Barrel Length

[bluemark]

How much does barrel length impact longer range shooting? I just went to a Savage lightweight hunter in .270 with a 20 inch barrel, from a Ruger M77 7MM Mag.

 

[rekkr870]

It only affects velocity.

I find that shorter barrels are more “accurate” per say. Probably due to the stiffer nature and less barrel whip as compared to the longer barrels.

The shorter barrel’s loss in velocity can be compensated for with modern scopes with a ton of elevation in its internal travel.


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[Wapiti1]

Yep. Velocity is the trade off with barrel shortening. Compensate by using the highest BC bullet you can and shorten your max range.

Unfortunately, with a .270 you are hamstrung by bullet availability and rifling twist. I'd look at rebarreling that rifle.

Jeremy

 

[JimCraig]

As barrel length decreases, muzzle velocity also decreases. The slower the projectile is flying through the air on the way to the target, the longer it is affected by conditions like gravity, temperature, barometric pressure, and wind. A projectile's slower velocity in not simply just "compensated" for by dialing more elevation in the scope.

 

[jstamper1979]

It’s all about compromise between velocity and weight/handling characteristics for your intended use. Good quality barrels can be accurate no matter the length.

For long range hunting, impact velocity is important for terminal performance once you make a hit, so that’s another factor that plays into your compromise.

Loss of FPS per inch of barrel length varies among chamberings. In any case, you don’t know how fast your rifle is shooting unless you use a chronograph, or you can back-calculate a pretty good guess based on your confirmed drops. That’s where I’d start; chronograph your rifle. Then you’d have the only real answer to your question.

 

[Big Ern]

Barrel length (not talking extreme barrel lengths; thinking more in the 20” to 24/26” lengths) isn’t gonna have a dramatic impact on your hunting distances ie 500 yds and closer. Sure, a few additional adjustments, but not that big of deal. Also, Caliber and bullet selection i(both weight and bc) are important for longer distances.

Example: I shoot 6.5cm. Hunting rig has a 20” proof barrel on it. Comp rifle has 24” bartlein.


20” barrel muzzle velocity = 2,605 fps (143 eldx)
24” barrel muzzle velocity = 2,705 fps (143 eldx) (note: 2,798 fps with 140 berger hybrid which has great bc)

Mil adjustments 500 yds:

20” barrel: 3.1 mils (bullet 143 eldx)
24” barrel: 2.8 mils (143 eldx) ((2.6 mils w/ 140 berger)

0.3 elevation difference with same hunting. (0.5 vs the faster 140 berger)

a 1,000 yds:

20” barrel: 9.5 mils
24” barrel: 8.7 mils (8.0 mils w/ 140 berger)

0.8 elevation difference. (1.5 mil delta vs 140 berger)

With regard to wind, both rifles are 6mph guns with the 143 eldx. Same wind adjustments at each distance. The lighter 140 berger in the 24” is a 7mph gun.

 

[Pacific_Fork]

Good info here guys. Im kicking myself on my resent proof upgrade on my 6.5x284. I should have gone 20-22 over 26" to shave a little weight on my heavy ish rifle. Next build!

 

[amassi]

Good info here guys. Im kicking myself on my resent proof upgrade on my 6.5x284. I should have gone 20-22 over 26" to shave a little weight on my heavy ish rifle. Next build!

At that length a step down in cartridge would also make some sense

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[Pacific_Fork]

At that length a step down in cartridge would also make some sense

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Like a CM? I like the Norma because I can get a few hundred more FPS out of it.

 

[amassi]

Like a CM? I like the Norma because I can get a few hundred more FPS out of it.

A 20" cm or 260 might be close to a 20" norma with less powder, muzzle blast and throat erosion.

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[manitou1]

Barrel length (not talking extreme barrel lengths; thinking more in the 20” to 24/26” lengths) isn’t gonna have a dramatic impact on your hunting distances ie 500 yds and closer. Sure, a few additional adjustments, but not that big of deal. Also, Caliber and bullet selection i(both weight and bc) are important for longer distances.

Example: I shoot 6.5cm. Hunting rig has a 20” proof barrel on it. Comp rifle has 24” bartlein.


20” barrel muzzle velocity = 2,605 fps (143 eldx)
24” barrel muzzle velocity = 2,705 fps (143 eldx) (note: 2,798 fps with 140 berger hybrid which has great bc)

Mil adjustments 500 yds:

20” barrel: 3.1 mils (bullet 143 eldx)
24” barrel: 2.8 mils (143 eldx) ((2.6 mils w/ 140 berger)

0.3 elevation difference with same hunting. (0.5 vs the faster 140 berger)

a 1,000 yds:

20” barrel: 9.5 mils
24” barrel: 8.7 mils (8.0 mils w/ 140 berger)

0.8 elevation difference. (1.5 mil delta vs 140 berger)

With regard to wind, both rifles are 6mph guns with the 143 eldx. Same wind adjustments at each distance. The lighter 140 berger in the 24” is a 7mph gun.

Are you talking 1 mil per 6 mph? Just curious. Never heard it put this way... but am not a target shooter.

 

[Big Ern]

.1 mil for every 6 mph (90 degree wind). This is for my rifle/load based on my muzzle velocity, bullet, etc. below is how you figure it out.

An easy way to figure out Your rifle/wind mph is to find your 600 yard wind so it equals .6 Mils (hold) at 600 yards. This makes the math easy.

This would then give you the following:

100 = .1
200 = .2
300 = .3
400 = .4
500 = .5
600 = .6

From there you only use multiples of that mph.


for my 6mph rifle/load if I have a 12 mph wind then correction would be .4 mils at 200 yds; 1.2 mils at 600 yds. Wind direction at 1 o’clock, then 1/2 your wind correction.

an easy way to figure out the mph for your rifle is to just use your ballistic calculator; enter all of your data. muzzle velocity, barrel length, twist, bullet weight/bc, zero yardage, etc. Then enter in wind values in the calculator (at 90 degrees to the bullet path) until your wind hold at 600 yards is .6 mils. If that is 5 mph, you have a 5 mph rifle, or actually a 5 mph load.

now, the hard part is learning to read wind. Or use a kestrel if you have time.

 

[manitou1]

Well, that makes it easier. Sometimes a guy can feel pretty dumb for not seeing the obvious! Thanks.