223 Varmint load experiment

Discussion in 'General Reloading' started by 57MedDet, Aug 16, 2010.

  1. 57MedDet

    57MedDet G&G Newbie

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    Conducted a less than scientific varmint load experiment with a 16 inch Rock River coyote carbine and 10 different handloads. I have the results in an excel file which I will have to convert as it can't be uploaded. Suffice it to say, best accuracy and highest velocity were obtained with 25.2 of Reloader 10X and 50 grain Hornady Vmax bullets.
     

    Attached Files:

  2. gandog56

    gandog56 G&G Evangelist

    What is velocity error?
     

  3. 57MedDet

    57MedDet G&G Newbie

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    Sorry, let a field artillery term slip in where it didn't belong. That is the largest spread in velocities observed. I was really surprised by the performance of 10X and also H4895 as it was one of slower powders I used.
     
  4. DaTeacha

    DaTeacha Things are not what they seem. Forum Contributor

    I was working with the 69 grain Sierra Matchking in a 16 inch 1 in 7 tube the other day. I got my best results right around 24.0 grains of Varget. I didn't chronograph them, though.

    Looking through the Sierra manual, it seems their accuracy loads for most any load in the AR with a 16 inch barrel are around 2900 fps. Has anyone paid enough attention to their loads to know if this holds true in general?
     
  5. samuel

    samuel G&G Newbie

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    I would think 2900fps from a 16" barrel with 1:7"twist would be extremely "HOT".Hope you chrono some and check.As far as I know,they only get around 3000 from a 24"bbl with 1:12"twist which is going to be faster than a 1:7"twist. ,,,sam.
     
  6. DaTeacha

    DaTeacha Things are not what they seem. Forum Contributor

    That figure was from the manual. Let me check. Okay, my bad. My memory is letting me down again. They had a 20" 1 in 7. The accuracy load with the 40 grain bullets is at 3200, but the 52, 53, 60 and 63 grainers all show a 2900 fps accuracy load. The 69 grain is 2750, the 77 is 2600, and the 80 is 2550.

    I just thought the 2900 fps being so common in their information was kind of unusual.

    FWIW, they're showing 3600 fps using Viht N130 and the 40 grain Blitzking. They also show the Hornet bullet going that fast, but I think may not make it to the target.
     
  7. samuel

    samuel G&G Newbie

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    Nothing gives me more pleasure than keeping a "TEACHER" straight.You're a good man and a credit to the forum teach,keep up the good work.A PS on this,I may not have made it plain enough but the friction between a 1:7"twist and a 1:12"twist is considerable possibly making somewhere between 50 and 150fps difference.I don't have the figures right here but it is a lot.You people trying to get long range out of the .308win/.30-06 would be amazed at the difference in the pretty well standardized 1:10 and a 1:12"twist.Sometimes you can keep a 150gr or lighter bullet supersonic past 1000yds simply by using a slower twist rate and still have rpm,s enough to stabilise the bullet.Of course this would mean custom barrels.But if using a custom,you should talk it over with the barrel mfg,and especially the bullet mfg. ,,,sam.
     
    Last edited: Aug 17, 2010
  8. Palladin8

    Palladin8 G&G Evangelist

    The faster twist barrel will in fact cause higher pressures. The military found that out in the development of the M-4 with heavier bullets. That is why they backed down the velocity in the ammo because of over pressure.
     
  9. samuel

    samuel G&G Newbie

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    Higher pressure but not necessarily higher velocity.My own findings shooting over a chrono are that there is a significant difference in velocity.I found a forum article that gives views both ways on this issue.Read it and judge for your self. ,,,Fast Twist VS Slow Twist - LongRangeHunting Online Magazine ,,,sam.
     
  10. Browning

    Browning G&G Newbie

    I will add to sams post. High pressures doesn't always mean alot of kick. I loaded some .270 Win. loads the other day with 8208XBR, hodgdon list this as a very high pressure powder for the .270, but the kick of these rounds were much less than factory loads.