I now size my Pellets

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eodman

eodman

Member
Dec 29, 2017
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Cal, United States
I ordered a sizing die and holder from NOE Bullet Moulds ( got info from this forum) I built a stand so I could size pellets while watching TV. What a difference I no longer have a feeding problem with my .25 Crown. I'm using JSB MK2 Heavy. I now can shoot the MK 2s in my Impact with out feeling a drag when I chamber them. My speed picked up for the
speed shoots it feeds so smooth. Happy with the results.
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 The Sizer body bushing is .252.dia Their # 25BBAG-252

If you order you will need the die body to hold the sizer bushing. He will try to sell you the body and inserts. All you want is the die body and 252 bushing. Make your own push rod because his is too big and pushes against the skirt. You want the push rod to fit inside the base of pellet.
Make up a platform to hold the die and just push them thru while watch tv. One caution other people may get upset with the constant little noise when pellet drops in the tin.
Hope that helps.
.
 
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I just got a TR Robb sizer. I've not had the time to shoot any of my sized pellets, but it was very easy to get very consistent 0.252" pellets with very little fiddle-futzing. It's available here https://www.trrobb.com/product/adjustable%20pellet%20sizer%20177

It's a little slower to use that a straight push-thru die, but it does preserve the taper from the head to the skirt. It also pretty much eliminates dinged skirts

Once I get some range time with the sized pellets, I'll report back on accuracy, etc.
 
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Please note that all factory Airgun pellets have different head and skirt size.
head is sized for barrel bore and skirt has larger diameter than groove.

Internal ballistic of airgun:
head slides tight in to the bore and conical skirt assures straight fit. Once barrel is pressurized head keeps sliding and skirt is expanded to engage rifling and provide tight seal.

when using cylindrical sizer 
1. You are pretty much assured that your pellet will get misaligned - head will wobble in sizer and enter it under angle.
2. You are reducing skirt diameter. Your skirt will not engage rifling as good as factory one and air seal will not be as tight. Air will pass pellet and will create turbulence in front of pellet at barrel exit.


none of above adds to accuracy. 
 
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When I decided to size the pellet skirt it was to make the pellets fit and function in my crown magazines. After sizing pellets to skirt size .252 diam all of my feeding and magazines problems went away. Reading your response it seemed that you think the whole pellet was sized down that is not the case. Here are some facts on the 25 cal pellet. I measured about 30 pellets and here are the results.

Head diam = 0.2495
Skirt diam = 0.259 to 0.2560 
Skirt diam after sizing 0.525

As you can see the skirt is still larger than the head. I then pulled both barrels from my impacts. One barrel is a 700mm STX and the other is a 600mm STX. I pushed several pellets thru both barrels and inspected them. both the head and shirt made contact with the lands of both barrels. I the replaced the barrels and went to the range with my chrono.

Here are the results.

I shot a string of 10 sized and 10 unsized pellets. I filled gun to 240 bar before each 10 shot string so all was equal.

FX Impact # 1 600mm STX Barrel. FX Impact # 2 700mm STX Barrel. FX Crown STX Barrel
Unsized pellet average fps 717.70 Unsized pellet average fps 828.22 Unsized pellet average fps 731.64
Sized pellet average fps 729.65 Sized pellet average fps 820.62 Sized pellet average fps 737.37

Looks pretty consistent to me. Also all of the groups were same point of impact and all groups were tight all touching and no flyers. I was shooting at 50 yards with no wind.
As far as size of groups looks to be about the same with either sized or unsized. my conclusion Will keep sizing as there is no down side and much better feeding in my magazines.

Please note this is the results with my rifles yours may differ. I hope some of you other people who size will try some kind of test and report it here should be interesting.
 
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So with a Steyr Hunting 5, the magazines seem to size down the skirts without affecting accuracy. Not sure to the extent because I have not measured them yet, before and after magazine insertion. I suppose that I will need to verify to what extent the 'resizing' that takes place, but there is effort to push the pellets into the magazines (there are no 'O'-Rings holding the pellets in the magazine, just friction).
I will get back to you on the numbers though.
 
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"peole"Please note that all factory Airgun pellets have different head and skirt size.
head is sized for barrel bore and skirt has larger diameter than groove.
Internal ballistic of airgun:
head slides tight in to the bore and conical skirt assures straight fit. Once barrel is pressurized head keeps sliding and skirt is expanded to engage rifling and provide tight seal.
when using cylindrical sizer 
1. You are pretty much assured that your pellet will get misaligned - head will wobble in sizer and enter it under angle.
2. You are reducing skirt diameter. Your skirt will not engage rifling as good as factory one and air seal will not be as tight. Air will pass pellet and will create turbulence in front of pellet at barrel exit.
none of above adds to accuracy.
Click to expand...
I can only speak for the TR Robb sizer. It sizes by pushing the pellet head first into a tapered hole. The degree of sizing is controlled with an adjustable brass stop pin. So the taper you describe is preserved. Indeed, the pellet skirts are cleaned up and are made concentric with the head. Running sizer vs unsized pellets over a chronograph, I get similar velocities, but the sized pellets show a lower ES and STdev consistently. Just my experience...
 
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I got my Noe sizer in .252 and resized a tine of all 3 JSB 25 cal weights. Went to the range today with my 25 WC MKI and some high expectations. Overall, I think the resized pellets were tighter groups, but then the tightest group I shot all morning was with unsized pellets. Realistically, at 50 yards all the shots were ground squirrel killers. I, too, will resize just because I have the die and spend more time at the range comparing g results. I may even sort the sized pellets by weight and see what that does to group size.

I have no idea what speed my gun shoots, and as accurate as it is I am not sure I really want to know. So many adjustment possibilities, so little time.
 
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I had a chance to run a short experiment this evening and using the Steyr magazine as my guide, since I stated that is shrinks the pellets to that magazine opening size, I found that it does appear to do just that.
I checked a measured 5.54, 22 caliber H&N pellet with my PelletGage and found that while the head would barely make it through, it would not allow the skirt through (this is what one would expect, right). The head was not even close to going through the 5.53 gage opening. 
I then inserted the 5.54 pellet into the magazine, pushing it through as if firing it through the gun itself it is a very tight fit. After checking with the PelletGage, the pellet head would now go through the 5.53 gage opening as would the skirt with very minor resistance from both. Looking through a magnifying glass, there are shiny spots on the outer edges of both the head and skirt, which seems obvious, but verified.
Steyr being a well known and pretty darn accurate air rifle, has no problems shooting these pellets.
I'm not trying to cause a controversy, just posing the question. Why does this work and why would Steyr even consider using this method if it was not as accurate as a larger or tapered skirt? Help me understand this concept please. 
 
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