Bullet Uniformity Testing - 7mm Bullets

[Orkan]

Even a novice handloader should know that the focus of identifying and uniforming all of the variables associated with producing loaded cartridges is one of the most important aspects to rifle accuracy. If all other aspects of physically firing a rifle are performed with exacting precision and repetition, and the rifle itself is straight and true, the ammo is usually the only root cause left if presented with unruly groups. If you do not have uniform components, then your loaded rounds will not be uniform either. Most often, handloaders concentrate on their powder charge and brass uniformity, but we don't often look at bullet uniformity. I decided to take some measurements of 4 different brands of 7mm bullets and compile the results here.

Unfortunately we lack the facilities to adequately live-fire these projectiles in a manner that would produce any valuable data. So I'll provide the numbers, and you can decide whether the variables would show themselves while shooting.

The scale used to weigh the bullets is a Tree HRB-203. This is an economical analytical scale which has a readability of 0.01gr, a repeatability of +/- 0.03gr, and a linearity of +/- 0.06gr. It is quite sensitive, and is certainly accurate enough to measure differences in bullet weights.



Here are the results:


Having done similar tests many times in the past, I can tell you that the trend shown here among the bullets tested, is pretty indicative of what each respective manufacturer is able to reproduce consistently. They are all about even in terms of length measurements, with only one bullet measuring long on base-to-ogive which made Sierra's numbers look considerably worse than they would have. When it comes to weight, Berger and Sierra are the clear victors. Hornady is in a very close 3rd place, and Nosler picking up a distant 4th. Having weight sorted several of these bullet makers products in various other 22cal, 6mm, 6.5mm, and 30cal offerings... this trend does not surprise me in the least. Sierra always stands out with their uniform yet cost effective offerings. Berger is always just a little bit better (marginally so) with a substantial cost penalty. Hornady is there with some very value-oriented bullets, with just a bit less in the way of quality control. Nosler has been all over the board in their weights for every bullet of theirs that I've ever decided to test. In some of their 30cal offerings, I've seen as much as 1.5gr swing across 50 bullets. This is quite disappointing, as these new ABLR bullets are generating quite a bit of intrigue, and seem to perform fairly well. Obviously if any of the bullets tested would benefit from weight sorting, it would likely be the Noslers!

As I said early on, it is difficult to quantify if these differences would result in any deviation showing up on the target, but it is interesting none the less. Perhaps it may be of some use to you.

 

[gamestalker]

,

I agree that consistency regarding bullets is important, in fact, it is among one of the most important factors, but it isn't the single most important factor, IMO. The consistency of the brass on the other hand, is in my opinion, at the top of the list in this respect. But still, I don't feel it's the one single element that will assure sub moa accuracy, IMO.

I'm having trouble keeping my eye's open right now, but I sincerely look forward to resuming this discussing tomorrow, when I will hopefully have the ability to better project my thoughts and findings.

Good night everyone!

GS

 

[ironworkerwill]

Hornady may be a better choice than Sierra. The BTO and OAL are equal in the Hornady and Berger offerings. 2 out of 3 aint bad.

 

[jwrowland77]

Over the thousands of Sierra and Hornady bullets I've weighed and measured, I have found better consistency in the Hornady bullets than the Sierra ones.

As far as the Berger and Nosler, I've never used Berger and the only Noslers I use are the Partitions.

 

[ironworkerwill]

I really like how the cheap 139 gr .284 (fb OR bt) Hornady bullets shoot on paper. And the price - SO NICE.

 

[jwrowland77]

That's the bullet I use for deer hunting. Extremely good shooting from my rem 700 7mm rm. Single hole groups at 100....and yes I weigh my bullets. I use the group mostly 138.8-138.9 since I had more of those than anything. Hornady 139gr BTSP.

 

[41 Mag]

While I do not shoot in any sort of competition, there have been times when I gathered up my components and weight sorted them in an effort to garner a bit tighter group at longer ranges.

In the past 30yrs or so, I have probably done this over a dozen times, but in each experiment I found that in a blind test, the unsorted loads usually held right in there with the carefully prepped ones. While there might have been enough of a difference to matter to someone trying to eek out the last .001 of a group, for a hunting load where the range might be from 50yds or closer to out past 400, what I have personally found wouldn't matter in the least. Having ideal conditions at the time of the shot has been the deciding factor in whether or not it was taken.

In your tables above you list as well as say that Nosler is the worst and is all over the board. The funny thing is that when I want exacting accuracy from a load those are what I usually use. In most cases I have found them to be easier to hit an accurate load with, and also to be more consistent from lot to lot after working that load up. This isn't to say I am a huge Nosler fan, as I am far from that. I simply have to go by what has worked for me through the years and compare it to what happens at the time of load development. I would MUCH rather use Hornady overall, as the across the board averages for accuracy loads has been higher with them, but they aren't always the tightest grouping bullets. However I would rather have 4 loads for 6 rifles that will shoot into 1" with Hornady bullets than one load for the same 6 that will shoot into 1/2 - 3/4", yet cost me twice as much to shoot.

 

[Orkan]

41 Mag,

I'm not suggesting that Nosler makes "bad" bullets. Quite the contrary, as I've enjoyed using several of their bullets over the years. However, it is blatantly obvious that they cannot hold the same weight uniformity as other manufacturers. All of my previous testing of their bullets reinforces this fact. In that capacity alone, they indeed are the "worst" of those tested.

I'd suspect most people do not own rifles or the skillset to adequately test this weight variation. Even a 1gr difference in weight does not seem to change calculated firing solutions to 1500yds with a 7LRM. I'm of the mind that with proper load development, it would likely never be seen on the target.

Though it is noteworthy that many winning benchrest shooters believe in weight sorting bullets. Every person has a different delta for what they consider acceptable accuracy. A rifle that shoots 1moa doesn't get to exist in my house. 1/2moa is the largest that I'm willing to accept. A lot of this, as usual, is about perception.

 

[41 Mag]

Orkan,

I am in agreement with the post above totally. I guess what I was trying to say was that even with a spread of weights that the Noslers will still turn in some very fine groups in most cases.

That said the weight variations will start to show up, no matter which one your shooting, but I think you nailed it perfectly with saying that most folks would never notice it.

There is a whole lot more to it than simply pulling the trigger and everything magically goes into one hole.

 

[jwrowland77]

That's why whenever I do my load workup, I shoot everything from a lead sled. It takes human error out of the equation. Then, if I can't replicate the group, then it obvious, it's me doing something wrong.

For me though, everything gets weighed, because at 600yd and a 1000yd, every little thing you can make more consistent the better. Everything gets magnified at 1000yd. LOL. Especially when you're trying to hit a 5" ring @1000 or a 3" ring @600. The more consistent, the better.

 

[josmund]

Orkan,

Thank you for your work on this thread. I must admit, my skill set as a novice shooter would be a much greater factor in accuracy than anything else. It is very interesting.

FYI. I lived in SD for 27 years and have driven most every road in the state between work and pleasure. I miss my home state... at least from May to October.

 

[Orkan]

Yeah, I like it here. I could do without the 90-110 degree days in the summer, but all other times I like. Well the -50 degree days in the winter aren't fun either... but otherwise it's an awesome place to live as a shooter.