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.308 handload velocity question

Discussion in 'Handloading and Reloading' started by Goattman, Jan 10, 2013.

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  1. Goattman

    Goattman Member

    Jun 27, 2012
    I am loading once fired Black Hills brass.

    Powder: 42.1g IMR 4064
    Primer: CCI BR2
    Bullets: SMK 168 HPBT

    Dropping powder with RCBS chargemaster and checking with 505 scale, so I am confident of actual charge.

    Rifle: Remington 700P 26" barrel no modifications

    Chrono: Competition Electronics Digital (12' from barrel)

    Outside, 35 degrees, and sunny.

    Bullets are chronographing at 2480 fps average, SD 27 fps

    This is lower velocity than I expected. I was expecting in the 2600 fps range, only because this is what BH chrono at in summer.

    Is the velocity I am experiencing what others see as well or no?

    If No, any suggestions why?
  2. Walkalong

    Walkalong Moderator

    Nov 20, 2006
    From Hodgdon online data:
    24" barrel.

    Does sound a little slow. What OAL?
  3. USSR

    USSR Member

    Jul 7, 2005
    Finger Lakes Region of NY

    The primary problem is your Black Hills brass was made by Winchester, hence it has the Winchester's large case capacity. So, you essentially have a very light charge. Secondary causes are low temperature and mild BR primers. You've got plenty of room for more powder in that case, and you might want to also consider a hotter primer such as the Fed 210M that Hodgdon used in their load data. Hope that helps.

  4. Dthunter

    Dthunter Member

    Feb 2, 2012
    Alberta, Canada
    You definitely have room to increase your powder charge. Just do so incrementally (1 grain at a time). Eventually you will either reach your velocity
    Goal or find high pressure signs. Every gun is a little different, and thats the beauty of reloading. You can tailor your load to the specific firearm.

    Remember, above all, accuracy is found where the rifle likes it. It may be at a lower velocity, or a higher velocity. Just feed the rifle what it likes.
    Generally speaking, all my .308's are most accurate at or
    Near max velocities published in the loading manuals.

    Have fun, and be careful As You work up in pressures.
  5. Goattman

    Goattman Member

    Jun 27, 2012
    Walkalong, 2.800" OAL.
  6. 918v

    918v Member

    Mar 16, 2006
    Increase your charge.
  7. Slamfire

    Slamfire Member

    Dec 29, 2006
    This is what I got in my Ruger M77 Mk II with a 26" barrel and LC90 cases.

    So either your barrel is not as tight, the cases a bit bigger, or my primers a bit hotter.

    I would say bump your charge to 42.5 and 43.0. That should get you around 2600 fps.

    [SIZE="3"]Ruger M77 MKII 
    26 " Barrel 1:10 twist		
    168 Nosler 42.0 grs IMR4064 Lot2449 LC90  CCI#34 OAL 2.750"		
    	27-Nov-06		T = 60 ° F			
    Ave Vel =	2594						
    Std Dev =	22						
    ES =	67					 	
    High =	2629					 	
    Low =	2562					 	
    N =	10		 				
    excellent accuracy	[/SIZE]
  8. 41 Mag

    41 Mag Member

    Jan 22, 2005
    Texas - Born and Raised
    To be honest with the average your posting your not that far from where you think you should be IMO. I have seen WAY bigger discrepancies.

    There can also be a number of other influences as you mentioned the temp between dead summer and winter, chamber dimensions, brass dimensions, powder lot, bullets and so forth. Could be as simple as the primers. Only testing will tell.

    One thing I have found many times is that what I expected a load to be was not always what it actually was. It could also be as simple as the lighting on your chrono as well. Sometimes the brighter it is the further off my readings are. I try to use something like a target clothes pinned to the top of the screens to give me as close to a standard as possible. It helps when it goes from bright sun to a cloudy day in keeping my readings a bit more consistent.

    But like others have mentioned it is simple to creep up on your charge and see where your at there as well.
  9. Trent

    Trent Resident Wiseguy

    Dec 6, 2010
    Cloudy days means your chrono needs a shield. It's "too bright".

    It's the reverse of what you'd expect, but sunny days are actually "darker" to the chrono (from it's viewpoint) than cloudy days, where the whole of the sky is lit brightly. It's harder for a shadow to be picked up by the sensors when the light source is "everywhere" above it.
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