Anyone with quickload or other generally reliable pressure prediction software, could you run some numbers please?

.280 Remington cartridge. Hopefully there is a standard case capacity in the software...???

140 grain Sierra Gameking BTSP.

Bullet in firm contact with lands (3.35" OAL, most accurate) AND bullet .15 short of lands (if possible to do both ways)

H4831SC powder

22" bbl

Current chrony results:
humid wet day:
2903 fps at 59 grains
2854 fps at 58 grains
Dry sunny hot day:
2918 fps at 58 grains
2844 fps at 57 grains
2803 fps at 56 grains

Hodgdon says 58.5 grains of 4831 is max...and I'm well aware of the low-ish SAMMI limit on this cartridge. My accuracy is improving as I go up...so:

Where do I hit 65kpsi per Quickload?

Spare the lectures, I'm well enough versed to not give sw predictions 100% faith, and I understand the pressure issues quite well. I expect 4831 to be pretty well modelled by SW though, due to it's popularity and longetivity. If someone could run the numbers I'd be grateful to have another data point to use in making sure I stay safe. Thanks in advance!

quote:

Originally posted by CDH:
...Spare the lectures, I'm well enough versed to not give sw predictions 100% faith, and I understand the pressure issues quite well. ...

Quickload 280 Rem, SRA SPBT 1905 140 gr .284, 58.6 gr H4831SC [3.32"= 102.3%, 3.35" =98.3% case fill], 24" barrel:

3.35", 2822 fps, 46,139 psi
3.20", 2891 fps, 50,491 psi

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Quickload does not allow for jamming into the lands , which can be like 2 more grains of powder.

Quickload 280 Rem, SRA SPBT 1905 140 gr .284, 60.6 gr H4831SC [ 3.35" = 101.7% case fill], 24" barrel:


3.35", 2934 fps, 51,727 psi

But from the looks of your velocity, you are not jamming hard into the lands at 3.35"
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Quickload also thinks that if you want 65k psi 3.35" try:

58.6 gr W760 3,154 fps
58 N550 3,137 fps
57 IMR4350 3,120 fps
56.1 H380 3,107 fps
52.1 IMR4895 3,102 fps

I know I would do the last one, cause it makes less noise.

Actually I'm getting hard bolt closure (takes a moderate strike with the heel of my hand to get the bolt down) and rifling marks at that OAL...short throat I guess. Surprising in a factory rifle...Ruger M77MKII no less.

Don't forget the 22" barrel.

Wow, QL really doesn't think I'm getting much pressure at all! Funny for max loads in several load manuals...

With a 22" barrel, 3.35", Quickload thinks you would need 59.4 gr to get 2804 fps, 48,551 psi

So it looks like you are getting about 1 gr of powder effect from jamming into the lands.


The Sierra load book is usually good.
You should report back what you find out.

Whoops,
It looks like I didn't do that the best way.
To compensate for jamming into the lands, I need to alter "Shot Start Initiation Pressure".

http://www.6mmbr.com/Quickload.html

Interesting read.

I've been interested in QL for a while, but just don't load enough different (or new) guns to justify it. Yet!

Right now the numbers you provided seem to indicate a preference for faster powders than most load guides show in .280Rem. Maybe the higher pressure limit does that, but first tests with VN560 were SLOW, 2546 fps worth of slow.

45 grains of IMR4895 (max per IMR) got me 2760 fps. That's a lot of increase to go to QL's 52 grain 3100 fps level. Maybe IMR is that mild with this load...

Such is the fun of reloading, right! Thanks again for running the loads!