Do Slower Loads Pattern Better than Faster Loads?

 

As it turns out, way did indeed lead on to way.  And when presented with ideal dinking-around-with-shotshell conditions this past weekend (wife out of the house, kids occupied, sunny and calm, no money to do anything else with), rather than pushing on with my investigation about how larger shot patterns tighter then smaller, I moved on to something else.  Besides, Hunter Joe pretty much settled the question in my mind with his numbers. 

So next up on the Received Wisdom Soul Train is what impact velocity has on steel shot patterns.  As I’m sure you’re aware, We All Know that faster steel shot spreads out more then slower.  And as I’m sure you’re also aware, I’ve never seen this demonstrated.  Now, after my last experience with the large vs small shot experiment and my own petard, I am going to assume that someone else has probably already tested this—and probably done a better job of it—and I will merely be the recreating that moment in 1998 where I told my older brother that Kurt Cobain had died. 

My first dilemma was how to design a load that could be manipulated over a wide FPS range and used a powder I have on hand other than Alliant Steel.  But that would require a lot more preliminary testing to get a handle on a non-Steel powder, and just thinking about it was making me lose interest.  So I bit the bullet (shot charge?) and decided on Lightning Steel (2nd Ed.) load #6 as written and loaded down by 4 and 8 grains.   

12 ga 2.75” Nobel Sport (Cheddite)
CX2000
38 g. Alliant Steel
CSD100
1 oz steel shot

1645 fps @ 11,020 psi
               A: 30 g
               B: 34 g
               C: 38 g 

This is a super easy load to construct, and didn’t require any fillers as the cushion on the wad self-adjusts for the different shot sizes.  I did have to put a bit of wad pressure on the 38 g load though.

For chronographing, I usually use Hevi Floor, viz. mixed-sized steel shot I’ve spilled and periodically collect with a magnet.  But this time, I used the steel #5’s.  I was given a partial bag years ago and have never figured out what to do with them.  I know some guys like them, but I imagine they have all the advantagesof #4’s, only more so.   Velocity measured at 9' 9" (it's just what I do). 

A: (30 g) = 1242 fps
               1271
               1181
               1254
               1238
               1266
 
B: (34 g) = 1425 fps
               1419
               1435    
               1424
               1433    
               1413
 
C: (38 g) = 1604 fps
               1590
               1595
               1622    
               1609
               I forgot to write down the last shot (mostly because I was so excited not to have shot my chrony again), but it was inline with the other four.

 A nice even ladder without any whacky outliers.  Looking at the 30 g loads spread compared to the other two, I wonder what its PSI is.  Not that 90 FPS is all over the place, but the other two loads are so much tighter.  The 38 g load is at max pressure, and 8 g of powder is twice the normal 10% reduction for a starting load.  Anyway, before the way leads on too far….

 For patterning, I used steel #2’s to make counting holes easier.  Also, unlike the 1.25 oz of #F’s, this might be a load I’d use if it works out.  Unfortunately, I ran out of paper after only two patterns of each load.  But hey, two is better then none, right?

Remington 870 Express /28" barrel 
Hasting’s Extended Steel Full (.706")
At 40 yards. 

A: (30 g) = 75.2%
                74.4%    
                76.0%

B: (34 g) = 85.6%
               88.0%
               83.2%

C: (38 g) = 70.4%
               74.4%
               66.4%
 

Is that enough to draw conclusions?  Well, this is America, and it is my birthright to draw conclusions based on scant evidence.  So, yes. 

If I'd just stuck with Load A and Load C, we'd be golden.  Which just goes to show once again, that thoroughness is the enemy of certainty.  But based on what I have here, it appears that velocity doesn’t necessarily impact patterns in a predictable way.  If I had shot five patterns per load, it MIGHT have turned out that the load A and B averages would switch places, but I bet (but not a whole lot what with the petard and all that) that we’d only see a marginal shift in the averages.

Let's pretend.

	Load A	Load B
Real pattern	74.4%	88.0%
Real pattern	76.0%	83.2%
Pretend	85%	70%
Pretend	85%	70%
Pretend	85%	70%
Average	81.1%	76.2%

So load A has to have a significant jump AND Load B has to have a significant decline in order to switch the averages in a compelling way.  Is that likely?   If just one of those pretend Load B's prints an 85% pattern, just like the real ones did, the average goes up to 79%.  

That's just numbers of course, which are good for what they're good for.  Here are some photos.   

Load A

93/125 = 74.4%

Load C

93/125 = 74.4%

Though both have the same number of hits in the circle, the slower load is more center dense, meaning, it has room to spread out without degrading, whereas the faster load is about maxed out.  Taken with the fact that these two patterns are the lower of the slow load and the higher of the fast load, it would lean you toward the slower load patterning better.

But then, here comes Load B messing up any trends. 

Load B

110/125 = 88.0%

So, yeah...