Weighing bullets

[charlie b]

Anyone take the time to do this? I would assume the bench rest guys do but what about the rest.

I asked for a couple of reasons. First, I have cast a ton of pistol bullets and never bothered weighing them but now that I am loading for my .308 it is an important factor. Second, that started me thinking about factory jacketed bullets so I got out some 155SMK's and 165 Amax's. The 155SMK's were all +/- 0.2gn. The Amax's were +/- 0.5gn.

Since the Amax's are a little less accurate than the SMK's for me I started wondering if they would be just as accurate if I culled out the 'fliers' by weight. And how close in weight do they have to be to be "accurate"? Is that what makes SMK's so accurate, more quality control on the weight?

So far my cast bullets are just under MOA if I keep the weights close. I am experimenting with how much the weight makes a difference and why there is a variance in weight.

[AllenOne1]

I have started weighing my bullets just to get rid of the outliers. I sort them into boxes in .1 grain increments with anything greater then .2 grain from stated weight getting culled out and put in a different box to use for foulers etc. I then load and shoot them grouped from the .1 boxes to keep each lot of bullets as close together as possible. Does it make a difference I'm not sure but it doesn't take a lot of time and it takes away the possibility of large swings caused by bullet weight variation.

[Robinhood]

Now you have to start measuring and sorting by bearing surface. And then BTO. What about your brass? Do that before you trim or pocket uniform.

[Stumpkiller]

Not for factory jacketed but DEFINATELY for my home cast lead. It's amazing how different they can be.

If you have the patience it is a valid practice.

[charlie b]

Yep, I know it is a slippery slope :) I have sampled case volumes and looked for variation in groups/POI but did not find much unless I used mixed brands. Then the case volumes could vary a lot. I also found that bench rest primers are worth the extra cost when trying for smaller groups.

One of these days I'll go back and shoot some jacketed in .308 and sort out the bullets by weight to see if it makes a noticeable difference.

Meanwhile I will keep my cast bullets sorted by weight since it does vary by quite a bit.

Note that I am only a .5 MOA shooter, no matter how good my ammo is, and sometimes worse than that depending on the phase of the moon and the alignment of the planets. I only mention this because my lack of shooting skill may mask accuracy issues caused by things like small variations in case vol, bullet weight, etc, etc.

[varget204]

I do not sort pistol bullets,all my rifle bullets are sorted by Ogive .002-.003 groups, and weighed in 1/10th groups,almost all my shooting is 600-1000 yards

[mikeinco]

if you are happy with .5 moa, and do not shoot long range, skip it.
i sort to .1 for any precision shooting
and yep cast boolits vary a bunch
visit castboolits
same slippery sloop, maintain melter volume, temp mold temp

[charlie b]

Yep, been on castboolits a lot longer than here :) And been casting pistol bullets for 40 years. Just never shot much rifle until the last few years. So I always used jacketed. Price of SMK's never bothered me until I started shooting a lot of them :)

[yobuck]

Anyone take the time to do this? I would assume the bench rest guys do but what about the rest.

I asked for a couple of reasons. First, I have cast a ton of pistol bullets and never bothered weighing them but now that I am loading for my .308 it is an important factor. Second, that started me thinking about factory jacketed bullets so I got out some 155SMK's and 165 Amax's. The 155SMK's were all +/- 0.2gn. The Amax's were +/- 0.5gn.

Since the Amax's are a little less accurate than the SMK's for me I started wondering if they would be just as accurate if I culled out the 'fliers' by weight. And how close in weight do they have to be to be "accurate"? Is that what makes SMK's so accurate, more quality control on the weight?

So far my cast bullets are just under MOA if I keep the weights close. I am experimenting with how much the weight makes a difference and why there is a variance in weight.

I wouldn’t be just assuming much of anything when it comes to opinions among shooters Charlie.
By and large most of us are satisfied with good enough accuracy for what we do.
Many years back i thought i might have some interest in varmit class bench rest shooting.
About 100 miles north from where i lived was a range at a place called Wapwalopen PA, where bench rest matches were held.
So i decided to take a trip up there on one of the shoot days.
All the targets at least to the naked eye looked about the same to me. The only way to determine the best was with accurate measuring.
What surprised me the most was how at least some of the shooters went about loading ammo. They had an open sided pavilion for All that and shooters were loading ammo right there.
I commented to one i was watching about him not weighing his powder charge.
He was dropping powder directly into his cases. He said his powder measure had been accurized, but a tenth or so didn’t matter anyway.
He wasn’t resizing his cases at all after he shot, just a new primer, dump the powder, and seat a new bullet with an Arbor press setup.
Im sure he had sorted cases initially, and he might also have separated his bullets, I didn’t ask.
I think today and probably even then, serious accuracy shooters are using custom bullets, and they aren’t using factory built rifles.
In my own opinion for what ever that’s worth, much of all this can be compared with the well known chicken soup recipe, and our right to choose yellow socks when wearing a Tux.

[charlie b]

LOL yeah it is interesting to see what some view as important and others not, in the same discipline. I also watched some bench rest loading videos and noticed how some do not weigh powder and others do. Some resize, some don't. Some clean primer pockets and necks, some don't. And on and on.

In my younger days I migrated to ball or very fine grain powders just so I didn't have to weigh every charge. I have a few test series going now using IMR4166 in my .223, experimenting to see how POI changes with the different charges thrown by my measure. I am keeping track of the charges thrown to see what the distribution is like as well. I have been surprised at how many charges are right on the button.

[mikeinco]

just make sure you are comparing apples to apples.
"benchrest" is a big field.
no one throws charges for 1000 yard benchrest today.
100/200 yard group is still an open area with some thrown and some weighed.
i am just starting 100/200 groups with a 6ppc and plan on using a charge master lite at the range.
i shoot
22rf benchrest
100 yard score benchrest
100/200 group benchrest
600/1000 group/score benchrest
2000 group/score, part benchrest part prone
what works at 100 often does not work at 1000 as far as process.

LOL yeah it is interesting to see what some view as important and others not, in the same discipline. I also watched some bench rest loading videos and noticed how some do not weigh powder and others do. Some resize, some don't. Some clean primer pockets and necks, some don't. And on and on.

In my younger days I migrated to ball or very fine grain powders just so I didn't have to weigh every charge. I have a few test series going now using IMR4166 in my .223, experimenting to see how POI changes with the different charges thrown by my measure. I am keeping track of the charges thrown to see what the distribution is like as well. I have been surprised at how many charges are right on the button.

[yobuck]

And the reason they don’t if in fact you are correct, has to do with their mind set and not necessarily fact.
Today, nothing is left to chance in the quest to win in the minds of most serious competitors.
That would include at least for some, buying and chambering multiple barrels and selecting what they deem to be the best.
A whole lot different from a guy buying a factory rifle and attempting to make it shoot better groups.
But another fact is, if like me you are old enough to have listened to this talk for a long time, is that nothing seems to make all that the much difference. Especially at the long distances.
A check on the record heavy gun 10 shot group sizes over a span of 30+ years will confirm that.
In the 80s Earl Chronister set a record with his 30x378 hunting gun wearing a Unertle scope with ammo he loaded on an RCBS press.
The current record, now closing in on 10 years old, might be at most a whopping 1/2” smaller.
If and when that record gets broken, it will have more to do with the conditions, than how the shooter went about loading his ammo.

By the way, Earl was a lousy long range hunter, mainly because his head was so full of the BS associated with L/R target shooting.

[mikeinco]

UPDATE

The current record for the 1k (1000 yards) is 2.6872” for a 10-shot string by Jim Roberts 2018

the last posted 10 shot heavy gun 1000 yard record is 3.99 inches in 2015.

5 shots is just over 1" AT 1000 LITE GUN

some people on these forums live in the past.

[6mmBR_Shooter]

I shoot mid-range F class (Master shooter) and do not weigh bullets. With a no-wind day, both of the rifles I have used are capable of cleaning the 600yd target with a solid x-count (10-ring is 1 MOA, X-ring is .5MOA). If you're buying a quality bullet, I would argue that for most people it is unnecessary. If I were shooting benchrest I no doubt would but even for my precision game I view it as unnecessary.

There's more to a bullet's inherent accuracy than just weight. It's easy to go way down a rabbit hole though... :-)

[mikeinco]

just for reference
the 1 moa /1/2 moa of f class is 6"/3" SHOT PRONE with some serious "bipods"
600 yard br is 2.8" 10 ring and 1.2" x
that is 7 plus sq in for the f class x and only 1.1 sq in for the br x,
more than 6 times as much ares to hit for an x.

I shoot mid-range F class (Master shooter) and do not weigh bullets. With a no-wind day, both of the rifles I have used are capable of cleaning the 600yd target with a solid x-count (10-ring is 1 MOA, X-ring is .5MOA). If you're buying a quality bullet, I would argue that for most people it is unnecessary. If I were shooting benchrest I no doubt would but even for my precision game I view it as unnecessary.

There's more to a bullet's inherent accuracy than just weight. It's easy to go way down a rabbit hole though... :-)

[charlie b]

just for reference
the 1 moa /1/2 moa of f class is 6"/3" SHOT PRONE with some serious "bipods"
600 yard br is 2.8" 10 ring and 1.2" x
that is 7 plus sq in for the f class x and only 1.1 sq in for the br x,
more than 6 times as much ares to hit for an x.

Using areas to compare makes it seem so much more difficult. The F class X ring is 2.5 times bigger than the 600yd BR X ring.

Not insignificant, but, it is not 6 times harder to hit, only 2.5 times harder :)

[mikeinco]

i disagree with your opinion.
it is not a straight line, it is the entire AREA of the x ring.
you have have vertical and horizontal at the same time..area, not a line
6 times more AREA


[/QUOTE]Not insignificant, but, it is not 6 times harder to hit, only 2.5 times harder :)[/QUOTE]

[mikeinco]

xxx

[yobuck]

Not that it matters for much, at least to most of us, but Mr. Kline’s (heavy gun) 10 shot record was shot at Williamsport in about 2010 with a 300 WSM.
I of coarse could be wrong because I don’t attempt to keep up with all this on a regular basis, but i believe that record still stands.
As for Mr Roberts (light gun) 10 shot record, it was shot at the Montana range in (2014), with a 6mm Dasher,
One would think that the smallest group shot, is the smallest group, but no because winners and records are separated by weight classes.
I believe however that had Mr Roberts shot his group with that same gun in a heavy gun match, he would hold the heavy gun record having bettered Mr Klines group, but probably not the light gun record.
Got all that? For gods sake write it down or at least try to remember, because it’s all very important stuff.

[J.Baker]

Well I see Mike's back to being his old "If you're not doing it my way you're doing it wrong" self again.

[GaCop]

Well I see Mike's back to being his old "If you're not doing it my way you're doing it wrong" self again.

[mikeinco]

well ladies and gentlemen,
if you are going to attack me...hmm i thought management said you could not do that, at least tell me what you are talking about. at least 2 different subjects here.

Well I see Mike's back to being his old "If you're not doing it my way you're doing it wrong" self again.

[wbm]

Well I see Mike's back to being his old "If you're not doing it my way you're doing it wrong" self again.

Lol! Yeah! Homozygous for the trait.

[charlie b]

This has all been made a bit more curious to me after doing some shooting.

First, cast bullets, weighed and sorted in tenth grain increments and then shot at 100yd. Total variance was 2grains (175 to 177) Virtually no difference could be seen in POI. The biggest difference was when I shot a group of rejects, mostly low weight (172-174gn) and they produced a scatter. To be expected, IMHO, since the low weight indicates possible voids and probably off center. These were all with a weighed powder charge of 23.8gn of IMR 4198.

Second, I had my trusty Axis in .223 with 77gn SMK's. This rifle, in my hands, is around .5MOA out to 600yd. I was testing the effect of using charges thrown directly from my Lee powder measure. I sorted cartridges by weight. From 23.2 to 23.8 gn of Varget. At 300yd the groups overlapped almost perfectly.

So, I did some more research and turned up this gem of a video. The guys here take two rifles (6x47 Lapua and 6.5CM) and test the ability of different powder measures to produce desired charges.

https://www.youtube.com/watch?v=mqvbG2hzUgM

It can be a bit of a chore but if you study the spreadsheets you will note that velocity varies when charges are equal by 10 to 20fps. If you check the velocity difference for a 0.5gn change in powder it shows 10-20fps change. Basically the charges thrown by the Harrell powder measure were very close in velocity deviation to the more accurate charges measured by the automatic units. Group sizes at 600 were a bit intetesting as well, especially the Lapua. The thrown charges were just as or more accurate than the automatic charges even with higher charge standard deviation. I am not as forgiving as the testers, who ;threw out' fliers. The important part of this test is the fliers as they 'should be' the entire issue of the test, ie, what is the worst variance of the tested powder measures.

The other good news is that my cheap Lee powder measure throws almost as consistent charges as the Harrell. FWIW, my loading technique is to throw a charge and measure it. If it is the weight I want I load it. If not I put it back in the hopper and throw another charge. I find that technique faster and less frustrating than using a trickler.

And, no, I do not recommend that very long range precision competition shooters should change what they are doing. If what you are doing works for you then stay with it. These are just my observations for purposes of my shooting.

I would like to see other people do some controlled testing of bullet weight and powder charge weight variations.

[charlie b]

PS just for grins I played around with a ballistics calculator.

.338 Lapua Two cases. 10fps change in muzzle velocity. At 2000yd it results in 14" change in POI. At 1000yd it is just under 2". At 600yd it is 0.5". At 200yd it is 0.03".