I never stop learning----This weeks lesson herein

Bang4theBuck

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As the title suggests, there is something new to be learned all the time with reloading, and this week was no different. I picked up a couple of rifles and some other goodies at the local gun club swap meet, and as would be the norm for me, I was anxious to put scope on the rifles and see what they were capable of. The two rifles were very different from one another. One was a Browning A-bolt Medallion in 30-06, and the other was a custom action with aftermarket barrel and trigger in 6MM Dasher.
I've got quite a bit of experience with the 6mm Dasher and already had good dies for it, so it was no surprise that it shot lights out (.114" @100 yds) with my first loading.
The Browning on the other hand did not shoot all that well (1.5" groups at 100). I wasn't too tore up about it at the time, as it was just a generic load with a small range of powder charges. Factory brass, completely prepped, including annealing. I reached pressure in my first round of reloads, and was not able to shoot 2 of the highest charges. I brought them home to be disassembled.
Another item I picked up at the show was a concentricity gauge with a dial on it. For giggles, I have been taking random samplings of my brass after it has been through the dies, looking at runout on the necks. I have also checked runout at the ogive, and near the tip of the bullet. In many cases, the runout is really good, and ironically, these are the rifles/loads that produce excellent repeatable accuracy.
Last night, I just happened to check those 30-06 rounds. Both the fired ones and the unfired ones. The fired cases had very good runout at the necks (.001 to .0015") however, the unfired rounds had HUGE runout. I'm talking like .015" or more in some cases. The runout near the bullet tip was almost .030" in some cases.
I deducted from these checks that the ammo I loaded was not concentric, but the chamber was concentric, so the process of firing was 'correcting' the error that the die was imparting on the brass......CRAZY!!!!! I had two different sets of (albeit cheap) dies, and both imparted runout as compared to a newly fired cases.
I'm now a few fathoms down a rabbit hole going through the ammo and fired cases from the 40+ different cartridges that I load for. I am feeling some new dies in my future.
I won't disclose which dies produced the crooked ammo, as there were a few, and it was not consistently bad by any one manufacturer, or price point. I will say, on the positive side, every one I've checked so far with Forster Full Length Bench rest dies (not bushing) have been spot on.
"if you or any of your friends are looking for a new rabbit hole, maybe pick up a concentricity gauge and measure your results" just beware of the answers that you might get.
 
Just what I need.... another one... 🤣
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As the title suggests, there is something new to be learned all the time with reloading, and this week was no different. I picked up a couple of rifles and some other goodies at the local gun club swap meet, and as would be the norm for me, I was anxious to put scope on the rifles and see what they were capable of. The two rifles were very different from one another. One was a Browning A-bolt Medallion in 30-06, and the other was a custom action with aftermarket barrel and trigger in 6MM Dasher.
I've got quite a bit of experience with the 6mm Dasher and already had good dies for it, so it was no surprise that it shot lights out (.114" @100 yds) with my first loading.
The Browning on the other hand did not shoot all that well (1.5" groups at 100). I wasn't too tore up about it at the time, as it was just a generic load with a small range of powder charges. Factory brass, completely prepped, including annealing. I reached pressure in my first round of reloads, and was not able to shoot 2 of the highest charges. I brought them home to be disassembled.
Another item I picked up at the show was a concentricity gauge with a dial on it. For giggles, I have been taking random samplings of my brass after it has been through the dies, looking at runout on the necks. I have also checked runout at the ogive, and near the tip of the bullet. In many cases, the runout is really good, and ironically, these are the rifles/loads that produce excellent repeatable accuracy.
Last night, I just happened to check those 30-06 rounds. Both the fired ones and the unfired ones. The fired cases had very good runout at the necks (.001 to .0015") however, the unfired rounds had HUGE runout. I'm talking like .015" or more in some cases. The runout near the bullet tip was almost .030" in some cases.
I deducted from these checks that the ammo I loaded was not concentric, but the chamber was concentric, so the process of firing was 'correcting' the error that the die was imparting on the brass......CRAZY!!!!! I had two different sets of (albeit cheap) dies, and both imparted runout as compared to a newly fired cases.
I'm now a few fathoms down a rabbit hole going through the ammo and fired cases from the 40+ different cartridges that I load for. I am feeling some new dies in my future.
I won't disclose which dies produced the crooked ammo, as there were a few, and it was not consistently bad by any one manufacturer, or price point. I will say, on the positive side, every one I've checked so far with Forster Full Length Bench rest dies (not bushing) have been spot on.
"if you or any of your friends are looking for a new rabbit hole, maybe pick up a concentricity gauge and measure your results" just beware of the answers that you might get.
This is good information! Thank you
 
So, last night, I took the fired brass that was very concentric and played around with ways to size the brass that don't impart runout. Initial finding are that if I pull the sizing plug back through the necks slowly, and or with lube on the inside of the case, there is quite a bit less runout. I was able to build some very straight ammo (12 trial rounds). I am going to try to find some time to go shoot them and see how much improvement there is.
Unfortunately, I kinda jacked up my test set as I decoded not to burn anymore of my favorite Hammer bullets until I got the reloading problem solved. So, I am going back to the range with a 165 Sierra Game King loaded over Varget. Instead of Hammers loaded over H4350. I suppose straighter ammo can't hurt in either case, but I won't be able to make a direct correlation.
 
When I got my concentricity gauge I measured some .300 win mag loads that I just finished. The worst one was .002" runout while most were less. I thought that I wasted money on the gauge or it did not work. For the next hour or more I was digging out boxes of reloads and some old factory loads from 20 years ago. The gauge worked just fine. I found that rotating the shell three times while seating the bullet helped. I also found one set of .308 dies just needed to be replaced.
 
Very interesting video. Obviously, not the be all/end all, but meaningful, for sure. One thing that comes to mind about this test and what might skew the result is the amount of jump you loads are built to. This guy (F-Class John) is a highly respected world class shooter. looking at these loads, the bullets are seated way long, and likely very close to the lands, meaning that the bullet is being 'straigntened or aligned' with the bore to some degree by simply chambering it. In a load like mine where I have a chamber that is long, and a bullet that is 'jumping' .100-.120" I can see where a misalignment could cause heavier engraving pressure and maybe initial engraving deeper on one side than the other. It's all theory that may not play out as expected in real world tests. Also curious if a softer cup and core bullet would react differently than a mono....

One thing that might have been interesting in this video is if he removed the chambered round from the chamber after being 'chamber corrected' and note just how much the action of chambering reduced the run-out. I am WAAAAAYYY out in the weeds now, I know, but it has me very curious.
 
It sounds like you're tensioning the cases on the upstroke out of the die. Maybe the cases are too thin? Weigh some cases against some "stout and well cleaned" cases ...like the military brass I use for 30-06. See if your cases weigh less. Measure the neck thickness as well. Could be the neck is thin, or it could be the case wall or the shoulder taper are thin, and they can't easily be measured. That's why I'd weigh them. I always lube the outside of the walls and the inside of the neck for easy full length sizing. Then I run them through an ultrasonic bath to make sure all the crud and lube is removed before priming, powder dump and seating. Do a concentricity check before you dump the powder to see if the cases are concentric. Dump the powder, and seat some bullets. Then do a final concentricity check. Sometimes seating causes bent cases if they're too thin.

Your post made it sound like you have multiple 30-06 sizing dies. If so, that's another variable to isolate. If you're straight on one mfgr's die and crooked on another it well could be the die....or it could be that the "good die" isn't sizing the cases enough. If they all chamber easily in all your rifles with all of the dies, but one of them yields un-concentric cartridges, then I'd toss the offending die(s), and keep the good one.

Good luck, and let us know how this goes. I bet you pop up from that hole in a new and greener patch of clover!
 
looking at these loads, the bullets are seated way long, and likely very close to the lands, meaning that the bullet is being 'straigntened or aligned' with the bore to some degree by simply chambering it. In a load like mine where I have a chamber that is long, and a bullet that is 'jumping' .100-.120" I can see where a misalignment could cause heavier engraving pressure and maybe initial engraving deeper on one side than the other. It's all theory that may not play out as expected in real world tests.

Jump is jump, being closer to the lands doesn't "straighten" anything. By the time a bullet travels down a 20"-32" barrel, say at 55k-65k pressure how would you know which side had the most engraving pressure?

Runout certainly isn't desirable but it's waaay down the list when it comes to making a rifle shoot small.
 

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