Bullet seating variations for fclass or BR, whats acceptable?

[DngBat7]

So I use a Wilson inline seating die with a hydro press. For what ever reason, I never checked my variations round to round for consistency. Don’t know why. But I got a Redding instant indicator in the mail (always wanted one) and so I measured 20 rounds for seating depth. The seating depth all ran about .001 apart from each other. I know that would normally be considered consistent, but was wondering for fclass or benchrest standards, is that still considered “good enough”?

 

[Tim Singleton]

For me shooting benchrest it is not
I want them the same.

 

[Falfan2017]

I want within a half thousand or less with br loads. Loading up a couple hundred for a weekend with f class that can be a pain.
I find the Wilson setup keeps good sorted bullets mostly within 1k with no reseating but certainly within 1.5k which seems to be good enough and save a lot of time.

When doing seating depth load development it seems like you need at least 2-3k difference in seating depth test to notice a real change in grouping with a stable load.

 

[Joe Salt]

Are you using molly or anything to lube the inside of the necks if not your wasting your time trying to get them the same. Mine are polished with 0000 steal wool on a brush to start, then I use molly. After firing, I lightly brush them, then add molly again. Some say leave the carbon! I say lightly brush apply molly. You'll like it.

joe Salt

 

[Bc'z]

I only compete with my self and the lil dot down range.
I like my seating depth variation to be within
.0005-.001, with .001 being max variation.

 

[mikecr]

Same issue as with anything that's based off a shoulder datum,, 2 variances at the same time..
You would be better to measure CBTO, every round, every time, and make every one the same.
Better still is qualifying ogives with a BGC before seating.

As long as you leave a carbon layer in necks no other lube should be necessary.
And it helps if your necks are not sized to an excess interference fit.

 

[Scott Harris]

So I use a Wilson inline seating die with a hydro press. For what ever reason, I never checked my variations round to round for consistency. Don’t know why. But I got a Redding instant indicator in the mail (always wanted one) and so I measured 20 rounds for seating depth. The seating depth all ran about .001 apart from each other. I know that would normally be considered consistent, but was wondering for fclass or benchrest standards, is that still considered “good enough”?

I think the answer depends on where you seat your bullets in relation to the lands and what type of bullet you are using and what your accuracy standards are. If you are just off the lands or just in the lands, then I would think seating depth consistency matters a lot. If you are .010" or more off the lands, then seating depth consistency matters less. If you use a tangent ogive bullet and you are well off the lands, then seating depth consistency matters a lot less. That is my formula: hybrid bullets and at least .015" off the lands. I set the depth when the barrel is new and never change it. Instead, simply add powder to keep the tuned velocity constant as the barrel throat wears. This has worked for me and others over the years...in f-class. We also stopped turning necks about 18 months ago and our results have not suffered a bit....

.001 is plenty good enough IMHO

 

[Ned Ludd]

I wonder how many that responded they want their bullets all seated to exactly the same depth are using calipers to measure each seated round? Calipers typically only have readability to +/- .0005", so even if the caliper tool gives you the same number every time, your loaded rounds are probably not seated to that tolerance. On top of that, how many of these same people test seating depth using .003" as their smallest increment, or possibly even .005"? Attempting to reliably hold seating depth to approximately one tenth of the increment used during seating depth testing is overkill.

It's all about limiting sources of error, which can also be interpreted to mean "limiting sources of measurement". In F-Class, it's not uncommon for shooters to use either .003" or .005" increments during seating depth testing. If the actual seating depth of their loaded rounds varies by +/- .001", then at the very worst, a loaded round will be .002" away from the next seating depth increment that was actually tested. If they tested and chose their optimal seating depth properly, I'd guess that very few F-Class shooters would ever actually notice the difference of .001" in seating depth. Although good precision is important, it's not totally about pure precision in F-Class. When you shoot 20+ shots over a time period that might typically last from 8 to 15 minutes (or perhaps 2 to 3 minutes for David Gosnell), reading the wind is going to become the limiting factor for most shooters. In other words, the difference between a 0.1 MOA load and a 0.2 MOA load is meaningless when rapidly changing wind conditions are sufficient to put your shots out by well over 1, 2, or even 3 MOA to either side when the wind picks up.

 

[Tim Singleton]

I wonder how many that responded they want their bullets all seated to exactly the same depth are using calipers to measure each seated round? Calipers typically only have readability to +/- .0005", so even if the caliper tool gives you the same number every time, your loaded rounds are probably not seated to that tolerance. On top of that, how many of these same people test seating depth using .003" as their smallest increment, or possibly even .005"? Attempting to reliably hold seating depth to approximately one tenth of the increment used during seating depth testing is overkill.

It's all about limiting sources of error, which can also be interpreted to mean "limiting sources of measurement". In F-Class, it's not uncommon for shooters to use either .003" or .005" increments during seating depth testing. If the actual seating depth of their loaded rounds varies by +/- .001", then at the very worst, a loaded round will be .002" away from the next seating depth increment that was actually tested. If they tested and chose their optimal seating depth properly, I'd guess that very few F-Class shooters would ever actually notice the difference of .001" in seating depth. Although good precision is important, it's not totally about pure precision in F-Class. When you shoot 20+ shots over a time period that might typically last from 8 to 15 minutes (or perhaps 2 to 3 minutes for David Gosnell), reading the wind is going to become the limiting factor for most shooters. In other words, the difference between a 0.1 MOA load and a 0.2 MOA load is meaningless when rapidly changing wind conditions are sufficient to put your shots out by well over 1, 2, or even 3 MOA to either side when the wind picks up.

Great post and makes perfect sense to me for
F class
In benchrest if you are not testing seating depth in .001 increments and maintaining the desired setting exactly as much as possible
You're probably not much of a threat to the ones that are

 

[Bc'z]

Great post and makes perfect sense to me for
F class
In benchrest if you are not testing seating depth in .001 increments and maintaining the desired setting exactly as much as possible
You're probably not much of a threat to the ones that are

I'm a threat to myself as I'm just begining another OCW test with 123 amax for wifes rifle. Sorted bullets varried by .007.

I get what @Ned Ludd is putting down..

But if seating die is set and a inanimate object the only variant can be the bullet unless it a compressed load.
Correct?
Same goes for measurements. If all are consistent with given set of tools the outcome should be repeatable?
Now my OCD is in hyperdrive!!

 

[Tim Singleton]

I'm a threat to myself as I'm just begining another OCW test with 123 amax for wifes rifle. Sorted bullets varried by .007.

I get what @Ned Ludd is putting down..

But if seating die is set and a inanimate object the only variant can be the bullet unless it a compressed load.
Correct?
Same goes for measurements. If all are consistent with given set of tools the outcome should be repeatable?
Now my OCD is in hyperdrive!!

My experience is limited to benchrest where we will fire 200 plus rounds in two days of competition 20 record 5 shot targets plus practice days before the match
So even a new set of 25 or 30 cases by day 2 have 10 plus firings on them
Some just have more grip than others some size just a little different
You have to watch each one and make any adjustments required or sort out the offender thats just different
.001” off on seating depth can be the difference in winning and loosing

 

[Ned Ludd]

My experience is limited to benchrest where we will fire 200 plus rounds in two days of competition 20 record 5 shot targets plus practice days before the match
So even a new set of 25 or 30 cases by day 2 have 10 plus firings on them
Some just have more grip than others some size just a little different
You have to watch each one and make any adjustments required or sort out the offender thats just different
.001” off on seating depth can be the difference in winning and loosing

^^^This. It's important to know what the limiting sources of error are in any particular type of shooting competition. Only then can you be certain that your reloading practices are meeting or exceeding those limiting sources of error. Although good precision is important in F-Class, it's not the same as BR, where groups in the .1s or 0s are common, or where tenths or even hundredths can be the difference between the top aggs. The effect of changing wind conditions during long strings of fire in F-Class will more often than not be the limiting source of error (i.e. cause the most points to be lost). For that reason, improving precision past a certain point becomes less critical than practicing and improving wind reading skills.

 

[Ned Ludd]

I'm a threat to myself as I'm just begining another OCW test with 123 amax for wifes rifle. Sorted bullets varried by .007.

I get what @Ned Ludd is putting down..

But if seating die is set and a inanimate object the only variant can be the bullet unless it a compressed load.
Correct?
Same goes for measurements. If all are consistent with given set of tools the outcome should be repeatable?
Now my OCD is in hyperdrive!!

The key to uniform seating depth at any given die setting is the distance between the seater die stem contact point, and the point on the bullet ogive that first encounters the lands. The point at which the comparator insert seats on the bullet ogive is presumably close to the point that first touches the lands, but may not be exact depending on whose comparator inserts you're using and/or whether they were cut with the actual reamer used to chamber the rifle.

Nonetheless, it is possible to seat bullets with significant base-to-ogive (BTO) variance to very uniform seating depth, because the points at which the seater die stem and the caliper insert contact the bullet are outside the BTO region (see image below). Bob Green's Comparator actually sorts bullets based on the distance between these two critical contact points. The caveat to having uniform seating depth with bullets that vary markedly in BTO is that although the bullets may be seated very uniformly with respect to distance from the lands, they will not have the same length of bullet shank seated in the neck. This can affect the effective internal case volume and the amount of friction gripping the bullet in the neck, thereby theoretically also affecting bullet release, pressure, and velocity. Hopefully, the differences won't be huge, especially if you sort bullets by BTO.

But the question again is what are the limiting sources of error in your chosen shooting discipline? If even such a small difference is detectable on the target, it needs to be addressed during the reloading process. If it is way down in the noise, you'll probably never notice it. In many cases, the only way to know for sure whether some aspect of the reloading process is critical for a given discipline is simply to test it and let the target tell you whether or not it matters.

 

[DngBat7]

Thanks for everyone’s advise. I measured 75 rounds I have loaded up after listening to all these comments. With berger bullets, I noticed that the variation is more than I originally thought. With the exception of most (89%) being within .001. There were some that were .002-.003. Some, but not many. For me, that was enough. So I have the bob green comparator with dial indicator on order and I also picked up a holland gold standard comparator for bto. If this does not solve my problems, I don’t know what will.

 

[Tim Singleton]

Thanks for everyone’s advise. I measured 75 rounds I have loaded up after listening to all these comments. With berger bullets, I noticed that the variation is more than I originally thought. With the exception of most (89%) being within .001. There were some that were .002-.003. Some, but not many. For me, that was enough. So I have the bob green comparator with dial indicator on order and I also picked up a holland gold standard comparator for bto. If this does not solve my problems, I don’t know what will.

So much of this is mental.
Confidence in your stuff, hard to put a value on that

 

[JFrank]

I'm a threat to myself as I'm just begining another OCW test with 123 amax for wifes rifle. Sorted bullets varried by .007.

I get what @Ned Ludd is putting down..

But if seating die is set and a inanimate object the only variant can be the bullet unless it a compressed load.
Correct?
Same goes for measurements. If all are consistent with given set of tools the outcome should be repeatable?
Now my OCD is in hyperdrive!!

If my neck tension is uneven my seating may vary.
Unnoticed with a ram style seater but evident with an Arbor press.

 

[Bc'z]

If my neck tension is uneven my seating may vary.
Unnoticed with a ram style seater but evident with an Arbor press.

I finished loading my OCW/OCD test with the 123 amax.
6 charge weights in .3 increments of rl16 starting at 42gr up to 43.5 bullets sorted to the .001.
Also loaded 8 with varying bbto measurements at 42.5 gr to shoot for group.
To test if its visible on paper.
All cases are hornady twice fired, annealed and full length sized moving shoulders .002.

 

[JFrank]

I finished loading my OCW/OCD test with the 143 amax.
6 charge weights in .3 increments of rl16 starting at 42gr up to 43.5 bullets sorted to the .001.
Also loaded 8 with varying bbto measurements at 42.5 gr to shoot for group.
To test if its visible on paper.
All cases are hornady twice fired, annealed and full length sized moving shoulders .002.

Is that the 260 Remington?
Bet ya it shoots great..
You da man

 

[Bc'z]

Yeah its mama's

 

[Texas10]

Your bullet seating process should be held to the same standard as your case sizing, base to datum (aka headspace), since that is what the chamber references from. Additionally, your sizing die should have the exact same angle in the shoulder as your chamber. If not, you're likely just chasing your tail.

So if you mistakenly bump back the shoulder an extra .002, and you're seating into the lands, your bullet is going to end up .002 deeper into the lands. And vice versa if you don't bump back far enough. And is seems to me that if the die is changing the angle of the shoulder, you'll get an inconsistent placement in the lands when the firing pin hits and drives the case tight against the shoulder, cold forming it to conform to the chamber.

But I'm no expert, so others may beg to differ. YMMV.

BTW: X-47B....incredible advancement in flying technology. Too bad it took the Gov't 40 years to figure that out. Or maybe they were just making sure to not leap way ahead in technology in order to keep the Cold War going longer. Imagine if we had a stealth bomber in 1949. Hmmmm...boggles the mind.