16" or 20" barrel?

Discussion in 'AR-15 Discussion' started by Vincine, Nov 21, 2011.

  1. Vincine

    Vincine New Member

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    I’m looking at a couple of RRA’s 5.56/.223s to punch paper out to 300 yards in the spring.

    Both have heavy chrome molly barrels with 1:8 twists and promise .75 MOA. One is a 16”and 7 pounds, the other is 20” and 8.4 pounds. All other things being equal, what does an extra 4” get me marksmanship wise, if anything?

    They also offer a 24”, 1:8 at 9+ pounds with no increase in accuracy. Why?
     
  2. pagj17

    pagj17 New Member

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    Well, you get yourself 1.4 pounds more weight, and a higher velocity, which leads to slightly better ballistics, and some would say "a more accurate" barrel.
    It all comes down to personal preference.
     

  3. Yunus

    Yunus New Member

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    I'm not knowledgeable enough to speak scientifically on this subject, I can only pass on what I have read. Accuracy from a barrel is more than just how long it is. How sturdy it is is a major factor as well. Length will give you higher velocity but also worse harmonics assuming the girth of the barrel doesn't increase as well. I tried to find the article that I have seen on the internet that had a good matrix of testing done to show this but I could not find it anywhere.

    I would go with the 16" one because it will be easier to carry without bumping into things.

    Barrel Length v. Accuracy Test
     
  4. Vincine

    Vincine New Member

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    Yes, but I guess the question is; Is the slightly better ballistics even going to be apparent on targets between 100 and 300 yards?

    (300 yards is the longest range available to me.)
     
  5. Yunus

    Yunus New Member

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    Don't forget the other factor in accuracy of a gun, the shooter. More weight, especially when it's far away from your body is going to make it harder to hold on target.
     
  6. Vincine

    Vincine New Member

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    Yeah, okay, so the additional accuracy provided by the length, if any, is more than given away if one is hand holding.
     
  7. Yunus

    Yunus New Member

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    It will vary shooter to shooter. I have a Howa 1500 in .223 with a 24" varmint barrel on it. From a rest this thing will shoot 1/2 MOA. In my hands unsupported standing, I shoot 1.5-2 MOA. I am the weakest link in the accuracy of that gun.
     
  8. Vincine

    Vincine New Member

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    Wow!​

    I think I just got it. The 16” for mobile shooting, the 24” is bench rest, and the 20” is the compromise.

    So, either get the 20”, OR get the 16” now, and get a 24” barrel in the admittedly unlikely event I max out on the 16”.

    Does that sound like a plan?
     
  9. JonM

    JonM Moderator

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    Depends on if your using open sights or an optic.

    My opinion:

    Open sights you want as much sight radius as you can. The more weight you have forward of the reciever the steadier and more predictable the wobble of unsupported shooting becomes. With a proper sling free floated barrel and enough but not too much weight a unsupported position becomes almost as solid as shooting off the bench.

    24 inch barrels are way too front heavy for my tastes especially once you put a sling or optic or bipod on it. I like 20" because im not losing any real effectiveness past 300 yards and i have enough weight and balance to make good shots.

    16" i dont really like since its a compromise to a true m4 and rifle length mainly due to idiotic federal restrictions on short barrels and the loss of balance for longer shots. They work fine off a rest but try and balance one off hand and its a mess. The loss of a lot of sight radius is a huge no go for me.

    If i wasclearing buildings 16" might be tempting but i really dont see that happening.

    I wish rra offered a pencil barrel rifle length upper really fast light weight and still has full sight radius.
     
  10. Vincine

    Vincine New Member

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    Ah, right, I forgot about open sights.

    Really? Good to know, thanks.
     
  11. JonM

    JonM Moderator

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    20" a2 style rifles built for service rifle matches are real tack drivers. Ive got a rra a2 national match that is sub moa with open sights off a rest. They also make them with removable sights forr using an optic. I kinda wish i had gone the a4 route.

    Lots of match types get lead weights to put under the handguards to increase the weight for unsupported shooting.
     
  12. NickySantoro

    NickySantoro New Member

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    OP,
    Don't put too much emphasis on accuracy claims by manufacturers. Even inexpensive barrels are capable of more accuracy than most shooters can deliver. IMO, accuracy will be dependent on the shooter, ammo, trigger, sights, and barrel in that order.
     
  13. oldpapps

    oldpapps New Member

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    "I’m looking at a couple of RRA’s 5.56/.223s to punch paper out to 300 yards in the spring.

    Both have heavy chrome molly barrels with 1:8 twists and promise .75 MOA. One is a 16”and 7 pounds, the other is 20” and 8.4 pounds. All other things being equal, what does an extra 4” get me marksmanship wise, if anything?"

    I have a RRA with 20inch SS Bull barrel. I love the accuracy. I hate the weight.
    For target use only, go with the longest barrel just for the small increase in velocity. You want to punch paper at 300 yards.
    I also have a 16 incher to carry around, much nicer to tote about.

    This is what I got at 100 yards wobbling about, I have only a scope. I got tired holding all of the weight up and this was with my junk/play loads.

    Image070811small.jpg

    Enjoy and be safe,

    OSOK
     
  14. Vincine

    Vincine New Member

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    Whoa! That's what I'm talking about. This was the 20" right? What does the 16" look like?
     
  15. Vincine

    Vincine New Member

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    I've taken notes, thanks.
     
  16. Fumbles

    Fumbles New Member

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    Holy crap!! You shot that ......standing...handheld..at 100yds? All 20 rounds. No benchrest? That is pretty damn impressive shooting. Yikes!!:eek:

    What riflescope and mount are you using?

    Nice shooting.
     
  17. oldpapps

    oldpapps New Member

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    Actual I was sitting. Had three major surgeries last year and I don't stand long very well. And my range is a measured 95 yards, I could do a full 100 but that would put me under my metal car port and the reverberations between the asphalt and the metal is no fun.

    The Mega/Rock is a 20 inch RRA upper set on a Mega lower with a Bill Springfield 3 lb trigger group. The scope is a Hawke Endurance 30X30 Plex 3.5-10X50 scope. The 'Red Dot' was removed as having no use.
    I seldom pull the scope to the full 10X and take off my glasses when I shoot with a scope. I know, but it makes scene for me.

    100_2845.jpg

    My 16 incher is a 1970's vintage AR-180 that I carried in patrol cars for years and years. It is short range use only but very handy.

    Enjoy,

    OSOK
     
  18. Fumbles

    Fumbles New Member

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    Oh man that makes me feel a bit better oldpapps. I figured since you said you were wobbling and getting tired holding up the weight that you were standing.

    Now, when you say you were sitting...you were using a benchrest right?

    Either way, that is very impressive shooting. I have been away from rifles since I was in the military in 1972, but in the two times out so far, with my new AR, I've managed to shoot a few tight-ish 3 round groups in the bull at 100yds. But the stock trigger is not conducive for that kind of accuracy, on a consistent basis.Hoping the Geissele trigger will help.

    But 20 rounds.......yikes! You have that rifle down pat. Too bad about the wind puffin' up and blowing those two rounds out the square:p...... and the bright sun blinding you for a second making you pull on that one a tickle low.:D

    I hope the recovery from the surgeries is going well oldpapp. All the best with that. I can relate somewhat, 4 major spine surgeries in the last four years. I'm good to go strength wise, I just don't fold up as well as I used to.
     
  19. Vincine

    Vincine New Member

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    Yeah, me too. .........
     
  20. oldpapps

    oldpapps New Member

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    "Fumbles
    Now, when you say you were sitting...you were using a benchrest...?"

    Sitting at a pick nick table with my back to the table and left foot on the seat, so stiff leg out and left knee for an arm rest, stable but tiring.

    Look at Bill Springfield's trigger work. He is listed on the internet. I'm sold on his work, granted it takes a touch of fitting to get it installed. But then, I have absolutely no over travel.

    The target doesn't care about excuses, so I don't either. This was just one of those groupings that came together. I was more surprised with how well my junk/play loads held together. Military pulled 55 grain FMCs stuck in mixed military brass.

    Two out of three surgeries went great. May have to have some more belly taken out later (not if I can help it). Worst part is I'm not allowed to drive my tractor any! Better part is I get to ride the 4wheeler to my target area. Nuff of this.

    My next build is to be a 16 inch, plain jane with a tight twist for heavier pills. Most likely will go with a RRA upper and build a lower from a stripped Mega.

    Enjoy and be safe.

    OSOK