Bullet weight variation

[Bugaboo]

A newbie question:
What would be considered an acceptable variation in weight for a high quality .308 175gr bullet?
I have no idea...

Thanks for all replies.

 

[varmint slayer]

How much of a variance are you seeing? I've really never seen much more than .2 grain but I don't weigh them much either. If its a match grade bullet and you are paying a premium for them, you shouldn't have to waste time weighing bullets but that's just me.

 

[Bugaboo]

Lapua ScenarL 175gr OTM
Randomly selected bullets give me from 174.3 to 174.5, so within .2gr, but below the nominal weight. Is that normal?

 

[Grizzdude]

the 300gr .338 Berger bullets vary by up to .5-.6gr in weight, I just sort them out. If your only seeing .2gr difference I'd say those are pretty good, I wouldn't even sort those.

 

[varmint slayer]

I wouldn't sort them at all regardless of the variance. For target shooting and hunting you won't see any benefit and I would say even hard pressed to see any at all.

 

[SoCal326]

I just sorted my 175 gr SMK HPBT in 30cal. Part number 2275. I used a RCBS Charge Master 1500 that weighs to the tenth of a grain. The Charge Master was calibrated and confirmed with check weights. These bullets came from two different boxes. I had used a few bullets from each box and decide to merge them.

grains : count
174.8 : 6
174.9 : 46
175.0 : 45
175.1 : 18
175.2 : 9
175.3 : 5

Total bullets: 129

 

[Rob01]

Load the bullet and shoot it. Stop wasting time weighing it.

 

[M40_A1]

grains : count
174.8 : 6
174.9 : 46
175.0 : 45
175.1 : 18
175.2 : 9
175.3 : 5

Total bullets: 129

^^^ This matches almost exactly the ratios and weights I see when sorting. I just keep the highs with the highs, and the lows with the lows when loading them into individual boxes. Works great.

If you aren't shooting long range like your score or life depends on it, you really don't need to worry about that small a variation. But, I like to KNOW, shot to shot, what's in my ammunition. If a shot goes squirrely, I know it's not my ammo.

 

[SoCal326]

It's good to hear that this is what others are seeing. I don't yet know how much this affects things but I have to find out for myself, at least once.

My tests will be at 300 yards, and from what others say, I won't notice a difference at that distance. I'll try it again when I get to a range with some longer distances.

Anyways, reloading is a tinkerers dream and obsessing on the small details is what keeps the hobby fun

 

[Greg Langelius *]

Match bullets are weighed and measured by the manufacturer as part of their quality control process. They test and know how much variation it takes to detectably degrade performance, and take serious steps to ensure their product does not vary by enough to be concerned about.

You may measure and weigh to your heart's content, but unless you are unreasonably obsessed with miniscule accuracy improvements, all you are doing is converting handloading from a necessity to an onerous chore (or an anal pursuit).

There is a term many handloaders, myself included, use called 'background noise'. Used this way, this term signifies a lower limit below which any particular technique's best degree of variance becomes undetectable within the many other environmental variances which can never be controlled.

If you can't accept that below a certain lower limit of dispersion cannot be anything but uncontrollably random, you are in the wrong pursuit.

In essence, that limit defines the difference between making meaningful accuracy improvement and pointless tail-chasing. I have extensively tested such things and have arrived at my own conclusions. Accuracy is like speed in racing cars; how much you get depends on how much you spend in both money and time, and we need to impose reasonable limits on our desires.

I believe that one may confidently open a box of match bullets from a reputable maker, and simply put them to use.

This confidence is one of the things you're paying extra for when you buy match bullets. Mistrusting such products essentially means you threw away what you paid for that confidence.

All components vary, and responsible quality control benefits the manufacturer by allowing customers to have confidence that the batch they hold in hand is worthy, and that the next one will be as worthy. Customers who second guess these quality control limits do little beyond wasting their own valuable time.

When you get to be my age, that's a good thing to know.

As my time becomes more limited, I have to make choices. My choices nowadays are governed by the term 'adequate'. I consider 1MOA at 100yd and 2MOA beyond 300yd as adequate accuracy.

Greg

 

[Rat807]

grains : count
174.8 : 6
174.9 : 46
175.0 : 45
175.1 : 18
175.2 : 9
175.3 : 5


I have Hornady, Sierra, Nosler and Berger hunting bullets that I have done load development on. What I have found is the bearing surface seems to have more affect on velocity than weight of the bullets. In the past I have weight sorted, bearing surface (BS) measurements and weight sorted, and now just sort by BS. Normally the BS measurement will have a small weight variance of .01 or maybe .02 grains. A box of 100 bullets may have 3 or 4 different BS lengths with the heavier bullets having longer ogive lengths and lighter bullets being shorter. For the weights listed above, I would measure the ogive length of the lightest (174.8) and the heaviest (175.3) and load seperate groups in this fashion. Out of the 11 bullets in these 2 groups, find the largest BS difference and load up 4 and shoot for groups at 200 yards or more. Then find the least difference in BS and load up 4 and shoot. The other 3 bullets I would use as foulers. These will be the extremes and if any difference in groups sizes is found, you will know more about QC with the brand you purchased. Normally, I cule the lightest and heaviest from the group and use as foulers. The rest will be stored by BS and loaded. Shoot a group with the 175.0 bullets and compare the three extremes (no BS Variance, low V and high V). If you shoot over a chrono, you should see different ES #'s as well. I also noticed the ogive length of the loaded rounds became a lot more consistant when sorting by BS

Disclaimer: This was done after a powder, bullet, primer and seating depth was fine tuned and had plenty of targets with data written on the targets to compare. Brass prep - All brass was prepped to be as consistant as I could get as to weight, length, necks turned, annealed, primer pockets and measurement to datum line. To be consistant, shoot round 1 from group 1 on target #1. Shoot round 1 from group 2 on target #2 and so on.

 

[mdmp5]

If you want to weigh bullets to see variance as an experiment, go for it. But if you plan on making decisions based on small variances, you are wasting your time. I know I cannot shoot the difference in variance.