View Full Version : A bit of patterning....

Dave McC
December 3, 2001, 01:33 PM
I realized recently that I hadn't checked POA/POI lately with my 870 TB, and I've changed my reloads a mite. SO, having an hour or so free this AM, I hied myself to PGC with some test loads.

When I started reloading, I had gone with the one the used MEC 600 was set up for. It was....

1 1/8 oz of Hard shot.

Win 209 primer.

17.3 gr Clays (MEC bushing #30,ostensibly 17.4).

CB clone of the WAA12 wad.

STS or AA hull.

Over time this was modified, first to an oz with the CB WAA12SL clone, then I tried the MEC #29 bushing, an actual 16.5 grains. This seemed to shoot well, was economical, and I've run 25s maybe 10 times with it since. But, it occurred to me some patterning and POA/POI checking was overdue.

Turned out to be a good idea...

The test loads were identical except for the powder charge, one was the aforementioned heavier load, the other was, well, the other. Both were otherwise matched up, in used but good STS hulls.

I loaded up 5 of each, with felt tip marks on one kind to keep them separate.

Shot was the West Coast Premium Magnum shot, in 8 1/2. This IS a trap load, and I do not recommend it on game.With 7 1/2s, it would make a good dove load, tho.

Anyways, I put up a standard patterning target and chambered one of the 16.5 loads. I shot from the furthest I could get from the target, about 33 yards. This is about where I break my trap birds.

After shooting the first round, I made safe and walked to the target. The pattern centered high left, almost every single pellet was above POA. A bit of elevation is a good idea on a trap gun, but this was pushing it past ideal.

Second shot was a repeat of the first.

New target, and I shot off two rounds of the 17.4 gr load. High left again, and a larger pattern with a bit more flyers than before. Sorry, I didn't feel like counting 400 plus holes each time. I went by eyeball and comparison.

So, next step was to take off the CHEEK-EEZ pad I had installed that gave me a bit more elevation and had centered the old patterns nicely. This took a few minutes, and I returned to the line with another fresh target and resolve in my heart.

This time, the 16.5 gr load impacted nicely, maybe a 75/25 pattern and centered. Most of the pellets were into about 26" nearly ideal, IMO. A couple more shots repeated the impact and spread.

The 17.3 gr load shot a bit lower, but still was too high and left, maybe 8". Many more flyers leaving the pattern, too.

So,happy to know which load was better and that the thing shot where I look, I packed it up and left.

Some conclusions...

Something changed since the last patterning. I've put on maybe 10 lbs, and I doubt that'll make much difference on a behemoth like me.Maybe my form has shifted a bit. I note that my trap stance is abit more erect than before, when I shot like there was 00 in the thing.

It pays to recheck often. If I do throw caution to the winds and do some ATA next year, I'd be under a handicap w/o rechecking and maybe doing a bit of load development.

And, patterning gives a two dimensional view of a three dimensional event, the shot string. But this can help us make an educated guess as to what a particular load and gun can do. Fewer flyers mean a denser shot cloud and a shorter string.

Finally,the loads given are right out of the manuals, but since I cannot control you or yout setup, I am absolved of responsibility. Use ONLY data derived from testing and published by the makers, or Lyman's excellent manual. Do NOT switch any components.

Questions,comments, donations?....

December 3, 2001, 02:39 PM
Good post as usual Dave.
One question.
What is a "standard patterning target"?

Dave McC
December 3, 2001, 03:54 PM
A 4X4' piece of paper, Mike. This one has an aiming point in the middle depicting a clay, but any aiming point will do.

December 3, 2001, 06:43 PM
What is the book published velocity for this load?

When I was shooting 16 yard trap(not to infer that I ever got better than this yardage) I found that patterns and hits improved as I lowered the powder load. The best load that I ever developed was a one ounce load hovering around 1100 fps.
This combo worked well with Bullseye and Win 452.


December 3, 2001, 06:49 PM
Dave, I've never loaded with Clays, but seem to remember than when going from 1-1/8 ounce to a one ounce load with WST, that you actually INCREASED the powder charge slightly. Is Clays that different; or do I dis-remember that badly? ;)

Dave McC
December 3, 2001, 08:29 PM
It's SUPPOSED to be about 1100 FPS, and quite low pressure, say 8K PSI. It busts them nicely from the 23 yd line, if I hold up my end and point it right.

Lots of load data for these lower weight loads are for fast loads, up in the 1300 FPS range. For this, I do not need that much speed.

January 27, 2002, 02:03 AM
Where do you guys find 4x4 paper to shoot? The biggest stuff I've ever seen in stores in 18x24 inch art paper. It works great with rifles but leaves something to be desired with patterning birdshot.


Dave McC
January 27, 2002, 08:47 AM
There's a coupla sources, Adam. Winchester makes the target I used, and it's available at some ranges.

'Nother choice,butcher's paper is about 24" wide, and comes in long rolls.Tape two segments together to get that 4'X4' size.

I've heard that blank newsprint does well, but have no idea for a source.

January 27, 2002, 10:44 AM
Blank newsprint has nearly zero wind tolorance. Definately a break of dawn target, when the wind is calm.


January 27, 2002, 08:41 PM
Unless you're patterning buck shot, blank news print is not so good. I tried that and it turned to confetti. I have since used butcher's paper (thanks Geoff) and that works great.

January 28, 2002, 05:29 PM
I downloaded a man sized silouette from some free target website. It printed off on nine 8X11 sheets that I taped together.

It worked real well for me with 24lb printer paper, but it's only 2'x 2 3/4'.