Hammer Bullets Pressure Testing Results

So Hodgdon recognizes how bullet design and construction (emphasis added below) can affect load data but yet their load data is quoted as being "absolute". Interesting a powder manufacturer recognizes this and accounts for it.

"All Hodgdon reloading data is generated using industry standardized laboratory equipment and procedures. Over time, ammunition components and even testing procedures can change. As an example, bullet construction continues to evolve and even the most current data may not be applicable to a new bullet design. With the variations and combinations of calibers, powders and components we appreciate how hard it may be to find the exact reload information for a specific combination. For obsolete powders, calibers, and components this is even harder and no current reload data may exist."
 
Here is the remainder of the email chain.

Me asking permission to quote:

Hey Charlie,

That is terrific news in more than one way! For Ed this gives him the data that has been so illusive over so many hrs of trying to get QL to line up with results in the field. I can hear his excitement coming out of the computer! For me, this validates what we have been claiming for years and flies in the face of those who find the need to publicly call me out that this is not possible. With that said, may I quote you?

Steve Davis
Hammer Bullets
406-261-0010

Charlie's response:

Steve,

Sure, go ahead.

I am afraid there are "Experts" that do not have the credentials to be thought of as "Experts".
I am not an Expert, just a knowledgeable individual that tries to verify my thoughts on some subject.

GRT and QL has 2 lumped sum parameters (IP and Sebert for GRT, and Start Pressure and Weighting Factor). The defaults as expressed by both programs are simply averages. Anyone that thinks the Start Pressure and Weighting Factor can or would be the same cartridge to cartridge, and bullet to bullet, is simply fooling himself.

The problem arises when generating a Simulation for Internal Ballistics is that the true value of those parameters are not directly measurable at any Reloader level of tools available. The designers of the software are aware of this, but they are also not able to measure these values. So what happens? They use an average value. Then when they develop a propellant model, it is calibrated to those default values. Then along comes Joe Reloader who's rifle is somewhat different than the barrels used to work up the propellant models, and he gets different outcomes.

Therefore, the simulation User thinks this software is completely useless. However, if the User is a bit knowledgeable, and realizes there are differences between barrels and bullets, and he can imagine in his mind what the differences may be, and project in his mind what the results might be, then he can make educated estimates. He then runs some test for velocity and adjusts things like the 2 lumped sum parameters, or the propellant models, or perhaps all three to bring the simulation into agreement with reality. At that Point the User can then pretty much rely on the simulation results if he changes things like bullets. A ladder test across 2 – 3 grains of propellant will show how well the propellant model tracks.

The big difference between GRT and QL is the Propellant models. GRT models were developed using User rifle reality data, and QL primarily uses data from Closed Bomb and Lab grade proof barrels made to very strict standards. Therefore QL will simulate better when using Lab Grade barrels than with Off the Shelf types. GRT works better with the Off the Shelf barrels, and therefore will usually not align well with published data that was taken in the Lab barrels. A propellant model developed for 50 to 60 grains of charge may not work well when used with a cartridge of 25 – 30 grain charge level as the penetration of the primer flash will be different amongst various other things.

The published data automatically contains a "Safety" factor as the Off the Shelf barrels will normally not produce pressures as high as the Lab barrels. This in not true 100% of the time as mistakes are made and published. I cannot tell you the number of times I have discovered transposed load data in various published documents. I can tell you that when I discover these transpositions (or other mistakes) it is the EU propellant companies that take the most effective action to verify and correct the published data in a very timely manner. Vihta Vuori is the best for this, and the USA manufacturers are the worst. There are some loads using Varget that will not even fit in the cases specified and over flow the case mouth.



Project Relations
Gordons Reloading Tool
Berlin, Germany
[email protected]
https://www.grtools.de/

https://discord.com/invite/3FEYWG4
 
This isn't the least bit scientific, just my results. I loaded a 6.5PRC savage with carbon barrel about a month ago for a man out of west Georgia. 124 grain Hammer Hunter. Book says H1000 range of burn powder. We loaded H4831SC and my 1st effort achieved. 3340 FPS. But a slightly stiff bolt lift.dropped charge weight .7 grains and got 3250s. Easy bolt lift and .367 inch group. It was just that easy. Told the gentleman I'm embarrassed to take money for loading hammer bullets because they are so easy to load.This guy is on the forum so maybe he will read this and confirm my statement. Sorry, forgot to mention, I start with a 60 thousands jump on most of the bigger bullets. Then adjust from that. But usually its right on.
 
This isn't the least bit scientific, just my results. I loaded a 6.5PRC savage with carbon barrel about a month ago for a man out of west Georgia. 124 grain Hammer Hunter. Book says H1000 range of burn powder. We loaded H4831SC and my 1st effort achieved. 3340 FPS. But a slightly stiff bolt lift.dropped charge weight .7 grains and got 3250s. Easy bolt lift and .367 inch group. It was just that easy. Told the gentleman I'm embarrassed to take money for loading hammer bullets because they are so easy to load.This guy is on the forum so maybe he will read this and confirm my statement.
My experience too with a couple of different cartridges.
 
There have been some discussions here in the recent past about how Hammer Bullets are capable of generating higher velocity than conventional bullets of the similar weight. Particularly the Absolute Hammers because of the very low engraving pressure by design. There have been a few folks on here that have said that it is not possible to generate higher vel with one bullet of the same weight as another without utilizing higher pressure. Charlie from the Gordon's Reloading Tool has been doing some pressure testing with his 7mm test rifle in order to calculate the start pressures for calculating loads for the Hammer Bullets. We sent him all of our Hammer Hunter and Absolute Hammers to test. His initial test was with the Hammer Hunter Bullets slightly jammed into the lands so that he could compare initial pressures compared to lead core bullets. His findings were that they were basically identical to the cup and core when jammed. This is not normal for pure copper bullets. They usually are higher. He then tested with a jump of 50 thou. With Charlies permission I am just going to copy the emails that I received from him regarding his findings.

I finally got around to running the tests to determine the basic IP settings for the Hammer AH and HH bullets in 7mm that you provided. So sorry it took so long. I have a reason, just too old to get up the energy to do so at times. Additionally, my helper got sick two months ago and has died just this week. That is what happens when your help pool and organizer are all in their mid 70s.


As you know the initial tests were with bullets loaded to what I term soft jam (basically just plunk able in the chamber). I did this in order to determine the charges for each bullet weight that represents pressure nearly to cartridge Pmax, or MAP in SAAMI speak. This week I loaded up the remainder of the HH bullets and set the COAL -.050" shorted.


For the 177 HH bullets using the same charges as the Plunk rounds and running the PTII device, it becomes apparent that with .050" additional bullet jump available the velocity will drop approximately 20 to 30 fps, and the peak pressures remain nearly the same, within the limitations of the measuring device. In order to balance the simulation the no jump bullets require a IP (Initial Pressure / Start Pressure) setting of about 2900 psi, while the .050" jump bullets require a reduction in IP down to about 1500 psi. So it appears the jump actually allows the bullets to engrave easier into the rifling. The 155 HH and 120 HH responded in a similar manner. No jump to .050" jump produced nearly the same velocity and peak pressures, but the jumping bullets all required an IP reduction to balance the simulation.


Next I tested the 172 , 155, and 120 AH bullets. There was a bit of surprise when loading these. Of course the 172 AH required a bit more propellant than the 177 HH to get similar velocities, however, the COAL required to find Plunk and Plunk -.050" were exactly the same as the 177 HH bullets.
This surprised me as the ogive ahead of the first driving band is cut away on the AH bullets. I had added an additional .66 grs. of propellant as compared to the 177 HH in order to balance the simulation to the 5 grs. less weight. The results on both the chrono (MSV3) and PTII were reversed from the 177 HH results. The rounds that were shorter by -.050" actual gained a bit of velocity and produced a bit more pressure than the Plunk rounds. On the order of 30 fps and 2200 psi. These are well within the variation between shots normally, and the differences may level out with a greater number of shots. The big thing that appeared was that the IP required to balance the simulation was drastically reduced from the HH bullets even for the Plunk rounds. It appears with my 284 Win and long freebore throat (completely different from standard 284 Win) the HH and AH bullets touch the lands nearly at the same place on the first driving band, however the cutaway of the AH allows the required IP to be much lower than that required by the HH. Velocities were nearly the same for both the HH and AH, but the relative pressure produced was approximately 3000 to 4000 psi less. This change could be seen in the primers as well.


With the 155 AH the results were similar except that the velocities for the HH and AH bullets were all within 10 fps no matter the type or jump. However, the AH produced approximately 4000 psi less pressure overall, and required a reduction in IP of 1400 psi between the Plunk and -.050" rounds.
The 120 AH followed suit. I am still studying the data, but I think it is safe to say that the AH type allows one to either obtain the same velocity for weight at a lower pressure, or obtain more velocity at the same pressure as the HH type. My limited testing does not indicate if one type is more inherently accurate that the other. I had no grouping of greater than 1 MOA, and most were within .75 MOA and a couple were below .5 MOA. The way my barrel is chambered I never see greater than 1 MOA with every bullet I have tried except for Noslers'.


If I were deciding between the AH and HH types, I think I would be choosing the AH and save the strain on the barrel.






Project Relations
Gordons Reloading Tool
Berlin, Germany
[email protected]
https://www.grtools.de/

https://discord.com/invite/3FEYWG4

Response from Ed.

Simplified, 1500 PSI for HH and 1400 PSI for AH? That should raise some eye brows in the GRT and QL community!!! 😳

Ed

Response from Charlie.

Yes, it appears the design actually does relieve the start pressure requirement that most monolithic designs required.
Of course, it was impossible to get a true reading since the bullet weights were not exactly the same between the AH and HH designs.
Never the less, it is apparent that the AH requires a smaller IP as compared to the HH type in 7mm, and I would think all other diameters.
The few bullets that were just above the nominal diameter by .0005" or so did produce higher measured pressures, but only in the order of 3 – 4000 psi.
Even lead core bullets generate a pressure differential of +/- 2000 psi most of the time.
I ran my targets through the GRT Group Analyzer and the worst group was 1.1 MOA, and the best .4 MOA. Most of the larger groups were shooter problems.
At 76 years of age, my ability to hold point of aim is compromised by floaters in my eyes, and my Parkinson like genetic twitch.

Both GRT and QL programs lump the IP as a single value depending of several factors, but in truth IP is different for every bullet / cartridge / propellant, with primer being a factor
In the smaller case volume types. Both programs assume the bullet is touching the lands, only GRT has compensation for bullet jump, but that option was developed using
Straight walled cartridges and cartridges with very shallow shoulders like 300 AAC.

I chose my 284 Win since it has 35 degree shoulders, and bullet jump becomes a very small portion of the IP as the propellant packs at the shoulder from primer impulse
and prevents much initial pressure from the ignition cycle from reaching the bullet base. Significant propellant burn has to take place before the bullet moves, unlike the 300 AAC
who's bullet will advance to the lands upon primer impulse and before a significant propellant burn takes place. Variable neck tension in these straight wall cartridges makes
it hard to achieve small SD/ES numbers, but if the reloader can set the bullets very near to the lands the SD/ES numbers in these straight walled cartridges will usually improve.

Charlie


Project Relations
Gordons Reloading Tool
Berlin, Germany
[email protected]
https://www.grtools.de/

https://discord.com/invite/3FEYWG4


Steve, Thanks for sharing this data.
 
Here is the remainder of the email chain.

Me asking permission to quote:

Hey Charlie,

That is terrific news in more than one way! For Ed this gives him the data that has been so illusive over so many hrs of trying to get QL to line up with results in the field. I can hear his excitement coming out of the computer! For me, this validates what we have been claiming for years and flies in the face of those who find the need to publicly call me out that this is not possible. With that said, may I quote you?

Steve Davis
Hammer Bullets
406-261-0010

Charlie's response:

Steve,

Sure, go ahead.

I am afraid there are "Experts" that do not have the credentials to be thought of as "Experts".
I am not an Expert, just a knowledgeable individual that tries to verify my thoughts on some subject.

GRT and QL has 2 lumped sum parameters (IP and Sebert for GRT, and Start Pressure and Weighting Factor). The defaults as expressed by both programs are simply averages. Anyone that thinks the Start Pressure and Weighting Factor can or would be the same cartridge to cartridge, and bullet to bullet, is simply fooling himself.

The problem arises when generating a Simulation for Internal Ballistics is that the true value of those parameters are not directly measurable at any Reloader level of tools available. The designers of the software are aware of this, but they are also not able to measure these values. So what happens? They use an average value. Then when they develop a propellant model, it is calibrated to those default values. Then along comes Joe Reloader who's rifle is somewhat different than the barrels used to work up the propellant models, and he gets different outcomes.

Therefore, the simulation User thinks this software is completely useless. However, if the User is a bit knowledgeable, and realizes there are differences between barrels and bullets, and he can imagine in his mind what the differences may be, and project in his mind what the results might be, then he can make educated estimates. He then runs some test for velocity and adjusts things like the 2 lumped sum parameters, or the propellant models, or perhaps all three to bring the simulation into agreement with reality. At that Point the User can then pretty much rely on the simulation results if he changes things like bullets. A ladder test across 2 – 3 grains of propellant will show how well the propellant model tracks.

The big difference between GRT and QL is the Propellant models. GRT models were developed using User rifle reality data, and QL primarily uses data from Closed Bomb and Lab grade proof barrels made to very strict standards. Therefore QL will simulate better when using Lab Grade barrels than with Off the Shelf types. GRT works better with the Off the Shelf barrels, and therefore will usually not align well with published data that was taken in the Lab barrels. A propellant model developed for 50 to 60 grains of charge may not work well when used with a cartridge of 25 – 30 grain charge level as the penetration of the primer flash will be different amongst various other things.

The published data automatically contains a "Safety" factor as the Off the Shelf barrels will normally not produce pressures as high as the Lab barrels. This in not true 100% of the time as mistakes are made and published. I cannot tell you the number of times I have discovered transposed load data in various published documents. I can tell you that when I discover these transpositions (or other mistakes) it is the EU propellant companies that take the most effective action to verify and correct the published data in a very timely manner. Vihta Vuori is the best for this, and the USA manufacturers are the worst. There are some loads using Varget that will not even fit in the cases specified and over flow the case mouth.



Project Relations
Gordons Reloading Tool
Berlin, Germany
[email protected]
https://www.grtools.de/

https://discord.com/invite/3FEYWG4

And when I tell folks QL don't work with Hammers I always get the same response " Well they put it in there so it's right"
 
And when I tell folks QL don't work with Hammers I always get the same response " Well they put it in there so it's right"
Hehehe….that reminds me of my former vehicle, a 1999 Honda CRV (before
They were all plastic haha) with a manual transmission. Gutless, but hands down the absolute toughest and most dependable vehicle I've ever owned (those late 90s Hondas and Toyotas are a different breed altogether I'm convinced).

Anyway, in the owner manual there was a whole multi page section on off-road driving tactics followed by this disclaimer: "this vehicle is not to be driven off-road" 😂
 
So Hodgdon recognizes how bullet design and construction (emphasis added below) can affect load data but yet their load data is quoted as being "absolute". Interesting a powder manufacturer recognizes this and accounts for it.

"All Hodgdon reloading data is generated using industry standardized laboratory equipment and procedures. Over time, ammunition components and even testing procedures can change. As an example, bullet construction continues to evolve and even the most current data may not be applicable to a new bullet design. With the variations and combinations of calibers, powders and components we appreciate how hard it may be to find the exact reload information for a specific combination. For obsolete powders, calibers, and components this is even harder and no current reload data may exist."
I have read this a couple of times now. The company that are producing reloading data, aren't going to show anything that they feel isn't a safe loads, and made disclosure to the effect using the lowest powder load and work up to their max. Bullet construction is different between manufactures of bullets. Some push down the tube easier than others. I tried all copper bullets a great many years ago. Found them to be hard to push down the tube, and were not very accurate in my rifle. Hammer bullets are built differently, and cuts down the reissuance, and pressure to push them down the tube. Hammer I feel has evolved the all copper to it's next level. Like any other manufacture they are working on improving their bullets all the time.
 
Fixed this as misread..

So, from what I read the HH had similar start pressure as a cup and core bullet.
Correct but there is also a reduced WF (Weight Factor) or SF (Seibert Factor) by 1200-2000 PSI not being accounted for that also accounts for increased velocity. The reduced starting PSI with reduced bullet to rifling contact equates to faster bullet in same weight category.
 
And when I tell folks QL don't work with Hammers I always get the same response " Well they put it in there so it's right"
Beside QL's are only a guide just like all the other info out there. Yes it help, but still only a guide. Hammer has changed the way or design of all copper bullets. I'll go along with ButterBean on this. 👍
 
I look to this forum to obtain information, but until I test it personally, I never accept the published data. So when I first started using the Hammer line of bullets, I did comparisons with other copper only bullets. I found that other bullets could be loaded 2 to 3 grains more than published data before pressure signs start showing up and at those same powder charges with the same weight hammer bullets, I would obtain 30 to 60 FPS more, but with no pressure signs. By adding another grain or two of powder added another 40 to 75 FPS to the load but without pressure signs. Probably more gains could be made, but I was already sAatisfied with the results and my brass was happy, happy. I also took the advice of other forum members that a slight crimp helped with accuracy, something I'll do from now on.
 
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