6mm Nosler Ballistic Tips!

[CanusLatransSnpr]

This is common knowledge for most reloaders but, I just figured out today that Nosler's 6mm bullets, not sure about anyone elses, are only .240" in diameter. What prompted me to measure them was I was neck sizing .243 Win brass and the bullets didn't feel right seating them! Come to find out I didn't have my neck sizing die adjusted right, my fault. I have Nosler 55, 70 and 80 gr. bullets on hand and they all measure the same. I was of the impression that they would be .243" in diameter. My Nosler and Sierra .224 bullets all measure .222". Must be common to undersize bullets a little. Just thought this was interesting and thought I would share!

Mike

 

[jerrschmitt]

I have some Nosler 70BT and 55 BT and both measure .243. I also checked my 58 VMAX, 65 VMAX and 60 Burgers. All measured .243.

 

[alf]

Me thinks your figgers are off.

Are you using calipers?

 

[CPorter]

Measured mine, calipers and micrometer. 55, 70 & 80gr ballistic tips are at .243"

 

[CanusLatransSnpr]

I was using my digital calipers! Granted they're not really expensive ones but, they seem to be accurate. Guess I'll have to get out the Micrometers and measure the bullets. Oh, and I was measuring the bullets with the fatter portion of the calipers so the bullet couldn't cant in the blades!

Mike

 

[SS427]

My expensive USA made dial calipers and cheap $20 dollar made in China dial calipers both measure my Nosler .224 bullets at .224 and .243 bullets at .243. The Chinese calipers were bought to measure groups as I wasn't too concerned if they were off a few thousands. I'm pretty impressed with how good they are.

 

[jo191145]

Just like everything in life. Stuff breaks!!! Even calipers.

Been using the same set of relatively cheap dial calipers since I started reloading. Always accurate enough for me. One day (without checking zero) I noticed my comparator COL's where not jiving with memory. Had to spin the dial .025" to zero. Thats huge!!!!! Must've slipped a cog I quess.

I also have another set of even cheaper digital calipers. Don't trust them for much of anything.
lots of flex(error) depending on how much pressure is used.

.240" to .243" is a big difference in bullet diameters. Something needs fixin.
To measure variations in pressure rings you need to go .0000

 

[CanusLatransSnpr]

Guess I'll have to order a new set of calipers, gotta order a new priming tool cause I broke my Lee Autoprime tool yesterday. Its only money, what the hell! LOL

 

[Steve Blair]

Take your calipers into a good tool supply and have them calibrated. Then, stop using them to measure things that have very tight tolerances. That is what micrometers are for.

 

[queen_stick]

Unless you're running .004" or more neck tension, a .240 bullet would fall into a case, then fall back out when tipped over. It wouldn't seat at all. Based on that alone, I think you're on the right track with replacing your caliper. Although, I have to agree with sleepygator - use a micrometer for critical measurements. I learned that few months ago, when I was getting funky numbers when measuring cases. I was pulling my hair out trying to find out why I was getting inconsistent numbers, and someone on this forum helped me figure it out... I was using a caliper when I needed to use a micrometer.

 

[CanusLatransSnpr]

On the subject of tolerances. What do you fellows use to measure the bump on the shoulders of your cases? I have yet to see a comparator body that attaches to a set of mics! I'm not being obstinate to using micrometers but, how do you measure this? Is this not a "critical" measurement?

Mike

 

[necchi]

http://www.cabelas.com/p-0056486216602a.shtml
Oh I get it. You wanna see something that fits a micrometer and not a caliper,
We use Mic's and calipers at work, as in professionally, they'er calibrated weekly, and for those guy's on this thread that say one or the other HAS to be used for a particular application,,well if that's what their comfortable with or if that's what they've learned that is their choice.

For me it matters little which I use, each has an application, somewhere that it comes in a bit more handy than the other. 001 is 001 no matter how it's measured.
But it's a good idea to have something with a known measurement around the vaildate the accuracy at a couple different
"jaws open" settings. Mechanical things do fail.
The biggest problem we have at work is several people checking the same thing and the amount of "squeeze" they put on the tool. We standardize by the rule of Mel. That means if your measure if different than that of supervisor Mel, your wrong and he's right But it does create a standard of the amount of pressure held too the tool.
You learn fast how much "thumb" he put's on the wheel!

 

[Steve Blair]

I use a calibrated Mitutoyo digital caliper that resolves .0005. It is regularly checked against a .500±.00005 carbide pin. It is adequate to measure the head-shoulder distance on brass cases. As in the original posting, bullets are manufactured to .0001 or .0002 tolerance and cannot be accurately measured by calipers.

Read this NIST definition of resolution. Use the correct tool for the job and you will get reliable, meaningful results.

 

[necchi]

That is very true,
ya can't measure .0001 with a .001 tool accurately