Hornady Concentricity Gauge

[Carlos Hathcock]

So my friend turned me on to this little tip, as I go deeper down the shooting rabbit hole. I'm sure many of you are aware of this but for those who aren't....



Allows for check (and correction) of bullets seated a little less than centered. In my first box of Hornady 6mm "Match" ammo I found most measuring between .004" and .006" out of center. The rest were between .002" and .004". With little practice I'm able to get them all within .002".

This variance might not matter to most but I'm just tossing it out there. I'm going to check some other ammo to see what comes up. Bought as part of a larger reloading set on Amazon but alone these can be had for around $100ish.

 

[Deplorable Me]

Firearm Reloading Equipment, Supplies, and Tools - Sinclair Intl

If you like this level of shooting precision get a hold of a catalog from Sinclair International. They of put everyone's gear into one catalog for comparison. Lots of good product descriptions to help you spend your money to get the most bang for the buck.

My Win 70 .308 has seen a vast improvement in groups since I started truing up the necks on my cases. Flash hole deburring was a good investment too.

 

[Acer-m14]

I have seen it , not for me yet .. my friends won't let me shoot down the 8 mile shooting lane here .. something to do with railroad tracks ..

 

[Mosinitis]

I have Sinclair tool that measures the run out. I am only using it to set up my sizing dies for minimum neck run out and check it once in a while. Waste of time for AR's and other semi's with generous chambers. You have to be very skilled bolt gun shooter to see any benefit. I mean bench rest competition level.
I get 0.000"-0.002" run out with an occasional case over that just by setting up my sizing dies to minimize run out.

 

[Carlos Hathcock]

I ended up doing about 4 boxes. Learned that not all can be corrected while others seem quite cooperative. I'd say the majority end up around .003 with a few at .005-.006 and and the rest .001-.002. Learning how much pressure to apply is obviously going to take some practice.

Decided to separate and mark the boxes to see if there's a noticeable difference when I get around to shooting.

 

[meketrefe]

two or 3 thou is nothing.
One thing that will help you is to have a custom seater for specific bullets. The self centering ones do not always work as
advertise so the best is to have the button honed to the shape of the bullet so there are at least two good contact points
and they are smooth and well polished so the bullet will self center the best it can.
I am lucky to make my own because I have a metal lathe that is quite precise to 1/2 of a thousand.
Needless to say, for precision reloading all other setup including the press has to be of decent quality.
I am reloading match with a big boss II from redding and redding or rcbs match dies.
everything is important starting with the brass.

 

[Mosinitis]

Forster Competition Adjustable Seating die works very well to minimize run out. It will also work with compressed loads unlike similar die from Redding.

 

[Carlos Hathcock]

I was sort of thinking about this as well. With these newer calibers like 6mm and 6.5mm so much of the bullet remains in front if the case. Am I wrong to think run out could be more of an issue for these types of bullets vs those seated deeper in the case?

 

[Mosinitis]

I was sort of thinking about this as well. With these newer calibers like 6mm and 6.5mm so much of the bullet remains in front if the case. Am I wrong to think run out could be more of an issue for these types of bullets vs those seated deeper in the case?

It doesn't matter as long as all of the neck is in contact with the bullet. The biggest advantage of the above die is you can adjust seating depth to chase the throat of the barrel. The throat keeps eroding as the rounds are fired. How much does chasing the throat helps is up for debate, but this is a popular accuracy narrative. In my experience with .223 the best seating depth was 0.025"-0.035" off the lands. A lot depends on what bullets you shoot, thickness of the jacket and so on. Some bullets shoot better when seated off the lands, some shoot better when seated into the lands.

 

[Acer-m14]

A lot depends on what bullets you shoot, thickness of the jacket and so on. Some bullets shoot better when seated off the lands, some shoot better when seated into the lands.

then you get a different LOT# of projectiles and your back to square 1 .. correct ? ..

 

[Carlos Hathcock]

I went through about 6 boxes at the kitchen table this morning. On average they seemed better than the 4 or so boxes I first checked. After some practice I can really get finished rounds down to no more than .003 run out. Majority are ending up .001-.002. I'm fine with that.

 

[tony]

I've never felt the need to check run out. I suppose the type of competitive rifle shooting I engaged in (200 yds. w/iron sights) did not require that degree of precision. I did weigh every charge. One thing I did do though when seating the bullet was seat it about half way, back the cartridge out of the die, turn the cartridge 90* and finish seating. Did it do anything? To be honest, I don't know... I thought, it can't hurt.

I do have a question for those who do check and straighten runout. When you push where ever you push to eliminate run out are you changing the neck tension on the bullet? You ARE stretching the already sized neck by pushing sideways. Something has to be moving... Tell me your thoughts

 

[Mosinitis]

I try to minimize run out when the round is assembled. I don't know if it helps, but it definitely doesn't hurt. The only extra time and effort was put in when setting up dies years ago. I don't think nudging the bullet to the center with the above device is an improvement. You don't know what you are disturbing to get that small to none benefit. Just my thoughts.

 

[Mosinitis]

Just for the sake of discussion I read in on of the forums an opinion from very old old-timer who worked for the government researching this and other ammo accuracy related matters. He said run out doesn't make any difference, because the force from firing pin will push the round forward and it will center up before going off.

 

[tony]

Pertaining to the old timers theory. Sound possible although it seems like a lot to happen in a very small amount of time. Having a rifle with a spring loaded ejector (like a Rem bolt action) addresses this as soon as you close the bolt provided there is clearance at the extractor.

As far as the Sinclair inspection tool is concerned. If your cases are not round whatever out of round condition you have will show up on the indicator as you are gageing from that out of round surface. IMO to get a true reading of projectile runout you would first have to gage and mark (high or low spot) on the case then read projectile runout in comparison to case runout.

 

[Robin]

Just for the sake of discussion I read in on of the forums an opinion from very old old-timer who worked for the government researching this and other ammo accuracy related matters. He said run out doesn't make any difference, because the force from firing pin will push the round forward and it will center up before going off.

Phew, dodged that bullet.
Robin

 

[meketrefe]

Just for the sake of discussion I read in on of the forums an opinion from very old old-timer who worked for the government researching this and other ammo accuracy related matters. He said run out doesn't make any difference, because the force from firing pin will push the round forward and it will center up before going off.

I would not be surprised. I think small differences are not going to screw anything up.
All my life I heard freebore would screw up accuracy and as it turns out today you have new research barrels coming out with only 1/2 of the barrel
rifled and in the air guns some are already in the market with amazing accuracy. It makes sense because one gets more speed w/o that initial
peak pressure and the projectile self aligns naturally before is being swagged by the rifling itself. In this scenario the lands have a much smoother angle
and rifle will last much longer.
Again this might not be the ideal with certain type of bullets or projectiles like those with tangent ogives but it could work fine with so many others.

Even some rifled chokes for smooth bore shotguns is amazing what 2 or 3 inches of shallow rifling does for the consistency of an otherwise average slug.

 

[Carlos Hathcock]

Just for the sake of discussion I read in on of the forums an opinion from very old old-timer who worked for the government researching this and other ammo accuracy related matters. He said run out doesn't make any difference, because the force from firing pin will push the round forward and it will center up before going off.

From an "armchair physicists" standpoint, I'm going to disagree. I picture a football thrown with a poor spiral. If it has a nice tight spiral it's going to fly better. If the bullet is seated cocked, it would be introduced to the lands with the tip of center and would have a slight wobble, albeit very small. I dont see the firing pin "moving" anything as the cartridge is seated in the breach. My goal is to align the cartridge along the center axis of the case from base of case to tip of projectile.

 

[meketrefe]

From an "armchair physicists" standpoint, I'm going to disagree. I picture a football thrown with a poor spiral. If it has a nice tight spiral it's going to fly better. If the bullet is seated cocked, it would be introduced to the lands with the tip of center and would have a slight wobble, albeit very small. I dont see the firing pin "moving" anything as the cartridge is seated in the breach. My goal is to align the cartridge along the center axis of the case from base of case to tip of projectile.

This is the thing...the free-bore might be slightly larger or smaller diameter than what it should be but a bullet cannot be a lot smaller or larger than the
actual bore size (1/2 thousands difference if any) so regardless of a minute run out the body of the bullet will have to conform to that bore
and the only way is by going straight that happens naturally. just like any cylinder traveling on a bore is going to be pretty precise and easy to seal.

If small run out was a huge concern factory ammunition with some run-out would not produce amazing accuracy and consistence but
in fact they do produce that accuracy and consistency like federal gold dot, out of the box black hills (used by elite snipers), lapua match ammo,
and so many others.

With all that said I don't think it is a bad idea to measure things at different stages to come up with the best consistency one can possibly and
reasonably achieve based on the objectives one has.

 

[Shoots100]

I have Sinclair tool that measures the run out. I am only using it to set up my sizing dies for minimum neck run out and check it once in a while. Waste of time for AR's and other semi's with generous chambers. You have to be very skilled bolt gun shooter to see any benefit. I mean bench rest competition level.
I get 0.000"-0.002" run out with an occasional case over that just by setting up my sizing dies to minimize run out.

Agree 100%.
Been shooting long range comps for a long time.
There are rifles that benefit from the extra steps and equipment used in the reloading process and some that don't.
Most long range shooters don't need to deal with a lot of the tools and products that were needed to load "Super Accurate" rounds nowadays, because their super expensive rifles are usually chambered for borerider projos, which are very forgiving.
The weekend warrior shooter would be better off buying more reloading components and getting more trigger time, instead of worrying about 1 or 2 thousandths run out.
SJC