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Thread: More .260 load development

  1. #1

    More .260 load development

    I have been trying some more powders in my 20 inch barrelled .260. I was given half a tub of H414 so looked at all the different manufacturer's recommended loads with the 120 grain Sierra Prohunter bullet.

    The most powder recommended is 45.5 grains on the Hodgson site.

    I weigh every charge and check the beam scales with check weights.

    Starting low and working up by one grain then half a grain everything was fine until I fired the 45.5 grain load, which gave a blown primer and sticky bolt.
    H414 in the .260 would seem to be one of those temperamental powders that give high velocity but quickly go into the red. At least it is so in my rifle.

    Sierra recommend 44.2 grains of H414 as the maximum with the Sierra 120 grain Prohunter. This load gave very consistent velocities with a five shot test. A low of 3,004 and high 3,024 so only 20fps extreme spread. This is from a twenty inch barrel so seems rather quick.

    I carefully examined each case as I had fired and there are absolutely no signs of excess pressure and the case ejects freely. So looks like a result as far as consistency is concerned.

    I haven't fired them at a target yet, however I have ten loaded in readiness.
    As the velocities are so consistent, does that automatically mean they will shoot well, or is that a will of the wisp ? Time will tell.

    As the velocity is significantly more than that predicted from the test barrels, I am just a little concerned as to why this should be ?

    Similarly I am wondering what the effect on deer (meat damage) would be with the 120 grain Prohunter travelling so quick ?
    Last edited by Uncle Norm; 26-07-2015 at 07:19. Reason: Typo

  2. #2
    Norm, please see here my experiences with a Pro Hunter:

    http://www.thestalkingdirectory.co.u...hunter+failure

    I'm guessing you are pushing the pressure envelope there, I certainly wouldn't go any higher than that 3K FPS load.
    Brian.

    Just because you are paranoid, doesn't mean they aren't out to get you......

  3. #3
    Quote Originally Posted by Claret_Dabbler View Post
    Norm, please see here my experiences with a Pro Hunter:

    http://www.thestalkingdirectory.co.u...hunter+failure

    I'm guessing you are pushing the pressure envelope there, I certainly wouldn't go any higher than that 3K FPS load.
    That's an interesting thread, thanks. I was thinking of taming them down a bit.

    As you know I have been trying several powders and intend to try N150, albeit Laurie has cautioned that the N150 can be somewhat unpredictable as the load increases too.
    I haven't yet tried any other bullets than the 120 grain Sierra Prohunter though. I have some Speer 120 grain on order but they have not been available yet.

  4. #4
    I've found the 120gr Pro Hunters in my 6.5x55 very accurate and certainly work ok on the larger deer but stopped using them on anything small like Muntjac. I was pushing them at 2,900 f/s but lowered this to 2,820 f/s. Having said that I don't generally use them anymore and prefer 140's in this calibre.

    I did find they blew up a little at close range out to 100 yards. I thought the Sierra website actually stated once that they were a good varmint bullet in magnum calibres pushing over 3000 f/s. However having checked their website that doesn't appear any more, maybe I was mistaken.

    Having said that if they were all I could get I'd use them but at around or just above the 2,800 mark.

  5. #5
    Quote Originally Posted by The deer man View Post
    I've found the 120gr Pro Hunters in my 6.5x55 very accurate and certainly work ok on the larger deer but stopped using them on anything small like Muntjac. I was pushing them at 2,900 f/s but lowered this to 2,820 f/s. Having said that I don't generally use them anymore and prefer 140's in this calibre.

    I did find they blew up a little at close range out to 100 yards. I thought the Sierra website actually stated once that they were a good varmint bullet in magnum calibres pushing over 3000 f/s. However having checked their website that doesn't appear any more, maybe I was mistaken.

    Having said that if they were all I could get I'd use them but at around or just above the 2,800 mark.
    Just re-checked the Sierra website and it was the 7mm Pro Hunter they say works well in magnum calibres as a varmint round. Well a 6.5 at magnum speeds would probably work quite well as a varmint round too?

  6. #6
    The question that I am trying to get my head around is:- 'Why (with H414 only) does this rifle with a 20 inch barrel, post consistent velocities of more than 100fps faster than the predicted velocities from 24 inch test barrels ?'

    With other powders it produces 80 to 140fps less than the predicted velocities from the 24 inch test barrels, which is what I would expect.

    The chronograph is fine (as long as I read the instructions and don't use it in bright sunshine). I have checked it with my .22RF subs and airgun too.

  7. #7
    FWIIW I developed a load for a friend in a 260 Steyr using 120 gr Prohunters loaded with 43.9 gr of N160 and Fed Match primers. These were seated 112 thou back from the ogive and gave an average of 2745 fps and shot well below .5" Needless to say anyone thinking of this recipe should start a couple of grains below.

    As with all calibres, one has to be aware that the deeper a bullet is seated the higher the velocity/pressure is encountered when filling with more powder

  8. #8
    Quote Originally Posted by PeterH View Post
    FWIIW I developed a load for a friend in a 260 Steyr using 120 gr Prohunters loaded with 43.9 gr of N160 and Fed Match primers. These were seated 112 thou back from the ogive and gave an average of 2745 fps and shot well below .5" Needless to say anyone thinking of this recipe should start a couple of grains below.

    As with all calibres, one has to be aware that the deeper a bullet is seated the higher the velocity/pressure is encountered when filling with more powder
    Thanks Peter.
    I am seating them to the oal recommended in the manuals and crimping lightly with a Lee factory crimp die.
    In my rifle (20 inch barrel) with N160, I have to load 45 grains to get 2,745 fps. 44 grains of N160 gives me 2,670 fps.

  9. #9
    Quote Originally Posted by Uncle Norm View Post
    Thanks Peter.
    I am seating them to the oal recommended in the manuals and crimping lightly with a Lee factory crimp die.
    In my rifle (20 inch barrel) with N160, I have to load 45 grains to get 2,745 fps. 44 grains of N160 gives me 2,670 fps.
    This would be my bet as to why you're getting faster than book. Also, these things are a guide, not a certainty, given the variances in chambers, brass, bullets, powders.... etc

    My experience with this bullet in this cal was good, all fell over as intended.
    I did also like the 140gr Gameking over N550.
    Found the Hornady's did not shoot well, at all.

  10. #10
    I tried H414 with 120gn bullets in my 260 initially and velocities were incredibly close (within 5fps across 3 shot groups), but just couldn't get them to group well. That was with nosler bullets. Can't remember velocities off top of my head but they were somewhere around 2700-2800 depending on load.

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