Factory AMMO & It's Velocity?

[Duster]

I just wanted to ask those of you who shoot and check your ammo out, if you have ever had that problem of factory ammo not coming close to or being erratic in its velocity?
I purchased several boxes of Federal 140 grain 7mm mags some time ago and checked the velocity of them against my chrony. Well I sure got a suprise I'll tell you. The findings were 140 feet per second difference in random bullets pulled from each box of ammo, out of the same LOT # mind you. So getting a good group with the 2 rifles on hand was not going to happen. I found that both guns fired 2.5 to 3 inch groups at 100 yards. My handloads cut this down to less than an inch for the one rifle and 1.3 for the other rifle. So much for factory ammo hey.

 

[danr55]

Duster. I don't think the phenom that you are experiencing is the least bit abnormal. There are several reasons for this result.
firts the test conditions may be less than perfect, the insturmentation may be better in one case than in the other, the firearms used will probably react differently that the mann barrels used to test ammuninition at the factory and last buy not least, figuring extreme spread doesn't really give you a true story considering the size of the manufactured lot of ammuninition and the several boxes that you tested at randon. If you figure that a standard run of factory ammunitition would be somewhere in the ranges of 1/4 million rounds depending on calibers, then the 6 or 8 or 10 boxes that you tested would not amount to a reasonable cross section. Ammunitition consistancy is figured based on standard deviation and statistical sampling.
When you tested the ammo, how closely do you control the environment? You can bet that in an ammo factory, temperatur, relative humidity are both controlled to the n'th degree. Powder will attract and hold moistute quite readily. Can't let that happen.
Don't misunderstand. I am not trying to invalidate your tests, only to explain the discrepancies that you brought up. I agree that most rifles will shoot better with hand loads, but trying to build one load for 3 or 4 hundred thousand rifles is quite a trick. You do the best for the most, without risking yuor assetts.

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Dan AZ www.huntandlodge.com

[This message has been edited by danr55 (edited 03-11-2001).]

 

[Duster]

Danr55, I guess that is just one of the many reasons I like to work up loads for my own rifles. I once loaded up some ammo for a big hunt, I was one pround puppy I tell ya. These rounds were cutting a one ragged one hole in the 100 yards target at the house in Arkansas. When I got to the mountains and checked the 2 rifles again, why I couldn't believe my eyes. Now both rifles same type action and caliber were indeed shooting eratic on me. In a pinch I went out and bought several factory boxes of ammo and settled on the Winchester Fail Safes. I got 2 inch groups with these. It saved the day I tell ya! I did find out later that the moly bullets I loaded for were loaded to low in the pressure department. They worked fine in the 90 degree weather I tested them in, but when the temperature made a drop to 14 degrees things went hay wire so to speak Dan.
It was the first time I had ever had any experience with moly type bullets and the last for hunting sake.

 

[danr55]

Duster, I odn't know what type of powder you loaded, but the results sound typicla for lots of powders that are temperature sensitive. However with any load, that much of a change in temperature is bound to have some effect. The density defferential of the atmosphere is considerable when you change the temperature that drastically. glad the something worked for you though.

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Dan AZ www.huntandlodge.com