What are the largest diameter .177 pellets

[nurek]

My best barrels are non-choked and I get the same, hardly any resistance on pushing through but the pellet will expand when fired !

Id try a few samples and see if one comes good


Chris

^ exactly what Chris says... the pellet skirt will expand once it has some air behind it

[hmangphilly]

^ exactly what Chris says... the pellet skirt will expand once it has some air behind it

Is there any available evidence to support this theory please ?

[nurek]

Is there any available evidence to support this theory please ?

I don't have any theoretical evidence, but I think it's self explanatory, higher pressure behind pellet + friction resistance, the soft metal skirt will expand as it's moving (if it has place to expand)?

Do you think otherwise?

I have done a test where I have squashed a pellet skirt and measured the velocity, as expected it was lower, however the skirt 'opened' up. Probably more pronounced in a springer due to higher pressure... I only shoot spring guns.

As you work with barrels, you could do an experiment, where you push a pellet through a barrel (hence 0 pressure on skirt) and see how the skirt is deformed, and fire one, if the markings on the one that has been fired are deeper, the skirt has expanded.

[hmangphilly]

I don't have any theoretical evidence, but I think it's self explanatory, higher pressure behind pellet + friction resistance, the soft metal skirt will expand as it's moving (if it has place to expand)?

Do you think otherwise?

I have done a test where I have squashed a pellet skirt and measured the velocity, as expected it was lower, however the skirt 'opened' up. Probably more pronounced in a springer due to higher pressure... I only shoot spring guns.

As you work with barrels, you could do an experiment, where you push a pellet through a barrel (hence 0 pressure on skirt) and see how the skirt is deformed, and fire one, if the markings on the one that has been fired are deeper, the skirt has expanded.

That's exactly what we did . We could see no noticable difference .

It only works with an unchoked barrel of course

I'll try find the pics

[32:1]

Is there any available evidence to support this theory please ?

Recently there was a thread and it showed a pellet before and after firing, It looked like an ftt or accupell, the difference was very noticeable indeed, I wouldn't of thought they were effected that much, post was by BigAl who is the barrel guy. Not sure if it was on here of the r7oc

Chris

[Lol Moore]

Is there any available evidence to support this theory please ?

https://photos.app.goo.gl/tpdLyAwW6voL8ua5A

[hmangphilly]

https://photos.app.goo.gl/tpdLyAwW6voL8ua5A

Thanks Lawrence .
What does this show ?

I see grooves formed by the lands in both the skirt and the head .
I do not see any sign of contact to the bore in the section between these grooves .
This is the part of the pellet that is believed to be blown out to make a seal with the bore . Not happening on this pellet , which looks like it has only been pushed / rodded through a barrel .

Ok found a couple pics of a fired and retrieved from down range pellet , i'll have to get help posting the images , but check the portion of pellet that is believed to be blown outwards and drag along the wall of the bore ......

[Lol Moore]

It shows a pellet that has been fired and clearly shows what was mentioned by chris and nurek...i.e. the pellet skirt expanding

No mention of the pellet sealing in the grooves, just expanding...not sure how you can say that pellet has been merely rodded?

Try this one for size

https://photos.app.goo.gl/zvz5gW6sVvQyGapw8

I followed your threads on the other channel with great interest but I think you have maybe read too much into the statements in this thread, I agree with almost all the conclusions you came to and admire the way you got there.

I was messing with barrel lead in shape after I had read the article where the photos came from.

[32:1]

I cant copy and paste Al's pic so heres a link, its the AGF on a thread called barrel polishing with solvo or something like that

https://www./community/index.php?att...dr-jpg.122248/




Chris

[hmangphilly]

It shows a pellet that has been fired and clearly shows what was mentioned by chris and nurek...i.e. the pellet skirt expanding

No mention of the pellet sealing in the grooves, just expanding...not sure how you can say that pellet has been merely rodded?

Try this one for size

https://photos.app.goo.gl/zvz5gW6sVvQyGapw8

I followed your threads on the other channel with great interest but I think you have maybe read too much into the statements in this thread, I agree with almost all the conclusions you came to and admire the way you got there.

I was messing with barrel lead in shape after I had read the article where the photos came from.

You could be right Lawrence .

I've just re-read my thread on the other site .

You're also correct in that i cant possibly tell that the pictured pellet has not been fired .
If it has then hats off to the contributor for capturing the pellet in such condition .

[bucketboy]

It a simple matter of physics, you need to apply a energy to get the pellet up to speed. The faster you want the pellet to go the more energy is required. Even at 12fte the amount of force required to push the pellet up to speed in the length of the barrel is not inconsiderable.

I takes very little effort to flatten the skirt of a pellet between your fingers, it takes much more effort to stop the air coming out ot the barrel by clamping your thumb over the end (don’t, it hurts) it stands to reason that if the discharge of air hitting the back of the pellet is enough to do damage to your thumb it’s enough to do damage to the pellet.

Bb

[Lol Moore]

You could be right Lawrence .

I've just re-read my thread on the other site .

You're also correct in that i cant possibly tell that the pictured pellet has not been fired .
If it has then hats off to the contributor for capturing the pellet in such condition .

Phillip....my name is Lol....confusing in this day of text speak I know

I think we are interpreting the picture differently, its two of the same type pellet, to my eye the skirt of the "fired" pellet has indeed expanded (it looks more rounded) as you say a very good job of capturing has been done. If you cover the bottom quarter of the skirt and just look at the top portion of the skirt it does look different.

This was not intended to join into the debate about whether pellets sealed completely in the grooves of rifling, it just shows that the pellet skirt deforms (as stated by a few on here) and as such the deformation will effect the pellet flight, which is ultimately what counts.

Before all your testing I believed that sealing was probably the case - not so sure now.

I agree there appears to be no evidence on this picture of "sealing".

Anyway, the article is by Hector Medina in the states, he writes some really interesting stuff (as do you ), here is the article:

https://www.ctcustomairguns.com/hect...to-the-rifling

The bit that caught my eye and set me off messing with breeches was this:

Careful experiments have shown that pellets DO DEFORM upon firing. And one of my preferred methods of choosing the best possible pellet for a barrel involves soft-capturing fired pellets and measuring how much they expand at the waist or the column. The more they expand, the less are we in control of the final shape of the pellet once we have pulled the trigger.
Once the pellet starts to move, depending on how the chamber was machined (or not), the head engages the rifling before the skirt and this also exerts a TORSIONAL stress on the waist or the column. At times, this stress may be enough to deform the pellet substantially, in most cases it is not, but it is still mentioned here to point out to problematic barrels that, in reality, need only to have their chambers fitted to the pellet the shooter wants to use.

Great believer in the importance of the skirt - how good do these Qiang Yuan bad boys look

https://photos.app.goo.gl/QXwKC4TaERJgQKxA6

One or two tiny nicks in there but easily fixable on the pellet tin lid with a rub