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Posted: 4/3/2013 6:37:10 PM EDT
| I'm nearing that point of finishing my first build. Now I'm trying to gather some info on the best type of barrels. I'm building a lightweight spr and I'm leaning more towards an 18" barrel. My question, is there really that big of a difference in accuracy between an 18" barrel and a 16" barrel? I know that an 18" barrel produces better bullet harmonics ballistics, but not sure if it really matters. I'm look for a good grouping out to about 200 yards. Thanks in advance. |
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longer barrels are more accurate when using iron sights, as a matter of geometry. when using optics, there is no difference I am aware of.
a longer barrel will give you more velocity, which is always better for ballistics, range, and terminal performance. for that reason, I own no 16" barrel ARs. I spend much effort obtaining optimal velocity when handloading, so I do not unnecessarily shorten barrel length. my 2 cents. |
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I used a 18" barrel on my SPR build to get the rifle gas system. I used a PRS stock and a JP enhanced spring and a rifle buffer. Shoots pretty smooth.
If I was going with a 6 position stock that was running a carbine or midlength gas system, I would have used a 16" barrel. I built a 16" REECE rifle with an adjustable length EMOD, a Comp, and a mid gas and it shoots pretty smooth as well. As mentioned, at 200yrds a 16" will suit you just fine. I built my 18" with the idea of shooting to 600yrds. My 16" REECE will ring steel plates at 340yrds pretty effectively so a 16" at 200yrds would be easy-peasy. What stock do you plan on running? |
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Quoted:
I used a 18" barrel on my SPR build to get the rifle gas system. I used a PRS stock and a JP enhanced spring and a rifle buffer. Shoots pretty smooth. If I was going with a 6 position stock that was running a carbine or midlength gas system, I would have used a 16" barrel. I built a 16" REECE rifle with an adjustable length EMOD, a Comp, and a mid gas and it shoots pretty smooth as well. As mentioned, at 200yrds a 16" will suit you just fine. I built my 18" with the idea of shooting to 600yrds. My 16" REECE will ring steel plates at 340yrds pretty effectively so a 16" at 200yrds would be easy-peasy. What stock do you plan on running? I'll most likely be running a 6 position STR or ACS-L. I'd like to get the UBR but it's a little out of the price range. I'll also probably go with a mid-length gas system. |
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I used a 18" barrel on my SPR build to get the rifle gas system. I used a PRS stock and a JP enhanced spring and a rifle buffer. Shoots pretty smooth. If I was going with a 6 position stock that was running a carbine or midlength gas system, I would have used a 16" barrel. I built a 16" REECE rifle with an adjustable length EMOD, a Comp, and a mid gas and it shoots pretty smooth as well. As mentioned, at 200yrds a 16" will suit you just fine. I built my 18" with the idea of shooting to 600yrds. My 16" REECE will ring steel plates at 340yrds pretty effectively so a 16" at 200yrds would be easy-peasy. What stock do you plan on running? I'll most likely be running a 6 position STR or ACS-L. I'd like to get the UBR but it's a little out of the price range. I'll also probably go with a mid-length gas system. Then I'd say go with a 16" barrel. |
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Ok,
My take on bbl length. The longer the bbl the better velocity and more energy transferred to the projectile... Now, the point of dismissing return seems to be 21" in my testing over the last few builds... My "sniper" or distance precision build is a 20" match bbl with rifle length gas system with a full free float rail and a Harris bipod...running a vortex 6-24x50 ffp scope...and the required backup sights are not there...this rig I wanted the scope as low as possible so didn't leave room for buis.. 
That's early winter testing... Now, I run a lot of 16" rigs too...and I feel they are quite a bit mor accurate than any sbr...this is most likely feel... Now, I also own a farm so I usually shoot 100m plus for just about anything... I'm not a fan of sbr's just don't like the feel... So, if you want a bit more speed and energy into your projectile go at least 16" or more... And to answer the question about accuracy...yes and no..l The both have the same accuracy in no wind and no elevation change shots...but, they are rarely any no wind shots... So, your bullets is still effected by gravity, wind motion, and bullet spin drift...now if you bullet is faster then it would be effected less by these factors, and given most people asking about bbl length are not quite up to carrying thier dope book with them or having someone call the dope after initial rounds...I'd say for all practical reasons yes a longer bbl is more accurate, or less effected by mother nature... Anyhow, length is a personal choice...if this is your first build...go with a 16"...it's a great weapon to 400m easily...and you'll know if you like the length or want longer... There is not 1 ar that can do everything... I've got my personal weapons: 16" all black vltor stock, ASAP, blam with tlr1hp, trijicon acog/rmr...this is my new gtg weapon for on property or non cqb use, even bug out rifle...spare Bol/pin and batteries, compas, etc...on board... Then my bedroom weapon, 870p My distance rig mentioned earlier... Now between those three I've got most things covered...but I still have pistols and deer rifles, etc...and I try to standardize as much as possible... So, first build go 16" you don't have to pin the flash hider and limit things for later and carbine length with an h2 buffer I'd suggest to start... Bret... P.s. I've been posting pics so I'll throw up a couple of them... 
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I have a 16in 1/9 twist that I can hit a 10in steel plate using stinky brown bear 55grain ammo. At 400yards.
The ammo makes a variation at that distance because it wasn't made consistent at the factory, but it's okay to tag metal at that distance. The hardest part is using a 3-9x50 that far. The round only hhits it hard enough to make a "ting" noise. My friend has a 270 that will put a pretty good swing in it. I'm just happy to hit at that distance. |
| Thank you guys very much for your input. I am still leaning toward an 18" because I already have a s&w 15-22 that I use to plink. And I'm about 6'2" 240 so I don't think the extra weight will bother me. I'd like to have a little more velocity to make up for the small round. |
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Thank you guys very much for your input. I am still leaning toward an 18" because I already have a s&w 15-22 that I use to plink. And I'm about 6'2" 240 so I don't think the extra weight will bother me. I'd like to have a little more velocity to make up for the small round. I understand, but the Main reason isn't weight or velocity for shorter bbl... It's where you will be using it... In a vehicle, small quarters, etc...the shorter to a point better... I myself even inside my house have very open shooting...and I'm on a farm...so cqb isn't a big concern for me... Now, the reason people will go through the trouble to legally buid a short bbl rifle is for cqb... Close quarter battle... I suggest everyone start off with a 16" if in any doubt...that is the shortest bbl without going through paperwork or pinning on a flash hider and making some changes much more complicated... I'm sure you'll end up changing things around by the time your done... Bret |
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Quoted:
longer barrels are more accurate when using iron sights, as a matter of geometry. when using optics, there is no difference I am aware of. a longer barrel will give you more velocity, which is always better for ballistics, range, and terminal performance. for that reason, I own no 16" barrel ARs. I spend much effort obtaining optimal velocity when handloading, so I do not unnecessarily shorten barrel length. my 2 cents. Hopefully you will not be required to do any close quarters work, you may damage a lot of drywall. |
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Thank you guys very much for your input. I am still leaning toward an 18" because I already have a s&w 15-22 that I use to plink. And I'm about 6'2" 240 so I don't think the extra weight will bother me. I'd like to have a little more velocity to make up for the small round. I understand, but the Main reason isn't weight or velocity for shorter bbl... It's where you will be using it... In a vehicle, small quarters, etc...the shorter to a point better... I myself even inside my house have very open shooting...and I'm on a farm...so cqb isn't a big concern for me... Now, the reason people will go through the trouble to legally buid a short bbl rifle is for cqb... Close quarter battle... I suggest everyone start off with a 16" if in any doubt...that is the shortest bbl without going through paperwork or pinning on a flash hider and making some changes much more complicated... I'm sure you'll end up changing things around by the time your done... Bret Good advice there. |
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