Ammunition Concentricity Guage

[The Varmint Guy]

Hey Rifle Shooters:
My engineer pal at the range recommended this tool to straighten out the actual bullet alignment in the brass. Hand loaders insert bullets crocked into brass most of the time. Pistol errors don’t amount to much due to the short ranges common for pistol shoots.
However, rifle errors magnify quickly when distance is added to the mix.
When the round is inserted into the breach, without knowing the bullet is not facing straight down the lands and grooves. Thus when the bullet takes off, the point is not facing exactly straight down the barrel. The second the bullet starts to fly…it wobbles and becomes non-accurate.
This little bullet lathe finds the errors and corrects the bullet pointing in the case mouth, so it is facing perfectly straight.
My pal says that this REALLY takes a lot of the “flyers” out of the game. It adds time to the final assembly…but I got all kinds of time before the varmints get up!

Does this work for you?

http://www.midwayusa.com/viewProduct/?prod...=220200#enlarge

 

[Walkalong]

How about just loading it straight in the first place, just a thought.

 

[Afy]

IMHO my 0.0002 cents adjusted for inflation: A concentricity gauge will make absolutely no impact on your shooting unless you're routinely shooting groups in the low 0.2's and under. After which it may help.

You could also ensure that the bullet is aligned with the bore by seating it into the lands.

 

[Walkalong]

Yep.

 

[EddieNFL]

Your link sent me to Winchester brass.

I agree with Walkalong. Use a concentricity gauge to determine if you have a problem. Then determine where the problem is and eliminate it.

There is a tool that straightens out-of-round projectiles made by Bersin. I've never tried it, but I just don't feel that's the way to go.

 

[USSR]

Hand loaders insert bullets crocked into brass most of the time.

How about just loading it straight in the first place, just a thought.

+1 on that thought.

Don

 

[ranger335v]

"How about just loading it straight in the first place, just a thought."

Well, that's a sure enough good thought. But, how can any of KNOW if we have it loaded straight without a way to measure it? And it DOES make a significant difference in rigs that shoot much larger groups than those mentioned.

It's only possible to observe run out greater than maybe 6 to 8 thou but RO half that does increase group size significantly.

Match ammo should have no more than 2 thou RO and less is better. And it's HARD to obtain that with conventional (un-prepped) cases and conventional dies. NRA experiments have shown that run out exceeding about 8 thou has no effect simply because the rifle's chamber will straighten anything worse than that.

I don't care for any tool that proposes to bend a bent cartridge straigher, perfer to use the gage to learn where the RO is coming from and correct it. The Sinclair RO gage is perhaps the best, most cost effective gage I know of.

The good idea to load it straight to start with applies but it can't be done without a gage to tell us where we are and find how we got there.

 

[Afy]

One will get better results with better brass prep. Watching the trim to length, bumping shoulders, neck turning (if required), annealing etc, will yield better results.

Match ammo should and generally does have RO of 2 thousandths or less. But that has more to do with dies than the concentricity gauge.

 

[Walkalong]

Well, that's a sure enough good thought. But, how can any of KNOW if we have it loaded straight without a way to measure it? And it DOES make a significant difference in rigs that shoot much larger groups than those mentioned.

He was asking about bending them straight. I never said don't measure them. Sure measure them.

Unless they are really crooked (and 7 or 8 is really crooked), it won't matter enough to get riled about with rifles that won't shoot really well.

It is still a better idea to fix what is wrong and load them straight thanto try to bend them "straight".

Use a concentricity gauge to determine if you have a problem. Then determine where the problem is and eliminate it.

Yep.

 

[EddieNFL]

But that has more to do with dies than the concentricity gauge.

It actually has nothing to do with the concentricity gauge. All the gauge does is confirm results.

Also, the press threads and/or ram and shellholder can contribute to runout.

 

[Afy]

How could you bend a loaded round straight?

 

[EddieNFL]

The Bersin tool holds the round in a jig and measures runout. You turn the round until the dial indicator reads maximum runout. On the opposite side of the dial is a knob you turn to "push" the bullet.

Take a look at the gauge. That will probably make more sense than my explanation.

http://www.centuryarms.com/bersin.pdf

 

[Afy]

Given that it is a Grunig tool, it should be available in Europe. I will check around and see if I can get my hands on it, and shrink my .3 inch groups to .15. Where can I buy it, and for how much?

 

[EddieNFL]

Try here: http://www.vjcsupplies.co.uk/index.html

 

[Offfhand]

"Hand loaders insert bullets crocked into brass most of the time."
To begin with, I'm highly doubtful of the above quote from an earlier post. Granted, some crooked ammo does get loaded, but certainly not "most of the time. By and large most handloaders, even beginners, turn out some first class ammo with no significant runout.
Ammo "straightening" tools, such as the Hornady have been around for a long time. the first I saw was made by Brown Precision and it was a much better made tool than the Hornady. Even so, it was never popular with accuracy minded guys. (Brown was a benchrest shooter and an early manufacturer of fiberglass stocks.) There are a couple problems with the concept; First, it is difficult to demonstrate that even a moderate degree of runout degrades accuracy and, Second: that attempts to "straighten" a crooked round results in any improvement. If a round is made crooked by poor technique or tooling, "straightening" it just bends it in another direction. Which basically, is why straightening tools have never been successful or been even worthwhile. As for runout gauges, that's another matter because they can be used to identify problems with equipment and tooling. They don't cure anything, they just let you know that there may be a problem with your equipment or technique that you might need to know about. which is useful information so long as you don't get hung up on the notion that ammo needs to be dead straight to be accurate. Go to a benchrest match and watch those accuracy fanatics load their ammo between relays. You'll never see them trying to straighten their ammo or even use a runout gauge because they know their tools load straight ammo to begin with. But speaking of good concentricity gauges, attached is a -photo of a superbly accurate gauge made by Ferris Pindell, a well know accuracy buff and co-developer of the accurate 6PPC cartridge. Though it works beautifully and is a pleasure to use, I seldom use it except to check new tooling, otherwise I'm confident my equipment loads ammo that is, at least, "good enough" and doesn't need to be bent straight. And I think that goes for most other handloaders as well.

 

[Afy]

No pricing or ordering info.. have sent an enquiry lets see what comes of it.

 

[JimKirk]

The Forster press and a GOOD set of dies will come as near to loading concentric ammo as any available method other than the dies the and setups benchrest shooters use. The reason is that the die "floats" and the shellholder kinda "float", thus the brass is kept concentric. The same with the seating die, if it is a "good" die to start with, there is no non concentric forces applied to the bullet and thus the more concentric ammo.
The mis-alignment of the ram and die of other presses cause much of the problem along with poorly made dies.
There is much discussion on this board about cheaper brands of reloading equipment and how it is just as good as others, same with presses. There is a reason that one set of dies is $20 and another is $60, there is a reason one press is $30 and another $300, think about it. A Yugo will get you to the same place as Lexus, but you may have to push it part the way.

Jimmy K

 

[Afy]

The only issue I have with the Concentricity creation Bersin tool is that it might play with the neck size and whack that out of shape. In a tight neck chamber tham might be an issue or not. I do not have the experience to comment on it.
If the tool is reasonably priced, I will order it and try it out, and report back. I expect my .3's to become .15's should be fun.

Personally though given the Savage action, and LW barrel I do believe that a consisten high.2's low .3's is the limit of my shooting ability and the rifles. Though I do get the odd group in the .1's and the 1.xx's

 

[dozernomore]

all this talk about concentricity alway's get's me worried about excessive run out on my hand loads,,I do own a RCBS case master gauge and use it only to measure case and bullet run out,,I just recently shot some 55gr v-max out of my 223 with a run out of .004 and still shot a .5moa,,,and all my rifles are strictly for predator and varmint shooting..my question is(hopefully with out being accused of hijacking a thread,,just thought this was the place and time to ask,,lol ),what is maximum run out for varmint hunting??

 

[Walkalong]

At .5 MOA, you don't have a problem. Straighter is never a bad thing of course, but don't expect miracles.

 

[dozernomore]

thank's walkalong

 

[woods]

I have a Bersin and have been using it for 2 or 3 years


It is expensive! A better solution (after the suggestion that you just load them straight in the first place which is like the suggestion that if you don't lose anything then you won't have to look for it) would be the new Hornady concentricity gauge


or the H & H which I don't have a pic of.

But what you need to know is that these devices like the Bersin are an effective runout reducer. IOW if you have .002" TIR (total indicated runout which is different than runout) then you will probably be able to reduce it to 1/2 that. There are variables that effect the effectiveness of pushing the bullet to reduce runout; the neck brass hardness (once fired, 4 times fired, recently annealed, etc.), whether it is crimped or not, the amount of bullet grip (.001", .003", etc) and probably others that I haven't figured out yet. There is a learning curve to using these such as how far to move the bullet in the initial push to get the best results and when to quit chasing the runout from one side to the other. If you keep pushing it from one side to the other then you will loosen the bullet grip.

That said the Bersin has made a small improvement in my group sizes



DAMN THOSE FLYERS! (30-378 went off on the next bench at the wrong moment)

But I keep my runout to almost nonexistant anyway. Recently I loaded 50 cases of 300 win mag and sat down to use the Bersin. Only 5 of them received any push at all because the runout was too much. On those 5 the Bersin worked to reduce that within the others range and possibly prevented a flyer.

 

[dozernomore]

what do most folks think is maximum runout???

 

[woods]

If you'll notice, the Bersin dial measures 4/10,000 inch per line and if the needle varies more than 3 lines off the median (.0012" runout, .0024" total indicated runout) then I will correct it. If you have more than .015" runout then it will be noticeable by rolling across the tabletop.

The consensus is that anything over .004" runout is detrimental to accuracy. It will depend somewhat upon how long a throat you have and what degree that throat is cut at. A 1.5 degree throat taper is considered custom and will minimize accuracy problems associated with runout but you are normally dealing with tight necked chambers in a custom chamber and have to neck turn anyway, so your runout will be reduced.

 

[dozernomore]

that's the answer I was looking for,,,thanks woods !!