Pattern Anomaly


Dear Guru;

When we last communicated, you suggested that I look for a used BT-99; almost miraculously, one immediately came up for sale. I bought it and have been very pleased with the way that it shoots and “fits me”.

Now, to the question at hand. I have started to reload, therefore, I try to read and digest any information that I come across concerning reloading. A recent issue of a “print” shot gunning magazine ran an article on the Remington STS cartridge. A series of patterning tests, from a Remington 11-87 with a regular contour barrel sporting a full choke tube at 40 yards (avg. of 5 shots / load) yielded the following:

*Premier Heavy Target (3-1 1/8-7 1/2) 1200 fps 85.6%
*Premier STS (2 3/4-1-8) 1185fps 78.3%
*Premier STS (2 3/4-1-9) 1185fps 73.0%
*Premier Nitro 27 (HDCP-1 1/8-7 1/2) 1200fps 89.1%
*Premier Nitro 27 (HDCP-1 1/8-8) 1200fps 81.9%

It appears that in all cases the pattern becomes noticeably more dense (smaller) with an increase in velocity and an increase in shot size.

A) Is this always true or was this some sort of anomaly.?

B) Does this mean that a 3 dram 1oz load will shoot tighter than a 3 dram 1-1/8 oz load of the same shot?

C) What other factors affect pattern size?

I await your golden reply with baited breath (whatever the hell that is) and a full container of “air freshener”.

Roy

Dear Roy,

Glad that you are properly prepared to receive my answer. I think that bated breath is actually (a)bated breath- holding ones breath. This, of course, is more polite than holding ones nose when about to receive advice from on high.

Over a year ago, I laid in an entire ton (well, actually somewhat more) of STS shells in 2-3/4 dram 1-1/8 oz #8 and 3 dram 1-1/8 oz #7-1/2s because I thought that they were good and I got a really good deal on them. The shot was extremely high quality and tested well on my shot crusher. It was just below Lawrence Magnum bagged shot in hardness and visually it was shiny and round. Remington says that they use Hodgdon Clays as a powder, which explains why the shells kick so much. I shoot an auto, so I don’t notice it as much, but the Nitro 27s in summer time were just too much for me.

As to your questions: Every barrel is a law unto itself. This gets me off the hook. My Beretta 303 with a .035″ screw choke (factory Beretta listed Full), did not reach the high pattern percentages achieved with the Remington you mention. I couldn’t touch 80% until I went to a .040″ choke (Briley listed as XFull).

Without getting into specifics, because I haven’t patterned all the shells you list, IF ALL THINGS ARE KEPT EQUAL, larger pellets pattern tighter than smaller ones and slower loads pattern tighter than fast ones. Gotta be. Larger pellets are less disturbed by wind and suffer less surface distortion on ignition setback.

None of that means that you can’t design a shell with small shot and high speed to pattern well, but you just will have to work a little harder to do it.

Yes, I believe that it would be easier to get a one oz load to pattern tighter on a percentage basis than a 1-1/8 oz load. Does that mean that the one oz load can put more #8s into a certain circle than the 1-1/8 oz load of #8s? Not hardly. Pellet count counts more than the small difference in setback due to the larger shot load. The small load may put a higher percentage of what it has into a certain circle, but it won’t make up for the larger pellet count of the bigger shell.

Remember, every 1-1/8 oz load has a 1 oz load riding in the front end. When you think of it that way, you will see that less is, well, less.

The Remington Nitro 27s are an impressive load at both ends. I don’t know which chronograph the magazine article writer used, but on my chronograph, I was getting about 1165 fps (three feet from muzzle center of screens) for the 2-3/4 dram STS, 1220 average for the 3 dram STS and 1320 fps (yup, I measured a bunch of them- they were early production lots) for the Nitro 27s. That may explain why they kick so much. It also makes the tight patters that the magazine reports all the more impressive. I’ll bet that something else is different in those Nitro 27s other than just an extra spoonful of powder.

Best regards,

Bruce Buck
Shotgun Report’s Technoid
(Often in error, never in doubt.)

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