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Hi all,
new here... I have a .243 win. Savage 11 with a McGowen 1:12 26" varmint Stainless barrel. So far I achieved 1/4 inch or better at 100 yards. At 300 not so good... 3 inches. I found JBM Ballistic Calculator and a Twist Calculator on line. I was told the JBM is better. Which would be the way to go... bullet weight or length?
If the rifle will honestly shoot .25" at 100 I wouldn't change bullets. Fine tune the load and practice more. Distance just amplifies the effects of field conditions, load consistancy, shooter technique and/or error, etc.. JBM is an excellent resource, especially for the price.
The ability of a barrel to stabilize a particular bullet is dependent upon the bullets length. A 12" twist barrel may easily stabilize a 90 grain round nose bullet but not a 85 grain VLD because the VLD is longer.
Ran into this on a more basic leval while working up a hunting load for my wife's .243.
Rifle has a 22" barrel with a 9.25 twist.
At 100 yards it was .5 all day long with the 100grn Sierras, went out to 200 and it was all over the place.
Bumbed the load 2grns and it went to just under an inch at 200.
I think I need to load at the range......
Partial quote from KRP: "Distance just amplifies the effects of field conditions, load consistency, shooter technique and/or error, etc.."
Absolutely!!!
In my experience, just because we can shoot a 1/2" group at 100 doesn't automatically mean a 1" group at 200 or a 1.5" at 300. It just doesn't work that easy. I wish it did though.
I keep reminding myself that just because I shoot a few screamer groups now and then it doesn't make me or my gun a small group contender at all times. Average group size (and count all the shots in the group) tells the true story.
Quote:
Originally Posted by MissedAgain
Before I rebarreled my rifle with the aftermarket, I shot 1 inch to 3/4 inch gruops at 300 yards CONSISTANTLY......
I have just been fighting with this also. I thought I would like to give the F-class thing a try so I have been playing with my 6.5x55AI a bit. I have been shooting tiney groups at 100 yards (cover with a dime) but set up for 300 the other night and had a tough time shooting a group that measured under 2".
I first tried the 130gr Berger VLD's that have shot very well. After a couple 5 shot groups right at 2.25" I grabbed my prairie dog rounds loaded with 120gr NBT's. This gave me a 10 shot group that measured right at 2".
I have no idea what to expect for shooting F-class as it will be a big learning curve. I figure going the first time will be more about learning then doing well but I was hoping for smaller groups then what I was getting. Along with tweaking the load a bit I'm thinking the guy behind the trigger (me :-[) is the biggest culprit.
I don't think it's you..... like I said, you see the difference in barrels. My sporter barrel from Savage is a 1:10 twist load with a Hornady 87 v-max charged with IMR 4064 38 grains worth.....
Seems that 1:12 is a bit finiky. I just have to keep trying. What's really holding me back is the 25 mile commute to the range.
keep in mind i've seen some rifles shoot like yours(great at 100 and bad past) and i've also seen some do the opposite(1-1/2 or so at 100 then 1-5/8 at 250). i would suggest you mess with your load a little more and see what happens. also, are you shooting at 100yds in the morning and then further later in the day? fatigue could be setting in both physically and mentally. i've seen this happen many times during matches.