As a rule, you'll find that most of the less expensive buckshot offerings (was that PC enough?
) will yield open patterns. If you're looking for a 'wide pattern' in your application, that's all well and good. If you want all your pellets on a silhouette target at 25 yards, you're most likely going to have problems though.
Inexpensive buckshot loads usually feature:
-roll crimps with over-shot wads
-dead soft lead pellets
-unplated pellets
-no buffering/grex
-no protective shot cup
-less than protective wads between powder and shot (none of the more modern collapsing/cushioning plastic wad columns)
These things tend to contribute to the widest possible buckshot patterns due to damage/deformation of the pellets on their trip down the bore. They get flat spots from being crushed together upon firing and during their dwell time in the bore. These flat spots make them 'frisbee' off in all directions when they emerge from the muzzle. Even a tighter choke might not help- in fact, it can do the opposite and make things worse by causing even more deformation to the pellets.
It's also been my experience that some loads using a stiff over-shot card wad with roll crimps will have holes in their patterns as well. Is it interference from the over-shot wad? I don't know, some have said in the past it could be.
If open patterns are what you want, and you have trained and practiced sufficiently to use them effectively- none of this matters. But if you expect tight patterns from inexpensive buckshot loads fired through open chokes, you may be in for some disappointment.
Premium buckshot loads usually contain hard lead alloy plated pellets, well protected by buffering material between and around the pellets. They have the best possible wad columns to protect the pellets. They have star crimps.
And generally, they work very well at what they do- delivering tight patterns at longer ranges.
The difference it makes? IMHO, you might not have to switch to slugs as soon to get effective hits, or to confine your projectile impact to a single target. In other words, tight-patterning buckshot demands that you shoot better, but it also extends the range at which you can keep all your pellets on a designated target.
hth,
lpl