Reloading Issue: Why do measurements vary?

[BillLarson]

Not necessarily.

A mono of the same weight as a cup and core will be much longer.

Shape of the bullet really effects length too. Higher BC bullets will be longer than the same weight lower BC bullets. Like the 7mm 168 Classic Hunter vs the 168 VLD. Or the 200gr SGK vs the 200gr SMK.

I get your drift fella..... and you are very correct.....
but........ I was talking about same mfg.bullets from same lot.
They will vary in length therefore vary in weight.
Thats why we meplat bullets....

 

[Rick Richard]

your comment was pertaining to Hammer bullets......
if they are more consistent in dimensions..... would,nt you see them used for that quality.... in competitions...???

Nope, not necessarily. Consistent dimensions within same manufacturer and higher BC from maybe another brand are two different things.

 

[lancetkenyon]

your comment was pertaining to Hammer bullets......
if they are more consistent in dimensions..... would,nt you see them used for that quality.... in competitions...???

No, because BC is much lower than the Bergers or Sierras.

Plus, cost. And one of the main factors, sponsorship.

 

[lancetkenyon]

I get your drift fella..... and you are very correct.....
but........ I was talking about same mfg.bullets from same lot.
They will vary in length therefore vary in weight.
Thats why we meplat bullets....

When the meplat is formed in the pointing process, that can and will effect OAL. But is does not effect bullet weight. OAL variances of .010"+ are not unheard of because if this, but BTO will be within .001", and weight will be within .02gr or less. This is for Bergers, and most SMKs.

On the other hand, tipped bullets are usually much more uniform in OAL, but I have seen far more variance in weight (up to .5gr) in some manufacturers.

 

[BillLarson]

When the meplat is formed in the pointing process, that can and will effect OAL. But is does not effect bullet weight. OAL variances of .010"+ are not unheard of because if this, but BTO will be within .001", and weight will be within .02gr or less. This is for Bergers, and most SMKs.

On the other hand, tipped bullets are usually much more uniform in OAL, but I have seen far more variance in weight (up to .5gr) in some manufacturers.

I believe we are talking about the same thing......
more consistent bullets are favored in the winner equipment column and are listed accordingly.

 

[Tex_Hunter]

Inconsistent neck tension will cause runout on seating depth. Cheap calipers can also give inconsistent measurements. I was having runout as high as .005 or even more sometimes when using a basic FL sizer die, dropped to .001" or less when I switched to a Redding Type S FL sizer with a bushing that sets neck tension at a consistent .002", you can get even more precise if you turn the necks and use an expander mandrel (I just use the floating carbide spacer and don't turn my case necks. Don't need that level of precision for PRS shooting.

ETA… you will also get inconsistent seating depth while you are working up a load of the powder starts to get compressed, you'll have to adjust your seater stem as charge weight goes up to get the same CBTO measurement.

 

[lancetkenyon]

I believe we are talking about the same thing......
more consistent bullets are favored in the winner equipment column and are listed accordingly.

I must have misunderstood when you said "they will vary in length therefore vary in weight".

Hammers vary in neither. And yet they are not used much (if at all?) in match scenarios.

But, look at the ELR shoots like KOT2M. They all use lathe turned tipped monos.

 

[XxaquadogxX]

Do you aneal your cases, it seems to help equalize the variants in the response of the brass to the tensions that are put on it. Also are you measuring from the ogive or the tip? The ogive should be constant, the bullet tip will have variances, that is why some people trim and repoint their bullets. You will also find changes if you operate the ram on the press more than once. The amount of resistance between the brass and the bullet are not a constant from case to case, annealing helps to stabilize the brass. The distance traveled by the ram does provide consistent distance and maybe even pressure, but it will not automatically overcome the resistance of what is being compressed. Unfortunately it is not an exact science, and it is a continual learning process.
I hope this helps, make it easier to understand.

 

[Bdubose]

I would think that inconsistent neck tension will result in "springing" or compression of the case resulting in a 0.001 or maybe a little more difference in measurements at the ogive.
Just a thought.

 

[TexSavage]

To me, and this is my two cents less a penny and a half, all the variables discussed in this thread come down to two things for me:
1) Safety to me and those around - First and always foremost
2) ROI - Return on investment - by that I mean will this device, process, method, component, etc be worth the time and effort.
Example: I use a Redding set of dies and I shoulder bump using a full length die and expand the case mouth using the standard button sizing stem in the Redding dies. I still shoot consistent 1/2 MOA groups at distance when I do MY PART IN THE SHOOTING PROCESS.

This means I don't turn my case necks, I don't use bushing dies, I don't weigh my cases, I don't weigh and sort bullets, etc. because to me it really will not make ammo that is better than what I and my rifle can shoot and it's gonna take a whole lot more time. This is my take and I'm excited folks like to do all that stuff, I enjoy the reading of and bantering that goes back and forth. This and a few other sites have given me a plathora of information and I'm deeply in debt to these sources.

I would rather spend more time learning wind call, mirage reading and fundamentals of marksmanship. Those items have, do and will give me more ROI. Currently I get 10+ reloads on my 300WSM using the above and yes I do anneal. The things I do have resulted from my 45 years of reloading experience. Your Mileage May Vary YMMV

 

[Chas1]

Too many variables come into play. The more consistent case prep then the more consistent measurements will be.

 

[RidgeTop]

Yeah, bullet weight can really vary, especially in the bonded bullet area. Try measuring the ogive to base lengths on some of those bonded bullets. They really vary. The monos and Bergers are usually very close in weight. I used to sort bullets, but I did a few tests with widely varying bullet weights and didn't find enough proof to keep doing it. Plus, I mostly shoot Bergers now and their weights are almost always right on.

I don't have a way to measure ogive.

 

[RidgeTop]

What you probably didn't know is SS pins and tumbling the brass work hardens the necks and increases neck tension, So afterwards you need to anneal, Your response does not make sense in regard to the topic.

In regards to the topic, Bullet Ogives are sometimes not consistent.

I responded to # 4 and 14 post. Neck tension hold vaiations. I don't agree that tumbling neck hardens brass and I never anneal. Tumbling does clean the carbon and other from the inside of the neck and therefore makes each neck have the exact same bullet hold. Look at all those clean necks in the picture.

 

[Harry Knutz]

I responded to # 4 and 14 post. Neck tension hold vaiations. I don't agree that tumbling neck hardens brass and I never anneal. Tumbling does clean the carbon and other from the inside of the neck and therefore makes each neck have the exact same bullet hold. Look at all those clean necks in the picture.

You can feel the extra pressure when you seat the bullets after wet tumbling. It work hardens the necks. You probably don't shoot in competitions either.