Super Domes, Super Powered????

[andyfr1968 772]

Have you tried your other pellets sinse? It could be that your 77 has just settled itself down after a good few more shots, there shouldn't be that much difference.

 

Normally (but not always) lighter pellets tend to give higher readings in springers. When I'm setting up a rifle I tend to set them up with RWS Hobbies first and then try other types after I've got the gun settled with those.

 

It sounds to me that your gun's just found it's sweet spot after all's settled and happy.

Edited February 7, 2013 by andyfr1968

[Halfinch 51]

Andy, i tried the other pellets again after the RWS, I even tried the Combro on my HW97 to check it wasn't that, and although they did fly faster from the 98, it wasn't by that much, certainly not over 100fps faster than the AA Field, they were about the same as the crossman in the 97.

 

I tried them again in the HW77, same result! i can't understand why they are that much faster, I'll try some other pellets tomorrow but whatever the results, I've got to get the fastest ones below the 12ftlb limit, which means the AA Field will be really low powered in this particular rifle.

 

Guess i'll just have to find the best pellet for power and accuracy once i've bought the limit back down.

 

Worse thing is, if i hadn't tried the RWS, I'd have been all smiles thinking the rifle is shooting nice and well within the Limit.

 

Cheers for your advice.

Edited February 7, 2013 by Halfinch

[andyfr1968 772]

It's got me beat then, mate. That really is an odd one but if you ever do get to the bottom of it, please let me know

 

Sounds like you've covered all the basses. Wierd.

[barrywhite 282]

your spring may be very over powered .I have had a similar problem I had a webley omega shooting at 12.5 with a new spring .the only pellets I could get to group where bisley long range gold .before the new spring allsorts of pellets worked .any way I chopped coil after coil of the spring with strange results .the power went up to 15ftlbs and chopping of more spring the gun went down to 11.5 and most pellets shoot fine again.....I feel the massive push from the piston distorted the pellets then bounced back giving 12.5 then the spring was perfect at 15 ftlbs then legal and smooth at 11.5 lbs . I will shoot super domes and aa field and tell you what I get .my gun was set with super domes a 11.5 ish .

[barrywhite 282]

superdomes the best 11.7 aa field best 10.9 .another thing I have a tx 200 177 shooting defiant pellets at 11.2 but when I try falcon accuracy plus the power drops a lot I think the soft lead pellet must expand and grip the barrel .The falcon are very accurate but only tried them out to 13 yards .

[andyfr1968 772]

That's the thing with springers, they're a complicated science. It's not about the amount of spring in there, as most folks think, there's a lot more going on. There's a mass of piston being accelerated up a contained cylinder which has then got to compress a given amount of gas (air) through a small hole (transfer port) which has then got to give it's energy to a projectile that can be anything from about 7 to 16 grains (average) and then shove it out of the end of the barrel.

 

There's a lot that can go amiss here, and that's where careful setting up comes in.

 

Sounds like Halfinch is suffering the the shitty end of this though. I hope it works out, mate.

 

Edit to add..... I'll stop rambling like a twat in future after I've had a drink.

Edited February 7, 2013 by andyfr1968

[barrywhite 282]

he has to cut the spring so then we will know .superdomes are good pellets in spring guns .so if my gun only shoots superdomes well thats fine .but if superdomes stop

[Halfinch 51]

ok, the latest is, I've cut just over one coil off the spring, squashed the last coil and ground it flat, Put her back together and I'm now reading. (Just the average here)

 

AA field Crossmans Superdomes

 

11.65 - 573 12.05 - 616 12.25 - 617

 

So I'm still over, but I'm going to sort that now with a bit more off the spring, But the Good news is that the difference between the Superdomes and the others is much much closer. And she is shooting very smooth.

 

Barry White, It would seem your theory was spot on, I could tell the rifle had been worked on, because it has a top hat and a nicely machined, tight fitting spring guide, i just dont know what spring it has, at the moment the spring is flush with the back of the gun, IE: no preload, except what you get when you screw the trigger block back it, around an inch or so. my Hw97 has about 1/4" outside, so definitely not an original.

 

Right, I'm off to cut and grind, I'll update later.

[Halfinch 51]

Happy Days!

Took just about one coil off, flattened and reground, all cleaned and re-lubed, now it is shooting sooo smoothwith these figures....

 

AA Field Crossman Premier Rws Superdomes

ftlb fps ftlb fps ftlb fps

11.14 - 560 10.89 - 585 10.86 - 581

11.19 - 561 11.11 - 591 10.95 - 583

11.20 - 561 11.02 - 589 10.95 - 583

11.24 - 562 10.95 - 587 10.90 - 582

10.92 - 554 11.25 - 595 10.95 - 583

 

I'm guessing these figures might creep a little over time, but i'm well within limits, so it shouldn't be a problem.

Looking back at the Original figures, it goes to show, that just because a rifle fires under the limit with a couple of types of pellet, it could be well over with another, although in my case it was down to whoever had it before, had, I Guess, Tried to do a "home tune" and although it was fitted with nice fitting and well made Top hat and Guide, the spring was far too powerful.

 

Less is sometimes more, and Halfinch is one happy chappy

[Mawders 595]

Good skills half inch it goes to show the pitfalls of air rifles, until the government standardise pellet testing everyone could fall into the bracket of having an over powered air rifle as it all depends what pellets your particular force tests them with should your rifle be seized for power testing.

 

Its a mine field alright so keep an eye on the power as it beds in. Another pitfall is it all depends what device you test your rifles power on as to what reading you get. I had a rifle purchased new that once bedded in crept over the legal limit to about 12.3 ft/lb but when I packed it up and took it to another device and tried again it was 13.5 ft/lb. when I took it back to the shop they checked it and their reading was 12.8ft/lb all using the same tin of pellets. There should be one power testing device and a standardised pellet for testing.

 

Mawders

[pianoman 3,589]

My local police FO told me they used Eley Wasps for years to check spring air rifles confiscated in vandalism and accident/incident investigations. Apparently, these pellets would show up a hot rifle's performance, where another brand might be keeping it under limit.

[Halfinch 51]

I absolutely agree, it should be a standardized test with a specific pellet, If it was say, AA field, my rifle would have been fine even though the domes went over.

I'm sure the Police would use the most efficient pellet they can when testing, and i think that is only fair, BUT, they need to let it be known what pellet it is that they test with because it would be nigh on impossible for anyone to test EVERY available pellet.

 

Pianoman, are Eley wasps a very light pellet then? as i understand it, light pellets= more power in Springers, Heavy pellet = more power in PCP's

Strange how it works different considering they are both only big pea shooters really.

Edited February 7, 2013 by Halfinch

[Mawders 595]

Don't forget however that two brands of pellet that weigh the same will produce different results. Far to many variables!

[barrywhite 282]

I would think wasp pellets were a good average pellet to use .quite fair, not what one is led to believe of the police today .

[barrywhite 282]

HALFINCH shoot a stupid heavy pellet like logan penetrator 20.5 grain ect .watch the power drop .