Last Minute Observation

[cris]

For all Team USA members shooting .22 caliber in HV.

The standard pellet for power testing is a .22 H&N pellet showing 21.14 grains. There were discussions before that these pellets produced very slow velocities, in many rifles, when shot over the chronograph, which lead people to think they could actually shoot above 20 FPE with the pellet of their choice.

I measured the heads of my tin of 200 pellets using a .2160 RCBS coated bushing. Some pellet heads went in and some would not. The ratio was approximately 3 large heads to 1 small head. The tin read 5.51mm heads.

The large head pellets were difficult to seat in my barrel's chamber, the small heads fit very nicely.

The large head pellets had a POI easily .500" lower than the small heads. Now, I did not chronograph these results but this usually indicates a significant difference in velocity. This was from my USFT at 1400 PSI. My last chronograph session was with 14.35 grain Cometas at 785 FPS, +/- 5 FPS.

Just a thought before everyone begins their journey.

 

[therealld]

Not sure of your point. Are you NOW saying the power testing will NOT be done according to the rules, and as has been stated for months, using the 21.14gr pellets for .22 cal, or are you saying not to use the 21.14gr H&N for the match without sorting, or what?

 

[cris]

Sorry my point was unclear. To be more precise,

1. Yes, power testing will be done according to the agreed procedure.

2. Yes, the H&N pellets marked as 21.14 grains will be used for .22 caliber.

3. My point is, depending on the pellets you are given to shoot during power testing, may or may not make a difference in your rifle/barrel results.

 

[therealld]

Yes, now I see. My experience is that with few exceptions, airguns that are spring powered often give lower power outputs with heavier pellets, and that precharged and co2 powered guns most often give slightly higher power when heavier pellets are used.

It is my feeling that the rulesmakers were familar with these trends, and assumed that so long as the competitors were aware of the rules, they could tet their guns accordingly so as to be assured they would be in compliance when competing. I suspect that any variance between fpe as tested by the rules commitee and that as actually being used with a competitors choice pellets will not materially affect the outcome of the match, since its been my observation that power levels need to be changed a fair amount in order to observe any significant scoring advantage.

I really feel relative differences in VELOCITY are more important than energy with respect to outdoor accuracy. See, a 12fpe .22 caliber gun, as tested with a 21.14gr pellets needs to hover around 500fps, while a 12fpe .177 using the common 7.33gr pellet can be putting them out at 850fps! Another comparison, but with the 20fpe limit guns are 650fps for the 21.6gr test pellet, versus 935fps for a popular 10.2gr pellet. Obviously there ARE many other weight pellets that could fly much faster in each caliber than those I selected, but I just give plausible examples.

I could cite a couple of examples where different model pellets of the same caliber and weight often give higher or lower energy (and therefore velocity) differences from the same gun, but theres no need, since I feel the main thing is that inspection using standardized test pellets is a good thing, and should have little influence in the match outfome, other thn to reduce the hassle of tech inspection.