Weird groupings

madluk18

madluk18

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Location
Peace River AB
So, yesterday, went out to the range to try out some loads I'm working on for coyotes for my 6.5x55 swede. loaded up 40 rounds of 129 gr SST. 10- 44grs of 4350 and 46grs(max) of 4350 and 10- 34grs of varget and 37grs(max) of varget.

The first load of 44 grs at 100 yards shot well, about 4 inches high at 100 which is about right. the second load, 46gr, was dead on at 100 yards. I didn't think much of it. I went on to the 34 grs of varget, and it was the same, dead on at 100 yards. now before I go much further I should mention my rifle was zeroed at 200 yards (about 4 inches high at 100) with 140 gr close to max loads. So i was kinda thinking everything should be high. lighter bullet moving faster, should be higher than my 140gr zero. This dead on pattern more or less continued as I shot. my groupings would go to being dead on to low. the 37 gr of varget was 4 inches high for 2 groupings, then the last grouping was dead on. 34 grs of varget went from being dead on, to being about 2 inches low. groupings varied from maybe half inch to 3 inches. it was just a weird day.

If anyone has any ideas about whats going on, I'd more than appreciate it. The only thing I can think of, is that there is something wrong my with scope. I don't believe its my shooting, this has never happened before.

Thanks Lukas
 
Nothing unusual about it. A barrel flexes and whips as it fires. Different loads will flex differently and change the point of impact.

This is why you zero your rifle with the load you decide to use.

By the way, Varget is kinda fast with the Swede. A good range of powders starts with 4350 and goes slower from there. I have had best results with 4831SC, H1000 and RL22.
 
On top of harmonics, lighter bullets often have a lower POI due to not causing as much recoil and muzzle rise as the bullet is accelerated down the bore. Heavier bullets hit higher in a fair number of my rifles at 100yds.


Mark
 
are you sure you rested the rifle on its forehand everytime
and not switching between resting on the barrel and the forehand?
it happened to my uncle a few years ago. he was shooting at 250 yard
with is 7rum and was wondering why some group were dead on and some others
were 12-14" high. then i noticed he was sometimes resting the barrel on his bag.

i actually see that often done by the "pros" on wild tv...
john hunt the other day was wondering why he was missing wolves at 180 y
on both shot he missed,the rifle was resting on it's barrel...
 
I'll take a look at barrel harmonics, seems interesting. thanks for the information guys. I was just gonna end up zeroing it at whatever load I decided to go with anyways. Was more curious then anything.

Ganderite,
I"m trying Varget as it was suggested to me by an old timer at the range, says he uses it and gets good results, and it actually did shoot quite well, but I think i'm gonna go with 4350, it grouped slightly better. I'm gonna play with the grains a little more though, and see if i can't tighten things up.

coldmaker,
I always rest the gun on its forehand.

Thanks again
 
Some report great accuracy with IMR 4895 and light bullets.I've done well with RE22 and the 130-140gr slug.........Harold
 
The best load i've found so far is this:

Bullet: .224 140gr Hornady SST
Brass: Prvi
Primer: CCI No. 200 Large Rifle
Powder: 42 gr. Hodgdon BL-C(2)

I can keep them in about 1.5-2" at 100 yards with the irons on the old m96.

Are you using loads that you've used before? Or working up new ones? If there are new loads, you might want to try increasing the powder in 1/2 grain increments as opposed to 2-3 grains :O
 
I see IMR4895 lots in the reloading manuals, probably time to give it a try eh. I'm looking to try some 85 or 100 gr sierras, anyone got loads or a powder they found worked good for them??
 
I'm currently propelling 144's (lapua fmjbt) with IMR4831 and it seems to be a winner! Fine tuning to follow but seating 20 thou off the lands and spinning up 5 loads ranging from 44 to 46gr they all shot suprisingly well with 44.5gr being the best sub 1" 5 shot group @100yds before tickling the powder charge a little more and finally adjusting seating depth. Shooting 140amax's and 139gr Scenars next... I love this calibre :)
 
Accurate load in my Husky M-38 with 85 grain Sierra HP was 42 grains IMR 3031. Moderate load. Reasonably fast. Very accurate. Likewise Varget. Same loading.
 
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