IMR 4451 with 140 BT in .270 Win

NYDAN

Handloader
Sep 17, 2013
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IMR's website provides the following load data for 270 Win. with a 140 gr. SFT SP:

Case: Winchester
Primer: WLR
OAL: 3.280"

Starting load: 49.9 gr = 2,775 fps
Max load: 53.7 gr = 2,977 fps

I loaded up some cartridges with new Norma brass, and WLR primers, and 140 BT's. I used a bullet jump of 0.050". I was hoping to get to 2,900 fps.

My results were:

52.5 gr. = 2721 fps
53.0 gr. = 2737 fps
53.5 gr. = 2777 fps
54.0 gr. = 2795 fps
54.5 gr. = 2807 fps
No pressure signs.

Three of the five shots grouped at 1/4". Four of the five shots grouped at 5/8". The fifth shot was wide, resulting a five shot group of 1.2".

With my large overflow case capacity, the velocities are significantly lower than the published data. However, the accuracy looks very promising.

Anyone have a suggestion on what to do with the velocity? More powder? Magnum primer? Go back to IMR 4831?

Dan
 
Dan,

I would take accuracy or velocity, within reason of course. You could give a magnum primer a try, just might get your speed closer to where you want to be.

JD338
 
I haven't tried it with a 140 but I'm using 57gr with a 130 Partition for 3124 out of a 22" barrel. Its a standard primer. Does a Norma case have slightly more capacity compared to a winchester or remington. If your not seeing any pressure signs I'd just add a tad powder. I'm using winchester cases and it hit advertised velocity with a max load at a grain more than listed.
 
Bruce Mc":3ke0rymq said:
Does a Norma case have slightly more capacity compared to a winchester or remington.

Bruce,

The overflow case capacity of the Norma cases in my rifle is 72.0 grains, which others have said is quite high for a .270 Win.

Quick load projections run with this case capacity and IMR 4831 result in much higher powder charges than the IMR load data. For example, Quick load projects 2917 fps at 55.0 gr indicates I could go up 58.0 gr. I am using 55.0 grains of IMR 4831 to get 1923 fps. The Nosler data lists 53.5 grains will get 2910 fps.

Dan
 
Capacity on .270 cases from my Model 70 are 70gr for Nosler brass and 69.5 for winchester.
 
I'd keep going up until you hit the advertised speeds Dan. Speed is really the only true sign of pressure we have so if you stick close to book speeds (in regards to barrel length) I think you'll be good.

Sounds too accurate to not try it. That's some great groups.
 
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