Weirdly one of my guns hates .177 JSB exacts...

[Shed tuner]

Why is it Weird. You have been around long enough to know barrels are individual. And that even head size or batch/Die number can make a big difference.

Absolutely - I guess the title is a bit simplistic.. it's more that:

i) it hates them to such an extent, in both power and accuracy, compared with others of similar weight / size / shapes

ii) the barrel used to be very happy with them, with a different powerplant

[Longstrider]

None of my rifles like the .177 JSB's.

All my air rifles are .22 calibre ! :lol:


Sorry .. I'll get my coat ..

[RobF]

Absolutely - I guess the title is a bit simplistic.. it's more that:

i) it hates them to such an extent, in both power and accuracy, compared with others of similar weight / size / shapes

ii) the barrel used to be very happy with them, with a different powerplant

same batch though?

[Archer50]

I've just run tests with my .177 HW100, using all the available head sizes of JSB Exact, Exact Heavy, Exact Express, AA Field, H&N FTT and Superdomes. I shot four groups of 10 of each of them at 35 yards indoors, off a bench rest.

I have never done anything like this in a systematic way before. I was not too surprised at the scale of the differences between different types of pellet, but I was very surprised at the enormous effect head size had on the Exacts. Overall, on the basis of CEP and standard deviation, two pellets came out streets ahead of the others: AA Field and the FTT's, with the AA's slightly in the lead but not enough to be sure without even more testing The clearest result of all was that the more or less 'standard' Exact 4.52's were by far the worst performers on every measure and none of the JSB's did well, for me in my gun.

So, it looks like I've got another gun that hates Exacts and it's AA Fields for me unless something better comes along, or I just get bored......

[Amac]

My eldest target shooting son has an uncanny ability to recognise the individual physical characteristics of different batches of JSBs. Sad, but true! Thats what you get when you become over absorbed in detail when engaged in the never ending search for the ultimate pellet I suppose.

Andy

[Shed tuner]

same batch though?

Tried two batches, one better than the other, but both cr@p
Barrel was previously tested / happy with one of the batches (the better one as it happens)

[RobF]

Tried two batches, one better than the other, but both cr@p
Barrel was previously tested / happy with one of the batches (the better one as it happens)

fair enough

i'm not sure if power plant or barrel is why one batch i have shoots poorly in my pop's but not in my springer

[Steyr]

Absolutely - I guess the title is a bit simplistic.. it's more that:

i) it hates them to such an extent, in both power and accuracy, compared with others of similar weight / size / shapes

ii) the barrel used to be very happy with them, with a different powerplant

sounds like a power plant and harmonics issue then....

[Shed tuner]

sounds like a power plant and harmonics issue then....

Or air blast / sizing, but yes...

Going to swap power plants between rifles see what happens

[Shed tuner]

Well, the pellet batch was the main problem:
http://www.airgunbbs.com/showthread....89#post6682789

That was worth about 6mm of my 30 yard group size increase.

Another 1-2mm was down to the barrel itself, and a further 1-2mm down to the powerplant (easily sorted - the port was too small, so limiting the blast that "sizes" the skirt)

Mystery solved, but there was a whole lot of testing, swappping things around between guns and more testing to get to this resolution !

HTH - JB