New guy 300 win mag questions

[GaBoy]

Long time lurker here finally joined.
The quesion is I just started to build my long range rifle a 300 win mag my dad actually bought in the classifieds. We mounted the scope with much detail lapped the rings leveled scope etc. We went to sight in with another rifle as well and the results were interesting and a little confusing. Great group at 100 yards
1/2 inch group about an inch high. When we moved to 200 this is what confused me the group was about 3 inches high 2 inches higher than 100 yards. My thinking tells me that the arch of the bullet hasnt peaked yet at 200 or is close to peaking at 200 but im not really sure.

Here are all the specs
Rifle : Magnum reasearch 300 win mag with krieger barrel 1:10 twist rate
Scope : vortex viper 6.5 x20
Bullet: hsm with 185 grain bergers

Shooting conditions
95 degrees
85 % humidity
30 inhg pressure

Thanks in advance for any help

 

[ATH]

Physics dictates that the bullet starts falling from the bore axis the instant it leaves the barrel, with the rate of drop accelerating at 9.81 m/s2. Any arc is introduced by elevating the axis of the bore over the axis of the ground. If your scope is mounted in line with your bore, what you describe is not possible. You did not mention mounting on a canted base.

To me an inch high at 100 yards, the gun is zeroed at roughly 180 yards. So you can't be shooting both 1 inch high at 100 and 3 inches at 200 yards.

While a scope mounted high from the bore axis can create some interesting geometry with impact points, especially at close range, the most likely reason for what you observed is that the true center of the groups is not where you measured them, or it was shooter error. The last time I had a gun which shot to the same zero at both 100 and 200 yards the scope was shortly in a box back to Bushnell for warranty repair.

 

[Bravo 4]

To me an inch high at 100 yards, the gun is zeroed at roughly 180 yards. So you can't be shooting both 1 inch high at 100 and 3 inches at 200 yards.

Yep, something is definitely off here. A .204 Ruger with velocity over 4,200 fps wouldn't do what you encountered. With your .300 WM, and assumed velocity of around 2900 fps or more, your 1" high zero would have be about 50 yards.
Was this repeated or just one group at 100 and then one group at 200?
If not some kind of crazy human or range error then I would look to the scope for fault, as ATH stated. The Viper is a decent scope but it is still a budget scope. The good thing is Vortex will take care of you. I however would have a hard time trusting one if it failed right out of the box.

 

[dmj]

Were the distances accurately measured or just estimates? Probably a stupid question, but I've been guilty of this from time to time.

 

[GaBoy]

Thanks for the response i shot a group as well as my dad and had the same result. Possible shooter error because we were both hot and fatigued. I guess the best thing to do is go and shoot a few more groups when im fresh

 

[LaHunter]

what type base / rings are you using on this setup?

 

[ATH]

How was the shooting done with regards to timing? Did each of you shoot a 100 group then a 200 group with no cooling?

Some guns shoot higher when they start to heat up. But from your gun description this is not an off-the-shelf rifle to be suspected of bedding issues.

 

[GaBoy]

Im using talley one piece mounts

Heres how shooting went shot two groups at 100 confirmed with1 inch high at 100 holes touching

Waited 1hour pulled trail cams etc shot group at 200 3 inch high. Shot another rifle while waiting for barrel to cool. Shot another group simalar result. Waited 30 mins dad shot group simlar result.


The only thing i can think of is it was us because we had been shooting for four hours i know my shoulder was sore (thanks 300 wm) but its odd to me that both our groups were so similar. Idk im hopefully going friday am to try again with a fresh shoulder and see if its me or not

 

[StrutNut]

Get a brake on that thing! I have one on my Savage an love it. You can shoot all day and not worry about a sore shoulder.

 

[GaBoy]

Yea ii tthink i might have to put that next on my list

 

[ATH]

How big were your 200 yard groups?

Yes, recoil anticipation would be one of the "shooter errors" I mentioned. But I would expect the groups to open up as it typically is not so consistent as to just throw a nice group high.

I am NOT a brake fan. This was confirmed recently when I shot someone's 338LM with a brake. I can shoot a Sendero weight 300WM without a brake just fine, I just don't shoot competition with it. It's a hunting gun.

I take a bath towel and fold it up so it flops nicely over my shoulder, perhaps 4 layers thick. No more recoil issues and I can shoot it all I want on the range. In the field, 1-3 shots in a day, I don't even notice it.

 

[Catahoula]

Sell the Vortex, throw the Berger's away & start over with good stuff!
Worked for me.
Thanks, Kirk

 

[mightyman]

Hey thanks for the comments...(Im the dad)

Tough comments on the last one! Throw the Vortex/Bergers Away?

Well..not just yet...bergers work fine (less than 1/2 inch) in my
7mm
243
270...

But actually loaded some 180 Grain Accubonds..to try in it...with a couple different loads...

So..we are going to start over, and give the equipment one more chance...good weather...not 97 degrees, and 90% humidity...also let the shoulder rest.....

clean the rifle, fire some fouling shots..and see how it goes...report back soon...
thanks for the great advice...

Dad
(MM)

 

[Dgd6mm]

mightyman and GaBoy, just putting this out there for you. There is an excellent Gun Smith not to far from you in Screven. His name is Michael Deloasch, his businesses name is Nine Run Gun, I think I have his last name spelled correct . Anyhow he threaded a muzzle for me a couple of weeks ago. He does excellent work and a real nice guy to boot. I would double check the scope and mounts. As far as the Bergers go they are pretty much top of the line for target bullet standards of today. I have a .300 WM Savage FCP and when I get back to loading for it I am going to give the 208 Hornaday Amax a try. Harrels sells good radial and tactical brakes at a very reasonable price, $30.00-$45.00. Keep up with your thread and let us know how to progress.

Don Dunlap