Switching Bullets Brands Lazy Load Development

[BoltBandit]

About to do some new load developement because Berger Target Hybrids are damn near impossible to find, so I'm working up something for the Hornady ED-M.

My question is this.

If I'm switching from Berger Target Hybrid 140gn to the Hornady ELD-M 140gn bullet, should I do a full blown load development? Or can I take the recipe from the Berger's and just simply tweak it.

I've always understood that finding an accuracy node is dependent on how much time the bullet spends travelling down the length of the barrel, which of course is adjusted by bullet speed through charge weight, seating depth, neck tension, etc. etc.

My theory here is that the bullets are the same weight, so the same powder charge should theoretically push the bullet out of the tube at approximately the same velocity. The big variable in my mind is going to be seating depth due to differences in diminsions of the bullet. If my starting point is .020" off the lands, one bullet may seat deeper than the other, resulting in more case pressure and more speed.

Does anyone have any real life experience with this?

 

[FredHammer]

This is handloading 101 here. Do an individual load development for each bullet selected. Bearing surfaces, nose/ogive shapes/lengths of bullets vary, pressure differently and like different COAL/CBTOs.

 

[Rio Precision Gunworks]

Just look at data posted online and look for the biggest trend with your bullet/powder combo. There's a reason people end up using very close to the same load. Especially when it's something as common as 6.5cm and 140eld.

Find the window where most people are on charge weight and seating depth, then work from there. It'll save you the time of starting from the ground up. Start a little below the bottom of the powder charge window and work up, and start at the longest seating depth and work back.

 

[Ledzep]

Firstly, I haven't seen evidence of an optimum velocity for dispersion.

Each different colored line is a different powder. All of this data is the same bullet in the same barrel at the same seating depth. Each point/dot is a 20-shot string worth of data. Left axis is mean radius at 200yd, bottom is velocity in FPS

Here's a similar graph in a different cartridge with a different bullet

So the general trend that I've seen between these tests and many others is that the lower the velocity/charge weight, the lower the dispersion. However, as you can see some of those trend lines are very flat and the functional difference between them is very small. Often times from a hit probability standpoint, a slight gain in mean radius is worth the 200+fps gain possible over the spread of safe charge weights... Conversely, sometimes a 100fps hit in velocity is very much worth the help in dispersion that results.

Anyway, with that basic supposition removed, and with some anecdotal experience of mine, I'd say NO, you can not expect to swap from a 140 Berger to a 140 Hornady and achieve the same results. From a safety standpoint, I would always suggest dropping charge 10% and starting over if you're anywhere near the top of book data. The idea that they're the same bullet weight so they'll have the same pressure/velocity is also not necessarily true. Bullet weight is one of the main contributors to the pressure created, but another huge part is the length of bearing surface and yet another part is bullet rigidity. You can get 10,000psi difference easily between two different 140gr 6.5mm bullets with the same jump and powder charge. One bullet is fine, the next one blows a primer if you're on the edge to begin with.

What I have seen, and what I suspect you will see if you care to test it in-depth, is a distinct and different level of performance between the two bullets with the same powder and charge (assuming both are safe loads). You may need to try different powders or a different charge weight to get the 140 ELD-M to the same level you currently have with the Berger, or it may very well shoot better right off the bat. You won't know until you try it out.

That said, 140gr ELD-M with 41-41.5gr H4350 with a .020-.040" jump (pick a number in there, they're not sensitive), is a good starting point in a 6.5 Creedmoor.

 

[BoltBandit]

This is handloading 101 here. Do an individual load development for each bullet selected. Bearing surfaces, nose/ogive shapes/lengths of bullets vary, pressure differently and like different COAL/CBTOs.

Yeah, I knew it was probably wishful thinking, and it working out like that was highly improbable, lol.

 

[BoltBandit]

Just look at data posted online and look for the biggest trend with your bullet/powder combo. There's a reason people end up using very close to the same load. Especially when it's something as common as 6.5cm and 140eld.

Find the window where most people are on charge weight and seating depth, then work from there. It'll save you the time of starting from the ground up. Start a little below the bottom of the powder charge window and work up, and start at the longest seating depth and work back.

Thanks for the reply. Yeah, definitely hoping to get lucky, but kinda what I expected. LD is just a tedious process, especially factoring the back and forth to the range. No shortcuts I guess, lol.

 

[FredHammer]

Yeah, I knew it was probably wishful thinking, and it working out like that was highly improbable, lol.

I get it. I kinda did the same thing wishful thinking switching between ELDMs and Hybrids in my 300WM. I didn't want to waste many components finding the Hybrid load, and I didn't, but the 215 Hybrid and 208 ELDM are very different creatures.

 

[Rio Precision Gunworks]

Thanks for the reply. Yeah, definitely hoping to get lucky, but kinda what I expected. LD is just a tedious process, especially factoring the back and forth to the range. No shortcuts I guess, lol.

Take an arbor press and inline seating die to range. Get a bunch of capped vials like pictured below. Fill enough vials with powder charges to test seating depth.

Load your initial powder charges and such, then use that data to decide what vials/charges to use and seat them in an arbor press.

Just takes a little logistic planning and you can take everything you need in one trip.

 

[BoltBandit]

Firstly, I haven't seen evidence of an optimum velocity for dispersion.

Each different colored line is a different powder. All of this data is the same bullet in the same barrel at the same seating depth. Each point/dot is a 20-shot string worth of data. Left axis is mean radius at 200yd, bottom is velocity in FPS
View attachment 8324743


Here's a similar graph in a different cartridge with a different bullet
View attachment 8324749

So the general trend that I've seen between these tests and many others is that the lower the velocity/charge weight, the lower the dispersion. However, as you can see some of those trend lines are very flat and the functional difference between them is very small. Often times from a hit probability standpoint, a slight gain in mean radius is worth the 200+fps gain possible over the spread of safe charge weights... Conversely, sometimes a 100fps hit in velocity is very much worth the help in dispersion that results.

Anyway, with that basic supposition removed, and with some anecdotal experience of mine, I'd say NO, you can not expect to swap from a 140 Berger to a 140 Hornady and achieve the same results. From a safety standpoint, I would always suggest dropping charge 10% and starting over if you're anywhere near the top of book data. The idea that they're the same bullet weight so they'll have the same pressure/velocity is also not necessarily true. Bullet weight is one of the main contributors to the pressure created, but another huge part is the length of bearing surface and yet another part is bullet rigidity. You can get 10,000psi difference easily between two different 140gr 6.5mm bullets with the same jump and powder charge. One bullet is fine, the next one blows a primer if you're on the edge to begin with.

What I have seen, and what I suspect you will see if you care to test it in-depth, is a distinct and different level of performance between the two bullets with the same powder and charge (assuming both are safe loads). You may need to try different powders or a different charge weight to get the 140 ELD-M to the same level you currently have with the Berger, or it may very well shoot better right off the bat. You won't know until you try it out.

That said, 140gr ELD-M with 41-41.5gr H4350 with a .020-.040" jump (pick a number in there, they're not sensitive), is a good starting point in a 6.5 Creedmoor.

Thanks Ledzep! This is a super informative graph. As I've responded before, I was expecting this response in general, but was hoping to get lucky. Also as you've pointed out, looks like I was on the right track in saying the difference in bullet shape would change the seating depth, pressure, etc etc. Now 10k jump in psi? Wow! That was not something I expected.

I'm definitely working in safe pressure ranges, at least based on visual inspection. My sweet spot with the Berger's was 42.2gn of H4350, and .020" off the lands. I'm sure I could tweak it more, but i was getting 3/8" 3 shot groups pretty consistently, which is more than accurate enough for PRS IMO. My time is way better spent on the barricade with a DFAT than on the bench.

I ran a ladder test (I know, not the most precise method), starting at 41.6 and went up to 43.6 in .02gn increments and no visual signs of over pressure (flattened primers, primer strike pushed back flat, or imprint of the bolt face on the case head. Unfortunately, I botched that test like a complete noob. My ladder test was grouping rather than stringing upwards. I'm using brand new Lapua brass as well. I was in a hurry, and forgot that I had adjusted the length of pull when I took my friend and his son shooting. Not much, but enough. It was cold as hell, a big poofy jacket, and I was in a hurry, so I think my recoil management went to shit, unbeknownst to me. Lesson learned, so I'm back at the bench to redo a sloppy test to begin with. That's my best guess at least.

 

[BoltBandit]

Take an arbor press and inline seating die to range. Get a bunch of capped vials like pictured below. Fill enough vials with powder charges to test seating depth.

Load your initial powder charges and such, then use that data to decide what vials/charges to use and seat them in an arbor press.

Just takes a little logistic planning and you can take everything you need in one trip.


View attachment 8324794

That's a fantastic idea!!! Thank you!

 

[Rio Precision Gunworks]

That's a fantastic idea!!! Thank you!

You can even get something like a Harrell's bench press and size at the range if you want.

 

[Niles Coyote]

In my last few 6.5 creedmoor barrel's the ELD was within a couple tenths of a grain from what I used with the 140 hydrid. The ELD has a longer bearing surface and may shoot at a few fps slower than the Berger.

 

[Chris1972]

Rio why the Harrells?

 

[Rio Precision Gunworks]

Rio why the Harrells?

Doesn't matter which. That's just the one I could think of off the top of my head. There are numerous presses made for a bench at the range.

Hell, if you wanted, you could weld up a platform that goes in your trailer hitch and mount your favorite normal press to it. Or mount a normal press on 2x6's long enough to span the bench and then use C clamps to hold the 2x6 down.

 

[nn8734]

The Harrels press is great for loading on the go... I take it along with the rest of my mobile reloading kit to do all my load development/testing/adjusting at the shooting spot. Saves me from making multiple trips and I can usually arrive at a final load for a given rifle that day...I size, prep and prime all brass ahead of time and just charge and seat at the spot, for efficiency...

Here's my crude but effective set up.

 

[Chris1972]

I take my Zero to the range but it’s a pain in ass transporting it. I have an extra rockchucker I may get a stand for.

 

[BoltBandit]

I take my Zero to the range but it’s a pain in ass transporting it. I have an extra rockchucker I may get a stand for.

Those look nice as hell, but just not in the budget anytime soon.

 

[Rio Precision Gunworks]

Those look nice as hell, but just not in the budget anytime soon.

SAC is releasing a press next week. I'm fairly sure it will be a co-ax style and expecting it to be cheaper than zero press.

 

[Chris1972]

The Zero is nice but I can’t say for certain I would buy again. The T-7 is a pretty impressive unit itself and I still use it for .260 and 45 Colt instead of changing heads on the Zero. Yes, the .260 is precision ammo. I wasn’t compelled to change.

 

[BoltBandit]

SAC is releasing a press next week. I'm fairly sure it will be a co-ax style and expecting it to be cheaper than zero press.

I'll give it a look. Im using a dillon 550 at the moment, and it works pretty well. Beats changing dies like i did on the rockchucker, but I'm always looking for new shit to buy!

 

[BoltBandit]

The Zero is nice but I can’t say for certain I would buy again. The T-7 is a pretty impressive unit itself and I still use it for .260 and 45 Colt instead of changing heads on the Zero. Yes, the .260 is precision ammo. I wasn’t compelled to change.

Ive heard great things about the T-7 as well.

 

[beetroot]

I'm a big fan of lazy reloading.

Typically I just do some Google searches to find what others are doing.
Find a range of about 2gr and jump straight in.

I had a 260 load that I changed brass, projectiles (amax to ELDs) and primers.
Did a test of original load and +/- .3, found the original powder charge ok and +.3 was excellent.

 

[MarkyMark007]

Ledzep, thank you for your research and data sharing.

In first your picture it seems that goup is getting bigger at 2750fps, and in second at 2650 (with a lot of imagination .

Can we have a theory that group is getting bigger after certain bullet's rpm=spinning?

 

[supercorndogs]

You can make a hypothesis anyway. A theory is not supposed to be a guess.

 

[mrcheesemoose]

Ledzep, thank you for your research and data sharing.

In first your picture it seems that goup is getting bigger at 2750fps, and in second at 2650 (with a lot of imagination .

Can we have a theory that group is getting bigger after certain bullet's rpm=spinning?

Likely it’s because when you push things faster there’s more forces imparted on the bullet, which exaggerates small issues on the internal, and external ballistics side. Based on the graph, the small issues on the internal ballistics side get exaggerated a whole lot more than the external ballistics since the type of powder has a much greater impact on whether it gets worse then not. Based on that, I think it probably has more to do with the barrel/bullet interactions and how the powder burns at higher pressures, then anything else.

 

[458win]

Load a few up and go try it. Easiest way.