New to reloading. bullet diameter question

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Cclark009

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Hello all,
I am pretty new when it comes to reloading so I thought it best to ask the pros.

I was recently given some projectiles by a friend that doesn’t reload and has had them sitting on his shelf forever, there is two unmarked but sealed bags and a box of CIL .308 180gr. The projectiles in the bags weighed in at 181gr, and the diameter measured 0.3125”, I thought it would be good reloading practice to use up these bullets, and target shoot with them out of my .300 win mag and .308 win. I am concerned with the bullet diameter I always thought .30 caliber rifles shot a .308 caliber bullet, so I measured a bullet from the box that was labelled.308 and it also measures 0.3125. Is it normal for a .308 bullet to measure larger like this? And are these safe to load in my .308 and .300 mag?
Thank you in advance
 
DON'T use those projectiles on anything that is 30 calibre (i.e. 0.308 diameter)
You will have a REAL bad day if you were able to get one to chamber in a 30 cal rifle.
Your friend was probably reloading for some cartridge like 7.7 x 58 mm Japanese or a 7.65 x 53 mm Belgian Mauser (both which use a 0.312 diameter projectile).

Just my advice but if I were you.... I would sell them on the Equipment Exchange or discard them immediately.
If you were to accidentally co-mingle them with actual 0.308 projectiles, you might have that REALLY bad day....
 
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Those are the correct diameter for loading 303 British, the 7.62X54 Russian, 7.7 Jap, and the 7.65X53 Argentine, as well as a few others. They are not the correct diameter for your 300 Win Mag or 308 Winchester.

I'm heading to bed. It's late! ;)

Ted
 
Cclark009 said:
Hello all,
I am pretty new when it comes to reloading so I thought it best to ask the pros.

I was recently given some projectiles by a friend that doesn’t reload and has had them sitting on his shelf forever, there is two unmarked but sealed bags and a box of CIL .308 180gr. The projectiles in the bags weighed in at 181gr, and the diameter measured 0.3125”, I thought it would be good reloading practice to use up these bullets, and target shoot with them out of my .300 win mag and .308 win. I am concerned with the bullet diameter I always thought .30 caliber rifles shot a .308 caliber bullet, so I measured a bullet from the box that was labelled.308 and it also measures 0.3125. Is it normal for a .308 bullet to measure larger like this? And are these safe to load in my .308 and .300 mag?
Thank you in advance
Click to expand...

Those .312 bullets are made for a japanese 7.7mm rifles or others but not .308 win.... I wouldn't fire them in a .308 winchester rifle..
 
Cosmic has a good point. I see you’re measuring to 4 decimal places, so probably using a digital calliper. Maybe try a non digital micrometer.
Seems unlikely bullets in a box marked.308 are not .308.
If you can’t do this, maybe a local machine shop. Or send a sample to me.
 
Thanks for all the input everyone! I’m glad I came here and asked first!
So I went and checked my bullets again, and I got the same result 0.3125. I got digging in the box of reloading supplies that I bought second hand, and found a box of Speer .308 150gr and .25 cal sierras. So I measured a few of the .308s and they also measured 0.3125, by Now I’m convinced my caliper is having issues so I measured the .25 cal bullets and they came out at 0.2605 (correct me if I’m wrong but they should be 0.257?) so it looks like my caliper is reading about 3-4 thou big. I’ll check them with another caliper when I get a change to get one and get this straightened out! Thanks guys
 
Cclark009 said:
Thanks for all the input everyone! I’m glad I came here and asked first!
So I went and checked my bullets again, and I got the same result 0.3125. I got digging in the box of reloading supplies that I bought second hand, and found a box of Speer .308 150gr and .25 cal sierras. So I measured a few of the .308s and they also measured 0.3125, by Now I’m convinced my caliper is having issues so I measured the .25 cal bullets and they came out at 0.2605 (correct me if I’m wrong but they should be 0.257?) so it looks like my caliper is reading about 3-4 thou big. I’ll check them with another caliper when I get a change to get one and get this straightened out! Thanks guys
Click to expand...

Cclark009,

Send me your PM - i have few PDF reloading manuals(or a library) I can share.

Cheers,
 
We had a set of tools at work that included an inexpensive pair of digital calipers for general, non-precision measuring. They seemed to work fine for their intended use but then they started to read +0.200" out. I couldn't believe it at first but then I closed them up, zeroed the reading, opened them up to about 4" and closed them again. 0.200" Changed the battery and it would still do it but just randomly. We replaced them immediately with a good dial caliper set up. I acknowledge that this was not a quality set of calipers but I don't think I would ever trust a digital set again.
 
Cclark009 said:
Thanks for all the input everyone! I’m glad I came here and asked first!
So I went and checked my bullets again, and I got the same result 0.3125. I got digging in the box of reloading supplies that I bought second hand, and found a box of Speer .308 150gr and .25 cal sierras. So I measured a few of the .308s and they also measured 0.3125, by Now I’m convinced my caliper is having issues so I measured the .25 cal bullets and they came out at 0.2605 (correct me if I’m wrong but they should be 0.257?) so it looks like my caliper is reading about 3-4 thou big. I’ll check them with another caliper when I get a change to get one and get this straightened out! Thanks guys
Click to expand...

Unless you are unusually lucky, you are fooling yourself if you think a calliper will give you accuracy to 4 decimal places - machinists and the like will use many hundred dollar micrometers to read accurately to 10-thousands of an inch. Your display on your calliper might display 4 digits - find the box it came in - most that I have quite clearly state accuracy is within .001" - so if it is reading .337", it might really be .336" or it might be .368" or some other value in between. Good micrometers, like from Mitutoyo, come with a standard - so at a given temperature, that standard has a very precise dimension that you set your micrometer to read - to have some confidence that your reading has value and is accurate.
 
Potashminer said:
Unless you are unusually lucky, you are fooling yourself if you think a calliper will give you accuracy to 4 decimal places - machinists and the like will use many hundred dollar micrometers to read accurately to 10-thousands of an inch. Your display on your calliper might display 4 digits - find the box it came in - most that I have quite clearly state accuracy is within .001" - so if it is reading .337", it might really be .336" or it might be .368" or some other value in between. Good micrometers, like from Mitutoyo, come with a standard - so at a given temperature, that standard has a very precise dimension that you set your micrometer to read - to have some confidence that your reading has value and is accurate.
Click to expand...

Yep I agree 100%, but for consistency’s sake I like to carry as many digits as is possible. However like you said the caliper should be accurate to .001. I will check here shortly to see what it is certified to it’s a mitutoyo so I’m sure it will be .001
 
You were wise to check against another set of bullets. Id replace the calipers if I were you, and measure again, but seems like you actually do have .308" diameter bullets.
 
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