Say WHAT, Chronograph?

[NVcurmudgeon]

Checked a few loads in my 3 1/2" Springfield Ultra Compact 9mm yesterday. Ambient temperature 70 F, all measured velocities corrected for mv.

Winchester case and primer, 4.4 gr. WW 231, NEI 431 boolit (clone of Lyman 356402 truncated cone 120 gr.) OAL 1.11" Lyman #48 mv 1264, Oehler 33 said 747.

Winchester case and primer, 4.3 gr. Green Dot, same NEI 431 boolit as above, same OAL. Lyman #48 mv 1136, Oehler 33 said 743.

These are both Lyman maximum loads that I have been using for practice for a couple of years. Point of impact, function, landing zone and appearance of fired cases was normal. I thought, "Oh well, Lyman tends to be a little conservative about what is maximum. Let's try a factory load for comparison."

Speer factory load with 124 gr. Gold Dot JHP, non Plus P. Speer mv 1150 fps, Oehler 33 mv 1332. Cool! guess I got a fast barrel.

Research will continue next week using a known .22 LR target load. Is the chronograph going bonkers? Are the cast boolits going stealth? Is a puzzlement.

[Bass Ackward]

Bill,

Don't bother testing 22LR in that 9MM. Doesn't work for squat. :grin:

Be interesting to identify what you find out. I'd say that there has to be a reason somewhere. maybe you need to put some tin in those WW slugs to sorta get a better reflection. :grin:

[NVcurmudgeon]

Bass, I use 2% tin in my WW. Don't remember if the covered firing point roof shaded the screens, but a sun vs. shade test is scheduled. My Oehler is a 1980 vintage M 33, with the old open top (no glint shields) Skyscreens. Strange thngs happen to chronographs. I remember measuring the speed of sound with a 2" S&W and no blast shields on the screens. It took five minutes for me to realize that my light .38 load was NOT developing 1104 fps with an ES of 2!

[longhorn]

That thing use batteries? Change 'em.

[fecmech]

It took five minutes for me to realize that my light .38 load was NOT developing 1104 fps with an ES of 2!

Yeah--I had some similar 1100 foot second hardball loads for about the same length of time myself!