How do ammo companies determine accuracy standards?

[c.latrans]

As a reloader I can usually duplicate factory velocities, often with a number of different powders, and I can select and tune these loads to an individual rifle to wring some extra accuracy over factory ammo. In my typical bolt guns, for example, 1.5 inch 5 shot groups are about the max I will tolerate, although I may at times give up a little accuracy in order to shoot a more strongly constructed bullet if the situation dictates.

But here is a question I have thought about for years but never asked. Knowing that every rifle is going to behave a little differently, and that one can often shoot a number of factory selections and find one that shoots better than the rest in an individual rifle, how do the big companies, in terms of accuracy, determine that the load they sell....say Winchester Silvertips in a given .30-06 load? How do they determine their accuracy standard given the wide range of firearms such a piece of ammo might be used in? I have no clue

 

[Slamfire]

If you notice they don’t guarantee accuracy. Neither do the bullet companies. You see more information in reloading manuals, you see the test guns and ranges bullet companies use in testing loads and bullets. I have seen pictures of all sorts of different actions and probably barrels.

A shooting bud of mine asked Larry Moore, an experienced Government small arms test engineer and competitive shooter, how many rounds did it take till he had confidence in the accuracy of a load. Larry answered him “about 20,000”.

The US military used to shoot 600 yard groups that took 100’s of rounds and brought those NM targets to Camp Perry for all the competitors to see. They could determine a mean radius and extreme spread from all these tests.

I believe manufacturer’s have several levels of accuracy. Cheap bullets are probably the least accurate. Hunting bullets better, match bullets would have the tightest requirement. Manufacturer’s have to pick a standard barrel and then go shoot a group. I mean, what else can you do? I really doubt they have more than a couple of different loads they use in each caliber. I can tell you, if your 308 rifle won't shoot a 168 Match well with 40.5 grains IMR 4895, something is wrong either with the bullet or the barrel. In a 38 Special revolver, if your 38 SPL won't shoot a 158 gr bullet with 3.5 grains Bullseye, its either the bullet or the barrel. Companies are not going to test ammunition in poor test equipment so its going to have to be the ammunition if groups are bad. Since they don’t guarantee accuracy all they would be looking for is abnormally bad bullets or ammunition. They have to compare results against their database of results. The match ammunition probably is tweaked to some extent. If the match ammunition does not shoot well the market will walk away from their brand.

Whatever accuracy criteria they use is going to be proprietary, standards they made up, and it would only be happenstance if another maker uses similar numbers. For profit companies have issues with standards. They don’t want to reject any product because it reduces profits. But, they can’t shovel out garbage forever because we catch on. I believe we, the shooting community, are the ones actually setting the standards for cartridge/bullet accuracy. If the bullet does not shoot well we are very vocal about it and that affects sales. If the bullet shoots well, we are very vocal about it and people copy success. That affects sales. I can tell you in the target community, people use what wins. If a good shooter consistently wins with a particular bullet, the herd follows. If a bullet is changed for the worse the word gets out very quickly and the herd walks away.

So, in the interest of improving the standards of our bullet and cartridge manufacturers, post your actual results, not the ones you wish you shot!

 

[c.latrans]

Interesting insight, Thank You! I don't quite follow your last sentence, though. Are you irritated with me for bringing the subject up? I am not complaining about the accuracy of factory ammo, only asking how they determine what is acceptable to put on the market given all the variables they face. Am I missing something?...wouldn't be the first time!

 

[ReloaderFred]

I've been in the ballistics labs of both Sierra Bullets and Nosler Bullets(twice for Nosler). Both of those companies use fixtures that accept test barrels into the solidly mounted test fixture. They work up their loads in those test barrels, shooting down their underground tunnels. Once they establish a load and accuracy basis, then they publish it in their loading manuals.

I would imagine the loaded ammunition companies do something similar. There is no way they would ever guarantee their ammunition would shoot an "X group" in your rifle. It just can't be done. They find the happy average and move on to the next caliber/load.

From what I see of the average shooters, they could load rocks for bullets and about 85% of the shooters wouldn't know the difference, since they can't shoot better than minute of hillside. When I see someone stand there and blast a whole magazine downrange as fast as they can in the general direction of the backstop, it makes me wonder what they're thinking in terms of accuracy, if they're thinking about it at all.............

Hope this helps.

Fred

 

[c.latrans]

Thanks Fred, good thoughts.

 

[Slamfire]

Interesting insight, Thank You! I don't quite follow your last sentence, though. Are you irritated with me for bringing the subject up? I am not complaining about the accuracy of factory ammo, only asking how they determine what is acceptable to put on the market given all the variables they face. Am I missing something?...wouldn't be the first time!

No, how do I say this, people all the time talk about groups that are statistically impossible. I have seen specifications that require military ball ammunition to stay within 3.5 MOA or so. Yet, I constantly read reports of shooters claiming sub MOA accuracy with the stuff. They are either telling us things that are impossible, or they are biasing the results by ignoring the “bad groups”.

Here is an example, I shot this Australian ball, at 100 yards, out of a good rifle and this is what I got:



And yet, I read lots of posts claiming target grade accuracy with this stuff!

This is also true about all the one MOA rack grade Garands that apparently exist. I have bought and sold a bunch of CMP Garands, sorting through them trying to find an extra accurate example. This is a typical 100 yard target with a rack grade Garand:



This rifle was actually pretty good because all the shots are in the black!

This one threw shots out



This one was not particularly stellar:



Rack grade Garands are not target weapons and they were never expected to shoot target grade accuracy. It may be that posters believe to have credibility they must make exaggerated claims about accuracy, when in fact, claims of consistent sub MOA performance with a rack grade Garand only shows a lack of credibility about their results.

Incidentally, this is true for almost all surplus service rifles. A good service rifle will shoot within 3 MOA. There are some better, the Swiss for example, but guess what, service rifles were never expected to shoot as well as a target rifle. The M14, for example, I have seen endurance test data that shows these things were 5 MOA affairs with ball ammunition.

Now my M1a Super Match, that will shoot close to an MOA, probably closer to 1.25 MOA, but it won't shoot as tight as a match bolt rifle.

 

[c.latrans]

Got you now although I have very little experience with Garands or mil-surps of any kind...never has been my cup of tea.

Internet heroism aside, if my big game center fire bolt guns up to .300 mag cant be coaxed into giving me consistent bench rested 1.5 inch 100 yard groups with hunting bullets, then in my view they are not "keepers". I also have a couple of bolt guns that produce substantially better accuracy....which I paid a lot of money for and spent a lot of time tuning loads to, but I don't expect them to produce that level of performance with green box off the shelf ammo.

I could have phrased my initial question better, but Fred got to the crux of what I was asking and nailed it down pretty well. Nice shooting with the Garands, by the way. Looks like they are doing precisely what they were designed to do, and they have always looked like a ball to play with.

 

[Bart B.]

Having been through Sierra Bullets' production line a few times, here's what their head ballistics tech I shot many a rifle match with told and showed me. Their lighter weight rifle match bullets for a given caliber have to shoot 1/4 MOA average or the production lot's sold as seconds. Heavy match bullets specs were 3/10ths MOA. Hunting bullets from 3/8 to 1/2 MOA. They shoot bullets in rail guns much like benchrest unlimited class barreled actions whose barrels are clamped in a block of steel with the action hanging out the back end. They ride on 3-point suspension and recoil back about an inch after each shot then get reloaded and pushed forward back into battery. He would grab 10 bullets as they came out of the pointing machine, load them in cases already full length sized, primed and charged then shoot them. Repeating this during a production run over and over again.

Sierra uses rail guns as they are only testing bullets for accuracy. Such things eliminate all human and conventional rifle parts and assembly errors. Sierra used conventional rifles working up loads for their published data. Those marked as "most accurate" had the lowest muzzle velocity spread; the actual groups sizes were never made public. Asking them about this, I was told that they have no control over what customers shoot their bullets in and therefore would not give any group size specs. Besides, nobody can hold a rifle to their shoulder and shoot their best match bullets into no worse than 2/10ths MOA like their rail guns would at times.

The only thing I know of regarding all their rifle bullets often published is they're all tested with full length sized cases; they tried all sorts of neck only sizing but never got consistant results that way. Their test barrels use SAAMI spec chambers typically at the minimum as far as dimensions sometimes with minor differences but never ever use tight "match" chamber necks for rifle bullets. And they never work up a load when changing components nor the barrel in their rail guns testing them.

 

[c.latrans]

Thanks Bart......that guy has a very cool job!

 

[twofifty]

Quoting Bart B:
"The only thing I know of regarding all their rifle bullets often published is they're all tested with full length sized cases; they tried all sorts of neck only sizing but never got consistant results that way."

Thanks for that piece of insight.


Couple of great threads out right now dealing with factory loading methods, this is one of them.

 

[Bart B.]

I've watched 7.62 NATO Garands rebuilt by the USN's Small Arms Match Conditioning Unit in San Diego tested for accuracy clamped in a test cradle. At 300 yards with a really good lot of M118 match ammo, the good ones would shoot 3 clips of ammo into 2 inches for all 24 shots. In one instance, a full clip shot into 7/8ths inch at 300 yards. With good lots of commercial .308 Win. match ammo, they would shoot into 4 inches at 600 yards. None of their .30-06 rebuilt M1's even came close to that.

 

[Owen]

Bart B,

What year was that?

 

[Bart B.]

Owen, that was in the late 1960's when I was on USN shore duty in San Diego.

 

[Owen]

Just wondering. The match conditioning shop has been in Indiana for at least 20 years now. I was just wondering how long ago it was in SD, CA.

 

[Bart B.]

Owen, the USN SAMCU moved from Camp Elliott (NE San Diego area) to Crane, Indiana, in the early or mid 1980's as I remember.

But this year, the USN Marksmanship Team was unfunded to go to the Nationals and no Fleet nor All Navy Matches. Thanks to sequestering.

 

[GaryL]

I've been in the ballistics labs of both Sierra Bullets and Nosler Bullets(twice for Nosler). Both of those companies use fixtures that accept test barrels into the solidly mounted test fixture. They work up their loads in those test barrels, shooting down their underground tunnels. Once they establish a load and accuracy basis, then they publish it in their loading manuals.

I would imagine the loaded ammunition companies do something similar.

I have been in a manufacturers underground test range, and have seen the same thing. So at least one of them does, and I was led to believe I was looking at an industry standard piece of equipment. You would know the name if I mentioned it. In a previous life I installed automation equipment into a number of different industries around the country. Everything from having to blow the crud off my clothes with an air hose to putting on a bunny suit before entering the manufacturing area.

 

[Bart B.]

I don't know about Nosler, but my visits to Sierra's inner workings have revealed the following.

Match grade barrels are clamped in a metal block about 6 inches square and a foot long with a Savage action screwed on its back end. The block rides on a 3-point suspension free recoil base; essentially the same as an unlimited class benchrest rig. It's sole purpose is to test bullets for accuracy. Rarely, if ever, has Sierra published their accuracy standards for any bullet except their 30 caliber 168-gr. HPMK that's been listed in their manuals as needing 1/4 MOA average accuracy. If I owned Sierra, no way would I allow any accuracy specs out of the plant. With thousands of folks shooting all sorts of rifles with a wide range of marksmanship abilities, less than 1/2 of 1% of them would ever equal what those test barrels shot bullets in a controlled envirionment.

Sierra's loading data was developed in rifles shot by people using chronographs. The data in all their manuals I've read list the firearm make, model and cartridge used. Their "accuracy" loads are based on the powder make and charge weight that produced the lowest muzzle velocity spread. "Hunting" loads are those that produced the highest muzzle velocity with reasonable accuracy.

Years ago, I asked some factory reps from Remington and Winchester how they tested their ammo for accuracy. Both said they used precision test barrels with SAAMI minimum spec chambers, bore and groove dimensions; the only way to have a consistant standard across test barrels as they wore out after a thousand or two shots and no longer were good enough for good testing requirements. Both knew the barrels in production rifles had a small spread in those dimensions and several of each make and model would all shoot a given lot of ammo to different accuracy levels. The rifles were only shot with proof loads to verify their safety. One exception was Remington's 40X centerfire target rifles that were tested at 100 yards by a person shooting them from a bench. The only number I've heard of is 1/2 inch for those in .308 Win. chambering.

I don't think any ammo or rifle company should publish accuracy specs for their products. If they did, with the wide range of shooting skills and firearm quality across their customer base, they would have to add a huge warranty covering expense to the cost they sold them to retailers for. Then spend that paying extra employees proving their products performed as advertised. Nor should they test ammo in factory rifles; a given lot of ammo will shoot to different accuracy levels across all those rifles of the same model and cartridge. Ammo factories are better off using standard test barrels of match quality in rail guns to eliminate all human error as well as manufacturing tolerances across a bunch of rifles.

Ammo and rifles properly tested in free recoiling shooting systems produce better accuracy than anyone can shoot them hand holding the firearm against their shoulder. Top ranked high power match rifles folks testing their custom made rifles with "perfect" barrels in "perfect" actions shooting "perfect" match bullets from "perfect" handloads from free-recoiling machine rests have produced accuracy levels equal to or sometimes better than what those bullets do in their factory's tests. But none of those great marksmen shoot them off their shoulders that good. A rifle and ammo so tested may shoot under 2 inches for a couple dozen shots at 600 yards. Shooting that rifle and ammo slung up in prone in a match, they're lucky to keep the bullets inside a 7 inch circle. Shooting that rifle with its stock on rests from a bench held against their shoulder may shoot 5 or 6 inches at 600.

My answer to: "How do ammo companies determine accuracy standards?". . . . They decide what those in decision making places feel is adequate for the quality of their product they choose to make and sell it to retailers at a price they're willing to pay. The ammo company decides what profit they'll make from selling it to retailers/wholesalers.

 

[ReloaderFred]

When I visited the Sierra plant, it was still on Painter Ave., in Whittier, CA, before they got smart and moved to Missouri. I've been in the Nosler plant, in Bend, OR, twice in the last ten years, and visited the ballistics lab both times. In fact, I was in Bend this weekend, but at a match about 20 miles east, and didn't go to the Nosler plant, or their outlet store.

I still have samples of the bullet making process given to me during the private tour of the old Sierra plant, but Nosler doesn't give samples, period. I used to have each step of the drawing process for the jackets, and core forming process, but over the years I've given some of them away to people who were curious about the process.

Hope this helps.

Fred