Couple of 12ga ammo questions

[GregGry]

Hello all I have noticed a couple of weird things with 12 guage shotgun ammo, which has prompted me to ask the experts . All the ammo has been shot through my Benelli 12ga supernova. Roughly 18inch barrel.

Ok here is what I think is weird, and I have no explanation:

When shooting 00 buckshot, 2 3/4 and 3" loads from 3 diffrent manufactures seem to have a large spread pattern. At around 10 yards some pellets might just miss a average sized person. However, the 3 brands I have shot of 3.5 00 buck shot would drill the target out. Easily 1/6th the size as far as pattern goes, compared to 3". I don't quite understand why that is, anyone have any ideas?

The other weird thing is slugs. Is it normal when shooting slugs, that they hit 5+ inches high compared buckshot? At 10 yards I would have to aim at the crotch of the target to hit center. At 25 yards I would have to aim about 4 inches low. Any ideas?

 

[Fred Fuller]

Shotgun patterns are more art than science. There may be explanations for why different shotgun barrels do the things they do, but I am not sure if those explanations could be understood by mere mortal minds.

Try some 2.75" buck and slug loads and see how they do, for SD/HD that's plenty, no need to rule them out just because there's bigger stuff on the market. The basic approach is to try everything you can lay your hands on till you find something that the gun shoots to suit you, buy lots of that load, then hope the manufacturer doesn't drop the load, change the load, go out of business or get bought up by a conglomerate that changes everything.

Oh, and don't worry about understanding the whys and wherefores. Shotguns ARE weird, that's normal. Just learn to roll with it.

lpl/nc

 

[Dave McCracken]

Like Lee said. I can double pattern size by switching brands of GOOD ammo.

Also, relationships between slug POIs and the center of buck patterns are varied. Usually the slugs are higher, but not always.

Once again, each of us MUST test our equipment to get the best results.

 

[obxned]

Buckshot is strange stuff - the only way to know the best load/choke combo for your gun is to try various combinations. Mine loves the 2 3/4" 12 pellet load of 00 and also the 3" load with 15. It does best with improved cyl, but modified and even improved mod are just about as good. With the 2 3/4" 9 pellet 00 load, my gun is not happy and sprays them widely.

Regular slug do hit high from my gun. This is sighted with iron sights for my turkey and buck loads. I tried low-recoil slugs and found that from my gun they hit just a couple of inches high at 50 yards with the same sight setting. Now I don't have to live with buck and slug shooting to different points. This might be worth a try on other guns too.

 

[Zoogster]

I would venture a guess, but it would just be a guess. If your gun is chambered for 3.5" shells and your 2 3/4" and 3" shells are way off the mark, then I imagine the extra chamber area for holding the larger shell, which is larger than the barrel is throwing off the gas expansion slightly and this could also deform the pellets from the smaller shells slightly like some bad forcing cone since from tip of shell to barrel is a transition and not a smooth barrel. If you think of an explosion going in the direction of least resistance, then it is going to fill the extra space between the end of the 2 /34 and 3.5" space prior to going down the barrel, but the 3.5" shell is going to shoot it right down the barrel without filling a small cylinder area prior to going down the barrel. So the expanding gases and the shot is going to have less...'turbulence' and be more uniform. Unfortunately this is simply a downside to having a do it all chambering. Though the harmonics of some guns might deal with it better if they cancel out the extra turbulent effect, firing the shorter shells means there is a gap of air that is wider than the inside of the barrel between shell and barrel. Imagine an explosion first going forward and outwards, before proceeding forward for the small shells, and an explosion going straight forward with the full size.


The likely reason for slugs hitting higher is because the slug is heavier and as un-aerodynamic as slugs are compared to a rifle bullet, they have more mass and better aerodynamics than a lighter round ball that may or may not be slightly deformed before leaving the gun. The multiple pellets also have more surface area to increase the total drag in comparison to the slug. This means it is less effected by wind drag in medium ranges than the round pellets and retains its energy better over distance and therefore dropping less and impacting higher on the target.

Another possibility in addition is slugs being solid metal, and even slightly larger diameter than the barrel sometimes force the explosive gas to stay behind them. This means they are taking full advantage of the explosive pressure behind them until they exit the barrel. The buckshot however depending on brand and your inside barrel dimensions and shot cup etc may have some of the air going through the shot or around it before it exits the barrel, that would impart less power and it would impact lower. However most good shot cups precent this from being a real concern.

 

[foxmeadow]

As for the difference in POI, what is the velocity of the different loads, slugs vs. buckshot? IIRC, most buck loads are around 1300 FPS and most slugs are at 1500-1600 FPS. Faster usually means flatter if all else is the same.