.300wm confusion

[jpbaker]

Ok folks, i went to the range a couple days ago to develop a new hunting round for my 300wm its an Abolt II

I found a load that appeared promising which included 185gr Bergers with 73.5gr of H4831. This printed a .6ish group that included 1 flier.

I went back out yesterday to chrony the new load and im confused by the results.

Here is the first three out on my rifle. Note the rifle was not cleaned prior, so it was already fouled.





Frusterated, i switched to another target about 8 inches above this one and here is the result.




Im confused, I checked the scope, action screws, etc. everything seems torqued down to spec.

What are you guys thinking?

TKS
JPB

 

[jasent]

Could it be that for the first group your ammo was warmer/colder than ambient temp from the car.then when you shot the second group it had cooled or warmed up to ambient. This could make it change speed and take you out of your node

 

[jpbaker]

Could it be that for the first group your ammo was warmer/colder than ambient temp from the car.then when you shot the second group it had cooled or warmed up to ambient. This could make it change speed and take you out of your node

No, I had been shooting my .308 for about a half an hr before this, so should not have been and issue.

 

[jasent]

Did they all chrono the same?

 

[baldhunter]

Could be your stock may be touching the barrel and causing the group to open up.When you switched to a different target,the front rest may have been in a different spot and the stock wasn't touching the barrel.

 

[rick523]

Was the barrel warm, or cold when you first found your node? Since it sounds as though it was warm when you shot the second group.

 

[jpbaker]

Did they all chrono the same?

Yes, They all chronoed the same. It could have been the stock flexing, but have not had that problem before.

TKS
JPB

 

[jpbaker]

Was the barrel warm, or cold when you first found your node? Since it sounds as though it was warm when you shot the second group.

It was cold when I found the node the day before, but didn't change when barrel heated up.

TKS
JPB

 

[Greyfox]

Are the three groups the only groups being referenced? If so, before looking to the rifle or load, I would shoot a half dozen three shot groups letting the barrel cool between groups in rule out shooter error. Ii's not impossible to throw a group with the big magnums. IMO.

 

[jasent]

Are the three groups the only groups being referenced? If so, before looking to the rifle or load, I would shoot a half dozen three shot groups letting the barrel cool between groups in rule out shooter error. Ii's not impossible to throw a group with the big magnums. IMO.

+1. Shooter error accounts for 75% of issues ime

 

[Shane Lindsey]

I would concur with the posts above. Magnums with standard barrels give me a hard time getting any consistency.

I have an old Ruger M77 w/tang safety in 300 Win Mag.

It takes about 12-15 rounds to settle down(foul). Once it does, I can shoot about an inch somedays with some loads and then bigger with others. It is a standard barrel no brake, so it is pretty light for a 300 WM. I really have to concentrate to ensure the "squeeze".

Shane

 

[roninflag]

repeat it. i would shoot 4 shot groups

 

[Bart B]

Group shooting; one of the most misunderstood things about testing for accuracy.

If you shoot several groups with the same load all the same way and they ain't within 10% of each other in extreme spread, you're not shooting enough shots per group for them to be meaningful and represent the accuracy level that load produces all the time.

If you measured a fish with a ruler and the numbers ranged from 6 to 12 inches, which one represents how long the fish is? Does the fish have an average length?

A given rifle and load will shoot all their groups the same size (within 5%) if enough shots per group are fired. How realistic do you want your assesment of the load's accuracy to be?

However, if you're only interested in how accurate the load is a small percentage of the time, then shoot a few 3-shot groups with different loads and pick the smallest ones recipie. Good luck equaling that smallest group at some later time.

 

[lloydsmale]

my guess is an answer your probably not going to want to here but it happens to me all the time. My first group sucks so i then tend to pay a bit more attention to my trigger work and consentrate a bit more and low and behold the group tightens. Theres some days i go to the range and everything clicks and others that i should have just stayed home.