J J Mac wrote:J J Mac comments in red Frank Lopez wrote:
kenner wrote:But in the article Frank posted, Brezney talked 'bout 18 pellets in the mallard...
While I'd expect a higher pellet count with smaller shot, I wouldn't get too wrapped up in that aspect of the article. Like most Brezny articles, the data supplied is relatively incomplete. What we know is that it was shot at 35 yards at a pinned (stationary) duck. We don't know the velocity of the load or the choke used. Still, if you can get 18 What I read said 11
pellets on the bird, you're doing something right.
I was quoting kenner.
J J Mac wrote:J J Mac comments in redBut, to me, the most amazing part of the article is the gel penetration tests! Again, using the data he supplies in the article, he says that there was 3 inches of penetration at 35 yards! THREE INCHES! According to JJ Mac's article on penetration, the #5 steel pellet would have to be traveling at 700fps just to get the minimum penetration of about 1.28 inches! I also noticed the 3 inches of penetration and googled the Perma Gel penetration test media. It is not gelatin. Of course, it is only one data point without any comparison to similar penetration data in that media with other shot sizes and was probably not calibrated with a BB using a gun with known and fixed muzzle velocity as specified for gelatin. Furthermore, I read on article which said that this gel simulated 10% gelatin vs the 20% gelatin data I think is used in Shotshell Ballistics. I don't know if this is true or not but if it is it would give much different results than 20% gelatin. Furthermore, Brezny did not give the velocity that the #5 pellet was traveling when it impacted the test medium and the distance was not specified for the gel penetration test even though Brezny said the pinned ducks were at 35 yd..
Agreed. I believe that I even cautioned in my first post that since it was Brezny and was full of ambiguities it should be taken with a grain of salt.
J J Mac wrote:J J Mac comments in redI've seen other test results of penetration at range that also contradict what the programs predict. Some are really interesting. I would like to read these results. Please list the references.
There's a recent Field and Stream article which claims testing by an independent lab (Nilo Farms, IIRC) that tested down range penetration on ballistic gel of two different Winchester BB loads. One load, Xperts (1550fps) and the other Dryloks (1300fps). The results showed penetration of 5 inches for the Dryloks and 5 1/8 inches for the Xperts. There may be a valid explaination here in that the Drylok pellets are much more uniform and spherical and would therefore retain velocity better and have better penetration. But, plugging the data into a program, such as Lowry's, would reveal some very different predictions than were actually observed. There was also another test, again by Brezny, so keep that in mind, with Winchester BlindSide Hex shot in #2, 1400fps MV. The finding was that "penetration was about the same as standard #2 steel". Again, given the ballistic coefficient of a hexagonal shaped projectile that tumbles randomly, not something you'd expect. In another F&S test, this one done at Federal Ammunition's high tech range, Black Cloud BBs in 3 and 3 1/2 inch loadings were pitted against one another. The long shell had a velocity of 1500fps and the 3 inch had a 1450fps MV. Granted, not much of a difference, both loads penetrated to the same depth! A little more searching will reveal other similar tests with similar results. Furthermore, high speed photography of shot patterns in flight are very interesting to observe.
J J Mac wrote:J J Mac comments in redTo the point that I'm beginning to think we need to rethink (or at least empirically revise) those ballistics programs with respect to shotgun loads. I can't believe you are drawing this conclusion on this very incomplete and statistically invalid work by Brezny.
Again, I agree that the work is statistically invalid and that it is by Brezny, so it is somewhat questionable. However, I also believe that you are reading too much into thing to suggest that I'm basing things on a single article. Ballistics Coefficients are typically established computationally. That number is then revised after several test firings and observations to arrive at a reliable number. To my knowledge, ballistics programs use the same BC when dealing with shotgun pellets. This may be a big mistake. Lowry observed that things weren't happening exactly as predicted with steel shot, so he revised the tables basing his work on 7/8 inch steel balls (IIRC). Still, the data was based on single projectiles, not pellets flying in a swarm. That swarm and the way the pattern blooms may have some effect on the pressure wave in front of the shot swarm.