270 Win load data

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shamus71

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Anyone have any data or experience on loading 270 Winchester with IMR4320 and a Hornady 140Gr SST? I bought some IMR4320 because it was the only thing left on the shelf. I really liked the IMR4350 with the 130Gr SP. The hodgdon site shows data for a 140Gr SFT SP. Would that be the same?
 
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There's IMR4320 140 grain data on Hodgdon's site. Doesn't matter who made the bullet.
"...Would that be the same?..." No. Ten grains makes enough difference to matter.
 
The start load should be safe but the max load will be different due to differences in length of the bearing surface.

Start low, work up slow and watch for pressure signs.
 
shamus71 said:
Anyone have any data or experience on loading 270 Winchester with IMR4320 and a Hornady 140Gr SST? I bought some IMR4320 because it was the only thing left on the shelf. I really liked the IMR4350 with the 130Gr SP. The hodgdon site shows data for a 140Gr SFT SP. Would that be the same?
Click to expand...

The two major differences I would suggest exist between the two bullets is construction (The webpage didn't specify a particular manufacturer for the soft point bullet) is the SST is a boat tail, plastic spire pointed bullet with expansion properties for deer size animals. The weight is the same, but the length may vary by a several thousandths of an inch. If you are seating the bullet to published depths, you are probably no where near the rifle lands so any pressure variances (presuming the previous is true) should be non-existant... just something to bear in mind, that caveat aside, and following published data for powder charge min-max..., the data would be the same for both bullets... basically a repeat of what 'wilbar' said.

As you already surmised, IMR4320 is not an ideal burn speed for 270win and while I have tried this before, H4831 and H4350 are far better choices in attaining higher velocities within lower chamber pressures. I am just rambling on now having already addressed your question. As to accuracy: I easily attained "minute of big game" accuracy with IMR4320 in 270win, but that powder shines in other calibers, especially my 222rem to the point of being a favourite I like having on hand. :) It does work in the pinch you now find yourself.
 
Data I have from hornady handbook of reloading
Vol 2 from 1970's states

270 Winchester. 130 gr interlock

IMR4320. Start 47.1gr
Max. 53.9gr
Velocities vari from 2800-3200 fps
This book has data for alot of older powders not used much
These days. Hope this helps
It lists cases used were Winchester , primer was federal
210 large rifle
 
I use a similar burn rate powder for 270, I get nice accurate groups but apparently lack the velocity, Not 100% as havnt chrono'd a load yet but 45gr of Varget gets me there with 130gr CL's.

I did a load at Min, shot that an then moved up in 2 gr incr until I was 1 below max, settled with the accuracy... not phased for fps.

WL
 
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