Optimize bullet seating depth

[DizzyJ]

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 believe the lead free Bullets need to start with a .050" jump. I've read any closer and the pressure spikes really bad.

As far as increments, hard to say what you'll see group wise.

I can tell you I've seen noticeable changes in group size using .005" increments in jump with my .223 Savage.

When I want to fine tune after I've got the most accurate powder charge, this is my next step.

 

[Koda]

I believe the lead free Bullets need to start with a .050" jump. I've read any closer and the pressure spikes really bad.

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.

As far as increments, hard to say what you'll see group wise.

I can tell you I've seen noticeable changes in group size using .005" increments in jump with my .223 Savage.

When I want to fine tune after I've got the most accurate powder charge, this is my next step.

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.

 

[Lilhigbee]

You have to test in 137.34Å increments. Nothing else will work!!

 

[Local Loader]

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.

What is the powder charge you've tried and which powders, what bullet weights and types and which ones are you planning to use? You might be able to switch to a different powder and/or bullet and get the results you want at a lower pressure.

 

[Koda]

What is the powder charge you've tried and which powders, what bullet weights and types and which ones are you planning to use? You might be able to switch to a different powder and/or bullet and get the results you want at a lower pressure.

Im lucky to have what I got, theres no powder available these days. Ive got very lucky and have plenty of IMR4831 and Ramshot Magnum. I had to back way off with the IMR powder and compromise on desired velocity. but I then scored some Ramshot and my first rough ladder test got better velocity close to what I wanted with no pressure signs so far, so Im trying to go with that and see what seating depth works best.

 

[No_Regerts]

When it comes to cup and core bullets, I've generally had my best luck closer to the lands. With monolithics, I seem to do better with a little jump.

My process with cup and core bullets has been to load .01 off the lands when the magazine box allows for it (Hint: I only buy rifles that allow for it). I start no more than 5% under max and work up .2gr to the desired velocity or pressure, whichever comes first. If groups are similar, I pick velocity. Otherwise, I'll go with the charge that yields the best groups. I'll mess with OAL down to .05 off to see if it makes a difference. Usually the best groups are closer to the lands. However, I have a 700 that likes Hornady Interlocks and isn't sensitive to OAL, so I just seat on the cannelure for looks.

I don't kiss the lands with hunting ammo to make sure cycling is problem-free.

 

[drstrangelove]

I don't neck size either if I want problem free cycling.

 

[Local Loader]

Im lucky to have what I got, theres no powder available these days. Ive got very lucky and have plenty of IMR4831 and Ramshot Magnum. I had to back way off with the IMR powder and compromise on desired velocity. but I then scored some Ramshot and my first rough ladder test got better velocity close to what I wanted with no pressure signs so far, so Im trying to go with that and see what seating depth works best.

If you can find/get some IMR4064, IMR4895 or Win 760. They might be worth a try since they offer a higher fps without compression with the TTSX and Nosler Partitions.

 

[No_Regerts]

I don't neck size either if I want problem free cycling.

David Tubb, who has won lots of high power championships, quit neck sizing his match ammo as well. He recommends full length sizing everything.

 

[Koda]

When it comes to cup and core bullets, I've generally had my best luck closer to the lands. With monolithics, I seem to do better with a little jump.

My process with cup and core bullets has been to load .01 off the lands when the magazine box allows for it (Hint: I only buy rifles that allow for it). I start no more than 5% under max and work up .2gr to the desired velocity or pressure, whichever comes first. If groups are similar, I pick velocity. Otherwise, I'll go with the charge that yields the best groups. I'll mess with OAL down to .05 off to see if it makes a difference. Usually the best groups are closer to the lands. However, I have a 700 that likes Hornady Interlocks and isn't sensitive to OAL, so I just seat on the cannelure for looks.

I don't kiss the lands with hunting ammo to make sure cycling is problem-free.

this is close to what Ive haphazardly homed in on, except Im now super cautious of starting close to any max loads after learning how to do ladder tests and working up to a desired pressure that was listed in a manual and getting over pressure signs. I basically started over and settled on a lower pressure below any max and just compromised on desired velocity.
Some of my ladder tests showed better 1" groupings .005" off the lands though, but I wont kiss the lands since this is hunting ammo. Ideally I think Id like to see around .010" off the lands for hunting which is partly why Im wondering if I want to test in .005" increments.

 

[Koda]

I don't neck size either if I want problem free cycling.

A very knowledgeable forum member here influenced me to full length size and I have no regrets. Not just for hunting applications but apparently even benchrest shooters are moving to full length sizing. I learned to back off the sizing die to just bump the shoulder just enough to cycle freely in the chamber, I measure the shoulder with a gauge and it bumps it about .005" back consistently now. At first I was all over the place messing with my first few ladder tests which led to a lot of frustration and part of why this has taken me so long but in the end I think this is worth it.

 

[orygun]

I recently ran one partial ladder test. I did a dual ladder with Magnum primers for one, regular for the other, all seated .010" off of the lands. I had been all about maximum velocity, but one rung of the ladder showed promise of tight groups that this rifle had NEVER shot before. That rung was about 100fps short of what I thought I wanted, but the promise of 1/2" groups overrode the max velocity hunt. Like Koda, I'd picked a powder and have a lot of it (RL22), with not much else available. I'm pretty much locked in with components and minor incremental changes are what I'm looking at, too.

 

[Member 34319]

1.5moa is fine for hunting, I just figured if Im taking the time to handload it can do better. Plus, in this caliber Im planning on an antelope hunt in the future and would like to start practicing out past 300 yds. I dont see any harm in trying to develope a more precise load if the rifle is capable of it.

Took my only antelope at 300 yards using Remington corelok 30-06.

Just by taking some measures to be more consistent will likely bring your group in tighter.

 

[orygun]

Took my only antelope at 300 yards using Remington corelok 30-06.

Just by taking some measures to be more consistent will likely bring your group in tighter.

With a different 30-06 I shot the best 100 yard group I've ever shot with 150gr Core-Lokts. I had 4 in the magazine, but chickened out when I saw the first three thinking all I would do was mess it up!


I believe that I will shoot a 4 shot group like this with the load I'm using now in my 30-06 AI, but until then, this is my bragging target. By the way, this was off of the hood of my pickup.

 

[Koda]

With a different 30-06 I shot the best 100 yard group I've ever shot with 150gr Core-Lokts. I had 4 in the magazine, but chickened out when I saw the first three thinking all I would do was mess it up!

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...

 

[RVTECH]

How people shoot such good groups with a factory rifle with factory ammo is beyond me.

Lots if factors can play into it.

How much coffee did you have that morning? Have any alcoholic beverages the previous night?

How good is the rest or bench you are shooting off of? Seating, height and comfort have a lot to do with it.

A blackpowder long range shooter once told me he drank nothing alcoholic the night before a match or coffee the morning of it.

 

[orygun]

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...

I understand. I did that on my birthday and I think it was a present to myself. I rarely can do anything like that.

When I said off of my truck's hood, there's a bit to that. Perfect height for me. Had a heavy coat for a cradle and the rifle was rested very solidly. These days I have a bench, but the seat's too high and I have to raise the rifle rest and scrunch down to shoot. I really figured that out the last time I was shooting there. Next time I'll take the saw and shorten the seat. Proper posture will help, and help deal with the recoil, too.

Lots if factors can play into it.

How much coffee did you have that morning? Have any alcoholic beverages the previous night?

How good is the rest or bench you are shooting off of? Seating, height and comfort have a lot to do with it.

A blackpowder long range shooter once told me he drank nothing alcoholic the night before a match or coffee the morning of it.

For sure! I used to smoke cigars. Coffee and a cigar on the way to shoot meant I shot patterns, not groups!

 

[Member 34319]

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...

That Remington 700 I used when I was going nuts trying to find crazy precise reloads would shoot Hornady Superformance 3-5 shot groups at .25". Pissed me off so much. Spending all the time and effort to make a perfect load and a box of factory ammo did better.

It happens. I've had guns that shoot pretty horrible with factory ammo too.

 

[Koda]

That Remington 700 I used when I was going nuts trying to find crazy precise reloads would shoot Hornady Superformance 3-5 shot groups at .25". Pissed me off so much. Spending all the time and effort to make a perfect load and a box of factory ammo did better.

It happens. I've had guns that shoot pretty horrible with factory ammo too.

Mine never held a good group except with cheap Hornady American Whitetail ammo, when I try other "premium" brands the group is worse. I started handloading for it because I figured that was another component to improving accuracy... im still in the process of learning reloading for this though but along with being able to select the exact hunting projectile Im hoping it will be more precise than the Hornady ammo.

 

[pharmseller]

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.







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.



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