6.5 prc velocity question

Discussion in 'Long Range Hunting & Shooting' started by Bro Dave, Jun 24, 2019.


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  1. Bro Dave

    Bro Dave Member

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    Just got a 6.5 PRC to test out the round. Did some preliminary accuracy results and was satisfactory. Started doing some accuracy / node testing with Hornady 140 gr and H1000 and got clear up to 59.1 grains and saw some slight shininess on brass from ejector but velocity was only 2911fps according to my Lab Radar. Hornady book claims 3100 for 59gr.

    According to Accurate Powder chart I should have got 2900fps with about 57.5 gr. Hornady Brass. Any thoughts or experience out there?
     
  2. lancetkenyon

    lancetkenyon Well-Known Member

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    New barrel. It should speed up after 100-150 rounds.
    Barrels are all different.
    Powder lots are all different.
    Same barrel length as book?
    Same brass as book?
    Same primer as book?
    Same CBTO/jump as book?
    Too many variables. A book is a guideline, not a Bible.
     
  3. CUTTER1

    CUTTER1 Well-Known Member

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    I run 135 Berger Classic Hunter with 25" barrel and 62.5 GR of H1000 at 3210fps. Tried Honady 143 and 147 and wasn't impressed! The Berger 140 runs best with RL26 which is in short supply! The 135 Berger CH has been lethal on deer and antelope.
     
  4. Bro Dave

    Bro Dave Member

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    Everything the same except primer and jump. Didn't think about that. I had set it up tight too at .005. Could be it.
     
  5. highdrum

    highdrum Well-Known Member

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    Usually if you're close to lands you'll get higher pressure. Give your barrel 100 rounds before getting super serious on load development. Most require that much or a bit more before velocity increase stabilizes. Berger bullets have less bearing surface in general compared to eld line and will take more powder vs equal weight eld to get pressure and velocity.
     
    jasonco and lancetkenyon like this.
  6. Litehiker

    Litehiker Well-Known Member

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    I'd recommend the following:
    1. clean ALL the copper from your barrel
    2. With either pre-loaded Tubbs barrel lapping ammo or a Tubbs lapping kit or a NECO Fire Lapping Kit shoot the prescribe number of bullets (usually 15 to 20) down the barrel, cleaning between shots with copper cleaner.
    These grit-impregnated bullets, from coarse to medium to fine grit (5 of each) should clean your barrel of machining marks and make for far less fouling.

    A lot of work but short of paying for a professional lapping job this will do it. I used a NECO kit on my .300 Win mag Browning and boy, it really collects far less copper for every 100 shots.

    Eric B.
     
    Last edited: Jun 26, 2019
  7. can1010

    can1010 Well-Known Member

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    clean your barrel spotless and check the setup on the lab radar. something doesn't add up I am getting 200 fps more with h-1000 and Hornady 140s with less powder.
    just finalized load development with the 153 A-Tip and am faster than that. none of my loads show any shinny spots or flat primers and have 8-10 reloads on Hornady brass and 210 primers
     
  8. Bro Dave

    Bro Dave Member

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    Good advice. I haven't checked the Lab Radar in a very long time. I was looking for the type of comparison you gave me.
     
  9. sable tireur

    sable tireur Well-Known Member

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    Before jumping to any conclusions, I think it's necessary to know the rifle and barrel manufacture.

    I also know that it's extremely important to get the Labradar set up and tested properly before shooting for data points. We shoot/test all day every day so we've seen the vagaries of the Labradar when it's not quite right. The instrument is not at fault, the way it's set up is.

    Trying to compare loads to others when you're starting with a new barrel is basically fruitless. All the information you get will fall into a bell-shaped curve; those with higher than normal velocities at one end, those with lower velocities at the other end while the vast majority will fall under the middling bell shape. There are to many variables and too many folks who don't understand all of them, so the information has some distortion.

    I'm sold on the performance of the Berger 135 Hunter for general hunting loads. We've even seen some 5-shot groups which are nothing short of exceptional.:eek: I shoot the 130 class bullets and will never go back to shooting any in the 140 class. I've been shooting a few of the 153s but so far the performance doesn't out weigh the expense, not at more than double the price.:(

    Clean your barrel and do a proper break in. Skip the fire lapping.

    Enjoy the process!:)
     
  10. Bro Dave

    Bro Dave Member

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    I've completed the break in process but only have 50 rounds on it. I will check the labradar and continue. Your observation on 130's is very interesting as I've wondered about that in the creedmoor but I thought if they were advantageous I would have read about it before so I have only worked with 140's. thanks
     
  11. sable tireur

    sable tireur Well-Known Member

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    I first made the switch when we were working on the 6.5GAP4S. The 140s are great but if I'm not competing with a velocity limit like PRS, then I want all the velocity I can manage with the resultant energy. Accuracy is a given of course. Now I shoot the 130s in most 6.5mm cartridges.

    Sometimes the information regarding certain components is not readily apparent on public forums. You might have to search for the more specialized boards to ferret out the information.

    Then your break in may not be completed even though you've fired the suggested number of shots.
     
    jasonco likes this.
  12. Bro Dave

    Bro Dave Member

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    I agree. I have had several experiances where a rifle didn't settle down until it had 200 rounds thru it. I have not seen this big a discrepancy between book velocity values and actual. I will reset the labradar. I understand the principle the labradar works on but do not understand the variables and vagaries. If it has a digital read out it must be right :)
     
  13. Litehiker

    Litehiker Well-Known Member

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    Bro, what is your barrel length?
    If you had a short barreled SAKO you'd loose velocity. That's the main reason I prefer the Browning X-Bolt Pro to the SAKO Carbonlite - plus the X-Bolt Pro has a factory lapped barrel.

    Eric B.
     
  14. Bro Dave

    Bro Dave Member

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    it's a 24". Probably down 100fps or so from a 26 but not as much as I am measuring.
    x-bolt is a nice rifle. I am thinking someone should start a thread about the ins and outs of labradar.