20" vs 24" barrel

[KimberPB]

I'm getting ready to start my next AR build. I've decided to build a long range 6.5 grendel AR. The only thing I can not decide is if I want to go with a 20" or 24" stainless bull barrel. I know the 24" will give me alittle more velocity but will I get any more accuracy out of it? Or are there any other pros/cons of going with a 24" over a 20"?

[festus]

There are pros and cons both ways. I have built a couple of tactical rifles, one with a 21" BBL and one with a 24" BBL. I prefer the 24"BBL due to it's ability to more efficiently use the powder burn for a slightly heavier round.
Both rifles were in 7.62 nato. The 21" BBL was a medium contour chrome lined FN/FAL and was an absolute tack-driver with 155gr Palma match bullets at 2700 FPS.
The 24" BBL is on a SAVAGE 10FP and makes the best use of twist rate and powder capacity with 180gr match grade bullets.
Both had Natl. Match head-spacing and have been air-gaged for accuracy. I was limited to Military powder burn rates for the 21" BBL but have been able to use civilian and military powders in the 24" BBL with excellent results.
Here is the bottom line. If you plan on hand-loading you will get more uniform velocity results with the longer BBL due to the increased powder burn area. This means less vertical stringing on long range shots. The fact that the front of the rifle is heavier, means that you will have less muzzle rise/flip and more control
The shorter BBL on the other hand will give you less harmonic vibration to dampen and consequently provide a more rigid platform for shorter range extended fire use. This is good for your overall group but hell on your shoulder and back.

Longer BBL=Heavier gun and more uniform velocity
Shorter BBL=lighter gun and easier to use a little closer in but brighter muzzle flash

You actual mileage may vary...

[KimberRB]

If it were me this is what I would do BUILD BOTH OF THEM!!!!!!!!!!!!!!!!!!! Its like a women and shoes you can never have to many. :i:

[KimberPB]

Originally Posted by festus

There are pros and cons both ways. I have built a couple of tactical rifles, one with a 21" BBL and one with a 24" BBL. I prefer the 24"BBL due to it's ability to more efficiently use the powder burn for a slightly heavier round.
Both rifles were in 7.62 nato. The 21" BBL was a medium contour chrome lined FN/FAL and was an absolute tack-driver with 155gr Palma match bullets at 2700 FPS.
The 24" BBL is on a SAVAGE 10FP and makes the best use of twist rate and powder capacity with 180gr match grade bullets.
Both had Natl. Match head-spacing and have been air-gaged for accuracy. I was limited to Military powder burn rates for the 21" BBL but have been able to use civilian and military powders in the 24" BBL with excellent results.
Here is the bottom line. If you plan on hand-loading you will get more uniform velocity results with the longer BBL due to the increased powder burn area. This means less vertical stringing on long range shots. The fact that the front of the rifle is heavier, means that you will have less muzzle rise/flip and more control
The shorter BBL on the other hand will give you less harmonic vibration to dampen and consequently provide a more rigid platform for shorter range extended fire use. This is good for your overall group but hell on your shoulder and back.

Longer BBL=Heavier gun and more uniform velocity
Shorter BBL=lighter gun and easier to use a little closer in but brighter muzzle flash

You actual mileage may vary...

Thanks Festus a lot of good info!

[KimberPB]

Originally Posted by KimberRB

If it were me this is what I would do BUILD BOTH OF THEM!!!!!!!!!!!!!!!!!!! Its like a women and shoes you can never have to many. :i:

Maybe I could talk my dad into sending some money may way so I could afford to build both! :headphone: