Want to get the best out of your rifle ? and find that perfect pellet it's easy..

[cpmwasp]

Do you get fed up of hearing that a certain pellet is best for a given rifle ?
or that the rifle works great but every now and then gets a "FLYER" or why a rifle doesn't work as well with the latest batch of pellets that worked fine before !!

So what's changing, apart from the weight and the profile of the pellet, your rifle should be able to send constant POI's regardless of what pellet you choose.
(Excluding of course a tin of highly oxidised or bent and irregular made pellets).

So here is what everyone can do. Find out what size skirt suits your rifle best for any given pellet..take a tin of pellets, any tin of pellets and after a quick visual check for bent skirts and slag or deformations, let's get started

What we need to do is to sort the pellets, and set them into separate piles sorted by skirt diameter size...now there are several ways to do this, the best is using a sensitive dial gage and setting it up over an anvil or flat surface and this can be done many ways. set the dial up for zero when using a 4.5mm or 5.5mm (177 or 22) feeler gauge. re test this measurement several times as this reference is very important.. the dial gauge should rest when there in no pellet being measured at a figure under the calibrated reference size so that it can measure under size skirts as well.
If you do not have a dial gauge then a caliper gauge will work but it's more difficult as you can squash the skirt if you apply too much pressure.
Or if you have no such tools then do a roll test..on a flat surface align the pellet facing left to right on a line. it helps if the surface is slightly tilted forward to allow the pellet to roll away forward from the line. By tracing the curve of the trajectory of the pellet as it rolls you can mark the curve and draw five or six different lines and use that to group the pellets..

OK now we can group the pellets from one batch into different tins marked -0.05, 0, +0.05, +0.10, +0.15,+0.20 thousands of a mm . make sure that the tins are clearly marked.

Next, set up a table with a solid rifle support or vice so that the rifle can be accurately aimed at the same point for each shot..i can even do this with a pump rifle, set your scope to the highest gain..and decide on the power level you are going to use for this test. the power level has to remain constant for 100 shots. the minimum required for a realistic evaluation of a batch of pellets..never correct the aim if they are off to one side, just keep aiming at the centre of the target.

next we set up a target card at 10 meters or 25 meters in an area away from wind. so a calm day (or nite) is best unless you have an indoor range.
shoot each tin of sized samples using them all on their own target and clearly mark the target card, make of pellet, weight, model, and measured skirt dia over stock ( the reference size either 4.5 or 5.5mm if using metric) . so if you only have 5 pellets that measured -0.05 then that all you can put into that target, then change the target and try the next batch.
You can use a multi target card like the 25 foot ones with 5 different roundels and the two logo roundels either side giving a total of 7 points of aim for one card..

Just keep aiming at the center of the target and take your time for each shot, relax and make each one the best you can do...then with the next tin of sized samples do the next target roundel etc etc making sure to record the amount of each size as well for reference,,, eg 5pellets at -0.05, 10pellets at 0.0, 22 pellets at +0.05, 54 pellets at +0.10 etc etc.
by using 100 taken at random from the tin or even better all 250 if you can, you will be able to record the percentage of optimum pellets in that tin..and now measure the spread for each group of sized pellets....
You should now have a set of targets that will show why you get flyers, as one size will be all over the place, others better and one size in particular will be a super tight group as good as your best ever group done with that rifle ever !!! You will be elated, and want to get drunk at this point as this is the big breakthrough you have been waiting for...!!

So now you know the best skirt size for that particular pellet in that gun, for that particular power setting. ..all you need to do is to make a pellet resizing tool to resize all the pellets into that sweet spot diameter and you will be able to get fantastic groups from every pellet!!! Now you can try a cheaper pellet or one that loads easier but gave erratic results and do the same test. over and over again with every new make or model of pellet you should repeat the test and you will soon find that sweet resized pellet that gives you killer accuracy...

I made my resizer by machining a disk of aluminium (dural or hardness over 250) making a tool that fits onto an empty tin ( i actually used an old tin of 500 concord pellets as the tin is deeper and you wont crush any pellets when they go through the holes.. my resizer is only 2 cm deep with a recess of 5mm on the top side and 3mm underneath to protect the holes when the tool is being transported.
I machined down from 5mm inside the edge down to a depth of 5mm to make a flat dish inside the disk, then i drilled two concentric rings of holes of the required diameter 10 in all and i you then just give each hole a tiny chamfer about 0.5mm on both side of each hole. mine are +0.05mm for diablo by rws in 177.
Just pour in a handful of pellets into the resizer and shake the tin in a circular motion. All the pellets will just drop nose first into the holes and sit there, one by one you use a pointed tool, to push the pellet through the hole, and when it emerges it is the correct skirt diameter...make a pusher tool by reshaping an old screwdriver on the grinder and have a taper of 1" or 2cm from the shaft dia 4mm down to a blunt point so that it fits into the back of any pellet type..by using a shaft thats 4mm dia it can be used for all the resizing tools you make, 177 and 22 the tool will work.

How accurate are the results..well i have a wasp nest in a wall, but i can't get near them as their so aggressive...so i have set up my shooting table in the barn 12 meters away and can pick them off one by one as they emerge from their nest..thats hitting a moving target at 12 meters or just under 40 feet...and it's fun...with my modified Rebel 4.5mm and a 6-24 x 50mm scope. pellets are rws diablo basic 177 resized to +0.05mm

comment, you will find that 90% of them were over +0.05 and mostly around +0.20 for `that particular pellet. so as my rifle loves +0.05mm i can resize a complete tin of 500 pellets in half an hour and no rejects, no flyers, and superb accuracy, and using one of the highest quality but low priced pellets for 177;
My other REBEL SS 0.22cal also uses +0.05mm with gamo match and gamo magnum pro, so with just two dies, i can reform pellets for both rifles.

Now you have found the sweet spot in size it's time to repeat the test on four targets and varying the power, most pcp are adjustable and the pump up rifles can be pumped to whatever power you want,,,so try 20 rounds at 200 mps, then 20 at 225, then 20at 250, and so on up to 300mps and see which power or speed gives the best accuracy...again do this in a sheltered area away from wind, you want to find the optimum speed for accuracy then it's up to you to compensate for windage not just go to full power to reduce flight time trying to reduce the affect of the wind...now you will be able to get the best from your rifle as far as the pellet accuracy goes...

Please comment if you found this usefull

[TonyL]

Very interesting, but surely head size and weight consistency will be even larger factors?

Full marks for dedication.

[rabbitwrecker]

Epic.......Not that I could ever be bothered to attempt it. I'll just stick to quality pellets straight from the tin....

[Brian.Samson]

I have a couple of questions for you..

Firstly, what evidence do you have to support your theory other than you are able to hit a wasp at 12 yards indoors?

When you mention +0.05, I assume you mean the head size of the pellet +0.05mm?
Are you assuming the head size on the tin is correct?

Lastly - what's the difference between your sizer and simply using the barrel to size the pellet skirt when the pellet enters the bore?

[angrybear]

Pellets straight out of the tin are accurate enough for me, beyond that the group sizes are governed by "Human error".

[Artfull-Bodger]

Skirt size is not that relevant as they get expanded by the air pressure, it's head size that really matters you want the head to seat in the rifling when you load it, and it's easy to feel a pellet that drops in not seats.

[Airsporter1st]

What a wonderful bunch lurk on the BBS. Someone takes a lot of trouble to make an informative post and, rather than offer encouragement or even constructive criticism, out crawl the 'knockers' and sceptics.

If the OP's musings appeared in Airgun World, they'd no doubt be fawning all over him.

[rabbitwrecker]

If the OP's musings appeared in Airgun World, they'd no doubt be fawning all over him.

Who's being sarcastic now?

[Airsporter1st]

Who's being sarcastic now?

Not me, sarcasm appears to be your preserve.

[piemanlarger]

personally, I think I could prove the op theory to be flawed if it was put into practice at my club.

Some will believe it however!

[lensman57]

My problem with all pellet sizing methods that rely on measurement by dial gauges etc is,
1) the human error factor
2) the natural resolution of the instrument

The first is self explanatory and the 2nd really depends on the set up, repeatabilty accuracy of the intrument and its resolution.
Even a prescision instrument such as a Mitutoyo dial gauge or caliper has at best a resolution of +- 0.02 mm ( I doubt any of us own lab quality mesauring instruments in our garages ) , combine this with the human error and the measuring error could be as high as 0.04~0.05mm. Use a cheap as chips Chinese one bought off the bay or from the ususal suppliers and the bets are all off.

I too think that the best bet is probably buying a tin of quality pellets and use them with care. I have no problem with weighing pellets nor with sizing for that matter but I have a much higher confidence in the measuered weight of a pellet verus a measurement of size that has to return an accuracy better than +-0.02 mm.

Kind Regrdas,

A.G

[RichardinDorset]

I would imagine that tiny inconsistencies in axial balance of a pellet would make significant differences to accuracy, rather than skirt diameter, as the pellets are all 'sized' by being pushed into the bore when loading?

I have noticed that I get about a 1 in 10 flier with H&N FTT and none with Air Arms Field.

The back (rear inside of the skirt) of the Air Arms pellets appears to be cleanly formed by the die when manufactured where as the H&N appear to be left rough, so maybe this is what makes the Air Arms pellets better (in my gun anyway).

I'd like to know if the way Air Arms pellets are actually made is any different to H&N's.

[Airsporter1st]

My problem with all pellet sizing methods that rely on measurement by dial gauges etc is,
1) the human error factor
2) the natural resolution of the instrument

The first is self explanatory and the 2nd really depends on the set up, repeatabilty accuracy of the intrument and its resolution.
Even a prescision instrument such as a Mitutoyo dial gauge or caliper has at best a resolution of +- 0.02 mm ( I doubt any of us own lab quality mesauring instruments in our garages ) , combine this with the human error and the measuring error could be as high as 0.04~0.05mm. Use a cheap as chips Chinese one bought off the bay or from the ususal suppliers and the bets are all off.

I too think that the best bet is probably buying a tin of quality pellets and use them with care. I have no problem with weighing pellets nor with sizing for that matter but I have a much higher confidence in the measuered weight of a pellet verus a measurement of size that has to return an accuracy better than +-0.02 mm.

Kind Regrdas,

A.G

I think you may be out by a factor of 10 there. Most Mitutoyo dial guages I have used have a resolution of the order of microns, i.e. 1000ths of a mm, not 100ths as you suggest.

[ZAKDINGEL]

W,T,F realy here is a proven method get hold of a few different pellets "some are available in samples" of a few different ones stick up a several targets at your chosen range and shoot at it one target for each pellet you will find some targets like a pin cushion these don't suite your new gun you will find a target with a tight hole in the centre these are the pellets to stick with: this a proven method used for many moons by seasoned shooters and also you have fun in shooting your gun

[lensman57]

I think you may be out by a factor of 10 there. Most Mitutoyo dial guages I have used have a resolution of the order of microns, i.e. 1000ths of a mm, not 100ths as you suggest.

Depends on the grade of the instrument, however, it is extermely unlikely that an instrument even with a possible resolution of .001mm can return a reliable measurement by hand to that degree. When we were taught machine tool tech at uni we were told that one of the rare advantages that the imperial lathe had over metric was that an experienced machinist could reliably work to 0.001" tolerance using calipers and gauges, the same person could not achieve the same accuracy with a metric machine even if the machine was accurate to the calimed 0.01mm.

Having done quite a bit of model engineering I have learned that to be true, 0.01mm tolerance and better is probably in the territory of CNC machining or very expensive Tool Room Grade lathes.

In any case measuring pellet size rquires a precise jig to hold the pellet exactly perpendicular to the axis of the micrometer. This can not be achieved reliably by hand holding and measuring. Pellets are also very soft, slightest pressure exerted by the tip of micrometer or even worse a caliper is sure to either compress or distort the shape, remember that we are working to a tolerance of 0.01mm on soft lead.

In any case having pushed through quite a few pellets down the barrels of my guns I have noticed that the barrels have a tight section at the breech end. I can only assume that this is to prepare the pellet for the barrel.

I had a look at the specs of the Lothar Walther barrels and the 4.5mm ones for example all have a land diameter of 4.46mm and a groove diameter of 4.62mm. I presume that the breech end " choke " will make sure that the pellets are sized accordingly.

Regards,

A.G