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Posted: 9/1/2026 7:30:44 PM EDT
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Normally, I have been shooting Hornady bullets and using their load data for ranges for 6.5 G and 6.5 CM. I decided to try some some Sierra 130gr TGK and looked up their load data. Sierra for their bullets for H4350 says to use 40,5 - 43.8 grains. Hornady for their 130gr CX for H4350 says to use 37.4 - 42.1 grains. Same weight of bullet, but such a wide spread. 6.5G has similar for the same bullet with the differences between the two. I plan to start the low end for the Sierra to work up, but wondering why such large differences? |
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Hornady has seemed conservative on many loads I have worked up. Speer has seemed to be pushing the limits. Lol. I own many books, and always reference many. Different rifles, brass..... and lawyers on staff when publishing data. |
| Those are totally different bullet types though and I am guessing that's where the discrepancy is. I've heard the copper bullets are a bit different than traditional bullets and sometimes longer. |
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Different manufacturers, different levels of conservatism. Different projectiles, different bearing surface, etc. |
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| https://hodgdonpowderco.com/articles/loading-monolithic-copper-bullets/ |
BikerNut:
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
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Originally Posted By ALASKANFIRE: https://hodgdonpowderco.com/articles/loading-monolithic-copper-bullets/ Did not know that, thank you!! |
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| I bet if you look around you could find some people that really get into it I've never loaded them. The excess pressure is why they started cutting the grooves in them. I think it cut the friction down enough to help. |
BikerNut:
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
Normal people like motorcycles. Real people like motorcycles.
People who don't like motorcycles are just... weird.
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Originally Posted By KILLERB6: Different manufacturers, different levels of conservatism. Different projectiles, different bearing surface, etc. Different brands/lots of primers, powder, and cases. Different bullet construction, different rifles/different barrels in universal receivers. Lots of variables involved. Reloading data in not scientific fact. What it is is a report of what happened when these components listed where used with this firearm. Which is why all the components, OAL, and firearm is listed in the data. |
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Originally Posted By dryflash3: Different test equipment, different testers. Different brands/lots of primers, powder, and cases. Different bullet construction, different rifles/different barrels in universal receivers. Lots of variables involved. Reloading data in not scientific fact. What it is is a report of what happened when these components listed where used with this firearm. Which is why all the components, OAL, and firearm is listed in the data. This Published data is one reference point, not an absolute fact on what will work best for your specific setup. |
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E. All of the above. Main thing OP is that the bullets are made of different materials and will react differently in the bore, compression, science, etc. Then lawyers. And yes, Hornady book is more conservative and others a little more spicy. Regardless, it is all just a recommendation. Start low, work up. |
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Bullet design and bearing surface affects how much force it takes to engrave into the rifling. Cup and core bullets can deform a bit, partition bullets or solid copper projectiles are more resistant and will usually have a lower charge for a corresponding weight. A very long bearing surface can have the same effect, essentially an earlier pressure spike. |
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Originally Posted By JKinAZ: Bullet design and bearing surface affects how much force it takes to engrave into the rifling. Cup and core bullets can deform a bit, partition bullets or solid copper projectiles are more resistant and will usually have a lower charge for a corresponding weight. A very long bearing surface can have the same effect, essentially an earlier pressure spike. |
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The biggest item to consider from the get go is the brand of brass used in development of the data. The internal case capacity as measured in grains of water with a fire primer in the case. Bullet construction is another variable as mentioned above, solid copper bullets are longer than say simple weight classic copper jacket with a lead core. Testing fixture can impact the results. |
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Don't be too timid and squeamish about your actions. All life is an experiment. The more experiments you make the better.
R W Emerson
| Those that said material and bearing surface win the prize. First, the copper bullets have a higher start pressure. Additionally, copper bullets are lighter for the same volume. So, for same weight, copper bullets must be longer/fatter. Longer is hard to fo and fit mag length or twist rate, so it is preferred to lengthen the bearing surface. |
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Best bet is to always run a velocity ladder test from min to max charge to log velocity and inspect the brass after every shot. For my initial load development, I load up 10 rounds in appropriate increments from min to max, and two sets of powder charges with 5 rounds in each; the powder charges are ones that were reported to (or are expected to) yield good accuracy. I also scour the internet to see what data I can find for that same powder/bullet combo for reference. |
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Ruthless ruler of cubicle B300.2C.983
Ruthless ruler of cubicle B300.2C.983
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I consider a chronograph to be a vital tool when reloading, otherwise I'm just guessing at maximums from my rifles and looking for pressure signs which don't usually rear their ugly heads until I'm well past maximum. Alway consider the data rifle's barrel length when comparing velocities. I cringe whenever I see men posting maximum velocity loads (24" or 26" test barrel) when firing their ammo through an 18" or 20" tube. You can be over pressure and show zero signs of it. The chronograph doesn't lie. I stop whenever I reach a maximum powder charge or maximum velocity (taking barrel length into consideration), whichever comes first. Lake City/IMI 7.62x51mm brass is at or over maximum pressure when using published starting charges from most reloading sources. These military surplus cases weigh close to 180 grains, empty and unprimed. Most commercial .308 cases weigh between 155 and 165 grains depending on which brand and lot number you have. There is no way maximum loads in Winchester brand commercial cases will be safe when used in Lake City. In fact, you will probably damage something. |
| Ronnic, I just bumped an old thread to the top for you. Several pressure tests performed by Wm. C. Davis Jr, U.S. Armory ballistician using different brands of brass and primers with identical loads. Pretty amazing pressure differences when changing brass and primers. |
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Totally different bullet construction with one being a solid copper bullet. Bullets of the same weight may also have different bearing surfaces. That being said Hornady is probably the most conservative of all for load data. I mainly use QuickLoad or Gordon's Reloading Tool these days to play around with different combos. |
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Originally Posted By AR-180: Load manuals are a series of results with a given set of components at a given place at a given time. Different inputs lead to different outputs. Compare several sources whenever possible, but pay attention to your own data as well. |
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Ruthless ruler of cubicle B300.2C.983
Ruthless ruler of cubicle B300.2C.983
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