AI for Load Development

[Sgt_Mike]

Interesting ,,,
What was the recommended method, has been the method I've used in working up loads for a good bit. (0.3gr increments, 0.003" seating increments, usually best loads are around / within 1ish grs of listed max for the upper node, in my experience)

Although the components I used in the Remington PCR 700 (6.5 CM) was Winchester 6.5 StaBALL powder Barnes 145gr Match Burners, in SRP Starline Brass.

I asked grok using the components listed above just to see how close the response would be to my load.

Grok's response was start at 54.0grs, now a quick review of Hodgdon website shows the max for that powder to be 43.3grs with a 147gr bullet (2grs heavier bullet than my listed bullet). The real life node I found was 0.5gr wide, 42.0 to 42.5 grs.
The bullet seating was within 0.010" of what I had the bullet (I was longer).

Not quite sure why it showed 54.0 gr for a start, or where that came from. Heck I honestly don't think 54.0gr will fit in the case. The only thing I can think of was the manner in which I asked the question? I did list the model of the 700 which is Remington 700 PCR (Precision Chassis Rifle) which may have caused the fluke being so close to the 6.5 PRC round.
However it did list the specs exactly for the rifle in twist, length, barrel profile, including the 6.5 CM cartridge.

Just looked up the 6.5 PRC after typing the above, yeah 54.0grs of Winchester StaBALL HD would be a safe start load with a 147gr bullet. StaBALL HD is quite a bit slower than 6.5 StaBALL on the burn charts. The PRC case has more volume. Grok had to have given the StaBALL HD 6.5 PRC load data, even with identifying the correct caliber.

GIGO --- Garbage in Garbage out.

If it is that sensitive to input yeahhh maybe not for me.
Outside the suggested start load, like I said it did align with the methods I already employ so that is good in my opinion. Understand I'm not slamming Grok /AI just sharing the experience / observation with it. Had I just listed Remington 700 and the caliber then components, the response might have been more in alignment with reality.

 

[Animalaxe]

Yea, it’s not perfect and sometimes you have to clarify. “54 grains exceeds the max load in 6.5 CM. Are you using 6.5 PRC data?”. I have a long running thread about reloading with grok, so I usually start out with something like “do you remember my load development with the 6.5 CM Ruger American with the Banish 30?” If it comes back with more detailed data about my rifle and load I know we’re on the same page. If not, I feed it more details until we are. It’s a little bit of a learning curve getting the right questions asked, but I’ve been hand loading for a long time so, like you, I can tell when the data it spits back is a little wonky.

 

[Animalaxe]

Here’s another Q&A:

I have three pounds of Varget on the shelf and I want to use it to reload 6.5 CM, 6 CM and 22 Creedmoor. What bullet weights work best with varget in these calibers.

Answer:

Varget (Hodgdon) is an excellent extruded powder—temp-stable, consistent, and accurate in many short-action cartridges. It shines in medium-burn-rate applications but is on the faster side of the spectrum for these Creedmoor family cases. It delivers top-tier velocity and accuracy with lighter-to-midweight bullets, while heavier bullets often perform better with slower powders like H4350, RL-16/17, or StaBALL 6.5.


Always use current published load data from Hodgdon, Hornady, Sierra, or Lyman as your starting point. Begin 10% below maximum (or at the listed start charge), work up in 0.3–0.5 gr increments, and watch for pressure signs (flattened primers, sticky extraction, etc.). Factors like barrel length, twist rate, brass, primers, and OAL affect results. Your 3 lb jug is enough for extensive load development plus hundreds of rounds across all three calibers (typical charges run 33–42 gr).


Here are the bullet weights that work best with Varget in each caliber, based on manufacturer data (Hodgdon/Hornady/Sierra/Lyman) and real-world reports:


6.5 Creedmoor


Best: 115–130 grain bullets (sweet spot 120–130 gr).


Varget gives excellent accuracy and efficient velocities here (e.g., 123 gr Sierra MatchKing or 130 gr TMK/ELD-M at ~38–40 gr yields 2,850–2,960 fps with sub-MOA groups in many rifles). It’s commonly praised for 120–124 gr hunting/match bullets.


• Heavier 140–147 gr bullets are possible but suboptimal—Varget is a bit too fast, so you get lower velocities than with H4350.


• Lighter 85–107 gr varmint bullets also shoot well but aren’t the typical use case.
Examples from tested data: 123 gr SMK ~39.2 gr Varget for ~2,900+ fps; 130 gr loads in the high 2,700s fps.


6mm Creedmoor


Best: 85–108 grain bullets (particularly 95–105 gr).


Varget works nicely for mid-weight match and hunting bullets. Lyman data shows good charges for 105 gr Berger Hybrid (31.0–34.9 gr). Hornady lists it for lighter varmint bullets (58–75 gr V-MAX at up to ~42–44 gr). Some PRS shooters have used it successfully with 105–108 gr Hybrids (~36 gr).


• It’s not the optimal powder for 108–115+ gr heavies (slower powders like H4350 or RL-16 deliver higher velocity). Hodgdon’s online data center doesn’t always list Varget for the heaviest 6mm CM bullets, confirming it’s better suited to the lighter end.


22 Creedmoor (SAAMI-standardized)


Best: 60–75 grain bullets (especially 62–68–75 gr).


Hornady’s official data specifically lists Varget for these lighter, high-velocity loads:


• 62 gr ELD-VT: ~35.9–38.3 gr (3400–3600+ fps range).


• 68 gr BTHP: ~33.6–38.0 gr (3200–3700 fps range).
User reports confirm excellent results with 69 gr Sierra MK (~39 gr Varget for ~3,340 fps). Great for varminting or light match bullets.


• 80 gr+ (ELD-M/X) is possible but suboptimal—Varget runs too fast; Hornady and forums recommend slower powders (H4350, RL-26, etc.) for best velocity and pressure with heavier bullets. 85–90 gr is generally too heavy for Varget.


Quick tips for success with your Varget:


• Twist rate matters: 1:8” is ideal for stabilizing the weights above in all three calibers.


• Use a chronograph and work up carefully—Varget meters well but compression can vary.


• For maximum performance across all three, you’ll eventually want a slower powder for the heavier bullets, but Varget will get you plenty of accurate, fun-to-shoot loads right now.


If you tell me your barrel lengths, specific bullets/brass you own, or desired velocity goals, I can help narrow it further or point to exact starting charges from the manuals. Stay safe and enjoy the reloading!

 

[Sgt_Mike]

Yeah the way I posed the question was
"Most accurate load for Remington 700 PCR 6.5 Creedmoor, Winchester 6.5 StaBALL powder, Barnes 145 gr Match Burner, Starline SRP brass"

Which spit out the above listed 54 grs. Which honestly, I decided to refine the question at which point it wanted me to log-in create an account. Not desiring to do that I just let it lie right there.

 

[Animalaxe]

I took “PČR” out of your question and left everything else the same. Here’s what I got:
Is this close to your real world results?


The most accurate published and real-world load for your exact combo (Remington 700 6.5 Creedmoor, Winchester StaBALL 6.5 powder, Barnes 145 gr Match Burner, Starline SRP brass) is 42.7 grains of Winchester StaBALL 6.5 at a COAL of 2.825”.


This node has been documented in precision forums delivering .26 MOA groups at 200 yards (~2,685 fps, SD ~12 fps) in a 24” barrel—exactly matching most factory Remington 700 6.5 CM configurations. A nearby node at 43.2 gr also produced sub-0.5 MOA with excellent SD/ES. These come from direct user testing with the 145 gr Match Burner and StaBALL 6.5; no single “book” load is magically the most accurate because every rifle (throat, twist, barrel harmonics) is unique.


Official Barnes Load Data (your exact bullet)


Tested in 24” barrel, Hornady brass, standard primers, 2.825” COAL:


• Start: 39.2 gr StaBALL 6.5 → 2,439 fps


• Max: 44.1 gr StaBALL 6.5 → 2,762 fps


Barnes lists this as compressed at the top end. Your Starline SRP brass has a slightly different internal volume than Hornady (real-world reports show it can run 0.5–1 gr “hotter” pressure-wise because of the small primer pocket design), so treat 43.5–44.0 gr as your practical max and watch for pressure signs.


Recommended Load Development Protocol for Your Remington 700


1. Primer: Small Rifle (CCI 450, Federal 205M, or CCI #41 if you want military-spec). Starline SRP brass + StaBALL 6.5 likes a good small-rifle primer for consistent ignition.


2. COAL: Start at Barnes spec 2.825” (gives ~0.050–0.100” jump in most Rem 700 chambers). You can seat longer if your mag allows (up to 2.850–2.900” common in Rem 700) and do an OAL ladder once you find a velocity node.


3. Charge ladder (0.3 gr increments, 3–5 shot groups, chronograph mandatory):


• 40.0 gr (safe start)


• 40.3 → 40.6 → … → 43.0 gr (expected sweet spot)


• Stop at first signs of pressure (flattened primers, sticky extraction, ejector marks).


4. Expected results in a typical 24” Rem 700: 2,670–2,710 fps at the 42.5–43.0 gr node with single-digit SD/ES and sub-0.5 MOA.


Starline SRP note: The brass is excellent and very consistent, but because it’s thinner-walled / different volume than Hornady, start 0.5 gr lower than you would with standard LRP brass and watch closely near 43+ gr. Many users run identical charges to book data without issue once they verify with their rifle.


Safety & Final Reminders


• Always begin 10% below the listed start or at 39.0–40.0 gr.


• Work up in your rifle only—do not copy anyone else’s max load.


• Use a chronograph and watch for pressure. StaBALL 6.5 is temp-stable and meters like a dream, but it’s a ball powder—clean your barrel after each session.


• This load is for your specific components; Remington 700s love it because of the barrel harmonics around 42.5–43 gr with heavy match bullets.


If you tell me your barrel length, current COAL, primer brand, or what velocities you’re seeing, I can refine the ladder even tighter. Load safe, shoot straight, and enjoy that sub-MOA 6.5 CM!

 

[Sgt_Mike]

@Animalaxe Grok output = 43.0 gr (expected sweet spot)

Start at Barnes spec 2.825” (gives ~0.050–0.100” jump in most Rem 700 chambers). You can seat longer if your mag allows (up to 2.850–2.900” common in Rem 700) and do an OAL ladder once you find a velocity node.

Real world 42.0 to 42.5grs was the Node. So the actual load is dead between the two.... 42.2grs ( 0.8grs difference in my load and Grok suggest)
Bullet seating Real world 2.266 CBTO (COAL is 2.979").

So actually not far off at all to a actual load that was worked out prior to you posting this question. (the primers are win #41 5.56mm primers).

I didn't use a chronograph (yet) when I fired these, which all the 5 shot groups was within a 2% variance for five different groups at differing times, thus far 0.45 average .
-------sidebar--------------------------------------------
The other load that actually shot better than the Barnes was using the same powder (StaBALL 6.5) @ 44.7grs, Sierra 120gr SMK, (2.239" CBTO, 2.753" COAL) = 0.315 five shot group average again held with 2% for five differing times and groups.
-------------end of side bar back to topic------------------------
At the time I developed those two loads I didn't have a chronograph, but now I do so yeah at some point I'll chrono those two loads

 

[Sgt_Mike]

IIRC I started the Barnes 145gr loads at 40.4grs at 0.3 increments 1 round each. found the the widest node at 41.9 to 42.5. because most powder measures are within 0.1grs is why I say 42.0 to 42.5 .
In the pressure testing I went up to 43.7grs, still didn't have pressure signs. Having noticed the widest Node I settled the charge at that node and adjusted seating.

My jam or into lands length was 2.298" CBTO, I shot the pressure /ladder @ 2.288" CBTO, then adjusted CBTO using three shot groups went to 2.266 CBTO (0.032" Jump). AT which point I shot solely five shot groups to verify the charge and seating depth. (there was / is another node in the upper limit 43.4grs but is extremely narrow, so not useful)

Don't know if the above information help you in your choice to use / and or promote the AI concept.

While I'm not a initial fan, doesn't mean I won't be open minded and share honest data / results. From my point of view not Exactly spot on ... but it sure is close when one doesn't have a clue which way to go.

 

[hm1996]

Not reloading any longer and all my books and data are gone, but this is a very interesting thread. I wish I had kept the data from working up my load w/H450 (which was an obsolete powder) and an obsolete bullet (Nosler 100 gr. solid base SP) for my 243 WSSM when the 243 was a brand new cartridge. Hornady was the only book listing any data at all for that cartridge at the time. Can't help but wonder how ol Groc would compare to my results on that one.
Like Mike said, the recommended method of working up loads is almost identical to what I used for years. If I were still reloading, I would probably ask "Groc" when starting to work up a load just to see how close "his" predictions would be and work up the load as I have for many years (reference a number of different books, pick a starting load and work up in .2 to .5 gr increments depending on case size to find the node).

 

[Bob_Atl]

that's the key to AI, the detailed prompt, ie,
"the more I use it, the better I get at asking questions in a way that get me the info I’m looking for".

 

[Sgt_Mike]

I made the following comment:

From my point of view not Exactly spot on

Which I did not expound upon, It (Grok , AI that @Animalaxe is a fan of ) did narrow it down. But probably not to the actual desires of someone in their 20's and 30's would desire, which would be simply a easy button. In lieu of actually working the load. Which is why I said Not Exactly.. it in my opinion was really close
I was actually amazed at the results seeing how new the technology is.

I had figured it would need another 20 to 30 years. Maybe not???

I would probably ask "Groc" when starting to work up a load just to see how close "his" predictions would be and work up the load

Yeah Clarence pretty much what happened when Animalaxe and I sorta collaborated on this one. Basically told him the components etc,. he ran it. While I had already worked the load prior without telling him my results, until I posted them after his post.

And yeah I could have run the load hotter than the 43.7grs I stopped at, and went to say maybe 44.3grs (0.2grs over Barnes Data Max) and "might" have found a another node. But Barnes like many sources list Hornady large Rifle primered vs my Starline SR primed brass in their data. Figured best to find a reasonable wide node at the first time presented.

I don't know if not listing the action / maker would throw Grok's capabilities off or not. Just think about it there would not be much data for Grok to compile with :
1. Remington 721 in .244 Remington (6mm Remington) AI - Green Mountain barrel 1-7.5T
2. Remington 722 in 6mm Creedmoor - Bartein Barrel 5R 1-8T

Just don't think there would be much data points for Grok to do. IDK might prove me a fool to think such.

 

[Animalaxe]

Couple things…. Grok is just doing what we do as far as due diligence. Combing through bullet maker data, powder manufacturer data, forum posts, (he cites snipers hide, rokslide and this forum quite a bit but the citations don’t show up in the cut/paste). So it’s really just the compilation of a metric ton of data distilled down to your specific question. And he does it in seconds, not hours or days. When he extrapolates to fill the gaps in available data he shows the calculations and cites sources. And it’s not perfect. You’ll notice there’s always the disclaimer about blindly loading up someone else’s recipe without working up to it. So I agree 100% it’s not the “easy button” if you’re a brand new reloader. But I’ve been hand loading for 25 years so I have that to fall back on when things don’t add up. Then I reframe the question or offer more detail. It all results in getting me to a starting point that’s much closer to my goal when I fill in that first page in a range log for a new rifle. And that saves me time, components and trips to the range.

And it’s not just load development. Ask who has the best price on H4350 including hazmat and shipping right at this moment. Or what retailer offers mil/leo discounts. Or the trim to length for 300 RUM. Or what datum do you use to headspace a Creedmore case. Or the part number for your truck’s fuel filter. It’s just a better search engine is kinda how I look at it.

All that to say-it’s another tool in the box for me. If it helps any of you guys, so much the better.

 

[popper43]

Like AI knows everything about YOUR gun? Nope, not me.

 

[IndexFinger]

Like AI knows everything about YOUR gun? Nope, not me.

I think you wrong about that. AI is Brilliant Genius and knows Everything. I read it Posted on TikTok.. So I definitely know it's True .

insert internet Sarcasm Here ---> AI is the Future, the Past is Dead.
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