Barrel length and accuracy

[Sisco]

This is a great article that stands conventional wisdom on its head regarding barrel length, velocity, and accuracy. A good read.

http://www.thetruthaboutguns.com/2013/10/daniel-zimmerman/the-truth-about-barrel-length-muzzle-velocity-and-accuracy/

[D.R.D.]

Don't forget to read the replies/comments on the bottom.  Some guys do an even better job explaining why the study/testing was extremely flawed.

[98Z5V]

There's already a very lengthy discussion about barrel length and accuracy in a few places on this board - here's the first topic:

 

 

Smaller thread, but some different links:

 

 

Those two topics there ^^^  pretty much cover it all. 

[Sisco]

I am planning to do my own workups on my rifle and carbine out to about 500 yards. Guess we will see who is right.

Read the comments, by the way, was not impressed by them. More along the lines of a fan in the bleachers critiqing a professional ball player. Some people always have to contradict.

Edited July 15, 2014 by Sisco

[survivalshop]

I am planning to do my own workups on my rifle and carbine out to about 500 yards. Guess we will see who is right.

Read the comments, by the way, was not impressed by them. More along the lines of a fan in the bleachers critiqing a professional ball player. Some people always have to contradict.

 

   As most know here  I'm doing the same , but will not do over 300 yards till early November . I'm taking an early bow hunt in late October. I will go check out the range with the longer yardage before this & will take both rifles , just in case . <thumbsup> 

  Its been fun so far & a lot of work to just get loads that shoot well out of both rifles with different weight bullets , to make a good comparison between the two . I believe there may be an slight advantage to the longer barrel , but not enough to make a shorter one into having a disadvantage .

[Sisco]

As most know here  I'm doing the same , but will not do over 300 yards till early November . I'm taking an early bow hunt in late October. I will go check out the range with the longer yardage before this & will take both rifles , just in case . <thumbsup> 

  Its been fun so far & a lot of work to just get loads that shoot well out of both rifles with different weight bullets , to make a good comparison between the two . I believe there may be an slight advantage to the longer barrel , but not enough to make a shorter one into having a disadvantage .

It will be interesting to see what you find. My last effort got knocked awry by a wind that made accurate shooting difficult and that kept blowing my chronograph over. I have settled on my rifle load of 42 gr RE15 behind 168 SMK BTHP. My next visit to the range I am going to compare that load to 41 gr RE15 behind a 175 gr SMK BTHP in the carbine. Might have to go to a faster burning powder in the carbine to make sure all the propellant burns up before it leaves the barrel. Hope not.

[N Jensen]

I just don't believe a short barrel rifle would outshoot a longer barrel rifle at distances 500yds and out. If anyone thinks a short barrel gun could win a rifle match, I suggest you head to Camp Perry and enter the long range championship. The match is fired at 600yds and 1000yds. There is also the palma match thats 800, 900, and 1000yds.

[Sisco]

I just saw the rifle that won last years Palma. A long sucker! It all boils down to when the bullet goes under the speed of sound. Then key holing starts. As long as the short barreled weapon bullets stay supersonic they can compete. But above 500 yards, it is going to take a lot more to do that. And eventually the longer barrel will always win out. With a 308 a carbine goes transonic around 500 yards. The study above looked only out to 500 yards, probably for that reason. The carbine and the rifle have a chance to be equal, but only at limited distances. After 8-900 yards, the 308 rifle loses out to the 300 Winchester Magnum for the same reason. And the 300 WM eventually loses out to the .338 Lapua.

[Pegasus]

I read the article in the OP and I must say that I had tears in my eyes halfway through it; it was that funny!

 

My favorite line was this one:

 

"There is a downside to longer ranges and reduced velocities, that being increase susceptibility to wind as range increases.  Increased drift is not the end of the world, though, and if measured properly, can be overcome with ease."

 

Truly words spoke be someone who has never shot beyond 4-500 yards in any type of competition.

 

There is a reason why F-class shooters and Palma shooters have long barrels on their rifle and I can assure you that if short barrels were just as accurate at long range, I would swap length for a heavier contour in a heartbeat. 

 

I see people coming to the 1000 yard line all the time with their 20 and 24 inch "tactical" rifles and then wonder why their bullets are all over the target or even off it in stronger winds.

 

I have been using a 32 inch barrel for 1000 yard competition for years and every last bit of velocity you can extract and still be in an accuracy node is worth it.

 

"Measured properly."  How in the heck can you measure the wind 750 downrange properly?  I difference of a couple of MPH in a full value wind will push the bullet out of the 10 ring and maybe into the 8-ring.  The slower the bullet the longer it gets buffeted by the conditions.

 

Also, you need to be more than just supersonic to be precise, you want to be outside the transonic range and that's from Mach .095 to about Mach 1.25.  And don't forget that while the speed of sound decreases only with temperature, the air resistance increases even faster the colder it gets, so your bullets will go transonic faster when it's cold.

[Matt.Cross]

I knew it! I'm building a 32" heavy-profile barrel AR-10, and when you chumps want to compare 1000 yd results, im gonna pull that bad boy off the flatbed trailer I had to bring it on and when two of you have helped me set it on the bipod, I'll outshoot everyone. That will settle the whole question.....

[EasyEJL]

The carbine and the rifle have a chance to be equal, but only at limited distances. After 8-900 yards, the 308 rifle loses out to the 300 Winchester Magnum for the same reason. And the 300 WM eventually loses out to the .338 Lapua.

that's really it right there. Practically, 99% of us won't shoot past 500 yards except once in a blue moon. If you're hunting wild hog and deer in florida, outside of the range you'll just about never shoot past 100 yards. so why lug around the extra weight if there isn't a real advantage?

[Matt.Cross]

I don't understand why this comparison is always drawn up by F-class shooters and the like, it's apples and oranges to the AR platform. The whole point(in the AR's case) is to be the best combination of reliable, portable, and accurate as can be achieved in a balanced manner. To that end, with regard to the platform this forum centers around, a shorter thicker barrel lends itself better to accurate shooting. If you care to offer contrary data, by all means share your results. An opinion based on F-class experience doesn't mean a whole lot to me in terms of an entirely different animal.

[blue109]

amateur. talk to me when you step up to a tripod.

[Matt.Cross]

amateur. talk to me when you step up to a tripod.

:D

I 'stand' corrected... :P

[Robocop1051]

This is an argument of accuracy vs accurate-enough.

F-class shooters are no closer to being a Sniper than any other Joe at the range. When our SF snipers stop using 16"-20" LaRue and KAC rifles... then I'll listen more to the F troop.

[StainTrain]

I don't understand why this comparison is always drawn up by F-class shooters and the like, it's apples and oranges to the AR platform. The whole point(in the AR's case) is to be the best combination of reliable, portable, and accurate as can be achieved in a balanced manner. To that end, with regard to the platform this forum centers around, a shorter thicker barrel lends itself better to accurate shooting. If you care to offer contrary data, by all means share your results. An opinion based on F-class experience doesn't mean a whole lot to me in terms of an entirely different animal.

Well stated, sir.

[Pegasus]

Interesting.  The OP posted an article that stated barrel length made no difference in accuracy and totally dismissed the concept of conditions at long range with the specific text I quoted in my original post.

 

I thought this was a .308 AR forum, where we can discuss .308 ballistics.

 

I shoot F-TR, which is all about .308 Win and as it happens, my AR-10(T) also shoots .308Win.  I have some experience shooting the .208 Win at long ranges and I am here to tell you that shooting that cartridge from an AR-platform is not going to enhance the ballistics of the bullet over what comes out of my match F-TR rifles.

 

I know what can be done with a .308 Win at long ranges and I know what it takes to get that level of performance out of that cartridge.  I do not expect anywhere near that level of accuracy out of my AR-10 and I have no intention of shooting it at these ranges but it's fun to read what some people claim to be able to do.

 

So, I just thought I would share some of my experience with .308 Win ballistics with people who shoot the same cartridge and maybe help set their expectations to a proper level.

 

I do look forward to seeing pictures of your 32 inch barreled 308AR.  What barrelmaker do you plan to use for that?

[StainTrain]

This is an argument of accuracy vs accurate-enough.

F-class shooters are no closer to being a Sniper than any other Joe at the range. When our SF snipers stop using 16"-20" LaRue and KAC rifles... then I'll listen more to the F troop.

Excellent point. Plus...once you move from punching paper to a walking, talking, thinking 10 rings, your needs and priorities change......I'm talking about deer hunting. Edited September 5, 2014 by StainTrain

[Pegasus]

I will also state that I have no delusions of being a sniper.  F-class is NOT sniping; it's F-class.  At 1000 yards, we have to shoot 15 or 20 consecutive rounds at a target where the X-ring is 5 inches in diameter and the 10-ring is 10 inches, and so on.  Our target does not move, does not fire back, and we know the exact distance to it and that does not change.  On the other hand, we do not have a spotter to feed us corrections and every one of our shots counts and is scored.

 

As you can see, it's totally different.

 

Since I am a civilian and old(ish), I have no expectations or desire of ever going out to snipe at people at 1000 yards.  I compete in F-TR and I also enjoy shooting my AR-10(T) at paper targets.  Since it's all the same caliber, there is some synergy going on here and what I have learned in F-TR helps me set up my AR-10(T), albeit for much shorter ranges.

 

If your goal is to emulate snipers, I fear there is little I can contribute.  But if you want to talk .308 out of an AR, well, that's different.

[edgecrusher]

Your insight will be appreciated, but in your off in saying you can't be an efficient shooter at 1000 yards with a tactical rifle. Chances are the guys you saw failing weren't proficient to begin with. With practice and load development I have no doubt my LaRue could easily hit 1000 yds with decent groups. It has a 20" barrel. I have never seen that distance, nor plan to. I don't train professionally for that distance. But I took it out to Arizona to meet up with some members here, walked it out to 550 yds shooting steel, having never shot farther than 300 prior. There was a learning curve, but with practice I have no doubt it can be done. (Especially since on the magpul dynamic training videos they were doing it with a 16" barrel consistently)

You first post came across a bit crass, and you drew the wrong end of the shit stick for replies. Some people do build/buy these rifles for those distances, and have success. It may not be common from what you've seen, but it can be done

[Pegasus]

I realize this will sound even more crass than my second post (my first one was in the introduction forum,) but I have more experience pushing .308 caliber bullets from a .308 Winchester than probably anyone here.  I have been doing this for 30+ years, starting with Fullbore, Palma and more recently F-TR at the local, regional, state, national and world level.  I shoot competition every month, year in and year out and then add to that regional, state, and national competitions and the Worlds every 4 years.

 

I live and breathe .308 LR.

 

What people seem to forget is that competitors (like snipers,) have to shoot in whatever the conditions are.  Can you get a nice 3-shot group at 1000 yards with your tactical rifle?  Absolutely, when the conditions are right.  Now, can you go out on command and push 15 to 20 rounds on the 1000 yard target and get the same group, every time, regardless of conditions?  While I can do that with my long barreled F-TR rifle, I don't even want to go there with my 20 inch AR-10, even if I used the same ammo as in my F-TR rifle.  That extra 250-300FPS makes a huge difference and that's what my point was.

 

I don't really care about the replies I got, they just come from people who have never shot at 1000 yards, because anyone who has ever done that would not be disputing what I said.   Given the same level of marksmanship, a rifleman with a long barreled rifle will perform better than a rifleman with a short barreled rifle at long ranges.   I stated that article was a joke and it still is.

[sketch]

What scope r u using ?

[Matt.Cross]

My point wasn't to question your knowledge or credibility Pegasus, but by your own admission your data is based on a platform vastly dissimilar to the one this community bases it's experience on... Are there common elements? Absolutely, no question about that, but by and large it's apples and oranges.

I'm sure your opinion is dead on in terms of the platform that informs it, but data speaks louder than opinions. Show me your proof in the AR platform, and watch me eat crow. Otherwise, I'll take your opinion to be what all opinions are, some hot air packaged with noise.

As for the 32" AR, I'd vastly prefer to build two 16"-ers instead ;)

I hope my facetious rhetoric didn't catch you off guard. Sorry bout that if it did. Finally, welcome to the forums here. Glad to have the insights of another long range competitor here!

P.S. Check out this short barreled 1k shot....

http://m.youtube.com/watch?v=jJ3XwizTqDw

[D.R.D.]

I believe we are here to contribute and support one another in a common interest.  Pegasus, your motivation for participating in this thread is unclear.  I do not wish to begin any sort of argument here, just continue the friendly interaction that is daily fare on his forum.  I will not respond to any derogatory remarks.  I respectfully ask that you give the same courtesy to others as they have shown you.  If not, will the moderator please close this thread?   

Edited September 6, 2014 by D.R.D.

[Robocop1051]

Again.... accurate vs accurate-enough.

Shooter: Travis Haley (Veteran, Force Reconnaissance Marine)

Rifle: Spikes Tqctical AR15 9" Barrel w/ suppressor

Ammo: 300Blk Subsonic

Distance: 750 Meters

You can fast forward to 07:10 for the goods

Watch the whole thing if you want to see how a Sniper... A truly accomplished sniper... views accuracy.