Bullet weights - how exact are they?

tac foley

Gentlemen, in the interests of science, I decided to do something that has been long overdue, and to actually weight some premium quality bullets to see how much they actually did weigh.

To do this I used my trusty Lyman electronic digital scales - accurate to within 1/10th of a grain [that is to say, 1/70000th of a pound].

Using my normal set-up - positioning the scale on a one-inth thick piece of glass and leaving it there for an hour before commencing weighing, I opened up a brand-new box of 155gr Lapua Scenar match bullets, and got started.

The results were pretty interesting - in THIS box, there were

10 bullets @154.60gr

21 bullets @154.70gr

58 bullets @154.80gr

11 bullets @154.90

and 0 bullets at 155gr.

Not a single one.

I'll be weighing every bullet in the other nine boxes, and making up a 'to use in order' selection, as I have done with this lot.

I'm not going to buy any other bullets for the time being, but there are others that claim to be accurate with regard to weight. We'll see.

tac

gunhappy_ie

tac foley wrote: »

Gentlemen, in the interests of science, I decided to do something that has been long overdue, and to actually weight some premium quality bullets to see how much they actually did weigh.

To do this I used my trusty Lyman electronic digital scales - accurate to within 1/10th of a grain [that is to say, 1/70000th of a pound].

Using my normal set-up - positioning the scale on a one-inth thick piece of glass and leaving it there for an hour before commencing weighing, I opened up a brand-new box of 155gr Lapua Scenar match bullets, and got started.

The results were pretty interesting - in THIS box, there were

10 bullets @154.60gr

21 bullets @154.70gr

58 bullets @154.80gr

11 bullets @154.90

and 0 bullets at 155gr.

Not a single one.

I'll be weighing every bullet in the other nine boxes, and making up a 'to use in order' selection, as I have done with this lot.

I'm not going to buy any other bullets for the time being, but there are others that claim to be accurate with regard to weight. We'll see.

tac

Something Id love to get into... handloading.....

Id be interested to see if there was a difference in accuracy between a batch loaded to the same spec.

tac foley

gunhappy_ie wrote: »

Something Id love to get into... handloading.....

Id be interested to see if there was a difference in accuracy between a batch loaded to the same spec.

Strangely enough, all the variables that inevitably creep in, unless of course you are a bench-rester, tend to cancel themselves out. At least they seem to for me. I'm not a 500m bunny shooter or a deer shooter, just a paper shooter. I have neither the funds nor the inclination to shoot my food, and I only shoot Lapua bullets.

Maybe that will change now though.....[thinks]

My loads seem to get me a consistent group of around 5/8th inch at a 100 yds with a scope, and slightly bigger with the diopter-equipped target rifle, both in .308Win, and I'm quite happy with that.

tac

tomcat220t

Factory priemum ammo shoot well enough for my to suggest that their bullet weights , loads...ect are bang on,imo.

tac foley

tomcat220t wrote: »

Factory priemum ammo shoot well enough for my to suggest that their bullet weights , loads...ect are bang on,imo.

Ah, y'see I'm but a poor old disabled pensioner and I can either afford to buy 'factory premium' ammunition and eat the boxes, or I can reload and eat food.

The rate I get though the stuff I actually make would astound you.

Tuesday night - 60+ .357Mag revolver - maybe some .22 as well.

Wednesday - often - 20 x 7mm, 20 x .308Win, 20-40 7.5 Swiss

Thursday - 44cal ball and .451/58cal - all BP.

Friday evening - loads of .22 and more .357Mag.

Sunday - as wednesday plus loads of .22

I was not put on earth to make rich men of Messrs Federal/Winchester/Remington/Lapua/Norma - I'll leave that up to you guys over there ;=)

tac

ejg

Thought the scenar is made to be 10 grams which is close to 155gr.
Is 0.3 grains difference a lot compared to other makes? Lapua is known
for precision normally. or?
Youv'e got some interesting shooting there.
edi

tomcat220t

tac foley wrote: »

Ah, y'see I'm but a poor old disabled pensioner and I can either afford to buy 'factory premium' ammunition and eat the boxes, or I can reload and eat food.

The rate I get though the stuff I actually make would astound you.

Tuesday night - 60+ .357Mag revolver - maybe some .22 as well.

Wednesday - often - 20 x 7mm, 20 x .308Win, 20-40 7.5 Swiss

Thursday - 44cal ball and .451/58cal - all BP.

Friday evening - loads of .22 and more .357Mag.

Sunday - as wednesday plus loads of .22

I was not put on earth to make rich men of Messrs Federal/Winchester/Remington/Lapua/Norma - I'll leave that up to you guys over there ;=)

tac

The amount of shooting i do would hardly make any of the above manufactures rich ....and its hard to put a price on quality factory ammo when it shoots well.

tac foley

ejg wrote: »

Thought the scenar is made to be 10 grams which is close to 155gr. Is 0.3 grains difference a lot compared to other makes? Lapua is known for precision normally. or? Youv'e got some interesting shooting there. edi

Sure the way I shoot these days it wouldn't matter if I put them in back to front.

I just thort it was an interesting experiment to try for three reasons -

1. When we could get JLK bullets here in UK I used to shoot the 175gr BR VLD's. I used to batch weight them, but ened up with three piles - 174.9gr [a few], 175gr [most], and 175.5gr [a few].

2. Pulling a random ten rounds of Swiss GP11 [the military surplus 7.5x55 Swiss service cartridge], only ONE did not weigh 174gr. I weighed 173.9gr.

3. I HAD planned to steam up a couple of trains to celebrate the life of a well-known and much-loved model train guy, Ron Brown, who died last week, but the howlin' rain put me off the idea.

Just sayin'....

tac

tac foley

tomcat220t wrote: »

The amount of shooting i do would hardly make any of the above manufactures rich ....and its hard to put a price on quality factory ammo when it shoots well.

Ah, you seeem to have missed the point, Sir.

Apart from the .22 rimfire, I am the manufacturer of all of the above ammunition.

If I had to pay factory prices for THAT lot I'd soon be wearing cardboard shoes and sitting in O'Connell Street pretending to play a banjo with me raggedy ould dog beside me.

tac

Half-cocked

While nowhere near as critical as rifle bullet weights, there is a huge variation in shotgun shot sizes, even with premium cartridges. I remember reading some data compiled by someone who pulled apart dozens of No.6 cartridges from different manufacturers and mic'd the shot diameters. In each cartridge, about 10-15% of the shot was closer to No.5's and 10-15% closer to No.7's.

tomcat220t

tac foley wrote: »

Ah, you seeem to have missed the point, Sir.

Apart from the .22 rimfire, I am the manufacturer of all of the above ammunition.

If I had to pay factory prices for THAT lot I'd soon be wearing cardboard shoes and sitting in O'Connell Street pretending to play a banjo with me raggedy ould dog beside me.

tac

No ,im seeing your point very clearly ,Sir;).I just cut my cloth according to my measure with the amount factory ammo i use.

FISMA

Tac
I wonder if what we have here is a significant figures problem.

The box reports the mass of the bullet as 155gr, correct? 155 grains has three sig figs and tells me that their measuring device measured the 1, and the first 5, but the second 5 was an educated guess, still significant.

The box said 155gr, not 155.0gr, or 155.00gr. There's a big difference, sig fig wise.

Note: there is no one single correct way to handle sig figs from measurements. Thus, I have no idea by what way, if any at all, they handled their claim.

Also, no measurement is exact. Once you get out a measuring device, there's going to be some error. Did your scale come with any documentation that said +or- x%? Or did they just leave it as your stated 1/10th of a grain?

So you can measure down to 1/10th of a grain. Thus, the first decimal is significant. By the normal rules on an analog device, the second decimal, will then be chosen as a zero if the reading is right on a mark or a five if it is not. It may read numbers, like 2, 3, 7, or 8, however, they are not significant. When you cannot read the number, that place gets a zero or a five.

Again, it is one of many rules out there.

All of your reading end in a zero. That's a bit odd to me and statistically not likely to happen in a sample of your size. I would have expected to see 50% zeros and %50 fives. At the very least, a few fives. If I were you, I would start to question the significance of that second decimal place.

Looking at your masses and taking the results to 3 sig figs, you get 155gr every time.

Personally, I prefer the old school beam scales. I would like to reload too some day, I have cousins in the states that haven't bought a factory round in over a decade since they started reloading - they're that good.

If you let us know the model of the scale I'll suss it out. However, from what you are saying, it appears to be accurate enough.

Finally, if you were to take your bullets and put them on their scale, it would read 155.

Did you ever hear of the Physics teacher that spent the department's budget buying a cube of aluminum that cost more than gold?

As the story goes, and I may have some details or prices forgotten, the teacher wanted a cube of aluminum for density experiments. He emailed the machine shop and requested not 1.0cmx1.0cm, but 1.000cm by 1.000cm. We're almost down to a micrometer at that point. As the story goes, the teacher totally forgot about sig figs, but the machine shop did not! The teacher ended up getting a cube with tolerances down to 100,000th of a meter. The cube was worth more than its weight in Gold and the teacher spent the entire department budget on a cube. Whether it happened or not, who knows? But it's a useful analogy when talking about sig figs.

Slan

tac foley

FISMA wrote: »

Tac - I wonder if what we have here is a significant figures problem.

Sir, your post was almost identical to another eight or ten that I've had from other sites where I posted the same thing.

Thank you, and yes, I HAVE sorted it out. My digital scales only read to one significant post point figure, so, as has been pointed out by you and others, it could, in theory be as much as a tenth of a grain out no matter WHAT it actually read, as digital scales round up, or down.

It was also pointed out to me by others far more knowledgeable that whereas almost 100% of shooters are more than happy to shoot what comes out of the box, there are others who will turn the meplat to get it the same as all the others, and perform other operations on cases and so on to achieve as near as possilbe identical bullets and complete rounds.

...and then, the wind changes......

I think I'll stick to shooting what comes out of the box and reload my ammunition to the best of my ability and just get on with it.

And as for your friends who haven't bought a factory round in twenty years, well Sir, I haven't bought a factory round since March 2, 1968.

Thanks for all the comment.

tac