Home Forums Hunting & Shooting Custom Rifles & Wildcats Anybody with experience using H4350 in .280 Ackley?

Or .280 RCBS? Reason that I ask is according to Hodgdons website the date seems to not add up to me. Max load is not a lot bigger than the regular .280, just the pressure is way higher. Also it does not fit with max loads that I have found browsing the internet. Any help appreciated. I can use there data and chrono it, but was wondering it they are just playing safe. miles

What are you expecting the .280 AI to do? By using the AI you aren't increasing case capacity a whole lot,but adding more powder will increase pressure. If you're not getting the speed you want, my best advice is change powders. I'd also use Nosler data since the .280 AI is their baby, I realize though their online data doesn't list H4350.

What I am referring to is the fact the Hodgdon's site has the max load a lot smaller that other places that have loads published, with comparable speed. Their .280 Ackley loads are about like other places regular .280 loads, but the pressure is about maxed out, and their speed did not increase as much as what I would expect with the increase in pressure. I am wondering why their data is so much different than other places that I can find data, and wanted to find out what people here that actually use these loads think. miles

I have used a load of 59 gr of H4350 with a 140 gr Sierra PH in my 280 AI for years. I get 3120 FPS with great accuracy. This load works in my rifle with no pressure signs but you should work up accordingly since all rifles are different. You may get better velocity with different powders but I have never loaded my 280 AI for max. velocity. I would rather have an accurate load and not push the envelope with velocity.

This is what I am seeing everywhere that I find data that the max is close to 60.0 with 140 gr. bullets in the .280 Ackley, but Hodgdon has the max at 55.5 with the pressure over 60,600 PSI. 4.5 grains seems to be a lot of discrepancy for the max to me. Another thing is that their speed with the 55.5 matches most peoples speed using 60.0. I have some H4350 but have loaded none yet in the .280 RCBS which is very similar to the Ackley, but am trying to figure out where to start and stop. miles

As Ackleyman said all rifles are different, and I'd believe that's what Hodgdon's test equipment told them. A lot of things can change pressure with a rifle, and how a chamber is cut can be one of them. Hodgdon has had .280 AI data out long before Nosler standardized it. If they used a different reamer than the SAAMI reamer, they could very well have different data than other sources.

Like a said though if you aren't getting the results you want, change powders. Since mt experience with AI cartridges is limited, I feel they mask a lot of pressure signs, I'd make sure to shoot over a chronograph. I've never used the .280 AI just the regular version, but I did a lot of load development using .270 Win data and was very satisfied with the results over my chronograph.

Nosler max loads with IMR 4831 and H4350 was too hot in my 280 Ackley Montana FWIW.

Thanks, that is what I am looking for. Real world experience. miles

Nosler 280AI max loads seem pretty hot to me. Had a rifle that would not handle any of their max loads. My new rifle will but loves 2g below max of RL22 and 140 Ballistic Tips. I have not chronoed but guess is in the 3050-3100 fps range out of a 24" barrel. Nosler 280ai loads are shot out of 26" barrel. I plan to work up some 160-168g loads. Will start with RL22.