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Consistent bullet seating depth, and why can't we seat off the ogive?

I can think of a couple of reasons why manufacturers don't do what's been suggested (the seating stem contacting the bullet at the point where the latter's outside diameter reaches that of the rifling's lands' internal diameter - I can't think of an easier way of avoiding using the misleading 'O' word).

First, you might, no say again WOULD, have a very long seating stem to accommodate the longer VLDs. The risk of the bullet bottoming out would be that much greater than in existing designs, and it's a real possibility with the present arrangements. Die bodies might have to be longer overall to accommodate such stems and I'm not sure what effect all this might have on bullet run-out in the finished round.

Secondly, I don't want ANYTHING metallic to touch and risk damaging / distorting that section of the bullet jacket. I've had fragile A-Maxes end up with a marked ring further up the jacket caused by seater stem contact. While many of us on this forum use bushing dies, mandrel expanders or whatever to give light neck tensions, we've got to remember we're in a minority of handloaders so far as the die manufacturer is concerned. Most people use standard dies and end up with a lot of neck-tension on their bullets even from the most expensive makes like Forster and Redding. The die manufacturer has to cater for them first.

Fair enough for anybody who wants to alter the seater stem conatct area with a bit of lapping on a bullet or get the manufacturer to produce a custom stem. It seems to me there's a risk of having a seater die that only suits one bullet model though - OK if you only ever load the one like the many .308W/155 Fullbore and Palma shooters who find a load with one of the three or four best models on the market and stick with it for the life of the barrel.

Personally, I agree with those who're saying seater stem contact point is a non, or at the worst, minor problem. The large variations I've found in some makes and batches of bullets in their bearing surface lengths concern me more and that's what I'll check out before I'd bother about the exact place where the seater stem contacts the bullet shoulder and start looking to make changes in it.
 
6BRinNZ said:
hey Fitter,

does this article from German Salazar explain things?

http://riflemansjournal.blogspot.com/2010/09/reloading-measuring-bullets.html

below is a excerpt from the article.

************************************************
STRANGE
So, if I seat 10 thousands (0.010") into the lands, I should be safe - I hope - as I never seem to get the same seating depth no matter what I try. I probably will first try seating at the lands.

I must be doing something wrong with the seating die. I've thought of going to the Wilson seater with the arbor press but I'm not sure if this will correct whatever I'm doing wrong.

It's really frustrating when one bullet is 1.848" depth, the next is 1.846" and the next is 1.847".
************************************************************************

Also I am not so convinced that all seating depth irregularity is due to the projectile dimensions...IMHO the neck tension and seating force will play a part if you are measuring to within a .001". I sort bullets and will occasionaly get a bullet that seats .004" deeper, I mark these cases and put them aside as I am fairly sure the neck tension is gone...I just don't have a good way of measuring neck tension to be sure.

Excellent! (rubbing hands together)

..."Now here's the bullet with both marks. I have the calipers open to show the distance between the shank line and the stem line, but there is no way to precisely measure this distance and no matter how precisely you scribe those lines, the actual measurement will be imprecise enough to make it a futile effort. Unfortunately, this is the single most critical distance in a bullet as it will determine the uniformity of jump or jam to the rifling on the loaded cartridge. It is the variance in this distance that we should be trying to measure, but I don't know of any way to do that with a useful degree of precision. That's why I don't measure bullets."

So he says it's important but is not sure what to do about it. I guess it's just one of those things.

I think I should have not made such an absolute statement in my OP. I too believe how hard you push down, even on an arbor press can affect seating. Sometimes when I'm .001 long I will first put it back into the die and press again before I adjust the die. And sometimes it drops it that .001, and sometimes it does not.

Thanks for the article.
 
thefitter said:
MT 6xc said:
matched for each caliber! I like it...other than reply number 28 and the bullet sticking......Now if only your chamber throat & beginning of the lands matched the 2 matched comparator and stem diameter...then all would be blissfull........

I get your point. Thanks

I still have not found exactly how far off the lands I need to be. But I've got these BR guys adjusting their bullets seating depths at the range .001 at a time. And I can see in their groups how .001 one way or another makes a difference.

Now whether or not I can (or should even try) to fine tune my own loads that well to a factory rifle is another argument all together.

Your just not gonna find that little piece of Nirvana with Sierra bullets. Too many different lots getting dumped into the same boxes. Not saying they can't be accurate. Just no where near BR quality.
They usually perform better with a jump. Ogive shape may be part of that. Ogive variations may be another.
 
"So he says it's important but is not sure what to do about it. I guess it's just one of those things."

The main point I took away from the article is to find out what tolerances make a difference for your shooting application...

Good luck!
 
6BRinNZ said:
"So he says it's important but is not sure what to do about it. I guess it's just one of those things."

The main point I took away from the article is to find out what tolerances make a difference for your shooting application...

Good luck!

You are right. That's why I'm studying everything I can. Then I will decide what works or is too much trouble.
 
..."Your just not gonna find that little piece of Nirvana with Sierra bullets"...

I'm starting to see what you mean. I've been trying some Lapua and they seem a bit more consistent in their tolerances. Unfortunately I'm having a hell of a time finding a great load for this rifle with them.

I'm going to try some Bergers this month.
 
Fitter,
This has turned out to be a great thread, you have a lot of great minds on it helping you, and I have learned quite a bit my self. What distances are you shooting right now? 40Xguy and I had a on going pm for a while on measuring bullets we both tried different ways and tools and he finally bought the John Buhay comparator I think it is the same tool that Tubbs is selling ( the one Lurcher posted) I haven't bought one yet but definitely plan on it! 40XGUY told me its by far the most consistent tool he has tried thus far. I don't shoot short range anymore, (600-1000) @ those distances consistency in everything becomes paramount if you want to be competitive, in 100 yd BR, I am not sure if those tolerances you are trying to achieve are paramount. I do applaud your efforts in perfection I am the same in that aspect myself I feel the closer to perfection you can be the more variables you have removed which should show up down range. I read somewhere Wilson has a different seating stem available for vld style bullets I will do some checking on that and will get back to you on it, good luck for now and keep your hat on as it may prevent you from pullung all your hair out,...LOL
Wayne.

P.S,.. Joe, I disagree with you on the SMKs, my experiences have been the opposite, just my $.02
 
Joe,
No I have never found any bullet to be perfect but Sierras seem to be pretty consistent as far as mass produced bullets go, Lapua's are very good also, I unlike everyone else on this forum have not found bergers to be very consistent @ ALL. As far as accuracy yes the SMKs have been very accurate for me,
( no wobbly bullets with SMKs ) LOL see ya Joe.
Wayne.
 
If you're really worried about the possible effects - ie variations in the amount of jump from the bore-dia bottom end of the ogive to the lands, there are too (relatively) simple answers:

The light neck tension soft-seating approach as used by John Whidden in which one over-length COAL is applied to all of his long-range .243W ammo and used in three (?) rifles with varying amounts of throat wear.

Or .... do what German says is too onerous in his article - ie check each round and reset individual OALs using a comparator and bullet calibre insert. It IS an onerous task if there are a lot of BSL variations between bullets in the box, but not if they're either very good from the factory, and/or have been measured and batched before loading. The 90gn Berger 0.224" VLDs I use in my long-range .223R ammo are superb in this respect with a total 5 thou BSL variance, and most within less. Even so, I split them into two groups (measured using two comparators, one on each calliper blade). What you do need is a micrometer top seater die that works in one-thou' increments - Forster Ultra or the Redding Competition to name two. I set my Forster Ultra at what I know will be the long end of the range (which is only 3 thou' anyway) and measure each round as it comes off the press. If it's two-thou over my desired (comparated) COAL value, I dial in two extra thou' on the die top and reseat - and yes, 99% of the time, the round comes out two thou' shorter and exactly right. My aim is a one-thou' variation across the contents of a 50-round box and I expect to achieve that with 48 or 49 of the 50 rounds.

So far as SMKs and their consistency goes, that's a variable feature in itself (pun intended!) as the different opinions on this thread attest. I have .243" 107s from some years back that are DIRE, while I have 200gn 0.308s bought as a 500-ct box last year that have virtually NO BSL variation, and I've given up looking for them. It seems Sierra has become sensitive to criticism on this and have upped their standards in recent times. (The 6.5-284 Loading Guide elsewhere on the 6mmBR site also says it WAS a big problem with 142gn SMKs when the cartridge started to become the long-range shooter's favourite making comparator based batching essential, but it's not been a problem with recent lots.)
 
;D ;D ;D Good one Wayne

I've found Bergers to be quite consistent in one lot.
They do change lot to lot sometimes. Different dies different lots and they do change dies and make subtle changes more than most. JMO's

Then there was those years right after Walt sold the business they were FUBAR. ;D Luckily they decided not to let the bean counters destroy a good business and rectified the problems.

I'm sure theres plenty of folks here that agree with you ;) Take care Wayne.
 
Yes, this has been a very good thread! I just got done sorting 200 Sierra 123 grain 6.5 cal MK's on my new Buhay tool yesterday after weight sorting, and out of 200 my results:

3 weight classes from 122.8 to 123.0 - 178 bullets. Majority at 122.8

Bearing surface's All 3 weights were very consistant,
All being within .002 of which I broke down into lots of the same weight and within .001 surface, out of 200 bullets, I had 22 culls of which were either high or lo weight, and of these 22, about 8 were way off on bearing surface from the norm up to .009. That would be a flyer all day long at a LR Benchrest match.

So yes you can get damn anal at this bullet sorting, but I feel now that this is the last variable that I need to get over the mental hump with myself. ;D 200 Hornady 123 A Max's were terrible, I don't have enough to even try to do load development with. But Lapua 123's were very uniform.

I always liked Sierra bullets, but IMHO you have to work with them, and they are more forgiving than some Berger's I have been working with recently.
 
bozo699 said:
Fitter,
This has turned out to be a great thread, you have a lot of great minds on it helping you, and I have learned quite a bit my self. What distances are you shooting right now? 40Xguy and I had a on going pm for a while on measuring bullets we both tried different ways and tools and he finally bought the John Buhay comparator I think it is the same tool that Tubbs is selling ( the one Lurcher posted) I haven't bought one yet but definitely plan on it! 40XGUY told me its by far the most consistent tool he has tried thus far. I don't shoot short range anymore, (600-1000) @ those distances consistency in everything becomes paramount if you want to be competitive, in 100 yd BR, I am not sure if those tolerances you are trying to achieve are paramount. I do applaud your efforts in perfection I am the same in that aspect myself I feel the closer to perfection you can be the more variables you have removed which should show up down range. I read somewhere Wilson has a different seating stem available for vld style bullets I will do some checking on that and will get back to you on it, good luck for now and keep your hat on as it may prevent you from pullung all your hair out,...LOL
Wayne.

P.S,.. Joe, I disagree with you on the SMKs, my experiences have been the opposite, just my $.02

Right now I'm still sorting things out at short ranges. My goal is long range like you, but that's a ways off.

I totally agree about removing as many variables as possible. Then if there is group issues I can assume it's 95% me and I can work on the fundamentals more. Thanks
 
thefitter said:
Thanks for the feedback guys. Believe me I am a total rookie. Let me ask my question more precisely.

I'm NOT talking about variables in any of these dimensions:

Base to tip
Base to ogive
Ogive to tip

I'm only talking about two different points on the ogive.

1) The point on the ogive where the seater makes contact.
2) The point of the ogive that contacts the rifling, or where a comparator makes contact.

These are 2 completely different spots on the bullets ogive.

On my 2 dies the seater contacts much closer to the meplat.

All I'm trying to express is that I am seating from one spot on the ogive and measuring from another. And that is why I believe I see .001-.002 seating depth variables. Thanks

Has that very small seating depth variation resulted in any provable accuracy problem? My loads shoot pretty well and I do not care about variation of a few thousandths.

If the seater stem contacted the bullet ogive at the same point as the rifling, it would be paper thin and unusable. I think what you have to ask is: "Is this a problem?" If the answer is no, why concern yourself with it? Not all variables are significant contributors to accuracy.
 
thefitter said:
All I'm trying to express is that I am seating from one spot on the ogive and measuring from another. And that is why I believe I see .001-.002 seating depth variables. Thanks


Fitter and everyone else. My apologies, I must have missed that.

I would'nt get too worked about that small a variation in a new factory barrel.
That barrels going to be telling you lots of things about its wants and desires before it gets to nitpicking about a couple thousandths ;D
They are just like women you know ;) Thats a given. ;D
 
thefitter said:
bozo699 said:
Fitter,
This has turned out to be a great thread, you have a lot of great minds on it helping you, and I have learned quite a bit my self. What distances are you shooting right now? 40Xguy and I had a on going pm for a while on measuring bullets we both tried different ways and tools and he finally bought the John Buhay comparator I think it is the same tool that Tubbs is selling ( the one Lurcher posted) I haven't bought one yet but definitely plan on it! 40XGUY told me its by far the most consistent tool he has tried thus far. I don't shoot short range anymore, (600-1000) @ those distances consistency in everything becomes paramount if you want to be competitive, in 100 yd BR, I am not sure if those tolerances you are trying to achieve are paramount. I do applaud your efforts in perfection I am the same in that aspect myself I feel the closer to perfection you can be the more variables you have removed which should show up down range. I read somewhere Wilson has a different seating stem available for vld style bullets I will do some checking on that and will get back to you on it, good luck for now and keep your hat on as it may prevent you from pullung all your hair out,...LOL
Wayne.

P.S,.. Joe, I disagree with you on the SMKs, my experiences have been the opposite, just my $.02

Right now I'm still sorting things out at short ranges. My goal is long range like you, but that's a ways off.

I totally agree about removing as many variables as possible. Then if there is group issues I can assume it's 95% me and I can work on the fundamentals more. Thanks

Fitter,
Seriously if your shooting short range right now I think if it was me I would work on shooting technique's, reading the wind, sounds like you already know how to precisley build ammunition. It sure is a fun and exciting hobby though, isn't it?
Wayne.
 
thefitter said:
I'm starting to see what you mean. I've been trying some Lapua and they seem a bit more consistent in their tolerances. Unfortunately I'm having a hell of a time finding a great load for this rifle with them.

I'm going to try some Bergers this month.

PM me your gun information and load data and I can help you get the Lapua Scenars to shoot.
 
Must thank all of you who have measured bullet dimensions and share the results with us.
Laurie, I use the Forster Ultra seater too. Because of how 'reliable' the depth adjustment seems to me, I have relaxed on checking the loaded rounds with a comparator. I might check a sample of 5 rounds at random in a box of 50 but thats it.
Every time I check the look of rifling marks on a bullet after chambering a round they look clear and even, and this leaves me feeling confident.
The setting should probably be called a light jam. Because of your comment on how sensitive accuracy is when seating 'at the lands' I intend to try some slight variation in seating depths in an attempt to find out how sensitive my favorite 223 load is to seating variation. It never occurred to me to investigate how tolerant my load is to certain types of variation. It would be good to know.
 
Laurie, I use the Forster Ultra seater too. Because of how 'reliable' the depth adjustment seems to me, I have relaxed on checking the loaded rounds with a comparator. I might check a sample of 5 rounds at random in a box of 50 but thats it. [Tozguy]

That's all I would normally do too. F/TR at national level (even club level where I shoot as around two-thirds of the top GB F/TR shooters are regulars plus some up and coming local young tigers) has become so competitive now that I give my match ammo the check and adjust everything treatment for the 800 to 1,000yd matches. Yes, I know that a marginal improvement in wind reading skill has a greater effect than the last 1% of minor improvements in ammo quality, but you might as well get everything as good as possible before setting out for a match. If I have a lousy day, I know who or what to blame and it's not the ammunition!
 
Laurie,
The mental management side of dealing with variables is facinating. On the one hand, wanting everything perfect because it can't hurt has to be weighed against the possibility of being distracted with relatively minor elements. Details are not all important to the same extent and because there are so many details to keep track of (at least more than I have learned to manage so far), attention to detail can become a distraction.
On the other hand, overlooking a significant variable might eventually hold an unpleasant surprise for us.
Your statement sums it up very well for me; get to the point where you will believe that if you have a lousy day, its not the ammunition.
 

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