Variable power hw99

[madcarlos]

One of my 99s (22) is causing imense frustration, checking power with Ftts 11.3, with RS 10.3 but with hobby 11.9!. My other 99 also 22 gives relatively constant power at 11.3-11.6 with same pellets , similarly my Hw30 remains constant with same pellets 7.7-7.9 so any ideas as to why one 99 can give such very variable power? Have stripped a few times and nothing appears amiss - good seals, bumslide lubed, spring, guides top hat all look good. Both 99s have had tins of pellets through them and I have cleaned bore in case such was cause.

Some guns may need a good few pellets through before settling down, I would shoot 10 or 20 pellets through it then try it through a chrony, I have 3 x mk1 80s , 2 of them after the first pellet or 2 settles down with hardly any variance, The other one tends te shoot late 11s for the first 8/10 pellets before dropping around 11.2 Some will take 1 or 2 shots some may take a good few more , Regular shooting normally wears them in quicker,

[maximus]

Probably just due to a particular pellets fit in the barrel. Being light you might expect the RS to give good muzzle energy like the hobby but there is obviously a difference which I think must be how well the pellets are sealing in the bore.

[averageplinker]

I reckon it is either the spring and/or barrel. If you can be bothered try swapping barrels over and see what happens. If that makes no difference try swapping the springs over.
Rich.

[Damned 69]

Have swapped springs and also tried a titan 10. Never thought about barrel but assume different batches and possible minute differences? - older one has registration number stamped on lhs whilst new one has it stamped on bottom.

[harvey_s]

Kind of unclear what you mean really...
It's common for guns to give different power outputs with different pellets.
As long as the same make/model of pellets gives the same power it's not a problem.

[Damned 69]

My query was that with one 99 the power spread between 3pellet types was relatively close, whilst the spread with my other 99 using same 3 pellets was what I would consider rather large at 1.6ft/lbs.

[averageplinker]

I guess another possibility could be a different transfer port size. Have either been adjusted?
Rich.

[harvey_s]

My query was that with one 99 the power spread between 3pellet types was relatively close, whilst the spread with my other 99 using same 3 pellets was what I would consider rather large at 1.6ft/lbs.

Ah, understand now...if it helps my own .22 certainly shows that kind of difference between say RWS Superdomes & JSB Exact.

[PCPShooter]

My query was that with one 99 the power spread between 3pellet types was relatively close, whilst the spread with my other 99 using same 3 pellets was what I would consider rather large at 1.6ft/lbs.

Those Hw star nut barrels in 22 ...emm........

As others have said - Combo of spring / seal set up / TP size, barrel choke (if any - or on hw if any intentional or barrels pinched for open sights) / lead in on throat of barrel

If I have a springer that handles most pellets within .5 ftlb - result - never sell that one then !