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In the UK, Tinbum (Mr. Nick Stanning) does them :

TbT Pellet Sizers and Pellet Seating Tool

Have fun :)

Best regards

I agree with Russ
I bought the TBT pellet sizer in 4.52 and 4.53 to try with the .177 cal 13.4 gr JSB Monsters with my Thomas FT and the 4.53 works like a charm for me. I'm tempted to try one for my .22 cal pellets with my Crickets.

Jamieinmd did a post on this subject a while back. You might find it interesting.


Peace and Pellet Sizer grease

Mitch, I think that pellet sizer that Ted used was a custom made job from a personal friend of his?

I haven't done near as much testing as I would like yet but wanted to share what little testing Ive done.
I shoot a .177 Thomas FT rifle. I bought a pellet gauge and sorted a tin of 13.4 gr JSB Monsters which I shoot about 820 FPS for 20 FPE
The majority of my pellets were in the 4.54 head size with 4.53 and 4.55 being on the outer fringes for a .01 mm plus or minus for the 400 count tin which I thought was pretty tight tolerence.


I have a Gempro 250 which I weighed these head sorted pellet with. My weights ranged from 13.2 grs to 13.6 grs with the majority being 13.4 grs giving a .2 grain plus or minus tolerence which again I thought was pretty tight?


I bought the 4.52mm and a 4.53 mm TBT head sizers


I tried the 4.52 sizer first .
Here's the 5 shot group left target sized and the 5 shots right unsized at 28yds ( my zero )
Looks like the 4.53 unsized group shot better than the 4.52 sized group? 1/4" grid paper

Weather was crappy and I was pressed for time before dark.
So the next I decided to use the 4.53 pellet sizer and was pleasantly surprised. The 4.53 sized group was considerably better than the 4.54 unsized group
Circles are 1/4" for comparison

With that one test I've found the tin of JSB Monsters have such a tight weight and head size tolerance that I don't even bother to sort anymore. I just pull the pellets from the tin as I'm shooting and visually inspect them then just push them through the 4.53 TBT sizer before each shot.

I shot these 50 yd Ten shot groups with my Thomas and sized JSB monster pellets at 4.53 head size straight from the tin without weighing as I was shooting. Had two crazy flyers out of 50 shots?


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Pellet sizers and sizing is like running barefooted in the dark where you have no idea if the ground is such as slick as ice, dirt, pavement, pebbles, or rocks. Now, you decide to size the shoes (pellets) and you decide on some 10 inch shoe size (254.00mm). Great! But you are not done because not all two people have the "exact" same foot size. Notice that I did not say foot "length" because feet are not perfectly rectangular in shape, they also have curvatures, densities, skin textures and different type of socks (Pb + %antimony, or PBA), unless you wear sandals then you wear no sock type (100% Pb only, which by the way is impossible to attain better than 99.9999% Pb, similar to H2SO4, or zero Kelvin, or perfect vacuum, or the speed of light, or the true value of pi etc. etc.). The variables are more than the caliber because no two barrels have the "exact" same size caliber tolerance to within one lead (Pb) atom diameter, so one barrel either before or after the manufacturing process will be either one lead atom diameter bigger, or smaller due to wear and tear of tooling and specification changes due to the stress and strains of the manufacturing process. In essence, modern man, no matter how modern he is cannot manufacture a test tube baby that will win the Olympics.Like the Greeks did upon the birth of a child, if it showed any form of deformity they would toss it over a precipes. Now, that is one wild and crazy type of "sizing". I say "Every pellet has its God given right to be shot!" What I find interesting is how modern man applies discrimination, segregation, prejudices and biases to projectiles (pellets). Why don't we have an NBA team with all pygmies that are white guys? I don't know, but what I do know is that in order to have pure accuracy you need pure gun an pellet precision (repeatability) AND knowledge and skill of the shooter. You can cancel out the knowledge and shooter skill of the equation if you attach the gun to a vice attached to the moon where there is no weather, or air variables. As to the other variables of the gun are the number of land and grooves and their depth and finish along with the metallurgy and metrology of the Pb pellet, so there is no quick trick to an answer. The fun and joy of airgunning is not just jerking the trigger, hoping, praying, wishing that you hit what your intended target, but the shear joy of calculating the myriad of variables, predicting and testing you hypothesis for accuracy then narrowing it down from wild guesses to 100% certainty. When I accomplish that, I will be ready to die and move on to a new challenge, which will be coming back to life. In essence; for example, a 0.177 caliber, JSB Monster pellet perfectly symmetrical in its center of gravity and center of force, weighing exactly 13.45 grains and a head diameter of 4.545mm with a skirt of 4.555mm can come out of a barrel at a velocity of 819 feet per second and out of its twin brother barrel at 821 feet per second does NOT mean that it came out at 820 feet per second, which is why we have the Olympic Games, people die, I miss Jesse Owen. In ;, pellet sizing works and it doesn't work; sometimes for the better, sometimes for the worse, and everyone is unique because "cookie-cutters" are only theoretical; especially when you do ballistic analysis like I do at the planck level, which by the way, is addicting. Picture this in the future: "Hello, my name is Francisco and I am a ballistic planck addict for over 55 years." "Welcome Francisco!". The future is tomorrow, which will never come because we are stuck in the present. A theoretical pellet once told me that time travel is inevitable.


Sep 7, 2018
Hessen, Germany
    why dont ask someone who works with cnc maschines they can make you a costum sizer

    i must size my pellets head and skirt in two different sizes becouse my Barrel choke is to smal

    here is my sizer in cal 25 in metric Units 11 holes from 6,34mm to 6,44mm