i just got my new 280 ai back from the gunsmith.and was going to start working up loads for it. i am going to load the berger 140 grain vld using rl 22 and fed 210m primers the problem i ran into is max load data my sieera manual lists a max load of 59.5 grains while nosler lists the max load of 64.0 grains. so my question is what is the max load

morgan

It is never a good idea to get max load data from a book. So much depends on the brass, the chamber, twist, the bullet, and the barrel.

It's always best to start with a mid-level load, interpolated from at least 2 or 3 different sources, and then work up from there.

A chronograph is a big help.

I have always found the Nosler Handbook to be a good one for the 280AI. RL 22 is a good powder for the 140 grain bullets but my maual shows a max load of only 60.5 grains.

If you go to heavier bullets you'll probably find that slower powders, such as RL 25 or 4831, are a little better.

Ray

cheechako that is what i normally do but the nosler books min load is still more then the sierra max load this is what has me confused

It's one reason to use at least two sources & avg. then work up your own load. I shoot a std. 280 & while RL22 is ok, IMR7828 was THE powder in my 280. Accuracy & vel. was better than w/ RL22. H4831sc is also a great choice for the 140gr bullets.

It really shouldn't be so confusing that one manual is different from the next. The rifle that was used to obtain the data for one manual is not the same rifle that was used for the other manual. The brass, bullet, primers, etc may be different as well. All this has an effect on the pressures generated by each individual rifle, and each rifle is unique. As Ray has pointed out, you start in the middle, and work up the load for only the rifle in question.

quote:

Originally posted by morgan8901:
...what is the max load

There is only one way to know good-old, time-proven, never-fail CHE.

I rarely disagree with Ray, but if it were me, I'd have zero use for a Chronograph while developing Loads for a Wildcat. There is no way to know what the Velocity "should be" for a specific Load in a Wildcat. And the same appiles for a Standard Cartridge too.

The Case Pressure Indicators are what is really important. You can't pick a random Load from ANY Manual and have a shread of confidence that it will be anywhere close.

Best of luck to you.

Hot Core

I think we still agree. I didn't mean to imply that a chrono is a tool to use in determining pressure, or even estimating pressure. But, it's good to know what fps you are getting from a particular load so that you know whether it's worth the powder and bullets to keep going. Nothing worse to me than spending time on a load and then finding out it's 300 fps slower than what I was expecting.

Ray

My Nosler #5 manual show 63 gr RL22 as max for the 140 gr bullet. In my gun the best for the 140 gr bullet was IMR4831 at 59.5 gr for a velocity of 3100 fps. 58 gr of IMR4350 worked well also at 58 gr for a velocity of 3150 fps.

The RL22 worked best in the heavier 160 gr loads and now I am loading RL25.

Hey Ray, Yes, we are still in complete agreement.

Good Hunting and clean 1-shot Kills.

berger will provide load data

I have three 280 AI rifles. for the go-between load works well in all three, I use 62 grains RL22, as any more showed DEFINITE signs overpressure in my battery of rifles. the 62 grains does OK in all three. I also found that getting anywhere near 63 or 64 grains was going to be a compressed load in my brass.

You do need to ignore and disregard the COTW 280 ackley loads of a few years back, as they are flat out wrong, and used bad assumptions. I ran down and bought their suggested powder, and only two shots and I tossed the notion.

BTW: 62 grains rl22 will drive a 140 grain NAB right at 3200 fps in a 25-26 inch barrel. also, 60 grains rl22 will drive a 160 grain NAB right at 3000 fps. in my rifles.
Also: I do not use magnum primers, so that can make a difference as well as the brass type.
load up to these of course.

Jameister

My old Nosler book shows a load max using a 140 gr. bullet and RL-22 to be at 60.5 grains.

(Forgive me Nosler for posting your book, but I gotta help a fellow reloader out..)

Kenati
I dont know about everyone else but I really appreciate the pictures and the info

In the case of the 280 and 280 AI there is a very specific reason for different load maximums. The SAMMI max for the standard 280 was dropped to 60,000 psi because of the actions of the remington rifles it was intended to utilize.

The 280 AI was intended strictly as a bolt gun cartridge and a lot of the data uses 65,000 psi as MAOP like the 270 Winchester. So you can have manuals that choose 60,000 as max for the AI or some that use 65,000.

Another 280 tidbit is that the SAMMI chamber is intentionally sloppy for ease of extraction in the 742 and 760 rifles. So at true max pressures you will get a bigger bulge at the base of the case above the web than some folks like to see.

Two ways around that are to either use a 7mm-06 AI reamer which cuts a standard 06 chamer at the web or use 9.3 x 62 brass to form 280 AI cases because it is slightly bigger in that area than 06 brass. That way is a PIA though, unless you like neck reducing in stages and annealing.

I think the pressure issue is where the 280 AI got a lot of its reputation as one of the more efficient improved rounds over the other -06 based rounds. Jump anything 5000 psi above the original and it has to look better than it's parent regardless of case capacity.

Quoting from above "My old Nosler book shows a load max using a 140 gr. bullet and RL-22 to be at 60.5 grains."

My Nosler No 5 book, shows on page 256, a maximum load for re22, and the 140 grain bullet, as 63.0 grains powder.

I believe, based on my experience only, that the NAB is a bit easier on pressures than the partition. but in any case, every rifle is different and every one needs work from below.

Jameister