I think GeneT answered it but a multiple hole type sorting device such as a Pelletgage should give you only the max head diameter as you eventually find the hole where the pellet will drop through. I would think your eBay gauge would be fine if all your pellet heads are perfectly round but could give you varying measurements if the head was out of round. You should be able to test this by measuring the same pellet several times to see if it always reads the same.
Looks like a lot faster way than conventional pellet guages.
Pelletgage will give you a "go" (pellet < a specific diameter) and a "no-go", so that you know within a range of 0.01 mm (0.0004 in) the diameter of a pellet. A trapezoidal slot will only check two points on the circumference rather than the entire cylindrical diameter (it also would seem to check two points that aren't perfectly diametrical). All Pelletgage apertures are guaranteed to be within 0.0025 mm (0.0001 in) of nominal diameter - verified by yours truly with class X plug gages. Pelletgage components (excluding the fasteners) are produced in Texas, USA, and I ship promptly - for about $5 USPS (free if you order more than one). There has not been any "shop load issues" since 2015, thousands have shipped to every state in the USA and more than 20 other countries. There are dealers in UK, Netherlands, South Africa, Maylasia, and Australia, and several stocking dealers in the USA. If you purchased a Pelletgage from me, and are dissatisfied, return it undamaged and I will refund your purchase price. I am proud of my little product, and stand behind it. https://pelletgage.com
The present Pelletgage calibers are:
Jcup, you quoted my post in your first response so I am not sure if you were just further expounding on it, or if you had issue with it. I believe I was saying about the same thing - that the slot gauge could give you differing results each time you measure the same pellet, unless the pellet is perfectly round, since it measures just at two points. I am hoping the OP reports back on his results with this slot gauge, particularly if he gets different measurements running the same pellet several times, and hopefully he will try an assortment of brands, lots, etc. My hunch is that he will see a different measurement each time.
Yes, I think "expounding" may be right. I also think that with soft lead (JSB) you might see a bit of compression where the pellet slides home. I have previously retrieved some trig functions - if you imagine the circumference of a clock face, divide into 60 second (6 degree) segments, a flat spot across one minute would reduce the radius at the "ding" by about 0.02 mm on a 4.5 mm diameter circle. I have always said a single chord diameter is unlikely to be an accurate way to get the real diameter of a pellet. Thanks for your reply.
When I was looking for one I sent him a message from his ebay account to see when more would be available and got mine that way.
