Weighing Projectiles - Variances

[BNO]

I just weighed a box of 142Smk projectiles. There was 2 distinct groups of projectiles 142gr (70% of them approx) then 141.9gr 15% then the difference was 141.8 and 142.1.

What is the acceptable variance for projectile weight for reloading?

 

[GordoNV]

BNO, That's a really good question. I weighed a handfull of the new Nosler RDF's that I got - They all were within +0.0gn/- 0.3gn of listed weight. None were over, and the majority were 0.1 under. I thought that was really good consistency but my experience is limited. Maybe some old hands at this will chime in and enlighten us. -G

 

[BNO]

BNO, That's a really good question. I weighed a handfull of the new Nosler RDF's that I got - They all were within +0.0gn/- 0.3gn of listed weight. None were over, and the majority were 0.1 under. I thought that was really good consistency but my experience is limited. Maybe some old hands at this will chime in and enlighten us. -G

Yeah i thought the same, considering Sierra have been known to be out in the past.

 

[Supersubes]

This is one of those questions that cant easily be answered. In my experience, what you're seeing will mean nothing on target. The shooter and the rifle has to be able to shoot the difference to determine anything though. A big ES in velocity will easily swallow variations in bullet weight or bullet jump. So many of these variables are absorbed in the inconsistency of the system(shooter/rifle). Its easy to take them to the range and form a conclusion based on a few groups. Realistically, the shooter's extreme spread will likely outweigh what you're seeing on the scale. Remove bias (blind test), add range(more is better), include velocities, and look for verticle dispersion. Nip it in the bud with a few tests. Most just sort them from the beginning. Probably better to test it. It'll let you know if you need to put in the effort, or forget about it. Most competitors arent concerned with minor but consistent deviations. Its that one round that will cause a true flyer. Like shooting consistent x's, then putting one in the 8 ring at 6 o'clock for no reason. To take value from it though, you have to be able to shoot the difference.

To throw a monkey wrench in things, sort them again by base to ogive length. The theory is that slight variables in ogive arc create variables in seating depth, which results in a variable jump to the lands. Same test method as above.


My guess is you see nothing with either, but dont take my word for it.


On a slightly different note, are these bullets out of boxes of 100, or 500? I seem to recall that sierra advertised at one time that 500 quantity boxes came from one machine, whereas the 100 boxes were a mix of multiple machines. Been a long time, and my recollection could be bad.

 

[BNO]

This is one of those questions that cant easily be answered. In my experience, what you're seeing will mean nothing on target. The shooter and the rifle has to be able to shoot the difference to determine anything though. A big ES in velocity will easily swallow variations in bullet weight or bullet jump. So many of these variables are absorbed in the inconsistency of the system(shooter/rifle). Its easy to take them to the range and form a conclusion based on a few groups. Realistically, the shooter's extreme spread will likely outweigh what you're seeing on the scale. Remove bias (blind test), add range(more is better), include velocities, and look for verticle dispersion. Nip it in the bud with a few tests. Most just sort them from the beginning. Probably better to test it. It'll let you know if you need to put in the effort, or forget about it. Most competitors arent concerned with minor but consistent deviations. Its that one round that will cause a true flyer. Like shooting consistent x's, then putting one in the 8 ring at 6 o'clock for no reason. To take value from it though, you have to be able to shoot the difference.

To throw a monkey wrench in things, sort them again by base to ogive length. The theory is that slight variables in ogive arc create variables in seating depth, which results in a variable jump to the lands. Same test method as above.


My guess is you see nothing with either, but dont take my word for it.


On a slightly different note, are these bullets out of boxes of 100, or 500? I seem to recall that sierra advertised at one time that 500 quantity boxes came from one machine, whereas the 100 boxes were a mix of multiple machines. Been a long time, and my recollection could be bad.

Was from a box of 100.

I did a comparison to some 140gr ELDs from Hornady all of them were 140gr on the nose zero variance.

Thank you for your reply too appreciated!

 

[Strykervet]

Did you call ammo maker?

From experience and from what they've told me, the SMK's are mostly spot on with a few outliers, generally not that far out of spec. and on the order of +/_1gn. This has been the case regardless of the bullet. SMK's exhibit this tolerance from at least 6.5mm to 7.62mm in all weights.

Never weighed my Nosler BT's, need to see if they hold up before loading. I use the 6.5mm 120's. Never weighed out the 77gr. SMK's either because I ended up with a bunch of 75gr. Hornady OTM's I'll use up first (and may stick with, who knows). And I only weigh out and sort ammo that's for precision loads, never bulk stuff like M855 or god forbid, .50 BMG API's.

Marine competitive shooters and some others (not sure how AMU does it) have their own in-house loaders as well as machinists that actually build their rifles. I know the Marine's do and they handload each round individually and they weigh out all the components (not just the bullets) and once sorted, they assemble ammo using those sorted components to optimize each rifle. Some do better with 168's dead on, some with 168.5's or 167.5's. They also heat the load when they make it and the shooter will bring the ammo up to that temperature on the range (typically with glove warmers). All this is to eliminate as many variables as possible.

I think it was History Channel that ran this years ago, may be able to find it on YouTube. Good info worth watching.

 

[BNO]

Did you call ammo maker?

From experience and from what they've told me, the SMK's are mostly spot on with a few outliers, generally not that far out of spec. and on the order of +/_1gn. This has been the case regardless of the bullet. SMK's exhibit this tolerance from at least 6.5mm to 7.62mm in all weights.

Never weighed my Nosler BT's, need to see if they hold up before loading. I use the 6.5mm 120's. Never weighed out the 77gr. SMK's either because I ended up with a bunch of 75gr. Hornady OTM's I'll use up first (and may stick with, who knows). And I only weigh out and sort ammo that's for precision loads, never bulk stuff like M855 or god forbid, .50 BMG API's.

Marine competitive shooters and some others (not sure how AMU does it) have their own in-house loaders as well as machinists that actually build their rifles. I know the Marine's do and they handload each round individually and they weigh out all the components (not just the bullets) and once sorted, they assemble ammo using those sorted components to optimize each rifle. Some do better with 168's dead on, some with 168.5's or 167.5's. They also heat the load when they make it and the shooter will bring the ammo up to that temperature on the range (typically with glove warmers). All this is to eliminate as many variables as possible.

I think it was History Channel that ran this years ago, may be able to find it on YouTube. Good info worth watching.

I could call the Sierra rep in Australia however would be a pointless venture. Ill just shoot them from my m96 and use the other ones for my 260 prs rifle.

I am still waiting on my RDF Noslers but they are so backlogged getting into australia it will be 2019 before i get them at this rate. Ill have a look for that doco you mentioned too

Thanks a bunch sir!

 

[domdoc]

It isn't enough variation to make a difference. If you get any significant base-to-ogive variation, and think that makes a difference, buy JLK bullets. Do not weigh them, do not point the meplat, and do not measure their base-to-ogive. Just find a load that makes them shoot well, and go shoot.

 

[BNO]

It isn't enough variation to make a difference. If you get any significant base-to-ogive variation, and think that makes a difference, buy JLK bullets. Do not weigh them, do not point the meplat, and do not measure their base-to-ogive. Just find a load that makes them shoot well, and go shoot.

If i could get them here in Australia I would consider it.

I have 3 boxes of projectiles (100 count) on order and wont expect to see atleast 2 of them for another 3-5 months. I managed to get my Hornady 140gr ELDs by sheer luck. Bergers are hard to by as they sell out so fast.

 

[Blazin]

Interesting discussion. I have been weighing (and measuring length of) bullets recently and have noticed my Bergers being more consistent than the Hornady and Sierra's. But Hornady's certainly seem to be consistent, especially given their price.

 

[Greg Langelius *]

This is not a new question. I'll simply say that it's easy to overthink handloading.

The producers of reloading components have quality control standards that protect them, and you, from variations that will have a significantly detrimental impact on their product's performance. The fact that they enforce those standards is evident in the occasional availability of blem/irregular components.

Honestly, if you think you can invest significant personal effort into beating those professional at their main game, by all means do so. I tried it and got bubkiss for my efforts. The target is the sole final arbiter of quality.

The problem with all this additional effort is a very real concept; called the law of diminishing returns. The producers could invest more effort, but then the product would price itself out of competition, and the resulting accuracy gains would not be worth the added cost to the consumer. The same is true of your effort, because the expected gains more often than not will disappear the the myriad of other small and cumulative variables that are beyond the control of the modern handloader. There is a certain irreducible margin of inaccuracy that may be obtainable, but may not be worth the effort.

You choose, but be prepared for frustration.

The components are what we start with. For the most part, good brass prep is a better investment of time than all the other components checking and/or culling/modification processes combined. I find that I get the best gains from improving the consistency of my charge weights than any other process that I can personally control.

I have found that bullets do fine straight from the box. It's my own quality control that needs the most attention.

I have invested in a Hornady Lock-N-Load automatic powder measure. It is an excellent financial expenditure that saves, rather than expends, valuable handloading time. I get perfect charges, and there's no time overhead.

I will always value time over money. At age 71, I have to.

Greg

 

[TheGerman]

There will be a larger variance in your trigger pull between rounds, than the difference a .1 or .2 grain variance in bullet weight will make.

 

[mojavejim]

I had a large lot of 140ELD's that varied 2.6gr per 100. It may not have made any difference at the range but my new barrel didn't like them & I lost all confidence in them after weighing so I moved on. Berger & Lapua seem to have the least variance @ about .2-.3gr. (90% @ .1- .16) It may not matter but with all the effort put out to make the best possible ammo I'm not taking any chances,