Concentricity-What is "Good Enough" for Safari Ammo

[Doug3006]

Sadly, most of us these days don’t have the opportunities to shoot that previous generations had. Urbanization has made it a chore to simply find a place to shoot. My range is a 30 minute drive. On the plus side, it’s a club range, not a public one. So, I usually have the place to myself. I can get a lot of shooting done in a short time, without the endless cease fires…which the range masters use to holler at people who can’t follow directions. I also made quite a few trips out west to shoot the dog towns. I can’t imagine better practice than shooting 8 inch tall prairie dogs at 400 yards…and more….in the stiff winds of Montana and Wyoming. we used to just show up in Douglas WY and shoot public land, or ask ranchers for permission….which they gladly gave. Now, the public lands are off limits thanks to the Black Footed Ferret restoration programs, and ranchers are leasing their land to outfitters, who have jacked up the price of admission.

 

[Shootist43]

I freely admit that I might be going overboard here, but when I take my handloads to Africa, I want them to be the most accurate that I can make them. I use an electric powder dispenser that reliably drops H 4350 within three kernels plus or minus the desired amount. In addition, I weigh every 5th charge on a digital scale. My completed rounds are run through a Hornady Concentricity Gage. Anything over .0025" out of round gets tweaked. Being a Bullseye shooter, 10 shot groups determine the accuracy of a firearm and its' ammunition. When you get 8 or 9 good shots and a flier or two, it is generally because the fliers weren't concentric. I want errant shots to my fault and mine alone. Maybe not necessary, but that's what floats my boat.

 

[Red Leg]

I have hunted a great deal across a number of different time zones over the last fifty years. Other than it relevance to artillery firing at 20+ kilometers or so, I can barely understand the intent of the OP’s post. Nothing shot in Africa at a range a competent PH will condone, will be affected by the concentricity of what killed it.

 

[uplander01]

I have hunted a great deal across a number of different time zones over the last fifty years. Other than it relevance to artillery firing at 20+ kilometers or so, I can barely understand the intent of the OP’s post. Nothing shot in Africa at a range a competent PH will condone, will be affected by the concentricity of what killed it.

Red leg—couldn’t agree more, I am not a long range hunter nowadays. The thread was simply started to get feedback from other hand loaders as to how they view this variable. I personally feel that on big game rifles you could drop powder from a manual powder drop within a few grains, jam the bullet in there, crimp it and go do some killing.

 

[PARA45]

I don't believe it is necessary for our hunting rifles, and our hunting applications. Now, if we are talking competition, and using customs rifles, then that's a different story.

When I went to Africa the first time, I reloaded for my 300 Weatherby, and sorted out the brass by weight, reamed the primer pockets, and I also weighted the bullets and sorted them out to the nearest .01 grains. I powder charge was checked on two different scales. This load was amazingly accurate on my rifle, my SD was in the single digits. Was all that work necessary? Probably not. Did the animal notice the difference? Probably not. But I felt good about it. LOL!!!

 

[fourfive8]

Yes, you have to use any tool consistently and be able to objectively assess results. A dedicated runout gauge will give absolute numbers but the measurements have to taken using close to the same setup parameters each time cartridges are checked. If I check a cartridge and the neck runout is 10-15 thous I can pretty much be assured that cartridge has quite a lot of runout... no matter how I set up the gauge as long as three parameters are set up fairly consistently- indexing stop, contact point on upper body and contact point on neck. One time it may show 8 thous and the next time 17 thous. Matters little other than showing there is runout that is on the high side. Not a thing the gauge can do about runout anyway For target ammo runout the generally acceptable limit of neck runout is about .002". For hunting ammo I don't pay a lot of attention to the runout but if my groups on paper are not acceptable, then checking for and correcting runout could be be needed. IIRC, of all the various hunting ammo I load, a runout of about .006" or less seems normal. If there is excessive runout, then the loading techniques are suspect and a correction needs to be made. Also, sans any dedicated gauge, you can visually check for excessive runout by rolling a loaded cartridge across a smooth surface like a pane of glass or mirror and observing the wobble of the bullet's nose.

pic of tool I use for checking runout (concentricity)

 

[R.M.C.]

Dang it lol I thought when I came home to relax I wouldn't be reading about concentricity. I'm a machinist so run out and concentricity comes up a lot, I hate it lol. In my opinion you're not going to see any difference in real hunting situations messing with concentricity.

 

[steve white]

I would probably only go overboard on accuracy if I were going after a crocodile.

 

[Inline6]

Dang it lol I thought when I came home to relax I wouldn't be reading about concentricity. I'm a machinist so run out and concentricity comes up a lot, I hate it lol. In my opinion you're not going to see any difference in real hunting situations messing with concentricity.

It's funny you should say that. I check runout on my barrels when chambering them. I don’t check my ammo, never have. Have hit targets at over a mile. If I'm hitting 2" targets at 600 yards, until I get to the point I can't do that constantly. I guess I'll keep doing what I have been.

 

[R.M.C.]

It's funny you should say that. I check runout on my barrels when chambering them. I don’t check my ammo, never have. Have hit targets at over a mile. If I'm hitting 2" targets at 600 yards, until I get to the point I can't do that constantly. I guess I'll keep doing what I have been.

Now checking run out in a barrel makes perfect sense to me, ammo not so much. Especially shooting those kinda ranges.

 

[baxterb]

I never thought about concentricity with my reloads until my brother brought it up. He’s a gnats-ass detail guy etc etc. I just reload using an old RCBS press and am quite happy with my rifles shooting an inch or so.

he brought over his gauge so we could test my rounds since he thought I could probably get some more accuracy out of them.

he set up the gauge and ran a dozen or so random rounds through it. The needle didn’t move.

that put paid to me ever worrying about it ever again.

 

[Doug3006]

I’ve experimented with concentricity when loading. Based on my results, I think reducing the amount of run out makes a difference. In my varmint caliber loads, I’ve seen about 1/4 inch reduction in group sizes at 100 yds. This was with 22-250 Remington and .223 Remington cartridges. I also measured factory loads in these calibers and corrected any run out. I saw the same improvement of about a quarter of an inch in group size. So, I’m a believer. However I wouldn’t waste any time doing the same with any Africa game caliber. Just not worth the effort.

 

[Firebird]

Reading this all. I was reminded of my deceased friend/boss Bill. He was a master fly fisherman and tied his own. Each fly painstakingly crafted and flawless.
When we went fishing he spent a lot of time sitting and correcting my “horsewhipping.” Once I asked him why he didn’t actually tie on a fly and get it wet.
“Too pretty, too perfect, would hate to ruin it!”

 

[Inline6]

I’ve experimented with concentricity when loading. Based on my results, I think reducing the amount of run out makes a difference. In my varmint caliber loads, I’ve seen about 1/4 inch reduction in group sizes at 100 yds. This was with 22-250 Remington and .223 Remington cartridges. I also measured factory loads in these calibers and corrected any run out. I saw the same improvement of about a quarter of an inch in group size. So, I’m a believer. However I wouldn’t waste any time doing the same with any Africa game caliber. Just not worth the effort.

This is the part that is confusing to me. My comp rifles shoot under a .25MOA when I'm on when I'm really on it will shoot in the teens with an occasional group in the .00X. This is not often, it does happen. I don't own a tool to measure concentricity of my ammo. I load and shoot. I'm very analytical in all other aspects to keep my SDs as low as possible. Hell my charge weight is within .02gr one way or the other. My SDs on my match ammo is usually @ or below 5fps (depending on how good of a pipe I have).

 

[CoElkHunter]

Not far enough down the rabbit hole. For an even powder burn, you really need to check the water capacity of each case and weigh the primers. View attachment 534037

And check the humidity in the reloading room along with the phases of the moon. Full moon phase with the more gravity pull will affect your reloading outcome. LOL

 

[CBH Australia]

I have wondered how much concentricity of ammo matters.

I have seen it on you tube and I like my hunting rifles to be accurate. Ideally an accurate rifle on the bench will compensate for a little human error in the field.

I wonder how much concentricity matters when the bullet is going to be chambered and fired in a chamber that should be concentric to the bore.

How much does this matter once the shot is fired and travels through the barrel and leaves the crown. If the chamber barrel and crown are poor the cartridge concentricity is probably irrelevant. Not saying it doesn't matter but how much can we gain measuring runout in a half decent hunting rifle.

I have 2 hunting rifles that I have shot groups under 1/2" with. I put a lot of that down to the gunsmith who rebarrelled these rifles for me. I've seen him setup up to machine a barrel and with a little knowledge I can see he is meticulous in his work.

The .280a.i he set up for me printed a great group with Woodleigh PPSP projectiles, not even a Wizz bang high BC or Ballistic Tip variety. I think a lot of it is in the rifle. I think my rifles could all do better in better hands so I haven't gone down the concentricity rabbit hole. I left that step to the gunsmith.

I might venture into concentricity and neck turning when I learn some more long range skills.

 

[WAB]

This is the part that is confusing to me. My comp rifles shoot under a .25MOA when I'm on when I'm really on it will shoot in the teens with an occasional group in the .00X. This is not often, it does happen. I don't own a tool to measure concentricity of my ammo. I load and shoot. I'm very analytical in all other aspects to keep my SDs as low as possible. Hell my charge weight is within .02gr one way or the other. My SDs on my match ammo is usually @ or below 5fps (depending on how good of a pipe I have).

I have similar experience. I have some very accurate rifles, some in the same zip code as what you are experiencing. I have been reloading for ~45 years and have never owned a tool to check concentricity. I’m not saying the results are not correct, or that it is not a good idea, as I have no experience to do so. However, I am getting some pretty good results without.

 

[steve white]

And check the humidity in the reloading room along with the phases of the moon. Full moon phase with the more gravity pull will affect your reloading outcome. LOL

Don't forget plastic bags near balance scales throwing off charges, lol
BTW, moon phases affect potato spoilage if not adhered to in terms of harvest times, and sometimes a hole will not hold the dirt that came out of it, while other times it doesn't seem to be enough to fill it.

 

[CoElkHunter]

Don't forget plastic bags near balance scales throwing off charges, lol
BTW, moon phases affect potato spoilage if not adhered to in terms of harvest times, and sometimes a hole will not hold the dirt that came out of it, while other times it doesn't seem to be enough to fill it.

Yeah, the plastic bags can create static electricity which could ignite the powder and blow a reloader up? My wife's long arm quilting machine in the basement is close to my reloading "space", so I've told her she can't quilt anything when I'm reloading. She basically told me to F*** OFF! Plan B on the horizon. LOL

 

[Doug3006]

This is the part that is confusing to me. My comp rifles shoot under a .25MOA when I'm on when I'm really on it will shoot in the teens with an occasional group in the .00X. This is not often, it does happen. I don't own a tool to measure concentricity of my ammo. I load and shoot. I'm very analytical in all other aspects to keep my SDs as low as possible. Hell my charge weight is within .02gr one way or the other. My SDs on my match ammo is usually @ or below 5fps (depending on how good of a pipe I have).

Then you don’t need to even worry about it! My guess is that your dies are already producing virtually concentric rounds (perfect concentricity is not possible) so you can ignore that factor.