True. My 25wssm is averaging around 2950 - 3000 fps with factory 115 BT's...down 100fps from published velocities.

Try setting up at least 15 feet away from the Chronograph. Sometimes muzzle blast can adversely affect the velocity reading.

Trshep: Was your machine giving you FPS readings 10 feet in front of the muzzle? If so then that is not the muzzle velocity.

There is a formula that will give you the ACTUAL muzzle velocity (like the factory published numbers ARE!). Granted once you have used the formula to find the ACTUAL muzzle velocity it will be higher than your readings (your highs, your lows, your averages etc) but probably still not up to the factory numbers.

I will go retrieve the formula for you to figure your ACTUAL muzzle velocity and you can compare your real muzzle velocity with the published factory "readings".

Yes I have been "victimized" (fooled?) by factory printed FPS exuberance's on several occassions in the past and that is one reason I bought my Oehler Chronograph (to combat these). I think though once you use the formula to find your ACTUAL muzzle velocity and take into consideration your "short" barrel length (both my 204's have 26" barrels which are more properly consider the norm for a high intensity Varmint cartridge - I think) the factory numbers won't be that far out of touch with reality. I have just been to busy in the last few months to chrono either of my new 204's with either factory loadings or my wonderfully accurate only handload tried in them so far.

Here comes the formula: To find the actual muzzle velocity when taking readings 10 feet in front of the muzzle - you need to find or figure out the velocity 100 yards from the muzzle, of your bullet. Subtract the velocity at 100 yards from your 10' in front of the muzzle number (I am guessing you will have a figure around 300 to 400 FPS loss). Divide this loss by 20 and add this result to your average velocity (or low velocity or high velocity etc) and you will have "real or actual" muzzle velocity numbers.

So lets add say 20 FPS to your readings to estimate the "real muzzle velocity" of your Rifle and add say 80 to 160 FPS to that reading (if you had a more normal barrel length) and you are right up there pretty near the factory numbers. Which in my opinion are pretty phenomenal!

Enjoy your 204 - its shooting fast!

If you have used the formula already to make your initial posting then other factors may interject themselves into your lower FPS readings - like a looser fit between the bullet and the lands and grooves of your CZ"s barrel, chrono variance etc.

Good luck with your new Rifle and I hope you will be as happy with it in the field as I am with my two 204's!

Hold into the wind

VarmintGuy

Glad you like the new chronograph. Your velocities are fairly consistent with what I found with 32 gr. Hornady factory ammo when I was first breaking in the barrel on my Savage Model 12 Varminter Low Profile in .204 Ruger. This rifle has a 26 inch barrel. My first 6 shots with my rifle gave me an average velocity at 12 feet 9 inches from the muzzle of 4,041 fps. The next 5 shots gave me 4,079 fps at the same distance from the muzzle. The outside temperature at the time was about 57�.



Not quite two months later, I had 200 rounds down the barrel and set up to chronograph the factory rounds again. This time my average velocity for 10 shots with the factory ammo at 12 feet from the muzzle was 4,160 fps--that's 81 fps more velocity than when the barrel had only 11 shots through it. The temperature, however, was a wee bit warmer, at about 80 degrees and that could make some difference, but I don't think all of the 81 fps difference was due to temperature changes. My last trip to the range shooting factory 32 gr. ammo over the chronograph was on August 30th with the temperature at 85�. The average velocity at 12 feet from the muzzle with a 5-shot string was 4,192 fps. I plugged in the BC of the bullet, temprature, relative humidity, barometric pressure, etc., etc. and my ballistics program tells me that the bullets averaged 4,215 fps at the muzzle. Pretty close to the 4,225 fps advertised by Hornady.

Varmintguy: Using your formula to calculate muzzle velocity I came up with 3989 fps for the 32 gr and 3758 for the 40 gr.

My CZ varmint has (according to CZ) a 25.6 inch bbl so I am real close to 26.

Please don't take my first post wrong, I am not complaining.

I think come spring the 204 will be a blast on ground squirrels up here and I am really looking forward to actually doing some hunting with the 204, unfortunately we still have to go through winter. Maybe I can find a dumb coyote this winter.

Thanks for the input.

Shep