Finding the perfect barrel length
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jpd676
Well-Known Member
Great video. Thanks.
Go to Varmintal.com
Look on the left hand side at topics, select light rifle with tuner
At the bottom of all this analysis is a little gem, here's the heading.
Barrel Length vs Accuracy & Muzzle Velocity
What he shows is that for .223 caliber the best accuracy is for 17 inches or so. But the curve is flattish out to about 22 inches, so you can go 22" to get more velocity without losing a lot of accuracy. So, 22 inches is fine for hunting for sure.
His analysis also shows as you would suspect different accuracy for different bullet and powder combinations. But not dramatic difference in optimum barrel length outcomes.
This analysis may differ some with higher magnum calibers and slower burning powders.
This site offers great insight into the whole science of barrel harmonics.
Look on the left hand side at topics, select light rifle with tuner
At the bottom of all this analysis is a little gem, here's the heading.
Barrel Length vs Accuracy & Muzzle Velocity
What he shows is that for .223 caliber the best accuracy is for 17 inches or so. But the curve is flattish out to about 22 inches, so you can go 22" to get more velocity without losing a lot of accuracy. So, 22 inches is fine for hunting for sure.
His analysis also shows as you would suspect different accuracy for different bullet and powder combinations. But not dramatic difference in optimum barrel length outcomes.
This analysis may differ some with higher magnum calibers and slower burning powders.
This site offers great insight into the whole science of barrel harmonics.
7.62 Gunner
Well-Known Member
I cant wait for all the 6' builds to start showing up in the mountains 
bt707
Member
Cool video. I like shorter rifle barrels personally. I run and 18in right now.
8 footer might be just right for Paul Bunyan....I cant wait for all the 6' builds to start showing up in the mountains
Aint he up in the Canadian outback somewhere?
Thats north of Idaho.....
comfisherman
Well-Known Member
We did a less cool version in 2011 with a 7 rum and a 270 wsm, with bullet weights from extreme light to heavy. Didn't really shoot for groups, we just wanted to see how velocity did. We have since done it with an older 300 rum at 33 inches.
More is better to a point. Less isn't so bad and then it really is... it's like a weird shallow d log e curve.
More is better to a point. Less isn't so bad and then it really is... it's like a weird shallow d log e curve.
Correct, and barrel harmonic changes on every cut while ammo stays the same. It simply was not their goal.
You can not possibly find the most accurate length simply by shooting groups. You would have to develop a load at each length and the costs of that in time and money is ridiculous. Generally speaking the shorter the barrel the higher precision capability and the longer the barrel the faster. Most cartridges never burn all the powder in the barrel lengths we run. This has been documented countless times by numerous individuals.
fnlights
Well-Known Member
Ryan - what barrel length do you find to be a good middle between precision and speed? Mainly in the magnum calibers like a 7 PRC, .30 Nosler, 338, etc on a hunting rifle (so weight can also be a concern).
Shocks me that a shorter barrel would have higher precision capabilities
It really depends on the game. Long range most including myself would give up some true precision to get the speed which will provide better ballistics. The thing we are all weakest at is reading the wind and the velocity does matter. I don't think most of us can shoot the actual difference in precision based on barrel length but we can shoot the difference the velocity affords. My personal compromise is 26". I don't understand suppressors and I don't understand short barrels unless you are traipsing through thickets in which case a precision rifle is not even needed and most would be better off with a gun from Walmart or a cheap rifle from a pawn shop.
Here is a simple summary from varmintal.com that I quoted in post 3 above.
Here they did take into account different powders, same bullet at each barrel length. It was for the .223 as I pointed out in post 3 above.
BARREL LENGTH VS ACCURACY.... Richard Lomax at AccurateReloading.com used a Sako S 491 rifle in 223 Remington caliber for the test. He shot 5-shot groups with 3 different powders as he proceeded to shorten the barrel on the rifle. It is difficult to see the trends in the data tables posted here at http://www.accuratereloading.com/223sb.html. I used Richard Lomax's data and created plot files of the data so the trends can more easily be seen. Here are the complete set of curves I used to view the data and show the trends.
ACCURACY SUMMARY.... Collecting the three average group size curves on one plot shows that a barrel length of between 16 to 17.5" in length
appears to produce the smallest groups and the best accuracy.
Interesting, once you find the best powder for group, it stays that way
at each bbl length in this example. The answers for different powders don't really appear to radically change the optimum barrel length for accuracy ie good groups either.
