Seating depth precision...

[boisepaw]

I'm never gonna win the Snipers Hide Cup. I'm never gonna win a PRS match with the local girl scouts troop. But I sure do enjoy reloading and shooting the longest distances that I can...so far out to 1000 yards at steel but I'd like to go further.

So...if I am measuring from the base to the ogive on my reloads, even using what I think are pretty good dies...it is not at all uncommon for me to find that from one load to the next there might be a couple thousandths difference in the length. Just to pull numbers out of the air from my 6 CM, maybe from 2.120 to 2.123 or even 2.125.

Do I keep adjusting the die to make sure it is EXACTLY the same seating depth each time or if it is within a couple of thousandths is that good enough?

 

[pmclaine]

What are you loading on for a machine?

I load progressive so have come to the conclusion I suffer varied OAL for speed.

I understand people loading on a Coax handle their shit more but get consistent everything.

 

[Supersubes]

I think this matters more the closer you load to the lands. Try pausing at the bottom of the stroke while seating. Usually works pretty well. Also, you’re measuring to the thousandth, not the ten thousandth.

 

[never_summer]

What bullets are you loading and do you sort them?

Are you having trouble down range with the current load that makes you question it?

 

[boisepaw]

What are you loading on for a machine?

I load progressive so have come to the conclusion I suffer varied OAL for speed.

I understand people loading on a Coax handle their shit more but get consistent everything.

Bullet seating is done on an old RCBS RockChucker Jr. One at a time. Slowly and tediously...

 

[boisepaw]

What bullets are you loading and do you sort them?

Are you having trouble down range with the current load that makes you question it?

I'm loading a very wide variety of bullets for at least 3 different calibers. And...much to my embarassment...I have never sorted any of my bullets by weight. Just take 'em out of the box and seat them.

I'm not having any trouble downrange...just wondering if I would have even greater success downrange if I didn't have that little tiny bit of variance in the seating depth.

 

[boisepaw]

I think this matters more the closer you load to the lands. Try pausing at the bottom of the stroke while seating. Usually works pretty well. Also, you’re measuring to the thousandth, not the ten thousandth.

I am staying quite a ways away from the lands...often .130 or so. So that shouldn't be a problem.

I used to think I was good with numbers...sheeesh! How embarassing. I'm correcting that now before I look any more foolish...

 

[Femadog]

I'm loading a very wide variety of bullets for at least 3 different calibers. And...much to my embarassment...I have never sorted any of my bullets by weight. Just take 'em out of the box and seat them.

I'm not having any trouble downrange...just wondering if I would have even greater success downrange if I didn't have that little tiny bit of variance in the seating depth.

There is a recent study that looked at maintaining seating depth and distance to lands versus barrel wear. I forget the details (I'll try to find the link) but you would need to adjust seating depth every 100 rounds to maintain the same distance. They saw the change in impact was more pronounced the closer to the lands you were (e.g. the effect of .010 versus . 020 was more than the difference between .050 and .060) I went to seating bullets at .050 for my PRS loads (6.5x47 140 Hybrids) and haven't looked back. Fewer flyers since I started doing that. YMMV. I recognize some bullets prefer jamming or small jumps but I'm not bench rest shooting.

 

[boisepaw]

There is a recent study that looked at maintaining seating depth and distance to lands versus barrel wear. I forget the details (I'll try to find the link) but you would need to adjust seating depth every 100 rounds to maintain the same distance. They saw the change in impact was more pronounced the closer to the lands you were (e.g. the effect of .010 versus . 020 was more than the difference between .050 and .060) I went to seating bullets at .050 for my PRS loads (6.5x47 140 Hybrids) and haven't looked back. Fewer flyers since I started doing that. YMMV. I recognize some bullets prefer jamming or small jumps but I'm not bench rest shooting.

Very interesting...if you find the link, please pass it on.

 

[never_summer]

I'm loading a very wide variety of bullets for at least 3 different calibers. And...much to my embarassment...I have never sorted any of my bullets by weight. Just take 'em out of the box and seat them.

I'm not having any trouble downrange...just wondering if I would have even greater success downrange if I didn't have that little tiny bit of variance in the seating depth.

Just asked which bullets because you will see different variance in quality bullets versus cheap ones. Your headed down a rabbit hole, weighing bullets for variance is one aspect but also the base to ogive measurement is another along with oal.

 

[db2000]

I read lots of anecdotal reports from long time shooters that a few thousands in BTO is not going to make any significant difference, especially if your not right on the lands. I've found this to be true myself.

 

[stevenc23]

Very interesting...if you find the link, please pass it on.

Bullet Jump: Is Less Always Better?

About 2 years ago, Mark Gordon shared some preliminary research he’d conducted with the Applied Bal...

precisionrifleblog.com

 

[Femadog]

^^^^^What he linked

 

[Deleted member 10043]

OP, it's normal and you won't notice any different.

As for checking every 100 rounds. I think that is obsessive. I just finished off 500 rounds 25-07, 7 twist, 131 Blackjack bullets and COAL didn't need to be changed yet.

 

[Dthomas3523]

I test jump every 300 rnds or so. That’s when I clean as well.

Typically, a couple thou won’t hurt you.

 

[Doom]

5 thousandths seems a little excessive. Are you sure your seating stem isn’t seating off the tip of the bullet? This can happen, especially with secant ogive bullets.

 

[Dthomas3523]

A *very* important factor is to make sure you put the round in the comparator the same way every time.

Its very easy to twist one 3 times to settle it in and not twist the next, you’ll be off up to several thou from just user error.

A lot of times the best way is to take an undersized comparator and use a hand reamer that’s the size of your bore and get a comparator as close to your bore as possible. Then theoretically you can just put it in without needed to settle the bullet to much and get consistent measurements.

 

[Steel head]

I'm never gonna win the Snipers Hide Cup. I'm never gonna win a PRS match with the local girl scouts troop. But I sure do enjoy reloading and shooting the longest distances that I can...so far out to 1000 yards at steel but I'd like to go further.

So...if I am measuring from the base to the ogive on my reloads, even using what I think are pretty good dies...it is not at all uncommon for me to find that from one load to the next there might be a couple thousandths difference in the length. Just to pull numbers out of the air from my 6 CM, maybe from 2.120 to 2.123 or even 2.125.

Do I keep adjusting the die to make sure it is EXACTLY the same seating depth each time or if it is within a couple of thousandths is that good enough?

Bullets vary.
Better bullets vary a bit less.
You can sort bullets, I certainly don’t.
That bit of variation isn’t going to do squat to hold you back from shooting 1000+

 

[boisepaw]

Just asked which bullets because you will see different variance in quality bullets versus cheap ones. Your headed down a rabbit hole, weighing bullets for variance is one aspect but also the base to ogive measurement is another along with oal.

That makes more sense of the question. The bullets I end up with tend to be the more expensive ones...SMK, Berger Hybrid, Hornady BTHP Match, Nosler RDF etc. etc.

 

[boisepaw]

Bullet Jump: Is Less Always Better?

About 2 years ago, Mark Gordon shared some preliminary research he’d conducted with the Applied Bal...

precisionrifleblog.com

Thanks for the reminder. I did see and read that one a couple of weeks ago...

 

[boisepaw]

I test jump every 300 rnds or so. That’s when I clean as well.

Typically, a couple thou won’t hurt you.

That's what I'm hoping...a couple thou will be fine...

 

[boisepaw]

5 thousandths seems a little excessive. Are you sure your seating stem isn’t seating off the tip of the bullet? This can happen, especially with secant ogive bullets.

I will check that out. I can't tell you if that is what is happening or not...

 

[boisepaw]

A *very* important factor is to make sure you put the round in the comparator the same way every time.

Its very easy to twist one 3 times to settle it in and not twist the next, you’ll be off up to several thou from just user error.

A lot of times the best way is to take an undersized comparator and use a hand reamer that’s the size of your bore and get a comparator as close to your bore as possible. Then theoretically you can just put it in without needed to settle the bullet to much and get consistent measurements.

Very interesting added touch to the whole process.