Pellet re-sizing. Good or bad?

I've have a NOE pellet sizer and have sized three different pellet sizes for my RAW .25. The sizes were 0.250, 0.251 and 0.252. All but the 0.252 didn't improve accuracy, but the 0.252 did. It eliminated my flyers. I've just ordered 0.253 and 0.254 dies to make sure I've identified the size my rifle likes best. 

I also have used a PelletGate to size pellet head sizes. But I've had problems getting consistent measurements for the same pellet. Hopefully, if I can provide my rifle with the diameter of a pellet she likes, the same head and skirt size shouldn't matter. 

I enjoy the quest for accuracy. If I can eliminate the gun (which I think I have), then it's either the pellet, scope or shooter. I'm hoping it's the pellet. 

"jps2486"The sizers, of course are incapable of sizing just the head and not the skirt. They both come out the same. With a smaller skirt, there is more energy expended in obturation of the pellet skirt during the shot cycle.

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There is an adjustable one that does manage to keep a size differential between head and skirt by using a tapered chamber, it is made by T.R Robb in the UK - I am not affiliated but have one and found it works well.
http://www.trrobb.com/product/adjustable%20pellet%20sizer%20177

My experience with this issue is that the barrel on my brand new Royale 400 seemed to be really tight and consequently pellets straight from the tin grouped poorly ie: occasional 5 shots sub 1/2" at 50yds but mostly larger and 4" at 100yds was normal. Resizing pellets down by about .04mm with use of above mentioned resizer and a Pelletgage reduced the group sizes in general, and to consistently sub 1/2" at 50 which was my basic expectation for this rifle. 

Interestingly at 100yds I was still grouping 2" - 3" for the most part which was not amazing, but an improvement, so in the quest for the sub 2" @ 100yd which I had been expecting from the FX, the next thing I tried was barrel polishing... This has been a revelation frankly. Using polishing compounds on a cotton mop in a drill I went at the last inch of the ST barrel for a while. The result was that now pellets direct from the tin were grouping virtually as well as the resized ones and at longer ranges, with the last two 12 shot magazines going into a 1.34" group (direct from tin) and a 1.25" group (re-sized) at 100yds.

So my conclusions are that because pellet head sizes vary direct from the tin, and as it seems also that the internal size of barrels may vary, it makes sense to me that improving the relationship between the two has the potential to significantly improve shot consistency and efficiency. Pellet weight is of course another important factor, but from my experience with this rifle it is secondary to finding the optimum head size.

This is just my experince though and my tests have not really been scientific enough to say that this is a general rule.

"Asa-J"Using polishing compounds on a cotton mop in a drill I went at the last inch of the ST barrel for a while.

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Does this mean the breach end of the barrel or the muzzle end of the barrel?

Muzzle end

Pellet sizing is a good thing , I've recently purchased some dies from NOE
I bought the 17 cal ones and opened them up 5 thousands my groups improved
by 50% in .177 at 55 yards went from 1" to .5" after sizing , and 4 out of the 10 shots
went through the same hole now I'd thats a major improvement . 

Asa, it sounds like that TRROBB sizing tool has a smooth taper inside, does this mean that it sizes pellets by simply squeezing down on the pellet head and skirt ?? I assume many others have a sharp edge inside that shaves of the excess material to get the correct size.

Chachoze, yes that's about right - it comes with a probe that you push the pellet down the chamber, tapered as you say, until it hits the stopper. The stopper is the adjustable part so the further into the chamber the pellet goes the smaller the head diameter will be, and because it is head first the skirt is proportionally larger depending on the length of the pellet.

One thing I have noticed is that with softer pellets ie: JSB, where the head hits the stopper it gets a tiny dimple which may concern some people but overall for me it still makes an improvement in consistency.

This is the only re-sizer I have used so not sure how others work...

If you have a sizing tool that removes lead ditch it. They should gently squish the head to size.

Ok, good to know guys, thanks!

I have a TRobb.177 resizer for sale in the classified section. Nearly new condition. Used on probably 100 .177 JSB 10.3's

Joe

I've been sizing .22 pellets and it has improved my groups substantially. I have sorting gauges for .177, .22, and .25 and they have also improved my groups; however, it is much easier to buy over sized pellets and run them through a sizer than to measure the heads. Also I have not noticed any problem with skirts and heads being the same diameter.

Being new to "precision" guns? Lots to absorb. On this topic my question is. If the head and skirt are sized the same, once the pellet is chambered and the trigger releases the blast of air into that skirt would it not expand into the barrel? Some air would get by but I wonder if it would make a difference?

I don't know. Like I said, I am happy with the results of simply running them through a sizer:

http://www.airgunnation.com/topic/ten-dimes-challenge-changed/page/5/  <= Top of teh Page

I too am a sizing believer, I noticed it first on my 25 marauder and halve cut my group sizes in half @ 110 yards out of my Vulcan. I bought a .248 and .250 die from Lee and the marauder loved the .248 but hated the .250. The Vulcan is the opposite. I just tested again last weekend and unsorted pellets would beat the .248 die but, the .250 die spits out laser beams.