Testing a new pellet gage

T

TCups

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A quick post to say that I have new respect for air rifle bench rest shooters. I told my brother I would do some testing for his new pellet gage using a 10-meter rifle off a bench rest to see if the gage made a difference. The results are, well, somewhat disappointing to me in that I didn't seem to be shooting very well, but at least the preliminary results, even at my level of skill suggest that pellet head size is making a difference in accuracy and POI, at least with my Walther LGR-Universal.

The pellet head size gage was my brother's idea. You can read about it, and if interested, order one. Versus the price of a decent set of calipers, it seems a bargain

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pelletgage.com

So, I am trying out head-sized Vogel Green pellets with my Walther off a makeshift bench rest, shooting from one bedroom, down the hallway, into another bedroom. My wife of 42 years (Saint Carol) still put up with this sort of thing.


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The sort:
Tested Vogel Green wad cutters, preferred by my my air rifle. The "tin", or plastic case specifies this lot number to be 4.495 mm head size and 0.53 g The gage says that the pellets actually running 4.51mm 4.52 mm and 4.53 mm and weigh, on my scale, 0.534 g - 0.540 g with most weighing either 0.534 or 0.536 g. Today, I was shooting 5-shot groups of pellets weighing 0.534 g and head sizes of 4.51 mm, 4.52 mm and 4.53 mm and comparing to 5-shot groups not head-sized.

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Shooting a single pump from a bench rest is a bit tedious as I have to raise and hold the air rifle to cock it every shot, and it's far from a professional set up. Also, I find my 62 year old eyeballs need a Klieg light on the target to dial the rear peep down to minimum, and to change out the front aperture to get the right sight picture. Played with all this set up yesterday, practiced some, then tested some groups more carefully today.

In short, I don't have anything like the skills needed to give much more than anecdotal results, but they seem to match what my brother is observing with diabolo pellets and field trial shooting. The head size definitely seems to affect both the group size AND the point of impact. I was a bit disappointed by my overall accuracy, but this target pretty much tells the story:

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Starting in the center, then, clockwise from top left, groups 1 and 2 of target -73 were not sorted for head size. Group 3 was 4.51 mm, group 4 was 4.52 mm and group 5 was 4.53 mm. Groups 3 and 5 were .339 in, edge to edge. Notice the shift in the POI from group 3 to 5. Target -74 was all 5-shot groups pulled, unweighed from the tin and not sorted for head size.

So:
1. Too poor a shot and not enough numbers to be significant
2. Vogel match grade pellets more often shoot well than not, but
3. IMO, I was seeing more "flyers" when the head size wasn't measured, and
4. My two best groups with head-sized pellets show a shift in POI between sizes 4.51 and 4.53

Brother Jerry says he and a few other field trial shooters are seeing POI shifts of up to about 1 inch at 30 yards shooting JSB Exacts with different head sizes. It would be interesting to see what difference matched head sizes might make for a true bench rest shooter using better equipment than mine. Check it out. Thanks.
 
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to see the same test shot while using a scope.

Pete

Yes, indeed. My brother just put these on the market 2 weeks ago. So far, most interest seems to be from Field Trial shooters, and the early results, like mine, mostly anecdotal. He has not had any results back from 10-meter shooters yet, so I told him I'd give it a try. Seems to me, from my limited experience with BR match shooting (50 yard, 22LR with a 52C) and purely amateur interest in 10-meter shooting, that true competitive BR and 10-meter shooters are gear and gadget intensive and interested in every aspect of potential improved scores, so perhaps he will find a market share there if the results are good.

I gave up measuring pellet head size with calipers as an overly tedious chore that, for me, had no value. I used to weigh and sort pellets, but actually, have moved back into shooting more powder burners than air rifles the last few years.

An interesting aspect of this gage, one that I didn't test, and one that isn't really intended, is that it will "shave" lead from pellets if not used carefully. The gage's stainless steel is very hard, with crisp, sharp, laser-cut holes +/- 2 microns tolerance. I found that if a wad cutter pellet fell through sidewise, as they sometimes did, that they would hang on the back side coming out. Domed head pellets tend to seat more naturally.

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I had to "finger center" wad cutters with a finger on the back side of the gage to see if they really passed the gage.

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If, though, they slipped through (at a narrow point on the diameter?) they would tend to hang up. Turning the gage over, the wad cutters would tend to center on their tapered waist, and hang up.

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A gentle pull, straight out, instead of wiggling the pellet, shaves a tiny bit of lead, which, I suspect, might be just the thing to true up both the head diameter and make sure it's perfectly round. The weight removed seems negligible, but might make a difference in fit of the pellet head.
 
Been sizing pellets the last 7 years which have turned 6" groups at 55 yards in to sub 1/4". Of course these are a sizer to spec not a guage so may well end up with very few in a tin usable not to mention extremely slow and damaging nearly everything fed in to it having sharp edges.

You do know actual size of hole is quite different to output size of pellet?
ie feed through a supposed 4.52 that more than likely will actually measure 4.47/4.48 the skirt wont come out 4.52, it will be quite different.
 
Been sizing pellets the last 7 years which have turned 6" groups at 55 yards in to sub 1/4". Of course these are a sizer to spec not a guage so may well end up with very few in a tin usable not to mention extremely slow and damaging nearly everything fed in to it having sharp edges.

Sorry, not sure I follow. Are you saying the sizer you use damages the pellets, etc, or that by comparison the sharp edges on the gage damage the pellets, etc.?

You do know actual size of hole is quite different to output size of pellet?
ie feed through a supposed 4.52 that more than likely will actually measure 4.47/4.48 the skirt wont come out 4.52, it will be quite different.

Again, not sure I follow. The gage is intended only to measure the pellet head size, not the skirt. My brother is the engineer. I know he says the laser is driven at the slowest, most precise cutting setting, accurate to +/- 1 micron, or +/- 2 microns on the diameter. Used to cut stainless steel templates for circuit board manufacture. Each gage is checked for accuracy with a high resolution optical micrometer. I know that the pellets I weigh carefully, and the head sizes I measure are variable, even in the best quality pellets I have on hand.

I know nothing about (re)sizing pellets to uniformity for air rifle BR, but sounds like you have it down to a science. I know the sharp edges on the gage can potentially damage, or at least alter pellet size if not used carefully. I don't shoot field trial at all, or bench rest competitively. Most of my bench shooting is related to my more avid hobby of reloading, and load testing. On my very best days I can rarely get groups under 0.5" CTC at 100 yes and under 1" CTC at 200 yards with my Heavy barreled CZ 527 varmint 223, and CZ 550 varmint in 308, if I do everything right and there's no wind. Tried my hand at 50 yard rim Fire BR, but wasn't really competive, didn't want to commit to the infrastructure cost and time it would take to become competive, and then couldn't find 22LR to shoot.

So, my intent was (is) to help my entrapeneurial brother with some pellet testing, to the best of my ability, maybe help get some feedback from those better able to give it, and, yes, "advertise" a bit for him on the few forums I occasionally visit where such a product might be of interest.

Frankly, one of my interests, if I can get him to cut me a gage or two to the right specs, would be a go/no go gage to measure case head expansion when working up loads and testing for pressure signs at the range. Maybe also to measure case neck dia for thickness on loaded rounds. Ball micrometers, digital calipers and run out Gage's aren't my forte, either, but I try.

Anyway, thanks for taking the time to comment. It is appreciated. I will pass this on to brother Jerry.
 
Just stating a sharp edge will damage the pellets upon dropping in to each gauged hole. It will be awesomely slow to do as well.

Head size rarely as printed on the tin, many come in sub 4.47/4.48 when labelled 4.52/4.53 - skirts 4.66+
In 13 years have only come across three batches of JSB made that measure as stated.

When I used to size it was to squeeze the skirt down to 4.5, it didn't touch the heads at sub 4.48 and took 2 seconds each.
 
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sorted head size vs unsorted

As I look at those groups, the unsorted ones seem mostly better than the sorted groups. A long time ago, I discussed sizing dies vs "sorting" dies with the late Don Nygord. While we FT guys were "sorting" Don felt he got good results by sizing his pellets the morning he was to use them, with the feeling the fresh raw lead gave more consistent results for his 10M shooting.

I found only a few of my guns "liked" sized pellets, but I did get fewer misses from screening out the "peewee" Crossman pellets (small skirts) common in some Crosman light lots. With more powerful guns using the heavier pellets, none of my guns prefers "sized" pellets, so I just look at em and weigh em (when I get a chance).

I still have a die Don made up in a larger diameter (.181") than his standard size (.178") for screening the small skirt ones.
 
Probably right there unsized dubiously better than sized. Only proper way is to shoot some range where the effects may come to light.
ie at short range could be a 4 shot single hole and 5th a nick, that at range can be quite widespread.
 
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