2900 fps too fast with 150g in 270 Win? New data

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thepitchedlink

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Hey guys, just starting to play with my 270 Win, Ruger mkII. I wanna play with some heavier bullets. Hornady 150's with Win Mag primers, 56g of H4381Crony says 2900 and change..my Lyman manual says 56g should give 2750. It was -2 degrees today, primers still have a round shoulder, bolt lift is same as always, easy. Even though she's not showing it, I've gotta be getting into warm territory here. What do other fellas get for speed with 150's in the 270 Win? This freakin' gun, just shoots everything, 53-56g with Mag primers all go within 1.5inches. It did the same thing with 130s and 140s. It's never shown a pressure sign...that I can find anyway.
 
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Something fish with your chrony.
Try some 22 ammo over it.
Or try your loads over another persons Chrony.

As a last resort shoot your loads out to 300, 400 and beyond. Plot the trajectory, then dive backwards into some ballistics software.
 
I got 3000 from a 140 gr acubond with I think 58 gr of h4831sc form a Tikka 695 a few years ago. I think it's a max load, but not totally out of the question.
 
I get 2900+ with 150 Ballistic Tip over IMR 4831 out of my .270 but that is with a 28" barrel. Getting that velocity out of a 22" barrel would have me backing off on the charge a bit.
 
In Europe most firearms [rifles] get fed a blue pill [60% overload]before leaving the factory then checked for any change in headspace.Not advocating hot rodding loads but books are just a guide.Some guns like it warm but most run best at 90-95% of MAX loads.Checking primers and case expansion are just common sense as you work up a load..................Harold********saftey first
 
thepitchedlink said:
Hey guys, just starting to play with my 270 Win, Ruger mkII. I wanna play with some heavier bullets. Hornady 150's with Win Mag primers, 56g of H4381Crony says 2900 and change..my Lyman manual says 56g should give 2750. It was -2 degrees today, primers still have a round shoulder, bolt lift is same as always, easy. Even though she's not showing it, I've gotta be getting into warm territory here. What do other fellas get for speed with 150's in the 270 Win? This freakin' gun, just shoots everything, 53-56g with Mag primers all go within 1.5inches. It did the same thing with 130s and 140s. It's never shown a pressure sign...that I can find anyway.
Click to expand...
My Hodgdon manual lists 150's over 55.7g of H4831 as a max load at 2804 fps. Given variances in barrel length, primers, and other factors if you are seeing no pressure signs then should be good?
 
No pressure signs, but this gun never seems to give any. Found one of my chrony eyes was loose, so probably reading at an angle. I'll try a couple more tommorow, but at least I've got a bit of conformation that 56g of H4831 with 150's isn't completely out to lunch.
 
I push 150 gr. hornady's around 2850 fps out of a 22" pipe with IMR 4831 (54 gr.) You're maybe a little warm but not too bad and like others said what is too hot in another gun might ok in yours and vice versa. You may find that load quite a big hotter this summer with another 15C tacked on, H4831 should not be too bad for in that respect.

Winchester factory 150gr factory ammo (supreme elite or something) is listed as flying 2950 fps on the box !! Havent' got a chance to chrony it...no idea of what kind of special powder they may have been using. (or lenght of barrel tested with).
 
Firstly. The new, modern H4831 is a slower powder than the old, war surplus H4831. Some years ago when the new came out, I checked one against the other in a 270. The new powder was about 100 fps slower than with the old powder.
The 270 with H4831 powder (old) was Jack O'Connor's favourite subject to write about. he credits himself with giving the old standby load of 60 grains with 130 grain bullet, to the reloaders of the world. He usually gave about 58 for the 150 grain bullet.
In short, 56 grains of the new H4831 with 150 grain bullet, is not a heavy load. As far as I am concerned, it is in the range of a staring load. 58 grains of the old gave me about 2850 in a 24 inch barrel.
Take the advice of having it checked on another chronograph.
NOTICE; DO NOT USE MY FIGURES FOR YOUR LOADING. YOUR RIFLE, OR COMPONENTS MAY BE DIFFERENT AND MAY CAUSE OVERLOADS, OR OTHER PROBLEMS.
 
Pathfinder said:
Winchester factory 150gr factory ammo (supreme elite or something) is listed as flying 2950 fps on the box !! Havent' got a chance to chrony it...no idea of what kind of special powder they may have been using. (or lenght of barrel tested with).
Click to expand...


I would get a box and shoot those and mike the cases, then compare them to your loads. As long as you are the same or less head expansion you should be ok.
 
Mag primers

The mag primers where just to try it out...plus it was -26 here back in Dec when I started this little circus, figured I'd work the load up and then switch back to regular primers and see what the difference is. I've got the Chrony glued up so that should help things...I''ll try a few factorys as well and mike the bases against mine...thanks for the imput guys.
 
better numbers

Hhhmmm, having a chorny that works properly sure helps, todays numbers make a bit more sense.
H4381 with Hornady 150 SP's, 3 shot groups
54.5g = 2700 and 1.5inch group
55g = 2740 and 1.25inch group
55.5 = 2770 and 1.0inch group
56 = 2790 and 1.25inch group

I ran a few with Mag primers just for a speed test
54g = 2700, 55g = 2748, 56g = 2808

And go figure those 3 mag primer rounds went within 0.5inch!!

No cratering on any primer, stiffer loads look a little flatter, but not much, still a bit of shoulder there. All bolt lifts where smooth and easy, no trouble extracting anything. So the use of Mag primers only seems to up the speed by a bit, can't see any pressure signs yet, of course warmer weather might change things...I think she's telling me that she likes mag primers for some reason. Might try another grain higher, as far as I'm concerned anything with itty bitty groups over 2750 is more then fine with 150 bullet. thanks for the help fellas
 
I have 4 270's, I use 57.5 grs of H4831sc win brass fed mag primers 150 nosler part. one of the four has a slightly flatted primer no problem with bolt and I get 2900 + with all four.
I was using 58grs but two of the rifles didnt like, sticky bolt, flat primers.

I find mag primers with H4831sc seems better at least from my experence.

I use the Jack O. load of H4831sc for my 130 gr loads no problem in any of the rifles

As always everyone can have different results.

Larry
 
thepitchedlink said:
Hhhmmm, having a chorny that works properly sure helps, todays numbers make a bit more sense.
H4381 with Hornady 150 SP's, 3 shot groups
54.5g = 2700 and 1.5inch group
55g = 2740 and 1.25inch group
55.5 = 2770 and 1.0inch group
56 = 2790 and 1.25inch group
Click to expand...

Yes accurate chronys are a must! Although it's easier to make a bullet go faster using an inaccuarte chrony than using an accurate one & ragged edge pressures :D
Even brand new ones can be +100fps off, I've seen it!
 
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