Bullet Weight Variance
Question:
: I recently purchased a bulk quantity of Winchester 7.62 123 grain spire : points. I weighed 30 bullets out of the batch on a very accurate balance and : found the weight varied from 121.2 gr. to 122.9 gr. : Is this much variance typical ? These are just for plinking so it’s not a : big deal. I am very curious however about the effect on accuracy of a 2-3 : grain difference in bullet weight on a long range hunting load such as a 7mm : 140 grain boat tail at 3000 fps. : Thanks, S. Moore I read somewhere, probably a Sierra brochure, that Sierra keeps their rifle bullets to within .3gr and the match bullets to within .2gr. I don’t know if that’s .3gr of nominal, or a spread of .3 max, but ither way it’s less than your 1.7gr. samg Hewlett Packard/Colorado Springs
Response:
The variance in bullet weight of 1.7 grains is normal. Normally for target shooting, bullet weight variences of more than one grain are set aside for non-target use. Dont worry
Response:
>I recently purchased a bulk quantity of Winchester 7.62 123 grain spire >points. I weighed 30 bullets out of the batch on a very accurate balance and >found the weight varied from 121.2 gr. to 122.9 gr. >Is this much variance typical ? These are just for plinking so it’s not a >big deal. I am very curious however about the effect on accuracy of a 2-3 >grain difference in bullet weight on a long range hunting load such as a 7mm > 140 grain boat tail at 3000 fps.
My friend weighs everything except primers. In his 6/284, he compared 70-grain Sierra Matchking hollowpoints with 71-grain Berger boattails. The Sierra bullets had almost no variation, as another post on this group suggests. But the Bergers shot groups half the size of the Sierra bullets. Maybe it wouldn’t have shot so well if he hadn’t sorted the bullets by weight, but then again maybe bullet weight isn’t that important.
Response:
Your variance is (by my calc — tho I’m no rocket scientist) a maximum of less than 1.5%. That’s not a whole lot. While I haven’t used Winchester bullets, I find that Sierra, for instance, can almost be used as scale "check weights." Rick — "My problem lies in reconciling my gross habits with my net income." — Errol Flynn (and me too!)
Response:
I recently purchased a bulk quantity of Winchester 7.62 123 grain spire points. I weighed 30 bullets out of the batch on a very accurate balance and found the weight varied from 121.2 gr. to 122.9 gr. Is this much variance typical ? These are just for plinking so it’s not a big deal. I am very curious however about the effect on accuracy of a 2-3 grain difference in bullet weight on a long range hunting load such as a 7mm 140 grain boat tail at 3000 fps. Thanks, S. Moore
Response:
:I recently purchased a bulk quantity of Winchester 7.62 123 grain spire :points. I weighed 30 bullets out of the batch on a very accurate balance and :found the weight varied from 121.2 gr. to 122.9 gr. : :Is this much variance typical ? These are just for plinking so it’s not a :big deal. I am very curious however about the effect on accuracy of a 2-3 :grain difference in bullet weight on a long range hunting load such as a 7mm : 140 grain boat tail at 3000 fps. : :Thanks, S. Moore S., I think it depends on the bullet/mfgr. I bought a box of 125gr Remington JHP’s for my .357, and 10% of them were 128gr (the rest nearly spot on at 125). I segregated those out and used them for plinking as well. I have also weighed Speer 125gr JHP’s and found them within .2gr +/- every time. The rifle bullet’s I’ve weighed (Nosler, Sierra, Barnes) were all quite accurate in weight. The difference you note above, 1.7gr range of variation on a nominally 123gr bullet, amounts to a 1.3% variance. I don’t think those would qualify as match bullets by any stretch of the imagination, but I don’t think you’d find a great loss in accuracy just due to that factor alone. If you found some 140’s that were off by 3 grains, that’s still only 2% in total. I’d be more concerned by "why" these bullets vary that much in weight – could imply inconsistent manufacturing quality control, and other factors e.g. weight distribution within the bullet itself, jacket thickness, etc etc may also be suspect. The articles I’ve read say that bullet makers box by weight, not by count, so 100 bullets weighing 140gr each is 14000 gr (or 2 lbs). I don’t know how accurately they measure this in bulk at the end of the line versus taking control samples along the way. Don’t know if I answered your question…. — I don’t speak for Dell.
