Hard and Soft Pellets

[Black Beard]

Thanks Jim. Were your more accurate results higher?

I figured that in a springer, where you have a slow build up in pressure as the cylinder moves forward a simple push rod in the back of a pellet would be okay. The skirt won't deform under the pressure but it will be forced into the bore with the larger skirt getting swaged down at its bottom edge.

[BTDT]

Thanks Jim. Were your more accurate results higher?

I figured that in a springer, where you have a slow build up in pressure as the cylinder moves forward a simple push rod in the back of a pellet would be okay. The skirt won't deform under the pressure but it will be forced into the bore with the larger skirt getting swaged down at its bottom edge.

I suspect they were higher, Andy but, hand on heart, I can't say for certain. The air pressure tests were with my old HW77, which has shallow and rounded rifling and a rounded lead-in, the push tests with an Anschutz 335, which has deeper and angular rifling, and a very different lead-in, so a comparison would not be reliable.

One point I think you will find interesting is that I tested .177", a friend independently tested .22", both using our HW77s, and with Falcon Accuracy Plus, the .177" start pressure was 120psi, the .22" was 80psi, almost exactly in inverse proportion to the CSA of the two pellets. I know that's how it should be, but it's gratifying when test results match the physics.

The thin skirts of soft JSB pellets definitely deform under start pressure or less. I have recently seen evidence of this (long story), and I think that the deformation and consequent reduction of blow-by, plus the soft lead, accounts for the low start pressures. I doubt thick and hard skirts deform, though.

Something else of considerable interest is the test results obtained by Mike Wright for the coefficient of (kinetic, or sliding) friction of hard and soft lead against steel at velocities between 30fps and 70fps (the limit of the equipment he used). The hard lead was Premier, the soft JSB, and the figures were under 0.4 for soft lead, 0.9 for hard, which roughly translated into a loss of a foot pound in the region of 10-11 ft. lb. We each independently tested the pellets and, sure enough, both lost around a foot pound with the hard pellets.

[TonyL]

Brilliant. Most interesting. Thanks Jim.

[BTDT]

Brilliant. Most interesting. Thanks Jim.

Thanks, Tony.

I'm hoping Phil will expand his pellet (rod) test to include H&N FTT and RWS Hobby.

[Phil Russell]

Some data for Hobby and H&N FTT
Note: I only have Hobby in .177 and H&N FTT in .20

But out of interest: Hobby lost 53% height in the crude pellet test, FTT lost 34.6%

In the rod test: Hobby lost 28% and FTT lost 23.8%
Re-reading my earlier post I note I did not give data for Marksman. They actually turned out to be the softest rod, losing 34.9% height, just pipping AA Field at 33.35%

So in rank order I have:
Accupel (Hard), H&N FTT, Eley Wasp, FX, Hobby, Superdome, JSB, AA Field, Marksman (Soft)

Excuses: There is a little 'bunching' of data at times so I expect errors in procedure such that: FX, Hobby and Superdomes could all form a pretty common group. Marksman, AA Field could be another common group.

Cheers, Phil

[BTDT]

Thanks for that, Phil. Suggests the Superdome and Hobby are probably the same alloy, which makes sense from the manufacturer's viewpoint.

[TonyL]

Thanks, Tony.

I'm hoping Phil will expand his pellet (rod) test to include H&N FTT and RWS Hobby.

Thanks for that, Phil. Suggests the Superdome and Hobby are probably the same alloy, which makes sense from the manufacturer's viewpoint.

Very handy, thanks for that, Jim and Phil.

The Hobby and FTT are pellets that I use a lot, so of interest.

I always guessed the Hobby would be in that softer range (doesn't take a genius to guess, I suppose) and, as I mentioned in an earlier post, for many years I would only use Hobby and Superdome as I guessed the composition would be, at the least, very similar, so my barrels may not mind switching between the two?

[evert]

....
So in rank order I have:
Accupel (Hard), H&N FTT, Eley Wasp, FX, Hobby, Superdome, JSB, AA Field, Marksman (Soft)
....

Interesting, because FX pellets are always assumed to be rebranded JSBs.
Could this mean that JSB do not always use the same alloy?

[Phil Russell]

Interesting, because FX pellets are always assumed to be rebranded JSBs.
Could this mean that JSB do not always use the same alloy?

My data may well not be absolutely accurate even though I think it is indicative when used to compare pellets. If you look at the .177 pellet data you will see that JSB and FX are extremely close on mean height ... vary by 0.05mm but when I look at individual pellet data this 0.05mm could well be due to sampling error (I have not analysed the data to that degree). Mean pellet compression was also very close. Its only when you go to the 'rod' data that you see a difference with JSB being marginally softer. Why the discrepancy? If we assume that the rod data are the more accurate and JSB are truly softer than FX then the only explanation I can think of for the similarity in pellet data is that the pellets vary slightly in design i.e. they are not identical moulds but even so, I suspect differences would be very small. and possibly to do with skirt thickness. Maybe JSB skirts are very slightly thicker than FX which makes the JSB appear to be the same as FX in the pellet test.
Cheers, Phil