Bullet weight fluctuations

[azar]

When reloading I know that some people weigh and sort each bullet, but how picky are you? I purchased a box of Remington 6.5mm 140g bullets and had fluctuations from 140.0g to 140.7g which seemed like a lot of variations. So, I sorted them into two groups; 160.0 to 160.3g and 160.4 to 160.7g. I figured since this was a plinking round that would be good enough.

Recently when I started reloading some Sierra 6.5mm 160g SP I weighed each bullet and no bullet weighed more than 160.3g. When you sort weigh and sort your bullets how precise are you? Do 160.0.g get put into a different box than 160.1g? And if so, how much of a difference does it really make? I'm mainly concerned about hunting applications, although I'd like my bullets as accurate as possible for that purpose. I'm not sure if it would be worth all the extra time to sort the bullets into tenths of a grain. But I would like to know how much a difference it can make in the end.

If my primary purpose is for hunting and then plinking, how picky should I get?

 

[Jim Watson]

Hunting and plinking?
Out of the box.

I have heard of target shooters sorting their bullets by weight, but I just buy Sierra, Berger, JLK, and Lapua and load 'em up.

I do sort my cast rifle bullets by weight, though.

 

[USSR]

If my primary purpose is for hunting and then plinking, how picky should I get?

You're wasting your time sorting commercially made bullets by weight for your purposes. I don't even do it for LR competition, although I will sort Sierra MatchKings by bullet base-to-ogive lengths.

Don

 

[BeJaRa]

yeah, I think most of us rifle shooters probably need alot more practice before the variation of bullet weight is our limiting factor. At least for me my equipment is never the limiting factor, I am

 

[taliv]

depends on the use of course. for HP matches with service rifle, I shoot em out of the box.

for my precision gun, I weigh them to hundredths of a grain (using an acculab scale) and what I find is they usually fall into nodes. for instance, maybe half of a box of 107g SMK will be 106.98g exactly. a bunch more will be 106.86-88g, and there might not be any that fall into the range between those two.

However, I also find a lot of "fliers" so I think weighing each bullet is a good idea. For example, for the sake of this post, I just grabbed a random handful and weighed them and found bullets ranging from 107.20g to 106.32g. Maybe a grain difference doesn't mean much for most sports, but when I'm trying to keep a 1" group at 400 yrds, I'd just as soon be using bullets that are all the same weight.

 

[azar]

I thought that it wouldn't make much of a difference, although I have had an occasional flyer that for the life of me I couldn't explain. The last time at the range I had one 4 1/2" left and 2" high of bulls-eye. The gun was rested on bean bags, the barrel was allowed to cool down after each shot, the trigger pull was a gentle squeeze, etc. I hadn't noticed any flinch or jerking of the trigger. And I haven't had a shot that far off... well, I've never had a shot that far out there with this gun.

It got me thinking about my consistency in reloading and if bullet weight fluctuations could have contributed. Perhaps it was just an anomaly (or maybe my shooting wasn't as good as I thought. ).

 

[RecoilRob]

Before someone gets really anal about bullet weight variations of less than a grain, they normally run all ammo through a run-out gauge as that is FAR more critical to accuracy than an infinitesimal weight variance.

I won't use ammo in my 'precision' rifles with more than .005 total runout of the projectile measured with the V-blocks on the neck and base and dial-indicator on the midpoint between neck and ogive.

If you check your ammo, you most likely will find the odd 'wobbly' one and, if you don't cull it for a fouler or other non-critical use, you WILL see it impacting far from the group.

Runout is THE major contributor to inaccuracy IMO.

 

[USSR]

The last time at the range I had one 4 1/2" left and 2" high of bulls-eye. The gun was rested on bean bags, the barrel was allowed to cool down after each shot, the trigger pull was a gentle squeeze, etc. I hadn't noticed any flinch or jerking of the trigger. And I haven't had a shot that far off... well, I've never had a shot that far out there with this gun.

It got me thinking about my consistency in reloading and if bullet weight fluctuations could have contributed. Perhaps it was just an anomaly (or maybe my shooting wasn't as good as I thought.

azar,

While it is d@mn near impossible to say exactly WHAT caused that unexplained flyer, the one thing I CAN say with complete confidence is, a slight variation in the weight of your bullet DID NOT cause it to move 4 1/2" left and 2" high of the rest of your bullets. If you truly believe that it was not you, take a look at scope rings and base being tight, try mounting a known good scope in place of the one on there now, examine the crown for imperfections, and consider having the rifle bedded if it isn't already.

Don

 

[taliv]

yeah, i've been scratching my head thinking of what might cause that. i think we're all assuming your shot was at 100 yrds, too. and let's say your last 10 shots were inside 1.5 to 2 inch circle...

external things that could do it, or could combine to do it:
dramatic change in wind, lighting condition, crimp (maybe?)

or maybe the bullet was mfg'd wrong. could be there's a big off-centered bubble in the lead that you can't see.

but i agree it wasn't just a slight change in weight.

 

[Walkalong]

Variation in bullet weight with good bullets is one of the least important things when it comes to why one shot went AWOL. Anything from a twitch in the trigger finger, a slip of the shoulder, to a slight switch in the wind.

Don't sweat that one. Work on all the others. If you have never shot over wind flags, it is a real eye opener.

 

[azar]

Yes, this group was at 100 yards. It was shot #8 that was the flyer. I'm not 100% sure it wasn't me, but I've never been that far off with this gun. #9 was about 1 1/2" left (most the entire group was left of the bull as the rifle is sighted in for a different load) and #10 was just inside the left part of the bulls-eye.

I won't worry about the weight of the bullets. I'd have to say that these Remingtons have been my least favorite bullets so far. They were dirt cheap at about $12 to $13 for 100 and I guess I see why. I basically grabbed them for a cheap plinking round and to get some more practice reloading. I'll probably grab some Speer HotCors as a replacement lower-cost round.

RecoilRob, pardon my ignorance but what is a run-out gauge? Where would I get one and what would be an estimated cost?

USSR, I doubt it's the scope. It was only that one shot. Shots before and after were about were I'd expect them.

Thanks everyone for replying.

 

[taliv]

runout refers to how straight the bullet is compared to the case. hard as it may seem to screw that up, you'd be amazed how crooked most factory bullets are seated. i think you could run a miniature hoolahoop on most remington factory ammo.

sinclairintl.com sells the best and priciest gauges.

 

[RecoilRob]

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=310955

I have used this one a lot and it works well...especially for the money involved.

Example: 50BMG Talon fired through Armalite AR-50. Some rounds have over .100 runout!! Carefull measuring and shooting only those with .010 or less (VERY few had less!) and the rifle goes under 4" @ 600yds.

After a good powder scale, this tool (or one like it) is THE next step to good shooting IMO.