Strange phenomenon with .300 Wby Mag

[Tumbleweed]

Need some good ideas or opinions to possibly explain weird ballistic issue with my custon built hunting rifle. I have a Rem 700 Classic in .300 Wby Mag. I recently had a #5 contour 27" lilja barrel installed. The action is pillar bedded and the barrel is free floated. I use a PE1 Shepherd riflescope. I use Barnes Triple Shocks in 180 grain. With this bullet running 3,250 f.p.s. to 3,300 f.p.s., according to my Shepherd literature, I should be hitting darn close to the center of my circles out to 1,000 meters. When I got this gun back from the gunsmith after the barrel job, I worked up a load that was running 3,250f.p.s. and shot a three shot group that measure 1/4 inch c to c. I shot at my target throughout the various distances to 1000m. I shot a pair at 1000m that were 2 and 3/4 inches apart. Bullet impact was very, very close to center of each circle, I was only about 1 m.o.a. low of center at 1,000m. After about 80 rounds or so through the new barrel, I noticed my point of impact getting lower and lower in the 700, 800, 900 and 1000 meter circles to the point of being clear out of the last two circles. I figured the gun is breaking in and the velocity may be falling off. I worked up a little bit hotter load, still accurate, but not much point of impact difference. I borrowed my friend's chronograph and fired three shots, 3,319, 3,325 and 3,329! Why am I falling out of my circles now when originally with that slower load I was right there? This makes no sense at all! The shepherd has been bullet proof, no crosshair problems or issues with things moving around so it shouldn't be the scope. I also use heavy duty Warne rings and bases, once again no movement. The only thing I could think of was barrel whip or vibration. My gunsmith says barrel whip cannot account for my point of impact being 2m.o.a. low at 800m, 3m.o.a. at 900m and 4m.o.a. low at 1000m. Any inteligent ideas or similar experiences? This does not make sense!

 

[NONYA]

temp change?wind?fouling?humidity?...

 

[J E Custom]

Give it a good cleaning and look for carbon and copper
fouling.

Then re torque to 65 or 75 inch lbs and if this doesent correct it
then I would have to go with temp,humidity or wind like
Nonya said.

It may have just settled in and needs to be resited for current
conditions.

Sounds like a shooter
J E CUSTOM

 

[blackco]

I'm still not very experienced in all of this long range stuff but with the way the bullet drops linear after 600 yards I would take a look at the scope also. I don't know a lot about the internal workings of them but could something be worn out? When you get to the end of the come-ups in a scope can the adjustments get tweeked. Just an idea, I could be wrong.

 

[Tumbleweed]

Thanks for the input guys. As for fouling, with this lilja barrel this has never been an issue. After each shooting, I drag a snake through as many times as I shot and give it a copper cleaning with Butch's and Kroil oil every thirty rounds or so. Always cleans up real fast. As for wind, I shoot over flat ground with no chance of updrafts or downdrafts. I usually have a constant left to right wind and depending on distance, i'll sit down and move my circles for the wind between 1 m.o.a. and up to 6m.o.a. at 1000m so I usually have a good handle on the wind. Humidity doesn't change much around here and I can't see it making a 40" difference at 1000m, if humidity was a big issue, I would expect to see a lot of fluctuation in p.o.i. as well. As for temp, I keep a record of temps when I shoot and have seen some p.o.i. changes but not significant changes like we're talking about now. As for resighting, the point of impact at 100 meters is still dead center of my little 100m circle in the shepherd just as mr. shepherd says to do. Any more ideas would be appreciated.

 

[LiveEye]

Thanks for the input guys. As for fouling, with this lilja barrel this has never been an issue. After each shooting, I drag a snake through as many times as I shot and give it a copper cleaning with Butch's and Kroil oil every thirty rounds or so. Always cleans up real fast. As for wind, I shoot over flat ground with no chance of updrafts or downdrafts. I usually have a constant left to right wind and depending on distance, i'll sit down and move my circles for the wind between 1 m.o.a. and up to 6m.o.a. at 1000m so I usually have a good handle on the wind. Humidity doesn't change much around here and I can't see it making a 40" difference at 1000m, if humidity was a big issue, I would expect to see a lot of fluctuation in p.o.i. as well. As for temp, I keep a record of temps when I shoot and have seen some p.o.i. changes but not significant changes like we're talking about now. As for resighting, the point of impact at 100 meters is still dead center of my little 100m circle in the shepherd just as mr. shepherd says to do. Any more ideas would be appreciated.

Hmmm...

I'm wondering if the Kroil is doing something to your accuracy?
Kroil is pretty hush hush on their recipe, but my father in law who is a retired chemist told me years ago that Kroil has lanolin (sheep grease) in it. Think about it... A dose of kroil, a shot or three superheating the lanolin would most likely build up a hard film in the barrel. Repeat, repeat, and that may be the issue.
I'd clean the bore thoroughly with de-natured alcohol to remove any cooked on materials and try again.
If you get your accuracy back you will know it was the Kroil.
Just a thought...

 

[Tumbleweed]

Thanks for the input. The only reason I use that mix of Butch's bore shine and Kroil oil is because that's what Dan Lilja recommends for his barrels.

 

[LiveEye]

Thanks for the input. The only reason I use that mix of Butch's bore shine and Kroil oil is because that's what Dan Lilja recommends for his barrels.

Well, you never know

If you do try my "experiment" please post your rersults.

I've got 35 yrs in boat/yacht repair etc. and Kroil is by far the best nut/bolt loosener out there.
However, I'm crispy brand new to this long range rifle world. Therefore, I'm not sure what the reasoning is by using it down the bore of a rifle?

Also.... Maybe the barrel gets tooooo clean with kroil?

Would a tooo clean a bore copper up faster?

 

[LiveEye]

Sili-Kroil side note?

Sili-Kroil is Kano Lab's silicone added Kroil product.

IMO, I'd never put anything "silicone" or a product w/ silicone in it down a bore!
When that material is super heated (900f) it turns to silicon dioxide.

Silicon dioxide is super super hard and also has an abrading property to it.

That could allow a bore impregnated with it, pull copper off a bullet in no time.

Silicon dioxide will also impregnate itself permanantly into the metal of the barrel metal.

I guess the question is, "what temp does the bore get to when that trigger is pulled?

 

[Tumbleweed]

I'm still not very experienced in all of this long range stuff but with the way the bullet drops linear after 600 yards I would take a look at the scope also. I don't know a lot about the internal workings of them but could something be worn out? When you get to the end of the come-ups in a scope can the adjustments get tweeked. Just an idea, I could be wrong.

The shepherd has dual crosshairs. One that you never move after sight in. The other is the circle string. This is a one piece vertical line with the circles all fixed in it. The circles cannot change distance between each other and when you move the circles as i've described, the whole string moves together. So this also cannot be the issue. Also, I have never had to move things clear to the end of the travel.

 

[Fiftydriver]

If your impacts are consistantly low for all circles, easy fix, adjust your scope so that your impacts are on center.

You say the Scope is bullet proof. In my experience, there is no such thing as a bullet proof scope. I have seen problems with NF and USO scopes so even the very best scopes have issues from time to time. The higher quality the scope, the less likely you will have problems but its certainly not impossible. In fact I have heard several reports of problems with these scopes on larger magnums, espeically large magnums with muzzle brakes. Not sure if your rifle has a brake or not.

Anyway, if your impacts are consistantly low at all ranges, a scope adjustment is a simple fix.

Also, what stock do you have and how is it bedded?

Kirby Allen(50)

 

[devildoc]

Are you shooting from the same lot of bullets that you shot your original groups with?

 

[Tumbleweed]

If your impacts are consistantly low for all circles, easy fix, adjust your scope so that your impacts are on center.

You say the Scope is bullet proof. In my experience, there is no such thing as a bullet proof scope. I have seen problems with NF and USO scopes so even the very best scopes have issues from time to time. The higher quality the scope, the less likely you will have problems but its certainly not impossible. In fact I have heard several reports of problems with these scopes on larger magnums, espeically large magnums with muzzle brakes. Not sure if your rifle has a brake or not.

Anyway, if your impacts are consistantly low at all ranges, a scope adjustment is a simple fix.

Also, what stock do you have and how is it bedded?

Kirby Allen(50)

Thanks for the reply Kirby.
That is what I'm doing currently in my last 4 circles. I bring my circles down a certain m.o.a. value for the last 4 circles to hit center.
As for the scope being damaged, if something was wrong with either reticles (dual reticle system) I would be able to visually see misalignment. Also the circles are in one solid verticle string that are all connected- the space between circles cannot change. And no my gun does not have a break. It also has the original wood stock. The action is professionally pillar bedded and the barrel is fully freefloated.
Jesse

 

[LiveEye]

What was the final outcome?