October 15, 2008, 05:48 PM
I have a custom barreled Winchester M70 that is chambered in 6.5X55. The typical bullet that I have shot in my Swedish Mausers has been the 140gr Sierra MatchKing HPBT. That bullet shoots fine in this rifle. But I have also developed a load with Sierra 85gr Varmint HP's that is extremely accurate and mild recoil. This load is dead on at 200+ yards.
My question is in regards to 300-400 yard shooting. My friend has a long range that I am going to be shooting at and I was wondering if I will have better accuracy at these longer ranges with the 140gr bullet vs the 85gr. Obviously the 140gr will have more drop, but will it be more stable on the longer flight?:confused:
I know that you long range shooters can help here...;)
October 15, 2008, 06:00 PM
The biggest factor is the wind will affect the lighter bullet more than the heavy bullet. Bullet drop can be calulated and adjusted for but the affects of the wind at long range is not something you can totally account for. Definitely the heavier bullet will perform better at the longer ranges. You know there is even a 160gr. 6.5
October 15, 2008, 06:07 PM
this is actually tougher than appears; an 85 grain 6.5 bullet still has some decent b.c., and yet, it is going to be about 500 fps faster than your other loade, I would imagine. That means, it is going to travel about 150 yds more, in that same time the 140 grainer flys. this gives the wind very little time to act on it, within 400 yds, really. I am going to go with the 85 grainer, all accuracy starting off equal.
October 15, 2008, 06:19 PM
I'd load some 123g Scenars, or 120g Bergers.
October 15, 2008, 06:21 PM
lencac is on the right track, but simply looking at BC I wouldn't automatically go for the heavier bullet. The lighter one will come out of the chute at higher velocity, and may (I stress "may") have a shorter time of flight. You could run the specific BCs and the muzzle velocities you're getting on a ballistics program to be sure;
There is another factor of course; your rifle may shoot better with one bullet verses the other. 300 to 400 yards isn't all that far for the bullet's BC to be the one and only deciding factor. We shoot .223 ARs at 400 using 62 to 70 grain bullets with good results. Beyond that distance it gets more and more important to have a good ballistic coefficient. IN short it may be more important to tweak your loads for best accuracy (with either bullet) and experiment.
October 15, 2008, 08:57 PM
300-400 yards is really not very far away. Of course the point of impact will change with the different grains but I would bet that any grain you pick will shoot accurately within 400 yards. Find a grain that shoots well from your gun and you will most likely do just fine.
October 15, 2008, 09:13 PM
+1 for what "Longdayjake" said.