the lands with a light load would probably be the better idea to avoid excess case stretch.

My last one had a 9-twist 24" Gaillard MR contour barrel.

It liked H4350 with the 120s for 3370 fps. No moly.

With the 140 TTSX it was VERY accurate with H4831 at 3150 fps. About 63 grains depending on lot. RL22 gave 3200 fps but wasn't quite as accurate.

Fireforming. You know this, but forget the reduced loads ala Nosler manual. Load up some snappy standard loads.

Yeah, that I know Rick- reduced loads are a waste of time, which I don't have!

I really don't think I can go wrong with 4350, 4831, or n165.

I've had a couple and used 140's with R22. I think I have load data from the 140TSX.

H4350 worked for me with both 120's and 140's

I would form cases with a bulletless method and then work up loads if you have some suitable fast powder. Load work up only once this way.

Or if your content to hunt with fire forming loads until you have enough cases. Load workup twice, once for forming and then once for final AI load.

With the powders you mentioned it would be hard to find a bad load.

I would just run the 120's to around 3300-3350 and stop and same for the 140's 3200-3250. Then pick whichever powder gave the best groups. But I'm not too picky if any load gives me several groups under an inch I usually stop and save the rest of the ammo for hunting.

Mine like Ramshot Hunter powder,139gr Hornady Spire points,Nosler 280AI brass

RL22 and 140 TTSX's...a good thing

RL17

140 NAB and VV N165. Scary accurate. MV 3206. Forever case life. Whats not to love?

I know a guy who might be able to get you some RL-22!!

Wanting to run 150 TTSXs. Have Fed 210s, IMR 4350, 4831, and RL22.

Anyone have better success with any of those powders? With a 24" Broughton #3

I am planning on running the 145 LRX in mine with VV N165 hoping to get 3100 fps out of it..280ackleyrized how much N165 are you running with the 140 AB ?

63.3. But as is the usual....back off and work up

I'm guessing N165 will top out around 63 in formed cases- but I can't seem to find N165 data for standard .280. How much N165 for fireforming?

I would try carefully working up to about 55grains for a 160gr. and about 58gr. for a 140. This is from VV data for the 7x64 which is within about half a grain in capacity to the .280 depending on brass weight. These are lower than a 5% reduction from the full power AI loads that I have seen recommended by Ackeley and others.

If these aren't hunting loads then just work up to the point where you get a defined shoulder instead of a pseudo venturied one and stop. Check the 7x64 starting loads from the VV manual.

But I usually use junk powder and paper or cream of wheat so haven't done this. Saving the expensive stuff for full power loads.

Of the powders you have available I have had the best results with H4350 with 140 gr bullets. RL 22 also has worked well especially with 160 gr bullets. Best results with H4350 using magnum primers. My favorite load is 59 gr of H 4350 with Fed 215 primers with any good 140 gr bullet. As always, start lower and work your way up and watch for excessive pressure signs. You are gonna love the 280 AI

I just uncovered 100 formed cases I had forgotten about. Now I can at least skip the forming stage.

140 grain Accubonds and 63 grains of RL 22. Awesome results.