Can anybody recommend a BB gun to use for calibration/ validating a gel block at the required 590 fps? I don't have a chronograph to check speeds, so I'm unsure of which model to choose from.
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Can anybody recommend a BB gun to use for calibration/ validating a gel block at the required 590 fps? I don't have a chronograph to check speeds, so I'm unsure of which model to choose from.
You have to have a chronograph to ascertain velocity of the BB. There's a chart to compare actual velocities to actual block penetration of the BB to make sure the gel block is compliant. I think the Crossman 760 is the popular test BB gun for this, but I'm sure there are others that work just fine.
It appears that Part 3 has been published:
https://www.policeone.com/police-pro...kEYB93TAd5o6J/
The following conclusions, some of them oddly phrased, are made in the article:
1.The clear synthetic gelatin must be calibrated by the user before use.
2. The clear synthetic gelatin currently demonstrates a tendency to limit bullet expansion and increase bullet penetration, compared to FBI-standard, 10% calibrated organic gelatin.
3. The clear synthetic gelatin currently does not appear to be a suitable substitute for FBI-standard, 10% calibrated organic gelatin if the bullets will be measured and evaluated according to FBI performance standards.
4. There is no apparent “conversion” between data derived from 10% organic gelatin and the current version of the clear synthetic.
While it "might" be possible to derive a scaling constant that "converts" test data for non-expanding/non-deforming projectiles obtained in Clear Ballistics Gel to its equivalent in 10% ordnance gelatin, due to the tendency of CBG to under-drive expansion and over-represent terminal penetration of expanding designs such a scheme is simply not plausible for the projectile designs that are best suited for self-defense.
Also, not sure how I missed your posting of the publication of Part 3 of the series DMWINCLE...apologies as I wasn't aware of your post prior to mine bringing this to light. I reckon that this is what I get for not reviewing these threads as thoroughly as I could/should.