Canadian Airgun Forum

greetings

i was shooting groups tonight using a new technique on artillery hold for the Diana 34, anyway, i did groups last night with the same technique and at 30 yards they looked very good indeed, but tonight, something funny happened, one pellet would go as low as 4 to 6 inches, and then back on the bull again, i thought the cracked stock or maybe scope slippage, but when i chronied the rifle it had an extreme spread ranging in the 30's and the 40's, so i knew something funky was going on with either the internals or the breech seal, i usually get an ES of 8 to 12

inspected the breech seal, it looked intact, so i took the rifle apart again !!!

i inspected the main spring, again fine, not broken or bent, then i inspected the piston seal, i did find a minute pit near the edge, but its so small i can't show you a pic cause my camera will just not capture that, it would be like me poking it with a sewing needle and leaving an almost microscopic dent, its that small using my press drill to have the piston turn; i took a 1500 grit sand paper to the outer edge and it pretty much took it away, de-burred the inside of the compression chamber which i should have done the last time , tested if it still sealed using the finger trick and it does, i will reassemble the rifle tomorrow and see if it fixed the issue, but here's a question, can a pit that small really affect it that much

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Can empty space really exist ?

I would not think that a very small imperfection would make an extreme difference that varied up and down. Did you put your specs into chairgun to see if that spread would make a 6 inch difference in pellet placement at 30 yards?

watertown.............you evil evil guy

i ran the numbers thru the chair program and the difference of 30 to 40 fps has very little effect on the POI at 30 yards, in fact less then a 1/4 inch

anyway, that drove me to reassemble the rifle tonight, i also changed the breech seal, although visually intact, the rubber was incredibly hard, anyway i re-chronied it with two strings of 5 shots, and now she has an ES of 5

i must have done something wrong the last time, she now cocks like she's new, and not like an old beater like my last re-assembly

i have a feeling she'll be shooting good tomorrow........thank for the boost bro

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Can empty space really exist ?

You'll Probably get offended by this but have you ever considered the possibility that maybe you just screw up the odd shot?

not offended at all, I do screw up shots and believe it or not, I already know when the shot's not going to be good, btw, I did consider that possibility but dismissed as it happened 2 to 3 shots on every group, plus trying it the same thing with my Airhawk yielded good results( I know, not the same but meh)

I know the Diana can do better

i'll see tonight

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Can empty space really exist ?

Have you tried different pellets or even the same pellets but from a different tin. I ask necause my 98 was shooting like a laser and then all of a sudden it was scattering pellets. I switched to a different tin of pellets (same pellets, different can) and it was bang on again. Top half of the tin was fine but the bottom half shot poorly.

Simple thing to rule out.

shot 3 cards of 40 pellets each, and its shooting fine now, any stray now is the shooter, not the rifle.....whatever it was, its gone, another factor i noticed is that i have to tighten the lock rings of my Leaper scope, after 30 shots or so, they come loose, that could also have been the cause, changing elevation or windage because of the recoil

yup, i did come across a bad tin or two of JSB exacts, that's the preferred pellet of this rifle

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Can empty space really exist ?