Optimize bullet seating depth

[dangerranger60]

The bullet im using is a Nosler Partition, but Im also going to develope a load using a TTSX lead free bullet. I havent started that one yet and will need to do a pressure test first to work up the powder charge.

I shoot a lot of TSX bullets. Barnes says .030 to .070 off the rifling, I found .050 best in my guns. [ some are longer than that due to mag length].
But when I first started using lead free there was not a lot of data available. I was trying to seat them like a lead based bullet up closer to the lands. What I got were erratic velocity and not much accuracy! Once I learned that solid copper needs a little jump to get started it got much easier.
I'll be honest with you. I would not use lead free if I were not forced by the state! They cost more for less performance.
Good Luck DR

 

[dangerranger60]

I plan to start with .050" jump, per Barns website. They say it affects accuracy, first ive heard it affects pressure spikes. Interestingly I have only read this for Barnes projectiles.


This is helpful, what I was looking for. Im aware it might not be what my rifle shows but it helps me decide if I want to test in .005" increments vs larger to save time.

I dont know if Ive got the most accurate charge, I chased my tail this summer with ladder tests trying to reach a velocity I wanted (per loading manuals...) and ran into over pressure issues so I backed way off to a safer charge/pressure and compromise on the velocity it gives me and decided to just go with that. I dont know another way with my limited experience just that Im tired of ladder tests right now.

The pressure spikes are common to all harder than lead alloy bullets. [ Barnes use solid copper but I have also tried Zinc and Tin bullets]
The thought is the harder bullets get caught as it hits the lands and pauses there creating the pressure spike. But with a little jump it pushes smoothly down barrel. The pressure spike is what causes the accuracy problem, as one is not always moving at the same speed as the next! DR

 

[dangerranger60]

How people shoot such good groups with a factory rifle with factory ammo is beyond me. My Rem 700 before I bedded and floated it was terribly inprecise. Even after some custom work Im still averaging 1.5MOA with only one brand of factory ammo. Maybe Im just a bad shot but I dont think im that bad...

My first three 5 shot groups from a new Savage Axis in 223 were all right at 3/4" at 100 yds. The first group surprised me, so I did it again. This was using factory Remington 55 gr FMJ ammo. The rifle is still in its plastic stock.
But not many rifles were that easy! I want to put the Axis in a Boyds stock but I'm afraid to mess up a good thing! DR

 

[BigGame]

To me, seating depth is critical.

I agree with pharmseller.

Once I have a charge worked out (which I usually do around 0.020 jump), I drop it a bit if I'm anywhere near max and run a seating test. I'll test from about 0.010 to 0.110 on increments of 0.020. Sometime I test even longer jumps. One of those tests will stand out.

I then bring my charge back up to match the velocity I previously liked. The actual charge may differ from the original - I key to the velocity, not the charge.

Last, if I want to refine further, I'll test seating depths +\- 0.005 and 0.010 from there. Maybe a finer charge test around that…. Just depends what you enjoy.

 

[Koda]

The pressure spikes are common to all harder than lead alloy bullets. [ Barnes use solid copper but I have also tried Zinc and Tin bullets]
The thought is the harder bullets get caught as it hits the lands and pauses there creating the pressure spike. But with a little jump it pushes smoothly down barrel. The pressure spike is what causes the accuracy problem, as one is not always moving at the same speed as the next! DR

that makes sense, what I thought was happening. I haven't heard of any accuracy problems with monolithics though... Ive heard nothing but good things performance wise.

I'll be honest with you. I would not use lead free if I were not forced by the state! They cost more for less performance.

I haven't read of any loss of performance in monolithics? In fact Ive read some great reviews from hunters. I'm aware there is a debate on requiring unleaded ammo, part of my motivation for developing a load is the fact that regardless of opinons, probably someday Oregon might require them (I read they recently just reintroduced California Condors to the Columbia river gorge area....), the other part is even if they don't Id rather not eat lead myself. Yeah, I know some don't think that's true but from what Ive read and observed it makes sense (the last elk I shot I recovered only half the lead based bullet...). Im not a stickler on the subject and ts not a deal breaker to me, I'm still developing a load with the Partition since its long established as one of the best performing hunting projectiles. In my 25-06 caliber I need penetration on elk and the monolithics are lighter, Im not certain if they will penetrate as much as the Partitions will? The Partition is heavier and has a stellar reputation for mushrooming and penetration, the monolithics have a reputation of retaining all their weight though but being much lighter Im not certain they will match the penetration of the Partitions in my caliber. Seems like everything is a give and take sacrifice.

 

[Koda]

I agree with pharmseller.

Once I have a charge worked out (which I usually do around 0.020 jump), I drop it a bit if I'm anywhere near max and run a seating test. I'll test from about 0.010 to 0.110 on increments of 0.020. Sometime I test even longer jumps. One of those tests will stand out.

I then bring my charge back up to match the velocity I previously liked. The actual charge may differ from the original - I key to the velocity, not the charge.

Last, if I want to refine further, I'll test seating depths +\- 0.005 and 0.010 from there. Maybe a finer charge test around that…. Just depends what you enjoy.

this is really good to read as Im still learning to reload Ive been wondering what others are doing to develope the best seating depth plus this confirms to me that seating depth is important to test in this process. Whats also cool is in my learning process I settled on .020" starting point from the lands (for lead based projectiles) so another clue I might be homing in on the best practice from the more experienced handloaders. I was also wondering about the need to bring the charge back up if say I got better accuracy closer to the lands. Good to know.

 

[BigGame]

I haven't read of any loss of performance in monolithics? In fact Ive read some great reviews from hunters.

Aside: I use monolithics in my hunting loads by choice due to excellent performance. I'm shooting Hammer Bullets.

I shoot lead core in my target rifle because shooting volume is much higher, the bullets are less expensive, and terminal performance is not a concern.

 

[Koda]

Aside: I use monolithics in my hunting loads by choice due to excellent performance. I'm shooting Hammer Bullets.

I picked Barnes for my 25-06 because they sell heavier 100grn monolithics but the Hammer bullets are a bookmark I keep coming back to and considering... their heavier bullets need a twist rate faster than my 1:10 but their 92grn Hunter projectile is tempting to try but I'm not certain it will matter much between the Barns TTSX Ive selected. I'm just so limited in my caliber for what I'm wanting to hunt with it so I tend to lean towards anything heavier even if just a few grains. I dunno if it matters I'm just trying to maximize my opportunity best I can.

 

[orygun]

To me, seating depth is critical.

Read this:

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

VLD bullets are designed with a secant ogive. This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection). While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifle.

bergerbullets.com

This is the exact process I've been using for years. I select my powder and work up charges over the chronograph in the backyard. I avoid compressed charges but I'm looking for a full case, 95% or better, for more consistent ignition. I look for pressure signs like extractor marks in the brass or stiff bolt lift, then back off half a grain or so.

Then I commence with my seating depth test.

Notice the following pics - the only difference is seating depth. I start with the shortest loads because if I find accuracy short I can always shorten the longer rounds.

View attachment 1075922

View attachment 1075923

View attachment 1075924

I stopped here. That's good enough for me, plus I was getting beat up by recoil.

This method has only failed me once, and that was on the rifle, not the process. I can't even begin to tell you how many loads I've worked up for various rifles over the last dozen years, for both me and my family.

YMMV, this certainly isn't the only way, but it works for me. Partitions, AB, BT, ELDX/M, TTSX. All the same.



P

Which cartridge are you shooting here?

The pressure spikes are common to all harder than lead alloy bullets. [ Barnes use solid copper but I have also tried Zinc and Tin bullets]
The thought is the harder bullets get caught as it hits the lands and pauses there creating the pressure spike. But with a little jump it pushes smoothly down barrel. The pressure spike is what causes the accuracy problem, as one is not always moving at the same speed as the next! DR

Backing off from the lands is a junior version of the Weatherby freebore. Gives the bullet a running start to the lands. Helps keep pressures in check.

Im not a stickler on the subject and ts not a deal breaker to me, I'm still developing a load with the Partition since its long established as one of the best performing hunting projectiles. In my 25-06 caliber I need penetration on elk and the monolithics are lighter, Im not certain if they will penetrate as much as the Partitions will? The Partition is heavier and has a stellar reputation for mushrooming and penetration, the monolithics have a reputation of retaining all their weight though but being much lighter Im not certain they will match the penetration of the Partitions in my caliber. Seems like everything is a give and take sacrifice.

The Partition loses almost half of it's weight once it smacks into an animal. It expands and sheds most of the front half leaving the rear half, which keeps penetrating. The monolithic bullets start out lighter, but lose less of their weight on the way through.
I've only tested Monolithic bullets once. Decent groups, but completely off center compared to a Partition, Interlock or Ballistic tip. I can make two loads with a Partition and a Ballistic tip that shoot very close to the same at 100 yards. The monos (Barnes) shot to the right enough to require a scope adjustment. Absolutely nothing to even talk about if that's all I wanted to shoot.

 

[Koda]

Which cartridge are you shooting here?

Backing off from the lands is a junior version of the Weatherby freebore. Gives the bullet a running start to the lands. Helps keep pressures in check.

The Partition loses almost half of it's weight once it smacks into an animal. It expands and sheds most of the front half leaving the rear half, which keeps penetrating. The monolithic bullets start out lighter, but lose less of their weight on the way through.
I've only tested Monolithic bullets once. Decent groups, but completely off center compared to a Partition, Interlock or Ballistic tip. I can make two loads with a Partition and a Ballistic tip that shoot very close to the same at 100 yards. The monos (Barnes) shot to the right enough to require a scope adjustment. Absolutely nothing to even talk about if that's all I wanted to shoot.

Ive read some interesting stories about the partition. Ive read stories it drove straight thru a huge moose, lenghtwise. Ive also read it loses its front half. I dunno what to think, except that Ive read way more that its one of the most reputable game stoppers, the metric all other hunting projectiles try to emulate. Its interesting because last elk I killed I recovered the projectile, a Hornady Interlock.... which lost its front half. yet it was a 1 shot kill I placed the bullet well. Maybe Im chasing my tail and wasting time if the interlock works the same. Some say its good the projectile breaks apart to inflict a larger wound channel, but keep in mind with a ligher .25 cal on elk Im guessing penetration is key...

I'm not concerned about a shift in POI with different projectiles as I find it pretty easy to adjust a scope zero in just one range session. I usually confirm with a second separate range sesson just cause Im OCD like that as well. (side note: I have a Leupole VX6 with a CDS dial, and plan on ordering a custom dial for each handload I develop. )

 

[BigGame]

I picked Barnes for my 25-06 because they sell heavier 100grn monolithics but the Hammer bullets are a bookmark I keep coming back to and considering... their heavier bullets need a twist rate faster than my 1:10 but their 92grn Hunter projectile is tempting to try but I'm not certain it will matter much between the Barns TTSX Ive selected. I'm just so limited in my caliber for what I'm wanting to hunt with it so I tend to lean towards anything heavier even if just a few grains. I dunno if it matters I'm just trying to maximize my opportunity best I can.

The basic tenants we learn about what makes an effective bullet are hard to shake. Using monolithics requires really examining some of the sacred cows. One of the things you'll eventually learn when you experiment with monolithics is that there's a great deal of variety in design within them. Monolithics are not monolithic. Barnes bullets are designed significantly differently from Hammer Bullets, for example. I'm happy to have a conversation about it with you one of these days, but it seems a bit offline to the original question of this thread. For the record, I'm pretty sure you derailed your own thread.

The Partition loses almost half of it's weight once it smacks into an animal. It expands and sheds most of the front half leaving the rear half, which keeps penetrating. The monolithic bullets start out lighter, but lose less of their weight on the way through.

What he said. This is the first basic tenants of monolithics you learn. Go lighter and faster and meet or exceed the penetration of bonded lead-core varieties. Some people find it hard to do this.

Maybe Im chasing my tail and wasting time if the interlock works the same.

Chasing our tails experimenting with bullets is what makes reloading so much fun. There are plenty of effective answers.

 

[Koda]

Barnes bullets are designed significantly differently from Hammer Bullets, for example. I'm happy to have a conversation about it with you one of these days, but it seems a bit offline to the original question of this thread. For the record, I'm pretty sure you derailed your own thread.

Were 3 pages deep into a post that answered my question a while ago.... feel free to "thread drift" if you want, your also one of the few here I trust with knowledge and are also always welcome to PM me if more prudent. I'm not certain Id believe in a "magic bullet" over another of the same class, but am very open to learning how different monolithic projectiles are manufactured and certainly if one is better than another Id go with that.
My decision on the Barnes TTSX came down to that or the Hammer. One day I found the TTSX on sale at Midway and in todays ammo crunch I instantly bought 300 of them, and they were on sale to boot. Further its not like Barns isnt a good brand.
I dont mind at all switching if I learn another brand is better... this is my hobby not my career or financial path I can make changes as I learn and dont care about cost or current investment.

 

[orygun]

I've only recovered one bullet and that's when I used a 30-30. 23" of penetration lengthwise in a deer. Recovering a bullet means it did it's job as the animal is dead. That was a Core-Lokt.
Using a 30-06 I've shot elk with Partitons. Dead elk, bullet MIA. I've shot deer with Ballistic tips. Dead deer, bullet MIA. I've shot deer with Core-Lokts. Dead deer, bullet MIA.
If you recover the animal or the bullet from it, the bullet did it's job.
Pick one and make it sing.

 

[Koda]

I've only recovered one bullet and that's when I used a 30-30. 23" of penetration lengthwise in a deer. Recovering a bullet means it did it's job as the animal is dead. That was a Core-Lokt.
Using a 30-06 I've shot elk with Partitons. Dead elk, bullet MIA. I've shot deer with Ballistic tips. Dead deer, bullet MIA. I've shot deer with Core-Lokts. Dead deer, bullet MIA.
If you recover the animal or the bullet from it, the bullet did it's job.
Pick one and make it sing.

Ive only recoverd a few bullets over the years and only more recently since I started elk hunting with the 25-06 I cared to keep track. Im one of those that think the 25-06 is to small for elk, but I know it can be done right and dont want to buy another rifle cause the 25 will just sit in the safe then. Anyways....
Years ago I took an larger antelope buck around 300 yards out, full frontal shot(he was looking straight at me) I aimed higher for the drop and hit him square in dead center in the spine, the 25-06 "pile drived" almost the entire spine wasting half the backstrap and exiting just over his bubblegum. I simply could not believe how much bone damage was done lengthwise to the spinal column from this caliber. Anyways, that's not an elk and I'm still concerned with frontal and quartering shots on elk at anything over 200 yards with such a light caliber. Ive taken 4 bulls cleanly with one shot but they were all 100yds or less. This year I sighted on a 4x5 bull I let go because I had a spike tag, he was exactly lasered at 195 yards out... prone position if I had made any slight error with all the excitement holding a nice bull in the crosshairs, I practiced on the spot that moment and its not easy being precise at longer distances with a heartbeat of excitement. From a benchrest at my gun club I coulda done a head shot easy... that moment in the field on the wet cold ground under a tree with a light drizzle of rain and my heartbeat (waiting for a spike to appear) where he could turn and dissappear in a moment, it was so much different than at the gun club benchrest. I coulda easily easily hit him square in the chest and took him down but I want that .25cal projectile to sail right thru him and I know I need to avoid heavy front shoulder bones.
I want a projectile that penetrates with this caliber.

 

[pharmseller]

Which cartridge are you shooting here?

.30–06


This one is more recent, from my brother's 7mm-08:





The three shots in the bullseye are the same as #8. So six shots in about half an inch.




P

 

[BigGame]

Were 3 pages deep into a post that answered my question a while ago.... feel free to "thread drift"

I'm happy to talk about monolithic reloading differences relative to lead core, and also happy to talk about differences among monolithics. But I'm also someone who has learned a great deal from forums like this and often it was through searching archives to find meaningful threads on things of interest to me. So I'm sensitive to making clean threads with meaningful topics. I'll start a new thread on reloading monolithics for hunting and let's all talk there. Bring Orygun and Pharmseller along. I know that Pharmseller and I share an affinity for the the mighty 7-08.

 

[Koda]

I'll start a new thread on reloading monolithics for hunting and let's all talk there. Bring Orygun and Pharmseller along. I know that Pharmseller and I share an affinity for the the mighty 7-08.

You have no obligation but as new to reloading for hunting if you start a thread Im listening and will watch for a thread. You Orygun, Pharmseller and a few others are names here Ive learned to trust on hunting and reloading.

 

[dangerranger60]

Ive read some interesting stories about the partition. Ive read stories it drove straight thru a huge moose, lenghtwise. Ive also read it loses its front half. I dunno what to think, except that Ive read way more that its one of the most reputable game stoppers, the metric all other hunting projectiles try to emulate. Its interesting because last elk I killed I recovered the projectile, a Hornady Interlock.... which lost its front half. yet it was a 1 shot kill I placed the bullet well. Maybe Im chasing my tail and wasting time if the interlock works the same. Some say its good the projectile breaks apart to inflict a larger wound channel, but keep in mind with a ligher .25 cal on elk Im guessing penetration is key...

I'm not concerned about a shift in POI with different projectiles as I find it pretty easy to adjust a scope zero in just one range session. I usually confirm with a second separate range sesson just cause Im OCD like that as well. (side note: I have a Leupole VX6 with a CDS dial, and plan on ordering a custom dial for each handload I develop. )

I have used partition bullets. They are an old design from before they learned to bond the core to the jacket. It was once pretty common to have the jacket separate from the core. So the jacket with the built in Partition was a way to keep most of that bullet intact. By the time I came along [ I'm in my 60's] Bonded bullets, and designs like Remingtons Core Loct bullets have made jacket separation practically a thing of the past. But Noslers Partition is still a good hunting bullet. It retains weight even after hitting something like a solid bone! Retained weight used to be a measurement that bullet manufactures advertised. Its what will push a bullet through a large animal! And in smaller calibers that weight becomes more important.
DR

 

[zenmariner]

If u follow Cortina seating nodes are about 6thou long, and my results have been that. I will load 4 rds of each depth Im testing and shoot 3 in a round robin. The 4 is in case I know I threw one

I will have a loose group then hopefully 2 tighter groups and a loose group. Your depth is between the two tight groups.

 

[DizzyJ]

To me, seating depth is critical.

Read this:

Getting the Best Precision and Accuracy from VLD bullets in Your Rifle

VLD bullets are designed with a secant ogive. This ogive shape allows bullets to be more efficient in flight (retain more velocity = less drop and wind deflection). While this result is desirable for many rifle shooters the secant ogive on the VLD bullets produces another result in many rifle.

bergerbullets.com

This is the exact process I've been using for years. I select my powder and work up charges over the chronograph in the backyard. I avoid compressed charges but I'm looking for a full case, 95% or better, for more consistent ignition. I look for pressure signs like extractor marks in the brass or stiff bolt lift, then back off half a grain or so.

Then I commence with my seating depth test.

Notice the following pics - the only difference is seating depth. I start with the shortest loads because if I find accuracy short I can always shorten the longer rounds.

View attachment 1075922

View attachment 1075923

View attachment 1075924

I stopped here. That's good enough for me, plus I was getting beat up by recoil.

This method has only failed me once, and that was on the rifle, not the process. I can't even begin to tell you how many loads I've worked up for various rifles over the last dozen years, for both me and my family.

YMMV, this certainly isn't the only way, but it works for me. Partitions, AB, BT, ELDX/M, TTSX. All the same.



P

The VLD Bullets can be EXTREMELY sensitive to jump.