Correcting Concentricity

[ggibson511960]

Looking for successful experience from anyone here at correcting wobbly cartridges. I have concentricity testers to check my reloads but no solution found to straighten crooked ammunition except culling out for non-precision practice. Any success stories?

 

[rockquarry]

Looking for successful experience from anyone here at correcting wobbly cartridges. I have concentricity testers to check my reloads but no solution found to straighten crooked ammunition except culling out for non-precision practice. Any success stories?

I've never seen how you can successfully straighten ammo, though allegedy it it's possible. Rather than straighten ammo, I'd find the cause of the eccentricity and correct that. Time better spent, at least I think it would be. I use a Co-Ax for all rifle ammo and have had no problem with ammo that wasn't concentric. Whether the press has anything to do with it, I don't know.

 

[Ivan the Butcher]

Hornady make a device for spinning the cartridge and then pushing against the high side. (FN used to straighten barrels the same method.) The device is about the size of a powder scale.

I use Bonanza "Co-ax" dies (pricey!) or Redding Bench Rest Dies (Very pricey!!). both use a free floating sleave to align the bullet and cartridge axis before completely seating the bullet. I have Bonanza for 375 H&H and 264 Win Mag. I have Redding BR dies for 223, 22 BR, 22-250, 6mm PPC, 308 Win and 338 Lapua Mag.

All my Redding sizers are the Collet type so I can fit the case neck to the chamber as well as adjust the neck tension. All the above cartridges have Full Length sizing and about half have neck sizing as an option.

I use the RCBS Concentricity Guage and have never found more than .002". (I believe those were the Hornady bullets and not the seating!)

The press can be a/the problem if the ram is out of alignment. My very old 1960's RCBS Rock Chucker and 2006 Redding T-7 are fine. But one of my friends returned his Hornady L-N-L Iron press 3 times and they sent him new presses but all were out of alignment! So he went to RCBS Rock Chucker. I guess that's why they make that tool!

Ivan

 

[WR Moore]

Back when Boots Obermeyer was still making barrels, the website had a section where Boots shared some of his experience. BTW, he was a serious across the course match rifle shooter.

One story he told was about how he spent all winter loading match ammo for the next year. He was most painstaking in his process and also measured concentricity and sorted his loaded rounds into practice and match ammo.

First match of the spring he set a new state record and was bragging about how it was all due to his rigorous loading practices. Then he got home and found he'd shot the record score with the culled ammo.

 

[rockquarry]

As long as I'm getting good accuracy, I don't check concentricity at all. If I'm not getting good accuracy, the problem is almost alway something other than a concentricity problem. That would be the last thing I would check. My Sinclair concentricity gauge sometimes goes years without being used. Easily the least used tool on the bench but I've had one for about fifteen years.

 

[mattri]

Interesting topic. I just started loading 38 special and looking at loaded rounds it appears the cannelure doesn't line up with the cartridge mouth evenly. I'm new to pistol loading and imagine it has something to do with how short the 125 xtps are but open to suggestions.

 

[jem102]

For X course I always found neck tension (usually lack there of), ogive to lands distance and flat, same depth primer pockets with all three being the same or close as possible round to round had more to do with consistent accuracy than run out. Paying attention to those three gave me "round" groups with the least stringing. As to concentricity; use good dies, Redding or Forester/Bonanza Co-AX, free-float the shell holder and check neck wall thickness. If you find lopsided ones chuck them or partially neck turn them to eliminate the high side.

 

[46er]

Loading cast in a 38-40 is a problem. I'll seat the bullet in 2 stages. First stage 1/3 to 1/2 depth, then make a correction by hand/edge of bench and then seat to full depth.

 

[rockquarry]

Loading cast in a 38-40 is a problem. I'll seat the bullet in 2 stages. First stage 1/3 to 1/2 depth, then make a correction by hand/edge of bench and then seat to full depth.

I'm curious why you have to seat in two steps. That cartridge was designed for cast bullets, at least I thought it was.

 

[M29since14]

“Correcting” concentricity is a fleeting thing, in my experience. I have often corrected a few cartridges after loading and then checked them a couple weeks later only to find they were no longer “0.002” or less.”

Like the old debate of neck vs. full-length sizing, this is probably a topic that will never be fully resolved. My guess is if, after fireforming twice, the case won’t load acceptably, it’s likely best to set it aside and use it only for foulers. Annealing the case (and re-fireforming) often helps. Brass is expensive, but there are a lot of variables and the cost of bullets, powder, primers, and barrels, is not inconsiderable. JMHO.

 

[rockquarry]

“Correcting” concentricity is a fleeting thing, in my experience. I have often corrected a few cartridges after loading and then checked them a couple weeks later only to find they were no longer “0.002” or less.”

Like the old debate of neck vs. full-length sizing, this is probably a topic that will never be fully resolved. My guess is if, after fireforming twice, the case won’t load acceptably, it’s likely best to set it aside and use it only for foulers. Annealing the case (and re-fireforming) often helps. Brass is expensive, but there are a lot of variables and the cost of bullets, powder, primers, and barrels, is not inconsiderable. JMHO.

Again, let your group sizes tell you if there is something wrong with your components, load, dies, rifle, or you. Shoot enough groups to provide meaningful information. Don't let gadgetry lead you astray.

 

[BB57]

It depends on where the problem is at.

I used Whidden floating tool heads so the case itself is concentric. Any wobble is in terms of a bullet being seating slightly off line.

That can be corrected using the thumbscrew that comes on tools like the Hornady Concentricity tool.

I will add the caveat that I rarely see anything out more than .0025” and correct the few that are out by more than .0014”, so the correction is pretty minor.

 

[46er]

I'm curious why you have to seat in two steps. That cartridge was designed for cast bullets, at least I thought it was.

It has a short neck with very thin brass and I found that it has a tendency to go crooked. I've only reloaded with cast and have shot very few factory jacketed. Winchester Hiwall ca. 1888.

 

[yeti]

I know this will rile up the FCD fans, but here goes...
I have had reasonable success getting my 2% abnormalities down to only a couple per several hundred using (gasp) a LEE FCD.
It is not always a work around since it can rectify ovalized or imperfect cases DURING a properly set up process. Every now and then things can go a little kittywampus even with the best setups. The carbide ring at the bottom is larger than a standard resizing die. Make sure you set the FCD up correctly and that the bullets you selected* aren't being resized.

* If you have a barrel that requires seriously oversized lead/coated lead bullets, the FCD is not going to be a viable option.

 

[zeke]

Am gonna guess the op is talking rife cartridges, but could easily be wrong. Have found it easier to increase concentricity through reloading steps, rather than to correct an assembled round. Squaring your resizing die, not using a draw through neck expander and a Redding comp seater may go a long way to increasing concentricity.

Am also agreeing with yeti for pistol rounds.

 

[mtgianni]

Am gonna guess the op is talking rife cartridges, but could easily be wrong. Have found it easier to increase concentricity through reloading steps, rather than to correct an assembled round. Squaring your resizing die, not using a draw through neck expander and a Redding comp seater may go a long way to increasing concentricity.

Am also agreeing with yeti for pistol rounds.

The time to correct concentricity is during the loading process. If that means checking ammo during the process before completing the batch, then that has to be done. Be careful with the sixing process especially on the return stroke of the press. Long cast bullets can get out of balance without careful sizing and so can cases.

 

[Alk8944]

Looking for successful experience from anyone here at correcting wobbly cartridges. I have concentricity testers to check my reloads but no solution found to straighten crooked ammunition except culling out for non-precision practice. Any success stories?

What are you using the ammunition for? If bench rest and you are looking for sub-1/8" center-to-center groups then concentricity may be an issue. If it is a hunting rifle for large game under 300 yards then concentricity isn't an issue they will shoot well enough!

How eccentric are your loads? Or have you actually checked them? What group sizes are you getting? Are they good enough for the purpose the ammunition will be used for! If so you would be wasting your time worrying about concentricity.