Ever chrono factory ammo to see if its correct?

[WEATHERBY460]

hornady 58gr 243 factory ammo 3750fps at muzzle as stated on box, i got 3560fps at 10' using my f1 chrony chrono. both shot from 24" barrels my tikka and there claim on the box
How does this sound?
I am doing this because i am checking my reloads and trying to get the velocity i want. I dont know if my chrony is off, factory ammo is over rated? or i loose that much speed in 10'...please share your opinions.

[eaglesnester]

Originally Posted by WEATHERBY460

hornady 58gr 243 factory ammo 3750fps at muzzle as stated on box, i got 3560fps at 10' using my f1 chrony chrono. both shot from 24" barrels my tikka and there claim on the box
How does this sound?
I am doing this because i am checking my reloads and trying to get the velocity i want. I dont know if my chrony is off, factory ammo is over rated? or i loose that much speed in 10'...please share your opinions.

You are wasting your time doing this. All you will get is a general idea of a comparison. Barrels, ambient temperatures, altitude, humidity, barometric pressure, chamber size, and the color of your skivies will effect bullet chrono speed. You can not duplicate factory test conditions.
Cheers&Tighter Groups: Eaglesnester

[kiwi3006]

From other reports I have seen factory ammo is overrated.

The best way to check your chrono is to shoot over it next to another reliable chrono ie put the one bullet overtop of both chrono's.

I would imagine your chrono will be close to true velocity.

Stu.

[Long Time Long Ranger]

Not long ago I chonographed a box of remington factory 180 grain nosler partition bullets in 300 ultramag against some of my top 180 grain reloads. The factory rounds averaged 3341 fps with only a 15 fps spread. I thought this was pretty good for factory ammo. They were very accurate. My accuracy handloads averaged 3452 fps with about 10 fps spread.

[J E Custom]

Originally Posted by WEATHERBY460

hornady 58gr 243 factory ammo 3750fps at muzzle as stated on box, i got 3560fps at 10' using my f1 chrony chrono. both shot from 24" barrels my tikka and there claim on the box
How does this sound?
I am doing this because i am checking my reloads and trying to get the velocity i want. I dont know if my chrony is off, factory ammo is over rated? or i loose that much speed in 10'...please share your opinions.

Factory ammo If tested at all is tested under ideal conditions and normally a longer barrel
than most factory rifles have. But most velocities are calculated and are normally Higher
than achievable in your rifle.

I chronagraph all loads that I shoot in my rifles and have found only one brand of ammo
that normally meets the velocity advertised. (The 378 based Weatherby cases).

Remember, velocity sells and they don't mind stretching/manipulating the numbers because
every rifle is different and velocities will vary from rifle to rifle. so they feel safe and will just
say it's your rifle and not the ammo.

Also if you place hot ammo in a short throated chamber it will/would be dangerous so they
overate it and play it safe by loading it down so it can be shot in every rifle regardless of
chamber and throat dimensions.

Some rifles will come close but most won't.

J E CUSTOM

[41mag]

I've done from time to time. I don't however worry about what it says on the boxes, I get a reading from my equipment, and use it to tune my own loads. I also generally don't buy anything but the bottom dollar stuff since I am only using it for comparison.

I can say this however, on more than one occasion, I have found that the plain labeled factory stuff shot very well, and was easily duplicated with handloads.

Anything like the Light Mag, or higher performance type stuff, you'll never touch with practical handloads.

[winmag]

We all want to beat the stated fps on the box with our handloads. Maybe its human nature. But as stated, and re stated,and stated again, Factory ammo is labled to make brand x look better than brand y. The ammo makers do this on purpose, in labs, under Ideal conditions for thier brand, and then run a calculation to average thier boosted numbers.
Just take the printed lable fps as most likely inflated, and just a rough estimate of what it would be under ideal conditions. WAY too many factors to get brand x to shoot the printed velocity. Its always fun to check it against a chronny tho, so you can see what roll-your-owns do against the factory stuff. Usually makes you feel better about your handloads. For me anyway