16" vs. 24" barrel question

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12 years 8 months ago #11204 by clubmanager
Hi,
I recenlty purchased a used Armalite AR10 with 16" barrel. At the same time, I got a used Zeiss Conquest 3-9x40 scope with tactical recticles to 600m. I've since found out that the Zeiss is meant to be used with a 24" barrel.

Will the 16" barrel affect range to the point where I will need to change either the scope or the barrel?

I can find a scope much easier than the barrel apparently but I did find a 24" barrel at Fulton Armory for a little less than $300....any thoughts on that?

My hope is to keep everything as-is because I like the 16" barrel applications coupled with the .308 power. I'm not going to shoot 1,000m but 4-600m is likely at the range.

The last option is to sell the Armalite and get a DPMS. I can get one with the 24" barrel for around $1100 and come out a wash give or take. I do like the one I have though....

thanks in advance...John

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12 years 8 months ago #11205 by JReaper
I have a AR10 w/match 20" barrel. MOA for my rifle is about .5 to .75, that's a 3" to 4.5" shot group at 600 yds. I would expect a 16" to be a little more than that and a 24" to be a lot less.

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12 years 8 months ago #11206 by jtallen83
No offense to DPMS owners but that swap wont be wash. Stick with the AR-10 and change the scope if you need. Armalite will not let you down.

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12 years 8 months ago - 12 years 8 months ago #11207 by faawrenchbndr
I had a LR308 that was a complete pig!
Could not get it to feed correctly, after six nmonths dealing with DPMS,
they replaced the entire rifle. I recently bought a AR10T with the sst
24" barrel.

I sold that barrel when I replaced it with a 21" Noveske.

Stick with Armalite
Last edit: 12 years 8 months ago by faawrenchbndr.

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12 years 8 months ago #11217 by Ekimnaheem

faawrenchbndr wrote: I had a LR308 that was a complete pig!
Could not get it to feed correctly, after six nmonths dealing with DPMS,
they replaced the entire rifle. I recently bought a AR10T with the sst
24" barrel.

I sold that barrel when I replaced it with a 21" Noveske.

Stick with Armalite


Yeah....And still waiting for that range report!! Have to look at that beautiful rifle here and on Arfcom and still haven't heard about the latest.... :cheer:

And to the OP... I just saw a 20" go for under $200 and faawrenchbndr just sold his 24", so they are floating around in your price range, especially of you put that 16" up for sale.

Before you go switching out anything though, I would give it a chance at the range. Think you are in for a pleasant experience with your setup!

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12 years 8 months ago #11218 by jtallen83
If you put that 16" up for sale let me know, a little voice in my head keeps telling me to build a carbine upper for my AR-10!

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12 years 8 months ago #11224 by 13fcolt
For 400m-600m your 16" will be just fine. You can check youtube, a few videos of 1000m shots with a 16".
The issue with barrel length is often misunderstood. Longer gives more velocity, not accuracy. In fact a shorter barrel can be more accurate due be better harmonics. A 16" will be less flexy under the compressional vibrations of firing, meaning it will deviate less.
The point where longer barrels come into play is twofold.
1, Lower bullet velocity means it will drop faster, you could simply run out of elevation adjustment.
2, The common occurrence of bullet instability as it slows through transonic flight is velocity dependent. ( it is also related to a projectiles Ballistic coefficient, how fast it sheds its velocity)
High BC bullets, with improvements in aerodynamics and propellants is a large part of why many shooters are replacing 24" barrels with 20" or even 18" and still enjoying success at the infamous 1000m line over the last 10 years or so. Also, the increased rigidity of the shorter barrels is aiding in making those groups smaller than they were with the previous technology.

At the end of the day, accuracy as it relates to barrels, has more to do with the quality than anything else.

I vote shop for a scope that best suits your intended shooting interest.

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12 years 8 months ago #11240 by JReaper
That's good information! I didn't know that or I would have gone with a 16" barrel instead of a 20".

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12 years 8 months ago #11243 by clubmanager
I'm so glad to hear all of that. Going to the range next weekend and will let you know how it goes. Pretty sure I'm just going to stick with it and get a difference scope if it's necessary.
I've asked someone at Zeiss to help figure out if mine is suitable considering their calculator doesn't allow for barrel length.
My goal is to have two so I may get the other in 20 or 24" depending on range, but either way, I think this one is a keeper!

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12 years 8 months ago #11251 by mts
Replied by mts on topic Re: 16" vs. 24" barrel question
As stated, you are not going to see the difference in barrel length until you move out to 600 yds and beyond. Higher speed pushes the transonic point to longer range and therefore affects long-distance accuracy the most. Longer barrels mean more problems finding a load that produces harmonics giving consistently accurate results.

My take on the bottom line is that shooting groups at 100 or 200 yds is only a starting point. There is no guarantee that you will be getting similar results at longer distance. With an Armalite rifle you have in my opinion the best that can be had, but it can be equalled by the competition with proper attention to loading.

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