Digital Micrometer Problems

[LDHunter]

I was getting pretty frustrated. My Forster Co Ax press wasn't producing consistent base of cartridge to ogive seating depths even when using the Forster Micrometer Bullet Seater Die but the reviews I read everywhere said this system is the best available and I'd been very careful in my setup.

Depths when measured after seating varied .003"-.005" and try as I might and fiddling with setup and even going back to basics got me nowhere.

So I decided to go back and re-measure every single cartridge I'd loaded and much to my surprise I found that even cases I'd loaded a few minutes before had magically changed depth... LOL

Yep... you guessed it. My digital micrometer was lying to me. sigh

Can someone recommend a serious digital micrometer that is not only accurate but consistent? By the way my eyes are getting kind of old and I don't want to have to wear reading glasses to use the old style non-digital calipers unless I'm forced to.

I watched a couple of videos in the last hour or two put out by Hornady and noticed that their techs were using non-digital calipers... I wonder if that should be my clue that digital isn't reliable?

By the way I'm using the Hornady Bullet Comparator system to measure base to ogive and although I don't suspect that's my problem I thought I'd throw that out there in case someone opined that this could be the problem.

Also the bullets I'm loading are Berger Hunting VLD 168gr and the cartridge is 7SAUM.

 

[WildRose]

I was getting pretty frustrated. My Forster Co Ax press wasn't producing consistent base of cartridge to ogive seating depths even when using the Forster Micrometer Bullet Seater Die but the reviews I read everywhere said this system is the best available and I'd been very careful in my setup.

Depths when measured after seating varied .003"-.005" and try as I might and fiddling with setup and even going back to basics got me nowhere.

So I decided to go back and re-measure every single cartridge I'd loaded and much to my surprise I found that even cases I'd loaded a few minutes before had magically changed depth... LOL

Yep... you guessed it. My digital micrometer was lying to me. sigh

Can someone recommend a serious digital micrometer that is not only accurate but consistent? By the way my eyes are getting kind of old and I don't want to have to wear reading glasses to use the old style non-digital calipers unless I'm forced to.

I watched a couple of videos in the last hour or two put out by Hornady and noticed that their techs were using non-digital calipers... I wonder if that should be my clue that digital isn't reliable?

By the way I'm using the Hornady Bullet Comparator system to measure base to ogive and although I don't suspect that's my problem I thought I'd throw that out there in case someone opined that this could be the problem.

Also the bullets I'm loading are Berger Hunting VLD 168gr and the cartridge is 7SAUM.

If you're shooting a compressed load you may not have a micrometer or die problem you may have a little "spring back" due to the compression.

 

[AZShooter]

I would like to see how you are measuring ogive to base with a micrometer. Perhaps you talking about a digital caliper?

I prefer a dial caliper or the old mechanical micrometers rather than digital. They don't act up, don't need batteries and don't require resetting zero.

 

[WildRose]

I would like to see how you are measuring ogive to base with a micrometer. Perhaps you talking about a digital caliper?

I prefer a dial caliper or the old mechanical micrometers rather than digital. They don't act up, don't need batteries and don't require resetting zero.

They do however require you be able to read a mechanical scale instead of an LED.

I know young people that don't know what "Watch your six" refers to other than looking behind themselves.

 

[gspman1]

Change you battery, put in a new one.

 

[Rich Coyle]

You might verify you are keeping one side of the caliper square with the case head. I hold mine up to the light. I have discovered high primers doing that, also.

 

[dsculley]

LDHunter, there are many makers of digital calipers that are good. You can spend from less than $20.00 to nearly $500.00. Amazon has a Neiko caliper that is accurate to 0.001" for $16.85. Most of the reloading supply manufacturers have one that is similar. If you are concerned about the precision of your caliper, have a piece of tool steel cut and hardened (needs to be hardened so it will not wear easily). Have it cut about the same length as your average cartridge length. This is your gauge. Measure it with your caliper. Record this measurement. Now you can check the repeatability (precision) of your caliper at any time, such as before each bullet seating session. Note: For this operation it is not important that your caliper is accurate, but it is important that your caliper is repeatable.

If it were me, before I bought a new caliper, I would make (or have made) the gauge mentioned above and test my current caliper.

A tip for using a mechanical dial caliper with old eyes: The Zero on the dial is usually easier to read than the rest of the number (at least to me it is). Take your first cartridge with a seated bullet and put it in the comparator. With this cartridge in the comparator, rotate the dial so that the pointer is on Zero. Now you can easily tell if your next measurements are above or below the zero. It may be difficult at first to resolve the lines to know how much above or below, but you will soon get a good feel for this.

FWIW

 

[TwoMore]

I would like to see how you are measuring ogive to base with a micrometer. Perhaps you talking about a digital caliper?

I prefer a dial caliper or the old mechanical micrometers rather than digital. They don't act up, don't need batteries and don't require resetting zero.

I agree 100% I would do myself a favor and get a set of dial calipers, they will repeat, I machine for a living and my digital's stay in the box and my dials are at the machines. I think every machinist has had to give the last rights and testaments to a scrapped part cuz the caliper lost home. just like the above posts, zero the dial at 0 and you will be able to repeat.

good luck

 

[Trickymissfit]

most all my reloading is done with a 4" pair of Mitutoyo dial calipers. Bought them in 1970, and used them all the way thru my apprenticeship. If they survived that, then they ere top of the line. Since then I've had a couple pairs of 6" Starretts, and would avoid them like the plague! Their digital ones are pretty good. Also have a pair of Brown & Sharpe digital calipers that I really like a lot. The nice thing about the B&S calipers is that you can connect them to a PC to store data (never tried it).

Still no matter how good a caliper is, a good micrometer is a must have. I never trusted the digital mics, even though I've had a couple pairs. Buy good ones, and never look back. You don't need or for that matter want carbide faced mics. Just get steel ones as they have a better feel. Taken care of, they'll last a lifetime or two. I have mics that my dad bought in the 1940's, and are more than good enough for anything I ever do. For micrometers, I recommend Starrett or Mitutoyo unless you can lay your hands of a mint Lufkin micrometer.

Lastly many of us run out and buy this equipment without the knowledge to use them properly. I learned to read mics in tenths when I was about 12 years old from my dad. Same way with a dial indicator or how to use them the right way.
gary

 

[Gord0]

Mitutoyo, Starret, Brown and Sharp, Tesa. Just about anything else is going to be junk. If you spend under $100 on a new pair you're probably getting junk. I was a big mitutoyo fan, but the last couple sets I got for the shop it seems the quality was slightly less than previous years. They're still excellent calipers.

 

[Trickymissfit]

Mitutoyo, Starret, Brown and Sharp, Tesa. Just about anything else is going to be junk. If you spend under $100 on a new pair you're probably getting junk. I was a big mitutoyo fan, but the last couple sets I got for the shop it seems the quality was slightly less than previous years. They're still excellent calipers.

you left out Fowler and Interrapid.
gary

 

[bigedp51]

Change you battery, put in a new one.

This, the voltage drop will cause the readings to vary.
I use a Headspace gauge and check the calipers for accuracy. If you have a battery checker that puts a load on the battery you can also find the weak batteries.
I know someone who had the same problem but can't say who because I never make any mistakes. (just chronologically gifted errors)

 

[Gord0]

you left out Fowler and Interrapid.
gary

I don't consider Fowler to be a good caliper. Interapid, Tesa, brown and Sharp are all made by the same company and I'm not sure if they are still making the interapid

 

[Edd]

I have a Starrett 6 inch Dial Caliper model 120A. I've used it almost every day for about 30 years. When it quits working, and if they still make them, I'll probably buy another one just like it.