I am trying to decide on optimal barrel length for M5E1 in 6.5 creedmoor. I want to shoot at no more than 1000 yards but at 1000 yards it must be a "kill", not just a paper punch. If additional inches give me just 1-5% improvement, I don't care and am willing to sacrifice them for better ergonomics of a shorter barrel. Suppressor in the future is not out of question but it's not critical. A lot of people are saying "at least 24" for 1000 yards" but I am not so sure. Currently considering Aero Precision but would consider other AR options in the same price range - probably that would be PSA only.
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Best barrel length for AR10 in 6.5 CR?
- Thread starter Kurbsky
- Start date
I'm of the opinion that 20" should get you to 1000 yards. You need more to go much longer. Here is some data showing some test results with different barrel lengths. You could plug those numbers into a ballistics program and calculate 1000 yard velocities.
https://www.bing.com/images/search?...tedindex=2&form=IRPRST&ajaxhist=0&vt=0&sim=11
https://www.bing.com/images/search?...tedindex=2&form=IRPRST&ajaxhist=0&vt=0&sim=11
To me AR style rifles are all about handling characteristics, especially if you're plan is to run a suppressor in the future. I wouldn't use longer than a 20" barrel and probably opt for something like an 18" on an AR-10 and 16" on the AR-15 as a suppressor will add in the neighborhoodof 5-6" of barrel length. An 18" barrel will keep you at 24" or less using a suppressor.
Plugging into JBM Ballistics App a MV of 2500 FPS for an 18" barrel and the 147 ELD bullet at sea level still has you supersonic to over 1300 yards. Staying supersonic makes shooting 1K easier, so understanding velocity and knowing it for your rifle is pretty important. So I recommend investing in a chronograph sooner than later as well.
Plugging into JBM Ballistics App a MV of 2500 FPS for an 18" barrel and the 147 ELD bullet at sea level still has you supersonic to over 1300 yards. Staying supersonic makes shooting 1K easier, so understanding velocity and knowing it for your rifle is pretty important. So I recommend investing in a chronograph sooner than later as well.
I am not an experienced long-range shooter - so I don't have specific velicity or drop requirements, but if a want a minimum 1 MOA at 100 yards, I would think it should be 10 at 1000 yards. I never reload - so it will be factory 6.5 CM ammo, not the cheapest but nothing too expensive either...probably a middle of the road Hornady.
stagpanther
New member
If you want something longer than 22" for an AR 10 you will likely have to go custom. There are plenty of 22" rifle+2" gas system barrels out there ready to go and they will get you out to 1000 yds. Keep in mind 1 MOA at 100 yds is not 1 MOA at 1000 yds--way too many variables come into the picture. Your choice of scope and ammunition will probably have more influence than an inch or two of barrel length--unless you truly want a match-grade behemoth boat-anchor rifle.
Thank you. At 1000 yards I believe reasonable and logical expectations should be 10 MOA. You know better than me" I would think. Anything longer than 24" is too bulky. Standard Aero M5E1 barrels are 18 to 24 inches anyway. No need to go custom. The % difference in velicity bettween 24" and 20" (Hornady ammo) is only 2.27%. That is negligible IMHO, unless you go to a competitive shooting where every millimeter matters. Is 20" barrel the way to go?
stagpanther
New member
What I meant was the accuracy of a rifle is not straight linear--if it can do 1 MOA at 100 yds that doesn't mean it can also do 1 MOA (10" +/-) at 1000 yds since at that distance other variables come into play. Your best bet in my opinion is something between 20 and 22 inches with rifle + gas system (unless you're going piston). All my creedmoor ARs are 22" barrels. Get a fast twist since you'll likely be shooting bigger bullets.Thank you. At 1000 yards I believe reasonable and logical expectations should be 10 MOA.
Do you think it'll shoot 10 inches at 1000 yards if it shoots 1 MOA at 100?I am not an experienced long-range shooter - so I don't have specific velicity or drop requirements, but if a want a minimum 1 MOA at 100 yards, I would think it should be 10 at 1000 yards.
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A rifle that shoots 1MOA at 100yds should do 10" at 1,000 yds, but only expect that if you are shooting inside a 1,000yd tunnel with no wind to affect bullet flight.
Outdoors (in the real world) there is ALWAYS wind, and it can be half a dozen different directions and speeds between you and that 1,000yd target.
that tends to make groups ...open up a bit...
And that's where you're going to get that "paper hit, not kill shot" and why.
Outdoors (in the real world) there is ALWAYS wind, and it can be half a dozen different directions and speeds between you and that 1,000yd target.
that tends to make groups ...open up a bit...
And that's where you're going to get that "paper hit, not kill shot" and why.
A rifle that shoots 1MOA at 100yds should do 10" at 1,000 yds, but only expect that if you are shooting inside a 1,000 yd tunnel with no wind to affect bullet flight and all bullets leave at the same velocity, LOF angle to the LOS and have the same ballistic coefficient.
A 50 fps velocity spread can cause a 1/10th inch (MOA) vertical spread at 100 yards if all bullets have the same ballistic coefficient and atmospheric conditions are stable. At 1000 yards, the vertical spread will be 20 inches (2 MOA)
A 50 fps velocity spread can cause a 1/10th inch (MOA) vertical spread at 100 yards if all bullets have the same ballistic coefficient and atmospheric conditions are stable. At 1000 yards, the vertical spread will be 20 inches (2 MOA)
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stagpanther
New member
I can't prove it exactly, but my experience has been for DI creedmoor barrels 22" along with rifle + 2" has given what I believe is the optimal balance (along with an adjustable block) for the creedmoor, which I find is a "touchy" cartridge as you move up and down in bullet sizes and charge sizes. Yes--I should have said heavier bullets--1:8 should be plenty for all factory loads, I have them in both 1:7 and 1:8 as I occasionally stray into "heavy and hot" that exceed SAAMI COL dimensions. Just my opinion, take with grain of salt. I advise calling a barrel manufacturer and talk to them--most of them are happy to spend time explaining the intricacies and matching up something that should fit your desires.Mr. stagpanther You prefer 22". Bigger bullets are heavier bullets? Also, what is faster twist? Is 1 in 8 fast enough? Thanks.
I understand your point about better handling. I have 3 AR15s, one M1A .308 and want something semi-auto for 1000 yards. If I wanted to work at 600 yards, I would be fine with 18" barrel in .308. I wouldn't even consider 6.5 CR - what's the point? The issue herr may be with the caliber... 6.5CR appears to be better than 5.56 in windy conditions but things still do not look very stable with gusts of wind at 1000 yards. I still dont want a .50 canon or expensive Lapua.