bulet weight variation

[rebs]

In a 223 rifle shooting 77 gr SMK bullets how much variation in bullet weight is acceptable ? weighted a bunch and the range was from 76.9, 77.1 and 77.2 grains. Is a 3 grain weight difference enough to cause flyers or other problems ? I am shooting 300 yd F-class matches.

 

[Highpower-FClass]

0.3 - 0.4 grain spread sounds about normal for SMKs. With Berger 80gr bullets I typically see a ~0.2 grain spread.

I do not weight sort my bullets but I do sort by BTO, I believe that makes more of a difference.

77 SMKs, while a great bullet, are not the most accurate bullet to use for 300 yard F-class in my experience. You might want to try the Berger 80 grain class bullets (80 VLD, 80.5 fullbore, 82 BT Target)

 

[JEFFPPC]

Your barrel will tell you what bullet it likes. At 300 yds I think .3 is negligible but very easy to test. Shoot out of the box and shoot sorted. If there is an difference is it enough to matter, and is it worth the time, you can decide.I doubt it.

 

[BartsBullets]

Short answer is no. Not at 100 and not at 1000 or anywhere in between.

Bart

 

[David Christian]

@rebs, some will argue that two bullets that were loaded identically and fired from the same rifle, but have different weights will most definitely impact differently on the target. What is missing in this argument is the fact that there is a ~1:1 ratio in bullet weight change and the bullet’s BC. Let’s take a look at the math using a sample Berger 184 hybrid.

Weight: 184 grains
G7 BC: 0.356
Muzzle Speed: 2,770 fps

1% increase in weight: +1.84 grains + 184 gr = 185.84
1% increase in BC: 0.00356 + 0.356 = 0.35956

Enter both sets of these numbers into your favorite ballistics calculator and here are the results:

Original weight and BC:
600 yard bullet drop = 79.4” 1000 yard bullet drop = 294.4”

+1% weight and BC:
600 yard bullet drop = 79.2” 1000 yard bullet drop = 293.2”

Difference:
600 yards = 0.2”
1000 yards = 1.2”

This example assumes an almost 2 grain difference in weight.

 

[Ccrider]

Short answer is no. Not at 100 and not at 1000 or anywhere in between.

Bart

This is helpful Bart. I will ask the next question and I think you may have posted the answer somewhere before. What weight difference do you sort for? Do you use the same cutoff for all dostances?

 

[BartsBullets]

This is helpful Bart. I will ask the next question and I think you may have posted the answer somewhere before. What weight difference do you sort for? Do you use the same cutoff for all dostances?

I don’t weight sort bullets at all. Waste of time.

 

[mikecr]

Weight in itself is one thing, but a difference could exist w/regard to WHERE the weight discrepancy occurs.
Open a meplat 10thou due to a shorter nose, and now ~.3gr less material to do so matters a lot.
But weighted bullets matching or different will not tell you this. Just like weighing cases will not tell you anything directly about them.
Shortcuts like this are better dismissed. Do something more important instead.

 

[WIB3]

Shoot a light one over the chronograph and a heavy one. Look where the land in the target and you can make your own determination.

 

[WIB3]

It all depends what your comfort level is. Me personally, when I set up I want everything to be perfect. Knowing that you have done everything possible is critical for your confidence on the line. Some might say that .30 is nothing to worry about but what if that also includes you powder charge! I am confident in saying that no BR shooter in the country would settle with that.

 

[JEFFPPC]

It all depends what your comfort level is. Me personally, when I set up I want everything to be perfect. Knowing that you have done everything possible is critical for your confidence on the line. Some might say that .30 is nothing to worry about but what if that also includes you powder charge! I am confident in saying that no BR shooter in the country would settle with that.

Those who throw and do not weigh do.

 

[WIB3]

Those who participate in 600-1000yd Benchrest do not throw. PPC is a completely different. Loading is performed at the range. Everyone brings pre-sorted components.

 

[Ned Ludd]

Some people will sort traditional lead core bullets by weight for the purpose of removing only extreme outliers. In my hands, it's not uncommon to find a few in every Lot of bullets. In fact, it's often possible to spot the outliers without even having to weigh them as they will often have noticeably large jacket folds on the nose/ogive. My suspicion has always been that there may have been something wrong with the lead core of those outliers, thus the nose folds. However, I can't state that with any certainty. Nonetheless, it has also always been my concern that if the weight of these outliers is way off, what else might be off? Even if nothing else is wrong, I view my concern over using them as potentially having a negative mental impact on my shooting. For that reason, I will generally load such culled outliers and use them as the first few fouling shots, so as not to lose some utility from them.

 

[INTJ]

Those who participate in 600-1000yd Benchrest do not throw. PPC is a completely different. Loading is performed at the range. Everyone brings pre-sorted components.

We also don't worry about bullet weight variations in LR BR. Not just Bart, but I know of an LR BR guy who has done extensive testing on this. While he definitely says we should measure and sort bullets for length, and spin them in a Bullet Genie, he says don't bother weighing them.

 

[newbieshooter]

Other references:

https://blog.ammolytics.com/2019-02-02/bullet-sorting-part-one.html

http://forum.accurateshooter.com/threads/ammolytics-bullet-sorting-experiment-part-one.3971874/