A pleasant surprise

R

Roadkill2228

New member
Yesterday I did a little shooting. I specifically was interested in chronographing 3 loads. Two were just so-so but one really impressed me! The so-so loads were a) 270 win with 130 grain hornady sp on top of a full case of the admittedly too slow imr 7828. Mixed head stamps. Five shots over the chrony showed velocities to average just under 3000 fps out of my 22 inch barrel (savage 111). All shots within about 60 fps of each other. Again, so-so. Even less impressive, 243 win 90 gr Sierra fmj over a moderate amount of win 760 . Around 2900 fps, but the velocity window into which all rounds fell was over 100 fps. Not very consistent. But then came the surprise. .243, new federal brass, 75 gr hornady hp on top of a charge of imr 4350 (I don't plan to post load data online). Only fired 3 (I didn't want to waste these) but the results were 3246, 3248, 3252. I was pleasantly surprised. Haven't done any serious accuracy test (shooting at stumps and bottles doesnt count apparently :D) but as consistency is at the heart of accuracy, I'm expecting great things. Shooting from an old savage 99, plan to go coyote hunting with these sometime. All primers were fed 210s
 
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Ok, was trying to rule some things out for your extreme spreads in velocity from one round to the next. Like if you had a hot chamber and allowed the round to "bake" in the chamber could account for an increase in pressure and velocity but that doesn't sound like the case.

Were the charges individually weighed or metered through a powder drop of some sort?
 
Individually weighed to within a tenth of a grain. I've heard that near max loads can exhibit greater consistency than middle of the road loads and the 90 grain fmj load was definitely nowhere near max. So maybe if I wan better consistency I'll work that load up a ways. As it is though, all I wanted from it was a less expensive plinking load and it is exactly that so in not complaining about it.
 
It's always nice when your velocities are consistent. Makes it so you can predict the bullet trajectory.

I worked up a load in my 30-06 with 165 grain sgk bullets and h4350 (a pretty hefty load) and my standard deviation for 10 rounds was only 7 fps. I know it's crazy but boy does it shoot.

That 243 load will be great for some reason or another the 75-85 grain 6mm bullets shoot real well. My pet 243 load uses a Sierra game king hollow point 85 grain and a fair dose of IMr 4064.
 
Was the ammo cold as the air temp? Some powders/primers don't work well at cold temperatures. I use magnum primers in colder weather for more consistent results. Check loading manuals and other places for powders that work well in cold temps.

I don't try for accuracy when conditions are cold, very hot, or particularly windy, or when there may be a lot of mirage or water vapor.
 
For those 130's in your .270, try H4350, or IMR 4350. Your rifle will like those powders more than IMR 7828, just to slow for 130 grain stuff...IMHO...

My .243 win. likes 100 grain bullets with winchester supreme 780...weather shouldnt effect the H4350, however the Supreme I'm not sure about..velocity with H4350 seemed consistant enough.
In the .243, with Supreme, I load near maix and get marvelous accuracy and consistancy.
 
As read it sounds like your getting both rifles dialed in. From experience the 243 just loves those little 75gr HP Hornady's. Amazing accuracy they give. Same can be said with the 270 and 4350 use. Nice when a plan comes to together isn't it.
 
Picher I haven't used mag primers in a standard cartridges yet. Where I live it gets very nasty in winter and even now. Yesterday I went shooting just a little to check a load (some 220 grain round nosers in my .300 win mag) and I was all out of mag primers. So I was using standard primers in a mag case at -20 Celsius and there were no problems reliability wise and they were quite consistent. I don't shoot for accuracy in the colder days but not because the temperature does anything to affect inherent accuracy in my experience; it's just that my trigger pull is not very good when I can't feel my dang fingers!!!!:D. I'll give that a try sometime tho.
 
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