James goes over barrel length and velocity for hunting long range with a 7 PRC

[Barbourcreek]

Thanks for the reply hopes this helps

All bullets work a little different
This is a general rule that cup and core bullets (lead core copper jackets) will expand at a minimum retained velocities of 1600 fps left on impact on an animal
I base this discussion on experience and testing

Retained velocity also is different at different station pressure or elevations

Rotational rpms left to stabilize the bullet is used to make sure the bullet is stable near transonic, we dont hunt in transonic but it guarantees stabilization at mach 1.4 - hunting distance or velocity. This is why we use a stability factor
1.6 minimum is my guidelines for my students

Thanks for the questions

 

[VinceMule]

Thank you James!

James, for me, I am some what sensitive to concussion. There seems to be one heck of a lot more concussion at 22 vs 26 with the brake I am using.

 

[Barbourcreek]

Thank you James!

You are welcome

 

[taylorms]

Great video. Thanks for the work.

I would like to request that you go to 18" on the 6.5 PRC, as I just built one and am very curious to see real numbers showing the drop off from 22" down to 18".

 

[bluedog69]

Awesome video! I teach math so I love the numbers.

 

[Barbourcreek]

Great video. Thanks for the work.

I would like to request that you go to 18" on the 6.5 PRC, as I just built one and am very curious to see real numbers showing the drop off from 22" down to 18".

Will do

 

[asd9055]

Episode 1 of 3
James goes over barrel length and velocity for hunting long range with a 7 PRC

James, Thank you for the video. As always, very educational. I am curious about the action. It sais Terminus Zeus, and had an allen screw on each side for "easy" barrel removal. Was that custom for you or standard on that action.
Thanks

 

[Allen Kitts]

Very interesting video. Thanks for putting it together.

 

[Barbourcreek]

James, Thank you for the video. As always, very educational. I am curious about the action. It sais Terminus Zeus, and had an allen screw on each side for "easy" barrel removal. Was that custom for you or standard on that action.
Thanks

Thank you nope. You can buy these direct from Joel at Terminus or if you order what we call a fuision Rifle from Barbour Creek it's the same action it's multi caliber, multi barrel.

 

[Takman]

Very informative. Thank you.

 

[comfisherman]

Do you have any thoughts on running faster powders with shorter barrels to minimize lost vel?

I've fair bit of confidence in answering this.

We did a good bit of playing with barrel length related experiments. Learned a lot of things.

1. Numbers guys/statisticians rain on the parade of preconceived hope in an outcome.
2. Ernie was right, fastesr powder combo at 26 inches will be fastest cut down.
3. Bullets on extreme ends of caliber spectrum loose more than "standard" for caliber.


We had thought there was some correlation, but the capacity of the tools we use to measure didn't pass the satastician smell test.

 

[RockyMtnMT]

I've fair bit of confidence in answering this.

We did a good bit of playing with barrel length related experiments. Learned a lot of things.

1. Numbers guys/statisticians rain on the parade of preconceived hope in an outcome.
2. Ernie was right, fastesr powder combo at 26 inches will be fastest cut down.
3. Bullets on extreme ends of caliber spectrum loose more than "standard" for caliber.


We had thought there was some correlation, but the capacity of the tools we use to measure didn't pass the satastician smell test.

Only makes sense that a faster powder that needs less barrel for full burn would lose less vel as the barrel gets shorter. Likewise for lighter bullets that perform best with faster powder than the heavier bullets. Less barrel needed for full potential.

 

[comfisherman]

Powder speed never made enough of an impact that it rose above data noise, was awash in significant figures. Only proved that the fastest load at 26 still was fastest short.

I'll say this, while I wasn't able to prove faster was better the fireball changed shape and color depending on powder and bullet. There were definitely combos that were harder to live with. Trying to remember what ramshot powder but it with an e tip for a 6.8 spc in a 270 wsm made a blue flame that felt like looking into a light bar. Made an unholy racket in the 16 inch tube.

 

[Monteria]

A load of H335 behind 110gr bullets from a 16" 30-30 will light grass on fire!

I've done a lot of testing before and after cutting. Never too scientifically, but short and long has always achieved the fastest velocity from the same powder in both, assuming the same bullet at both lengths. Not nessecerially the same accuracy though. On several occasions, I've noted better accuracy from faster powder after the chop.

Lighter bullets = faster powder for best velocity, 100%. You have to get to pressure. Can't do that with too light a bullet and too slow a powder combination.