was bored at the range with a 6.5 grendel and a hacksaw!!!!

[fmsniper]

So I took a 4 day weekend for veterans day and went to the range with my 24 inch 6.5 grendel.
I wanted to find the correct harmonics for the load I was shooting, 123 Hornandy Amax

I shot a group at 200 yards in 1.5 inch
I took a hacksaw and cut off 1 inch debured the crown and next 4 shot group was .7 inch group
I took another inch off and the group opened to 1.7 inch
another inch and 1.5 again
last inch as I am cutting it down to a 20 inch rifle for my wife and the group are around 1 inch @200 yards
I will pull the barrel tonight and toss it on the lathe true it and recrown.

observations:

the shot group went higher as the barrel got shorter, after 4 inches cut, my shot group went up 4 inches at 200 yards
for Amax Hornandy factory ammo and the AR Stoner barrel I used, 23 inches gives the best accuracy for me.

[JohnOD]

It would have been interesting to shoot over a chronograph at the different barrel lengths as well...

[fmsniper]

broke mine last year never got another

[LRRPF52]

I wonder if the critters will notice?

Interesting project. The bench rest guys did those tests with the 22 PPC, 6mm PPC, and .308 back in the day in Texas in a warehouse, and found that 21.75" was the most accurate barrel length for some reason across those calibers.

But no bit of information was, Virgil believes, more valuable than a little advice Jim Gilmore passed along. Jim said a barrel MUST be 21 3/4” long for optimum accuracy. That precise length, he stated, sets up a vibration pattern that duplicates well from shot to shot. Virgil faithfully followed that advice on his guns.

Anyone who strictly observes the 21 3/4" doctrine will screw off a failing barrel of that length and run a new one under it. Rechambering and rethreading, in order to achieve more pristine lands just forward of the throat, shortens the barrel. Shorten the barrel, spoil the magic length.

Through the years, the Houston Warehouse shooters were able to rate the relative accuracy of the various benchrest calibers — .22, 6mm and .30. In the perfect conditions of the warehouse, the .22’s outshot them all, followed closely by the 6mm’s. The .308 calibers were a not-too-distant third. The most accurate .30 caliber ever to find its way into the warehouse also belonged to Virgil. The rifle, built around a Shilen DGA action with McMillan barrel, shot consistently within a few thousandths of .100". The barrel length? You guessed it: 21 3/4".

http://www.angelfire.com/ma3/max357/houston.html

[Michael]

Any input on how a compensator would effect this 21 3/4" perfect length?

[LRRPF52]

Any input on how a compensator would effect this 21 3/4" perfect length?

They were shooting bull benchrest barrels, so I can't say. I suspect it has to do with longitudinal shock wave theory, since length was the only variable.

[JohnOD]

LRRPF52 I read THAT "Huston Warehouse" story in a shooting magazine years ago... its a great read.

[fmsniper]

Well i cut the crown Monday I will get to the range Saturday(weather dependent) and see how it does

[wheelguner]

Here is a link to "Secrets of the Houston Warehouse" and it is an interesting read.

http://www.angelfire.com/ma3/max357/houston.html

[Smud Dude]

Wow. Just wow.

[MrFrankZ]

Here is a link to "Secrets of the Houston Warehouse" and it is an interesting read.

http://www.angelfire.com/ma3/max357/houston.html

"Nice bullseye, now show me your 5-shot group"

"I did"

[usmc1371]

That was a great article. I wonder if anyone is willing to cut up their expensive bbl.

[fmsniper]

well 100 yards it shot great with the new crown, .5 moa
But opened up at 200 yards to 2.5 inch
time to cut it some more going down to 19 inch