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Over 500 Yards on a budget

Discussion in 'Rifle Country' started by ZWCoffindaffer, Dec 29, 2015.

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  1. Bart B.

    Bart B. Member

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    1.2 raised to the 8th power equals ~ 4.3.

    1.2 X 1.2 X 1.2 X 1.2 X 1.2 X 1.2 X 1.2 X 1.2 = 4.29981696.

    Which means a 1 MOA/inch group at 100 increasing 20% every hundred yards will subtend 4.3 MOA (43 inches) at 900 yards.

    Get some good ballistics software (Sierra Infinity) to see how velocity and BC spread, varying cross winds, and atmospheric conditions in each 100 yard band of range. For example, a 50 fps spread with 308 Win muzzle velocity causes a 1/10" spread vertically at 100 yards; it's 20 inches at 1000. Same cartridge with a 1 mph crosswind at 100 has 1/10th MOA drift; at 1000, it a full MOA; a 10X change and winds are not constant in speed and direction throughout the bullet's path. Very little's been published anywhere about this. I've probably put more words in forums on these facts than all the others put together.

    A check of benchrest aggregate group records shows them at about .2 MOA at 100 yards, .27 at 200 and 3.5 MOA at 300 yards. How's that for incremental group sizes in MOA growing as range increases? It's over a 30% increase for each range beyond 100 yards.
     
    Last edited: Dec 31, 2015
  2. Bart B.

    Bart B. Member

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    delete
     
    Last edited: Dec 31, 2015
  3. Bart B.

    Bart B. Member

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    Double post

    delete

    Dropped my pad twice; shame on me!!!!!!!!!!!!!
     
    Last edited: Dec 31, 2015
  4. Welding Rod

    Welding Rod Member

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    Very interesting Bart.

    So a rifle that I find shoots 1 MOA at 500 yards is really likely capable of much better accuracy at 100 yards than what I see, which would probably be only about 1/2-3/4 MOA . I suppose that would be due to increased aiming error at closer range?
     
  5. taliv

    taliv Moderator Staff Member

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    the dispersion part is probably right but the fault is with the ammo and wind calls not the gun
     
  6. acechanley

    acechanley Member

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    Look at the Cz 550fs 308 offerings. I have a manlicher 20 inch barrel with a sightron 1x4 that is under 1moa With hand rolled 165 gr bt.
    The set trigger on these guns is amazing!
    Ace
     
  7. Swampman

    Swampman Old Fart

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    So average aggregate benchrest group record size goes from .2 inch at 100 yards (.2"×1), to .54 inch at 200 yards (.27"x2) and then jumps to over 10.5 inches at 300 yards (3.5"x3)?
    I have no idea about the scientific validity of your 20% increase in group size for every 100 yard increase in range.
    But anyone that's studied ballistics even casually should know that 4.3 moa doesn't equal 43 inches at 900 yards. 1000 yards yes, but not 900.

    One minute of angle equals 1 inch at 100 yards (Actually 1.047 inch but the discrepancy is small enough to ignore until ranges get very long).
    So one minute of angle equals 2 inches at 200 yards, 3 inches at 300 yards, 4 inches at 400 yards, etc. etc. out to one minute of angle equalling 10 inches at 1000 yards.

    So, 4.3x9= 38.7 inches at 900 yards.
    And 4.3x10= 43 inches at 1000 yards.
    Putting out more words than everyone else put together isn't necessarily the best way to get your point across, particularly if you post obvious typos and simple mathematical errors that call into question everything in your post.
     
  8. lgbloader

    lgbloader Member

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    Got my son a used savage XP II 30-06, put a SWFA 10x I had laying about and can easily shoot to the 700 yd steel plate at Angeles range consistent.
    very happy with the 600.00 investment.
     
  9. Tophernj

    Tophernj Member

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    What my Ruger M77 did with a very loose nut behind the trigger at 100. No real load development.

    Sorry, the sight won't let me upload pics as it is already attached to another post (A for sale post) and i can't edit the aforementioned post to delete them from there as the editing time is up.

    I shot a .440 at 100 yards with a moderate load of Varget under a 167gn Lapua Scenar. FWIW, i am a sucky shot. Personally i was pretty happy with that group.

    C
     
    Last edited: Jan 2, 2016
  10. Bart B.

    Bart B. Member

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    Returning to this thread, I noted some issues with my numbers. I didn't make any mistakes; just weak in being right.

    Benchrest records I researched for 100, 200 and 300 yard 10-shot group aggregates were about .20, .27 and .35 MOA. Makes more sense than the 3.5 MOA at 300 I stated. 'Tis interesting that the biggest groups shot in those many group aggregates were about 50% bigger than the average.

    And yes, 4.3 MOA at 900 yards ain't 43 inches.

    Meanwhile, the reason they increase in MOA a little for each 100 yard range is bullet BC and muzzle velocity spreads as well as variable atmospheric conditions most of which are those subtle cross winds we cannot see. The winds are not constant throughout the bullets trajectory. Winds closest to the firing line have a greater effect on drift at the target than winds close to the target. And winds above the line of sight are typically faster than in the line of sight; it varies with the terrain that disturbs airflow. With a .308 Win shooting at 1000 yard targets on flat land with high grass, if the wind from 9 or 3 o'clock is 7 mph in a horizontal line of sight, at the max ordinate at about 570 yards of 11 feet above the line of sight, the crosswind's about 14 mph.

    My definition for accuracy is different than most. All groups fired with a given system will range between zero and some units of measurement. I use the biggest group; that's what you can count on the vast majority of the time to encompass all shots fired. The biggest groups happen about as often as the smallest ones. The smaller the largest group is, the closer to zero the tiniest ones will be.
     
    Last edited: Jan 2, 2016
  11. d2wing

    d2wing Member

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    I was joking when I posted about 20 degrees each 100 yards. You knew you did not mean that. Another factor is bullet stability. A bullet must be perfectly concentric, the mass distributed perfectly and the muzzle perfect as well. All of these factors can cause wobbles or yaw. Since the center of gravity in a bullet tends to be toward the base. Any imperfection would cause more dispersion as distance grows. Larger, faster, and faster spinning bullets would be more stable at greater range. Just my thoughts. Thanks for explaining that.
     
  12. adcoch1

    adcoch1 Member

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    Wow, sarcasm is not your friend on here! All kidding aside, this discussion about the math side of long range, and all the factors to think about is great for those of us who don't get to shoot long range very often. Reading this is like a mental day at the range.
     
  13. Poper

    Poper Member

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    Here's a target from my bone stock Tikka T3 Lite in .270 Winchester at 500 meters: (Post #13). Scope is Vortex 6.5-20x40.
    http://www.thehighroad.org/showthread.php?t=768159

    I'd say that's acceptable accuracy in a budget rifle. :)
     
  14. RoyRogers

    RoyRogers Member

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    Interesting and educational discussion. When referring to minute of angle, as in MOA, more properly I believe we mean minute of arc.
     
  15. Bart B.

    Bart B. Member

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    MOA has meant minute of angle in the USA shooting sports for well over a hundred years when it was first used. It was then based on 1 inch per hundred yards as rifle targets had inch-based spacing scoring rings and sights were made to adjust in exact inches per hundred yards for simplicity. The ~4.7% error from exact was never a problem until the 1960's when cheap hand held scientific calculators were available.

    Minute of arc is a good term for folks insisting a MOA equals 1.0472 inch per hundred yards.
     
  16. greyghost01

    greyghost01 Member

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    Try the Savage 10FCP-SR in 20" you will love it, BEWARE the cabelas rifle is NOT accu stock at least a bunch of guys are p.o. because they bought them and they were not accu stock. I paid 685.00 for mine mail in rebate of 100.00 so cost 585.00 very good deal.
     
  17. ZWCoffindaffer

    ZWCoffindaffer Member

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    It's a little beyond what I wanted to spend and I'm not usually into the "tactical" looking guns but I have become extremely intrigued with the ruger precision rifle. May need to shake the piggy bank a little and see what's in there
     
  18. Steel Horse Rider

    Steel Horse Rider Member

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    If you are just wanting to shoot 500 yards plus for fun get a Swiss K-31. I can ring an 18" x 26" steel gong at 600 yards with open sights pretty easily. If you want to compete spend thousands and listen to the experts here.
     
  19. Bart B.

    Bart B. Member

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    A Savage FTR in 308 Win costs a little more than a Ruger Precision but has an excellent record for long range accuracy in competition. Probably shoots test groups 1/3 the size of what the Ruger will do. The Ruger Precision's 20" barrel limits its acceptable accuracy range to about 600 yards.

    Ruger built 20 custom rifles as best they could for the USA Palma long range rifle team. They were called tub guns. The best of them shot washtub size test groups at 1000 yards.

    I suggest the 308 Win as the cartridge as it's the best compromise for ease of reloading, accuracy, barrel life and ease of shooting precisely. A 24" barrel is minimum to keep several bullet weights supersonic to 1000 yards; the FTR barrel is 30" and its 1:12 twist will shoot 150 to 200 grain bullets very accurate through 1000 yards. After its shot out for best accuracy at about 3000 rounds, have its barrel set back 2 inches and it'll be good for 2000 more very accurate rounds of barrel life with 168 to 200 grain bullets.
     
    Last edited: Jan 5, 2016
  20. ZWCoffindaffer

    ZWCoffindaffer Member

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    Im wanting the 6.5 Creedmoor, It comes with a 24" barrel. I will look into the savage though. Ive heard good things about savage accuracy.
     
  21. Bart B.

    Bart B. Member

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    Right you are on barrel length; I looked at a different one, not the Creedmore.

    My biggest concern is the Precision's barrel has hammer forged rifling. That's not good for best accuracy. Never used in rifles producing best accuracy. And the Creedmore has a little over half the barrel life as the .308 Win.

    What size target do you want to hit with 80% of your shots and at what range?
     
    Last edited: Jan 5, 2016
  22. Slinky556

    Slinky556 Member

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    I bought my Ruger American 308 for $325 brand new and set an $80 centerpoint scope on it 3 years ago. I consistently punch holes in paper at 450 but that's the furthest corner to corner I can shoot on my hunting property. The rifle is great and the scope has held zero without issue, no complaints at all. Love it
     
  23. ZWCoffindaffer

    ZWCoffindaffer Member

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    Why would the creedmoor have so much less barrel life? Its essentially the same cartridge with a smaller bullet? Higher pressure or something?

    I would like be able to consistently get every shot in a 12" target at 600 yards. I would like to be able land some shots in something a little bigger at 1000. I know it will require a lot of practice, but I hope to be able to hit at least a 3'x3' at 1000.
     
  24. adcoch1

    adcoch1 Member

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    There are others who can explain the exacting science behind it better than I can but when a cartridge is so small bored the velocity of the burning powder pushing through the cartridge neck erodes the throat of the chamber at a faster rate than a larger bore with the same powder charge. This leads to bad sealing of the bullet in the rifling and if bad enough, gas bypass of the bullet which deforms projectiles and further limits accuracy. As I understand it.
     
  25. farmerboy78

    farmerboy78 Member

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    Every savage that I have laid hands on will exceed what you are wanting... 12" @ 600 is a 2 moa target and 3' is about a 3.6 moa target @ 1000... once you figure out the rifles true trajectory with a specific load, getting to that distance is pretty easy if you do you part each and every time.... now the hardest part to figure out is the atmospheric conditions. It will give you the most trouble at doing what you're wanting to accomplish! I have become very confident out to 700 yds, but past that the wind and etc, has to be very consistent for me to be dead nuts...
     
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