GTA
All Springer/NP/PCP Air Gun Discussion General => Projectiles => Topic started by: Nvreloader on December 06, 2022, 02:48:23 PM
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I got out my pellet recovery tube, a 4' long piece of thick wall plastic water pipe,
stuffed full of those blasted W Mart bags etc.
Set up the tube at 3' and shot a couple of the newest Croman 22 cal 14.3gr pellets into the end,
and fired 1 pellet from the JSB OEM can, 15.89gr.
Put everything up and was searching the bags for the pellets,
I put 10-20 bags into one bag, and have several of these bags stuffed into the plastic pipe,
when you pull the first bag out and it has tails pulled into the second bag,
you know the pellets are in the second or third depending on where the tails stop.
Found the Crosman in the second bag and the JSB in the third bag,
upon checking the Crosmans, I found good strong riflings marks
on the head and tail sections.
Here is the rest of the story, That's Weird.....
On the JSB pellet, (all fired at the same time/psi 1500psi,
and the rifle has a bore size of .2175" etc,)
there was NO marks on the head or skirt sections, WTH is going on,
checked with the 20x lupe and could see some faint marks,
on one side of the head and on the opposite side of the skirt,
kind'a like the pellet had tipped in the bore and was marking on the side/tail of the skirt.
I miked the JSB pellet and is measured .2150" on the head and skirt. (OEM can)
I'll try to get some photo's today, the sun is out............ :o
This is a first for me,
rifling marks on opposite sides of the head/skirt and NO where else.
I'll redo this test again, and see if I have more of the .2150" size
and will head bump the JSB up to .2175" for the second test.
Tia,
Don
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Had a similar issue with JSB .22 cal 18.1's about 5+ or so years ago.
Shot like garbage .. then measured. Tins marked 5.53mm tho when measured were ONLY 5.46 to 5.47mm
2 sleeves ( 20 Tins ) went back to PA for credit.
Yup when pushed threw a known good barrel, nary a rifling mark was made.
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Thanks Scott
Checked the tin and about 1 out of 10 is undersized, (50+) so far,
I have been separating the .215" from the .2170" pellets.
I now can head bump them for better accuracy to the .2175" size, and do some testing.
Tia,
Don