Pellet Seating

[Xgboy]

Great forum. Long time lurker. Old thread, but interesting topic.

Like others, I bought a Beeman pelseat in the early '80s and used it for years (FWB 124D). Original instructions/illustrations that came with the tool described using the tapered end to reform/repair any deformed pellet shirt, and using the 'ball' end to uniformly flush-seat the pellet in the breech. It would seem that 'deep seating' the pellet (with the pointy end) would introduce 'dead air' into the compression cycle. I experimented a little with this and deep seating was detrimental to velocity and accuracy. In actual practice, I came to only use the tool (ball end) to seat stubborn pellets, or when my thumb got sore. If skirts were deformed enough to require reforming, I usually just discarded them. 

 

[Bill_in_TR]

I did a fair amount of experimentation with pellet seating recently. I posted a thread on here. My focus was on precision/accuracy not fps/fpe although I realize they are related.

For me shooting a D34 and an HW30S the key was consistent seating depth. I found that I got the best precision using a round nosed implement to make sure the depth was identical every time. For me personally fingers weren't good enough.

I also found that I could change the vertical POI by 2 to 3 inches depending on how deep I seated the pellet. I tried a couple of different implements and ultimately settled on a round nosed 9mm bullet for my .177 pellets. It assured me that my pellets were always at the same depth.

For me anyway this made a significant improvement in the consistency of my groups

 

[MDriskill]

A great read on this subject is Gerald Cardew's classic book, "The Airgun From Trigger to Target." The interaction of the pellet skirt with the breech chamfer of a springer is surprisingly complex and has to do several jobs, and the book explores this in great detail with a lot of instrumented experimentation to back it up the conclusions.

 

[Xgboy]

Gentlemen, thanks for the informative responses. Variations in seating depth absolutely produced noticeable to significant vertical stringing of groups during my (admittedly casual) experimentation. The 'ball' end of the tool did assure consistency. Over time, my thumb became sufficiently 'educated' to provide consistency sufficient for my purposes (informal 10m target, plinking, occasional furred or feathered edible woodland creatures). I will review referenced post and will attempt to locate the text. Again, thanks!

 

[270windude]

That’s the second time I’ve heard that book mentioned. I’ll have to see if I can pick it up somewhere. I like learning new things. 

I’ll say that pellet seating is a large part in my pursuit of accuracy. Every pellet that I test I shoot it flush where the skirt is just flush with the outer ring. Then I test 2 different seating depths.

I make my own seating tools with Allen wrenches. I’ll cut them and file it smooth. I use different sizes depending on the pellet so they don’t get damaged or deformed.

 

[MDriskill]

The first edition of Cardew's book is called, "The Airgun From Trigger to Muzzle." It's probably a bit cheaper to find these days, and still excellent on this particular subject. 

 

[Bill_in_TR]

The book is available as a free download of a PDF file. Just Google it and you will get more than one source for it.