I have .004 neck clearance between loaded ammo and fired necks. Brass gets sized less than .001 from the case head. And shoulders get blown forward 0.002, this is a good chamber. I'm not sure what you mean by high runout when the average of 32 loaded rounds is .002.
Sinclair Expander Mandrel Die Test
- Thread starter Jud96
- Start date
-
- Tags
- reloading precision
Help Support Long Range Hunting Forum
Savage 12BVSS
Well-Known Member
Mikecr
Well-Known Member
When you pull cases smoking from the chamber they should have less than 1thou TIR
Your ammo is up to 6thou TIR. That's very high, and you see that the cause of it is not expansion method.
When you get your loaded ammo down to actual 2thou TIR, then you may see expansion method reduce it to <1thou -if that runout is born in the necks (instead of body).
But with turned necks, your runout is likely coming from sizing of case bodies.
Out of curiosity, have you measured thickness variance with these?
Your ammo is up to 6thou TIR. That's very high, and you see that the cause of it is not expansion method.
When you get your loaded ammo down to actual 2thou TIR, then you may see expansion method reduce it to <1thou -if that runout is born in the necks (instead of body).
But with turned necks, your runout is likely coming from sizing of case bodies.
Out of curiosity, have you measured thickness variance with these?
I had one round from each group with .006 TIR. You nor I are good enough shooters in field conditions to know what round out of the mix had .002 or .006 runout. My runout is most likely from my seating die. This is a $35 set of dies. But I find an average of 0.002 runout on my loaded ammo to be acceptable. My fired case necks and sized case necks have 0.0005 or less runout. I would be interested to see what 32 of your loaded rounds measure for runout. I didn't pick and choose the best or worse, this is straight what I loaded and measured. If I had a set of $300 dies I don't think I would be able to tell on target a vast improvement. My standard method of using the standard sizing die has already delivered sub 1/2 MOA groups from my 10lb scoped hunting rifle. I can't ask for much more.
Last edited:
Don't know what brand of brass yours is, but you can get oddball pieces in many lots of brass. If you look at your total sample of brass I believe only 2 were outside the norm. Most of your TIR was quite acceptable - actually pretty darn good. When I get irregular pieces of brass I relegate them to the "fouler" round baggie and label them as such.
When I used to shoot p dogs, I loaded hundreds of rounds in preparation for a trip. While shooting I cleaned the rifle and let it cool every 25 rods or so and shot another rifle. Before shooting the clean barrel I fired a fouler. Junk cartridges do fine for this.
When I used to shoot p dogs, I loaded hundreds of rounds in preparation for a trip. While shooting I cleaned the rifle and let it cool every 25 rods or so and shot another rifle. Before shooting the clean barrel I fired a fouler. Junk cartridges do fine for this.
Barrelnut
Well-Known Member
Is this also the runout after expanding with the mandrel before seating bullet? If so, this would indicate that most of the runout is caused during the seating process.
Would be interesting to see if the .006 TIR cases repeated had high runout after being sized again. Like GLTaylor said above would then be time to move them to the fouler pile.
This is Peterson brass. This is some of the best brass I've ever used. I have 5-6 firings in most of it and it's as tight now as it was when it was new. Excellent brass and I'm not shooting a squib load either. They're also 45 mins from my house, so if they make it for any cartridge I shoot I buy it.
Yes this is after sizing. I will admit, I only measured a handful for runout that were fired and then sized. I think most of my runout is from seating.
Welllll, it's time for more testing. I'm sure you'll get to the bottom of it. Never used Peterson brass, but it has a good reputation. If it's any consolation, I've had oddball pieces of Lapua that slipped through the cracks!
Mikecr
Well-Known Member
I'm not trying to hurt your feelings about results.
Where I'm going with this is that you can't see improved variance from one action(expansion) -while the variance is caused by different action(seating).
I did not know earlier that you had determined seating in particular as your cause of runout. That would be my last guess, as it's unusual with turned necks.
Where expansion method makes a bigger runout difference is with presence of thickness variance in necks (new necks)
Where I'm going with this is that you can't see improved variance from one action(expansion) -while the variance is caused by different action(seating).
I did not know earlier that you had determined seating in particular as your cause of runout. That would be my last guess, as it's unusual with turned necks.
Where expansion method makes a bigger runout difference is with presence of thickness variance in necks (new necks)
My feelings aren't hurt lol. My point of the test was to see if there was any difference between the two methods of sizing the necks. I have seen many comments and posts in the past claiming mandrel sizing reduced runout and how bad a button is for runout. So this was the purpose of my test. As shown, neither sizing method was significantly better than the other. I hear more about seating dies and bullet seating technique causing runout way more than I do about sizing and chambers causing it. Seating in my opinion causes the most runout, that's when the bullet is aligned with the brass so that would be when the biggest misalignment would occur. That is why many reloaders advise seating your bullet a little, then rotating your cartridge once or twice before fully seating the bullet. I rotate my case after seating the bullet halfway and then seat it fully. I've never personally tested if this makes a difference. But that's how my Dad, very accomplished reloader and past competitor, taught me. David Tubb also taught this method in his old reloading videos with Sierra. Many accomplished reloaders and shooters have also talked of doing this. If seating didn't cause the most runout, then why bother with these techniques or dies with floating seaters and bullet guides.
You are correct. Mandrells make the most difference when someone doesn't neck turn for consistent neck thickness and tension.
For consistency in seating a bullet, arguably the best method is a Wilson in line seater ( or other) in which the "chamber" of the bullet seating die was cut with the same reamer that your rifle chamber was. This helps perfectly align the case prior to seating the bullet. Absent that, most good/better seaters allow for some movement in Hope's the bullet will center itself in the case neck. In these cases, rotating the cartridge can help to some degree while seating.
The only drawback (if you consider it one), is you have to use an arbor press to seat your bullets using an in-line seater. I have used in-line seaters for all my rifles for years. It is a carry over from my years shooting benchrest. Runout in all my cartridges runs .0005 to .001
Guess it depends on how important concentricity is to you?
For consistency in seating a bullet, arguably the best method is a Wilson in line seater ( or other) in which the "chamber" of the bullet seating die was cut with the same reamer that your rifle chamber was. This helps perfectly align the case prior to seating the bullet. Absent that, most good/better seaters allow for some movement in Hope's the bullet will center itself in the case neck. In these cases, rotating the cartridge can help to some degree while seating.
The only drawback (if you consider it one), is you have to use an arbor press to seat your bullets using an in-line seater. I have used in-line seaters for all my rifles for years. It is a carry over from my years shooting benchrest. Runout in all my cartridges runs .0005 to .001
Guess it depends on how important concentricity is to you?
I found a .307" drill bit at MSC. Cuts the donut out with just a few twists of the hand after the case has been resized.
So if I gather correctly, the majority of the runout is occuring during the seating process. Have you considered using a competition style seating die that aligns things better? I would be curious as to how much it helps.
FWIW I have a Forster mic seating die, and runout is never more than .002" on bullets seated with that. I get .005" occasionally with a standard redding seating die.
FWIW I have a Forster mic seating die, and runout is never more than .002" on bullets seated with that. I get .005" occasionally with a standard redding seating die.
