Jumping to the lands

[Archeryrob]

How much of anything is this to worry about for COL? I see people stating reload and set seating depth as close to the lands as possible. Other stating stop chasing them it does not matter.

I loaded cast for my Bergara B14 in 30-06 and got a OAL of 3.035. Then my daughter bought a Remington 770 in 30-06 and wanted to use my reloads. I can't chamber my reloads in her gun as they are too long. I made a dummy round and I kept moving the seating die until I hit 2.945 and they are Substantially different. Are chambers in different guns this far apart? I am thinking of pulling the bullet and trying again. I am wondering if I will loose grouping in my gun if I load to fit in hers.

Or am I worried too much?

 

[temccoy]

Hello - Loading the bullets so they are jammed into the lands will greatly increase the pressures and give you erratic results. It is not recommended. Also, why are you using cast bullets in a 30-06? Cast bullets are generally used in cartridges with lower pressures and velocities. Also, are you sure it is the bullet seating depth and not the case sizing? I would load just the empty case and make sure the bolt closes easily.

 

[4g64loser]

Hello - Loading the bullets so they are jammed into the lands will greatly increase the pressures and give you erratic results. It is not recommended. Also, why are you using cast bullets in a 30-06? Cast bullets are generally used in cartridges with lower pressures and velocities. Also, are you sure it is the bullet seating depth and not the case sizing? I would load just the empty case and make sure the bolt closes easily.

Rob uses cast bullets because he makes them himself and he likes to experiment. He has very graciously posted a lot of the results of his bullet testing for the benefit of members here, even a couple videos.

As to loading jammed, I will disagree with you as I often jam certain projectiles in my precision rifles. My 6br, for example, will shoot sub quarter MOA with 88 burgers jammed .018 to .020 hard with heavy neck tension. 105 VLDs also like a .010 or harder jam. The 105 hybrid is less touchy but still seems to do better at or in the lands. One of my .308 loads is a 155 VLD jammed .020 and it will usually outperform the 155 Palma (that prefers a .025 to .035 jump) in group testing though they are very close with their respective best loads. If you have a body of piezo test data or ballistic performance data that contradicts the several rifles I have worked up jammed loads in, I am open to hearing your results.

To OP, the throat depth in 308 and 3006 rifles tend to vary significantly. I have a Bisley reamer print 308 chamber in a Krieger that will *just* barely accept factory 168 federal gold medal match ammo. It was built to shoot 155 Palmas. I've measured factory chambers that you cannot realistically get a bullet to the lands. This makes the lawyers at the company happy, makes for comparatively high velocities (see materials on Roy Weatherby and his severely freebored chambers or measure a factory Remington ultramag chamber), and makes precision load tuning more of a.pain in the neck.

Given your intended bullet and use case, I'd suggest testing multiple seating depths in both rifles. Preferably after your establish the proper powder charge. If you want to measure your chambers precisely, shoot me a PM. I still have those SPC cases for you anyway.

 

[Archeryrob]

I did extensive testing on my Bergara and a ladder set and 37.5 grains spits them out very reliably at 100 and 200 yards at 2403 fps. I was just amazed how much different the sizing to the lands was between the rifles. If I did some, I could seat to 2.95 or 2.945 as I was just trying to see when it fit and not doing in the thousands. Then try them in mine and see if they can shoot both.

I wanted to switch to cast everything after the last mess. I believe in self reliance and I garden and kill deer and such the same. I would probably do primers if it wasn't such a PITA and so much past hard extra work into being anal about things. I think you can shoot cast out of anything. I might later try a harder lead in 30-06 and try and push it faster. I ran loads up to 2600 and no leading or problems, 2400, was just the consistent spot. I am working with running cast out of the AR and 6.8 spc now. Doing okay at 2250 right now and can't get any faster with a 140 grain bullet as I ran out of case for powder.

So, jumping .07 to the lands is not a problem that anyone knows of? I mean, they do look tapered like meant to channel the bullets into place. Watching video and some well know shooters said don't bother, other its terrible. I am just trying to get a feel for what other people know. I am assuming many commercial loads jump to the lands as if it loads in her rifle and I buy it for my Bergara, its got to jump!

I had the same thing with 30-30 and loaded based on the seating closest to the lands for the 336A about 1951 manufacturer date. Two buddies have 1980 -90 marlins 336's with micro grooves and they can't chamber my rounds as they bullet hits the lands, but it fits perfect in mine.

 

[4g64loser]

I did extensive testing on my Bergara and a ladder set and 37.5 grains spits them out very reliably at 100 and 200 yards at 2403 fps. I was just amazed how much different the sizing to the lands was between the rifles. If I did some, I could seat to 2.95 or 2.945 as I was just trying to see when it fit and not doing in the thousands. Then try them in mine and see if they can shoot both.

I wanted to switch to cast everything after the last mess. I believe in self reliance and I garden and kill deer and such the same. I would probably do primers if it wasn't such a PITA and so much past hard extra work into being anal about things. I think you can shoot cast out of anything. I might later try a harder lead in 30-06 and try and push it faster. I ran loads up to 2600 and no leading or problems, 2400, was just the consistent spot. I am working with running cast out of the AR and 6.8 spc now. Doing okay at 2250 right now and can't get any faster with a 140 grain bullet as I ran out of case for powder.

So, jumping .07 to the lands is not a problem that anyone knows of? I mean, they do look tapered like meant to channel the bullets into place. Watching video and some well know shooters said don't bother, other its terrible. I am just trying to get a feel for what other people know. I am assuming many commercial loads jump to the lands as if it loads in her rifle and I buy it for my Bergara, its got to jump!

I had the same thing with 30-30 and loaded based on the seating closest to the lands for the 336A about 1951 manufacturer date. Two buddies have 1980 -90 marlins 336's with micro grooves and they can't chamber my rounds as they bullet hits the lands, but it fits perfect in mine.

Your blunter ogives are likely to be more.jump tolerant than some secant ogive, longer nosed, designs (think berger VLD). I actually have a barricade practice load using speer 130gr 30cal pills that jumps nearly .100 and shoots at about half MOA in one of my match rifles.

There are no guarantees but you may find a jump to shoot fine. Must test. From a safety perspective, a .070 jump is not a hazard at all.

 

[atblis]

Hello - Loading the bullets so they are jammed into the lands will greatly increase the pressures and give you erratic results. It is not recommended. Also, why are you using cast bullets in a 30-06? Cast bullets are generally used in cartridges with lower pressures and velocities. Also, are you sure it is the bullet seating depth and not the case sizing? I would load just the empty case and make sure the bolt closes easily.

I used to never load bullets into the lands, and then I read and followed this process and it worked nicely. The biggest concern with “jamming” seems to be the situation where the bullet is left behind when extracting a loaded round. This is regarded as a bigger problem in a hunting versus a target shooting scenario.

How to Load a VLD Bullet

You don't need to be an advanced hand loader to load VLD bullets, just follow these simple steps and you'll be shooting vlds in no time!

bergerbullets.com

Cast bullets in high power rifle cartridge often shoot surprisingly well and provide a fun and cheap experimentation process.

 

[Archeryrob]

I was not worried about a hazard, but bullets off course, key holing and such. I wonder if a key holed bullet would kill a deer. better.

SARCASM!

 

[Doco Overboard]

That’s the idea, especially with cast bullets to be able to position the bullet in best position possible in the bullet seat.
By doing so, the practice is preventative to prohibiting hot gases from flame cutting the bullet prior to forcement, overcomes already established wear to the leade and helps support symmetry to the cartridge case and the prolongation of the bore axis. Especially when using rimless cases because of head gap and differences in chamber dimensions.
Ross, Newton, Pope and Lovell did the same thing with jacketed bullets and produced accurate systems because they controlled the ammo specifications for the firearms they manufactured.

 

[Archeryrob]

Well, I understand, but the bullet is past the neck barely in mine and further in with hers. 175 grains at .309 is fairly long and got to be filling the lands before the neck is open.

So are you saying it could allow gas around it and fail on mine with a longer jump?
If so, that would mean separate OAL's per gun.

 

[deerassassin22]

You need to get the hornady comparator gauges for this to get a pretty exact measurement its different for each gun and bullet these gauges take the guesswork, out of it and can help monitor erosion as well.

 

[Melnic]

waiting for John to weigh in cause he is very experienced with cast load accuracy and what to pay attention with.
Personally, there were more things to get accuracy on than loading to the lands and one was the bullet itself. I don't load rifle powder coated cast looking for accuracy. Compared to a purchased match bullet, nothing I cast and powder coat can come close. I"m sure John has done better and maybe it was not powder coated. I sort of feel that powder coating is for 2MOA accuracy and not much better but that is me. I just feel that the bullet to bullet consistency for everything that counts is just not there with PC. (at least mine)

Also, highly likely with PC he is not approaching high pressures to begin with even gas checked, but that is a good thing to look at before going to lands end.

 

[deerassassin22]

I think if you are trying to get accuracy with Lead you would have to sort them weight and base to Ogive then seat appropriately. Along with ensuring your powder charge is extremely accurate with .2grains

 

[guzma393]

How much of anything is this to worry about for COL? I see people stating reload and set seating depth as close to the lands as possible. Other stating stop chasing them it does not matter.

I loaded cast for my Bergara B14 in 30-06 and got a OAL of 3.035. Then my daughter bought a Remington 770 in 30-06 and wanted to use my reloads. I can't chamber my reloads in her gun as they are too long. I made a dummy round and I kept moving the seating die until I hit 2.945 and they are Substantially different. Are chambers in different guns this far apart? I am thinking of pulling the bullet and trying again. I am wondering if I will loose grouping in my gun if I load to fit in hers.

Or am I worried too much? View attachment 465786

Hey, those look similar to my 7.5 swiss casts which i have to seat a similarly fat ogived bullet to accomodate for a tight throat. I experimented with chasing the lands with casts and it was more trouble than it was worth (kept jamming the bolt action) with little gain.. The most accurate I have ever gotten casts to were following other practices, i.e. consistent grain weights, optimal bullet hardness, optimal velocities, consistent seating, and optimal fit to the bore.

 

[Archeryrob]

I think I am going to load 50 for her gun in that OAL and try some in my gun as 200 yards vs the ones I know in my OAL. See if they shorter OAL works in my gun still or the longer one is better.

I have the comparator gauges, but I thought that was for measuring the shoulders for full length resizing and setting the die.

 

[deerassassin22]

I think I am going to load 50 for her gun in that OAL and try some in my gun as 200 yards vs the ones I know in my OAL. See if they shorter OAL works in my gun still or the longer one is better.

I have the comparator gauges, but I thought that was for measuring the shoulders for full length resizing and setting the die.

You want this set

Lock-N-Load® Bullet Comparator - Hornady Manufacturing, Inc

Lock-N-Load® Bullet Comparator & Inserts Lock-N-Load® Bullet Comparator Measuring cartridge lengths across the bullet tips is not a reliable (or repeatable) method for meas...

www.hornady.com

 

[Archeryrob]

So this works with the shoulder set, or is a completely different set? It measures what? I measure OAL with calipers now, what does this do different? Measuring the ogive on each bullet? So flat meplats and spires will be way different in length on this thing, correct?

Still I fail to understand how this will help my current problem. I have two different rifles that the ogive would be drastically different. The same cast bullet seating much short in my daughter gun than what mine will allow.

Bullet Comparator – Complete Set Item #B14
Comparator body and all 14 bullet inserts for bullet diameters: .172," .204," .224" (5.56mm), .243" (6mm), .257," .264," .277," .284" (7mm), .308," .338," .358," .375," .416," .458"

 

[deerassassin22]

This will help you identify where your lands are for a given bullet. So every type you switch bullets you should do this so you know how far your jumping your bullets to the lands. This will also give you your base to OGIVE measurement which is more accurate then your COAL due to the fact that COAL various based on the bullet tipping process and type of bullet.

 

[deerassassin22]

So this works with the shoulder set, or is a completely different set? It measures what? I measure OAL with calipers now, what does this do different? Measuring the ogive on each bullet? So flat meplats and spires will be way different in length on this thing, correct?

Still I fail to understand how this will help my current problem. I have two different rifles that the ogive would be drastically different. The same cast bullet seating much short in my daughter gun than what mine will allow.

This helps your current problem by allowing you to reload for each rifle's sets of lands then you will need to adjust charges etc, if your loading to Sammi spec the loads should fit in both guns. But since you are using lead and coating them a lot of other factors could come into play like coating thickness, leading, etc. Have you put a borescope down them both?

 

[Archeryrob]

So we are back to a separate OAL for each rifle then. I am pretty sure I already fairly closely determined a separate OAL for her gun.

Also won't every guns lands be different than this comparator? I have two guns with different seating depths based on their lands. IMO, this comparator is only going to simulate a single set of lands.

 

[AlBeight]

I have no intelligent opinion on this matter, and only a minimal understanding of the topic, but I came across this video on YouTube by Eric Cortina. He’s a very well regarded champion long range and bench rest shooter. I just thought this video might help your decision(s). Not only does he not recommend doing it, but he calls it “stupid”, that seems pretty definitive.