300 yard groups vs 400+ yard groups

[T Bone]

This summer I've been messing around with two rifles after installing M1 elevation turrets. The 300wsm is very accurate out to 600 yards (my own limit).

My lightweight 30-06 is frustrating me some. I can get 5" groups at 300 yards, but it opens waaaay up at 400+ yards. At 600 I can't even get 75% on a 24" square.

The rifle is a Rem 700Ti in 30-06 with a fixed Leup 6x36. Bullet is a 150 grain partition.

Is it the lightweight rifle, the 6x magnification, the low b.c bullet, or just my awesome shooting form?

 

[BuzzH]

T Bone,

Its really hard to say what it is, may be a combination of things.

How well does the rifle shoot at 100 yards? MOA? Less?

In some discussions with breaksrunner, he explained to me that if a rifle is capable of honest MOA accuracy, you should be able to get out to 700-800 assuming practice and everything else on your platform is correct. I also took that to mean that if your rifle has less than MOA accuracy...you're effective range will be much less.

The one consistent thing I see is that everything starts to make a difference with increased range. Trigger control, breathing, your rest, wind, shooting form, any problems with the rifle itself, etc. etc.

I went through some pretty exhaustive things with my rifles to take away all the variables with the rifle...bedding/floating, crowns, scope mounts, level scope, crisp triggers, load development, barrels, twist, action truing, etc. etc. etc.

I also think that once in a while you just get a turd of a barrel that wont shoot. Been there and I wont fight that again...new barrels arent that expensive. In both cases I had rifles that wouldnt shoot, new barrels solved the problem.

Good luck...

 

[noharleyyet]

Buzz, all other variables you mentioned being acceptable, wouldn't a fixed 6 mitigate long range grouping negatively?

 

[T Bone]

The rifle will shoot 1" 3 shot groups at 100 yards with a front and rear bag. It's a finnicky rifle. The lightweight really amplifies the errors in my shooting form. When the barrel heats, POI goes for a walk.

Common sense tells me that mechanically, the rifle should be capable of 6" groups at 600 yards on a cold barrel.

My thought is with Harley's....maybe the scope is the most limiting factor.

Right now, I'm limited to 400 yards with that rifle, which is plenty for most hunting applications, and I really dig the M1 turret. It takes all the guess out of holdover.

I find myself wanting more range.

Buzz, what do you use in the field for front and rear rests?

 

[MinnesotaHunter]

I think Buzz has it figured out. My general observations have been as the bullet slows down after travelling 400+ yds it is more affected by the enviornment it is travelling through and any imperfections in its launch are amplified.

I used to think that if a rifle shot 1.1" groups at 100 it should shoot 6.6" groups at 600, but this obviously isn't the case for you.

NHY, I wouldn't say 6x is too low. I would agree it may not be ideal, but I use a fixed 4x (Trijicon ACOG) on an M4 cabine to repeatedly hit 19" wide targets out to 500-600 meters. After 600, the 5.56 round gets pretty unstable.

 

[noharleyyet]

I realize 6x isn't to low to hit or kill at 600....consistent grouping is what I meant. Agree on the 5.56.

 

[MinnesotaHunter]

You are probably right that grouping is probably not well judged using magnafication that low. I only meant he should at least be able to hit a 24" plate at that range if the gun was doing its job.

 

[BuzzH]

NHY,

I have to admit that I'm wayyy over my head on most of the finer points of scopes, rifles, etc. when it comes to long range stuff. I'm also hesitant to make recommendations or try to pin-point specific problems. I've just been learning mostly by the trial and error method and listening to guys like breaksrunner who really do have this stuff figured out.

T bone,

In the field I primarily use my pack for a front rest and a crown royal bag full of freeze dried rice for the rear...not the most scientific, but it works.

 

[Festus]

That cartridge isn't very effective in a hunting situation much past 400 yards anyway.
You are getting down to or below 1000 ft/lbs of energy at 500 yds.

http://www.biggameinfo.com/index.aspx?page=/balcalc.ascx

I can understand the need to get more distance, though

 

[bjtc_brian]

I reload for my 30-06 and it has 1000 lbs to 800 yards. It almost sounds to me like you may have something out of whack. Make sure your scope mounts aren't cracked and the rings are tight. I have ran into that issue. Other than that, it is technique or a really crappy barrel.

 

[1_pointer]

IMO, the scope should not be a limiting factor, but the target may be. A bigger aiming point, one that is not completely covered by the crosshairs, may be needed.

The low BC of the bullet should really only be an issue if there was lots of wind at the longer ranges. Have you checked to make sure the scope is making the adjustments the turret is indicating? What I mean is, are the crosshairs moving the amount they are supposed to for each click? While many advocate Leupolds being good at tracking and return to zero, I have read multiple accounts of them not moving the proper distance per click. For example, instead of 0.25" at 100yd they are moving 0.22" at 100yd. The difference will show up more at longer ranges.

That said, my gut (and it is a big one) tells me that exponential decrease in accuracy is more a shooter thing than a rifle/scope thing.

 

[belly-deep]

I don't see how it could be a broken scope or something similar. If it shoots good at 300 yards, it's not broken.

My first two guesses would be:

1) Light rifles are hard to shoot long distances with (I know from personal experience--I have a Kimber Montana .308).

2) Parallax

 

[cowboy]

It's looks to me it is either:

1) Operator error - but operator is doing fine out to 600 with 300 wm so operator error doesn't raise an immediate flag for me.

2) Something in the rifle (barrel quality??)

3) Your scope - I would suggest you take the scope off your proven 300 and put it on this light weight rifle and give her a test.

This won't cost you anything and if it is not the scope then you can decide if you want to re-barrel, trade it off or just live within it's capability.

I will tell you that 600 yds for an '06 is not anywhere too far for this cartridges capability.

 

[lastmountainman]

I reload all my .308 rounds and shooting a MOA for every one hundred yards out to a 1000 yards. I think that maybe the barrell needs time to cool down along with making sure your scope mounts remain tight. I had a problem after installing my scope, which I use a fixed 10 power scope. I noticed that after about 500 rounds my groups were getting bigger. I finally realized that the mount screws were coming loose from the vibration. Once I tightened them back up I was shooting my MOA groups again.

I do not use the 30-06, but if you can shoot the 500 yard groups I think that it may be your limit unless you reload your own rounds or look for some type of mag. round. I will not shoot a deer over 700 yards with the 308 and no elk over 500 yards. That is my limits due to the vel. of the round per my reloads. I use a 165 gr. ballistic tip with 46.5 grains of powder.

Don't know if that will help or not. Good luck on finding the problem.

 

[T Bone]

Thanks for the suggestions guys....

I've spent the afternoon reading and farting around with the rifle. Mounts are good. No cracks in the mounts or rings.

I did realize that as much as I've been shooting this summer, it's probably way over due for a good cleaning. I always overlook the obvious.

After reading the suggestions I'll try shooting cold barrel only.

I dug out an old note book from 10 years ago when I bought the rifle and was doing load development, I found another load that shot very well from the beginning. It was a Hornady 190 btsp. Beside the load info is a scribbled "RECOIL!" Although slow, that baby would penetrate and buck wind better than the 150 Partition.

It's a great rifle, especially in the vertical stuff. It's taken a couple sheep, goat, many deer, a few antelope, and a few elk.

Thanks for the suggestions all.

 

[sweetnectar]

Good thread....lots to concider.

 

[Corax]

When you say it opens way up at 400+, how big are the groups?

Several issues:

Wind, like gravity, is cumulative, so if the wind shifts, it will affect groups more as ranges get greater.

When a bullet is first fired, the long axis rotates in a conical manner. I think the word is "precesses". As it travels down-range it stabilizes. This is known as the bullet "going to sleep". The same behaviour can be observed in a kids top (do they still make them?) Anyway, without the effect of wind, the relative group size should actually be smaller at longer range.

Try borrowing a higher-power scope for a while.

Good luck.

 

[schmalts]

Frustrating isn't it?? That is why I dumped my Kimber Montana and got the Sako Finlite. I tried all kinds of loads with always having one out of 3 shots fly out to about 1.5 inches @100 yards.
Have you checked the trigger poundage for both guns? Remingtons are really easy to adjust lighter and less creep but make sure you do not go too far.
BTW, a gun that shoots 1" @ 100 may shoot even better than 6" @600 yards. Sounds weird at first because you think it may be a linear margin of error, but a lot of factors come into place. One factor that can make you shoot better than MOA at 600 is bullet stabilization that happens down range. Another factor that can degrade long range is when your bullet drops back down through supersonic it can become unstable. Although supersonic is probably going to happen past 600 yards just by guessing.

 

[bjtc_brian]

Just another thought, and I am not an expert by any means. But, if the scope isn't level, I believe you would get the same effects. My thoughts are you wouldn't see the effects until farther ranges, but it is something to consider.

 

[Carl]

T Bone,

At longer ranges, do the groups get spread out more vertically, horizontally, or just open up all over the place?

If you're getting vertical spread at range, the load you're shooting probably has a lot of variation in velocity. Do you by chance have a chronograph?

Parallax could be a factor, but I've not had much trouble with it in the 6x42's I've used, nor have I heard of problems from others. If you're really thinking it's the scope, try swapping with the one on your WSM, you know it's performing fine.

Carl