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.

FYI, I think the folks at the range thought I was nuts for cutting the barrel and shooting it

)))So no confusion, this barrel was getting cut down anyway to 20 inches regardless(((

 

[ChrisGarrett]

Too rich for my blood, but that's an interesting experiment.

You know, you could have just loaded hotter/softer rounds and looked for the low and high velocity nodes, right?

Chris

 

[saryan]

..........I would have too. Thats awesome. I would love to see a video of this being done...lol

 

[fmsniper]

yes I could have but the purpose was to cut it down to 20 inch for my wife to use for deer season, I figured why not test this since it is getting cut down any way

Too rich for my blood, but that's an interesting experiment.

You know, you could have just loaded hotter/softer rounds and looked for the low and high velocity nodes, right?

Chris

 

[BERTMAN77MK2]

I have had a few rifle barrels increase in accuracy when shortened, but never fired one until it was re-crowned!

 

[Rhyno]

Did you laugh maniacally while doing it?

 

[fmsniper]

I should have that would have done the trick

Did you laugh maniacally while doing it?

 

[McLarenross]

I have to say you are a braver man than I and sure went about shortening a barrel in a long and different way than I would have chose but props to ya for both the information gained and the original method.

 

[Smith97z71]

curious, what were your results after the recrown? Bet you wish you didn't cut past that .7 inch goup lol

 

[fmsniper]

yes on the .7 group but no issue like I said my wife will hunt with it no farther then 400 yards, after I cut it to 20 inch I verified the accuracy at 400 yards and it was around 3 inches so no issue.
I have my other 6.5 grendel that I use with a better barrel then the Stoner I cut.

as far as the re- crown, have not done it yet, I will get to it Tuesday as I am on a Military 4 day for Veterans day !!!!
I am picking up my DPMS 260 upper from the post office this morning when it opens, then off to the range (lucky the range is 2 miles from my house)
I loaded 3 loads for it to test today
all fit in the mag barely
140 VLD
130 VLD
140 Nosler Ballistic Tip
all with 46 grains of 4831sc powder

curious, what were your results after the recrown? Bet you wish you didn't cut past that .7 inch goup lol

a friend of mine posted this on 6.5 G forum
it is interesting that most accurate barrel length for these 3 calibers was 21.75 inch

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

 

[Smokerroller]

I find it interesting that after your first cut to 23" you accuracy improved. I understand the barrel harmonics at play but one would not expect removing the target crown via a hacksaw would not degrade accuracy more than barrel length can improve it.

 

[fmsniper]

believe it or not the crown has minimal effect on accuracy (some yes but not as much as you would think)

 

[Smokerroller]

Interesting. I have heard Numerous accounts of how critical the crown is. In fact so critical that how your cleaning rod/brush leaves the barrel and engages the crown can degrade accuracy.

 

[fmsniper]

my crown was ragged from the hacksaw and angled and it shot .7 @200 yards

but yes I am sure it would have made a small difference if trued

I seen testing, cant remember where, a crown was destroyed many different ways and accuracy was not effected

but like everything all barrels are different and harmonics can be changed

so to play it safe I would make a good crown, I will do that Monday or Tuesday when I get a chance

I would think the issue with a cleaning rod is un-even wear, at the crown

 

[Smokerroller]

my crown was ragged from the hacksaw and angled and it shot .7 @200 yards

Well I have now learned at least one new thing today. Thanks fmsniper.

 

[fmsniper]

no problem Keep in mind muzzle wear and crown damage are 2 different things, a worn crown can cause accuracy issues, damaged one too I would guess . Not saying that a crown is not important, because I always make a good crown on my barrels, but just my observations...... I will clean up this crown and true it, I will be interested to see how much of a difference it makes.

 

[fmsniper]

interesting read on crowns

http://www.longrangehunting.com/articles/rifle-crown-1.php

The Effects Of Crown Damage On A