Nice groups at 100, 200 no groups..
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25WSM
Well-Known Member
What bullet are you shooting? There are 243 loads that have high bc bullets. You may be on the edge of stability with the bullet your using. It's pretty hard to get 8 inch groups at 200 yards with just about anything. Are the holes at 200 yards perfectly round?
Shep
Shep
entoptics
Well-Known Member
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25WSM was referring to bullet stability, not wind affects. If it is wind (unlikely), then the groups will have an extreme horizontal dispersion, but vertical should be relatively small.
As mentioned, check your targets and confirm that none of the bullets are hitting at an angle. What twist rate is the rifle, and what weight are the factory Nosler BT? If you have marginal stability, the bullets could be getting severely disrupted between 100 and 200 yds, though I'd expect them to shoot worse than "ragged hole" at 100 yds if you're seeing 8" at 200.
Is this from one session of shooting? Did you fire a few groups at 100, then switched to 200 yds and got the extreme spread? Or is this an observation based on going back and forth between the two ranges? If it's the former, then it's possible something came loose (scope, action screws, etc) between 100 and 200.
As mentioned, check your targets and confirm that none of the bullets are hitting at an angle. What twist rate is the rifle, and what weight are the factory Nosler BT? If you have marginal stability, the bullets could be getting severely disrupted between 100 and 200 yds, though I'd expect them to shoot worse than "ragged hole" at 100 yds if you're seeing 8" at 200.
Is this from one session of shooting? Did you fire a few groups at 100, then switched to 200 yds and got the extreme spread? Or is this an observation based on going back and forth between the two ranges? If it's the former, then it's possible something came loose (scope, action screws, etc) between 100 and 200.
25WSM
Well-Known Member
That bullet comes in at least 4 different weights. The only thing I can think of that would cause that big of groups is instability. Typically a ragged hole shooting at 100 will still shoot awesome at 200. Unless you were shooting your 200 yard groups in a hurricane it wasn't the wind.
Shep
Shep
ShtrRdy
Well-Known Member
You're missing the point 25WSM is suggesting. Most factory .243 Win rifles have a slow twist rate. If you are shooting a load with a heavier bullet or one that is somewhat long to make it have a higher ballistic Coefficient it could be unstable.
waspocrew
Well-Known Member
I would assume your twist rate is 1:10.. I've read this is the minimum for the 95 gr Ballistic tip (which should work) but a 1:9 is better.
Niobium
Member
Check the scope mounts and the bases, did something shake loose from shooting? That would be my bet.
25WSM
Well-Known Member
Now if you shot ragged hole and then it shot crazy at 200 and then you shot at 100 and it was ragged hole again then it's probably not something that got loose. But if the 200 yard target was the last group you shot it could be anything that got loose to a broken scope. The next 100 yard group will tell you if it's something loose.
Shep
Shep
You can't trust Browning ! My 25-06 did the same thing as his 243. Finally checked the twist ---- 1 in 13 !
When Barnes came out with the 80 gr, I could finally kill something bigger than a Chuck.
When Barnes came out with the 80 gr, I could finally kill something bigger than a Chuck.
Absolutely correct. I've had multiple Brownings where the twist rate was grossly slower than advertised for the particular rifle. This is why first thing I do now is physically check the twist rate when I purchase a new rifle or barrel. There's an old post on the interweb where a fellow had this same thing happen with an xbolt & factory ammo. He was key holing @ about 300 yards and Browning would do nothing about it because they said they only guarantee it at 100 yards. So they sell high powered center fire bolt actions to only be good for 100 yards.
Boy, it's a shame if Browning's turning out rifles like that 
. I have a 1995 A-bolt medallion in .243 and it's a tack driver. I used check around every once in a while to see if I could find another one from that era and if clean, I'd buy it in a heartbeat. My interests have since changed but I've always liked the A-bolts.
I should add it's a 1:10 and shoots 95 Nosler BTs and 100 grain Speers very well.
. I have a 1995 A-bolt medallion in .243 and it's a tack driver. I used check around every once in a while to see if I could find another one from that era and if clean, I'd buy it in a heartbeat. My interests have since changed but I've always liked the A-bolts.I should add it's a 1:10 and shoots 95 Nosler BTs and 100 grain Speers very well.
I would say that your scope is good enough if you one hole at 100yds. Even your velocity extreme spread wouldn't cause this much variance at 200 yards. To check your twist rate: If you have a cleaning rod & jag, put a patch on your jag & get it started into the bore a couple of inches or more. Then mark something at top dead center ( directly up) on your rod near the handle end that is fixed and will turn with the rod as it turns when you are pushing it through the bore. Take a measurement from the rear of the receiver to a fixed point near the handle end of your rod. Push the rod with patch through the bore until your mark at top dead center makes a full 360 degree revolution back to top dead center again. Take a measurement between the two points you took a measurement from the first time. Subtract this measurement from your first measurement. This will tell you your twist rate. For example first measurement was say 26.75" and your second measurement was 15.75". This would mean you have an 11 twist. 1 turn in 11 inches. Take your measurement more than one try to be sure nothing is slipping and you are getting nearly the same measurement each time. This is easy to do once you get the hang of it. I would be willing to bet that your twist rate is actually slower than 10. Maybe 11, 12 or more.
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