H4350 vs H4831SC heat potential

[Pigdog]

Make Product Potential
1.) Vihtavuori N530 4100 kJ/kg
2.) Vihtavuori N540 4100 kJ/kg
3.) IMR 4895 4080 kJ/kg
4.) Hodgdon H4895 4060 kJ/kg
5.) Hodgdon VARGET 4050 kJ/kg
7.) Vihtavuori N550 4050 kJ/kg
10.) IMR 4227 4040 kJ/kg
11.) Vihtavuori N560 4020 kJ/kg
12.) Accurate Accurate 1680 4018 kJ/kg
13.) Norma URP 4017 kJ/kg
14.) Hodgdon 50BMG 4010 kJ/kg
15.) Ramshot Enforcer 4005 kJ/kg
16.) Alliant Reloder-10x 4000 kJ/kg
17.) Hodgdon H322 4000 kJ/kg
18.) Vihtavuori N110 4000 kJ/kg
19.) Alliant Reloder-15 3990 kJ/kg
20.) Alliant Reloder-17 3990 kJ/kg
21.) Alliant Reloder-22 3990 kJ/kg
22.) Hodgdon BL-C2 3990 kJ/kg
23.) Alliant Reloder-19 3980 kJ/kg
24.) Hodgdon H335 3980 kJ/kg
25.) Winchester WXR 3980 kJ/kg
26.) Hodgdon H380 3970 kJ/kg
27.) Norma 203B 3957 kJ/kg
28.) Ramshot X-Terminator 3950 kJ/kg
29.) Ramshot TAC 3950 kJ/kg
30.) Norma 200 3940 kJ/kg
31.) IMR 4007 SSC 3935 kJ/kg
32.) IMR 8208 XBR 3920 kJ/kg
33.) Ramshot BigGame 3920 kJ/kg
34.) Alliant Reloder-7 3910 kJ/kg
35.) IMR 4198 3910 kJ/kg
36.) Ramshot Hunter 3910 kJ/kg
37.) Hodgdon Benchmark 3900 kJ/kg
38.) Norma 203 (old) 3900 kJ/kg
39.) Norma 201 3894 kJ/kg
40.) IMR 4320 3890 kJ/kg
41.) Accurate Magpro 3880 kJ/kg
42.) Hodgdon H414 3880 kJ/kg
43.) IMR 3031 3880 kJ/kg
44.) IMR 4064 3880 kJ/kg
45.) Winchester 760 3880 kJ/kg
46.) Norma MRP 3873 kJ/kg
47.) Hodgdon H4831SC 3870 kJ/kg
48.) Hodgdon H4831 3870 kJ/kg
49.) Hodgdon H4198 3860 kJ/kg
50.) Norma 202 3852 kJ/kg
51.) Norma 204 3852 kJ/kg
52.) IMR 7828 3850 kJ/kg
53.) IMR 7828 SSC 3850 kJ/kg
54.) Vihtavuori N130 3850 kJ/kg
55.) Winchester 748 3840 kJ/kg
56.) Alliant Reloder-12 3830 kJ/kg
57.) Alliant Reloader-50 3820 kJ/kg
58.) Accurate Accurate 2495 3810 kJ/kg
59.) Accurate XMR 3810 kJ/kg
60.) Alliant Reloder-25 3810 kJ/kg
61.) Hodgdon H870 3810 kJ/kg
62.) Accurate Accurate 4350 3790 kJ/kg
63.) Vihtavuori 24N41 3785 kJ/kg
64.) Ramshot Magnum 3775 kJ/kg
65.) Norma 217 3766 kJ/kg
66.) Hodgdon H4350 3760 kJ/kg
67.) IMR 4350 3760 kJ/kg
68.) Accurate Accurate 2015 3754 kJ/kg
69.) Vihtavuori N140 3750 kJ/kg
70.) Vihtavuori N150 3750 kJ/kg
71.) Winchester Supreme 780 3750 kJ/kg
72.) IMR 4831 3720 kJ/kg
73.) Accurate Accurate 2230 3710 kJ/kg
74.) Hodgdon Retumbo 3710 kJ/kg
75.) Hodgdon US 869 3700 kJ/kg
76.) Vihtavuori N170 3700 kJ/kg
77.) Accurate Accurate 2460 3690 kJ/kg
78.) Vihtavuori N120 3650 kJ/kg
79.) Vihtavuori N133 3650 kJ/kg
80.) Vihtavuori N160 3650 kJ/kg
81.) Hodgdon H1000 3630 kJ/kg
82.) Vihtavuori N165 3600 kJ/kg
83.) Vihtavuori 20N29 3580 kJ/kg
84.) Accurate Accurate 3100 3550 kJ/kg
85.) Accurate Accurate 3100 3550 kJ/kg
86.) Vihtavuori N135 3550 kJ/kg
87.) Accurate Accurate 2700 3545 kJ/kg
88.) Hodgdon Hybrid 100V 3545 kJ/kg

got this list from the leroy rifle and pistol club website. What i found interesting is H4350 shows a heat potential of 3760kj yet H4831Sc a slower burning powder shows 3870KJ anyone got any idea on why this would be. Normally its the opposite ie the faster burning varget is hotter 4050kj

 

[watercam]

Good question for a powder manufacturer...

 

[SheepDog]

I'm not a powder manufacturer but this is the amount of heat per powder weight of equal amounts so it will depend on the amount of expansion allowed and the pressures acceptable in order to compare the results.
If you use 56 grains of H4895 in a 3006 with a 165 grain bullet it is likely to be fine and produce a certain amount of heat and pressure. If you loaded that 3006 with 56 grains of H110 and a 165 grain bullet you would get a lot more heat and pressure - in fact it would likely blow the gun apart.

The list doesn't provide enough information to reconcile the performance in any particular load or under any specific set of conditions.

 

[Laurie]

Burning rates and specific energy values aren't directly related. Specific energy levels result from the powder components, both in terms of the chemical mix (ie nitrocellulose of any given mix + Nitroglycerin contains more energy = heat than that same quantity / quality of nitrocellulose alone) and from the nature of the combustible component(s) and also the percentage of the total kernel / powder charge weight that it (they) provide. Some propellant grades have nearly 10% by weight of non combustibles and therefore will have a lower energy content than one using nitrocellulose of the same calorific value but whose NC content is say 97 or 98% by weight.

Burning rates are determined by the combination of two methods - kernel form and dimensions, the surface area being the key factor of the first element - the greater the kernel's area, the faster it burns initially. To avoid or at least mitigate the undesirable results of 'regressive' burning behaviours (initially fast / high gas production, reducing as the kernel burns down and its surface area reduces) nearly all extruded rifle powder kernels have a central longitudinal hole, ie are tubes. As the external surfaces become smaller, the internal hole burns larger increasing its area and partly compensating. The other method is chemical modifiers which until burned through 'deter', or slow, combustion, hence their common name of 'deterrents'. As ball powders lack the extruded type's central hole and the ball can therefore only see a reducing surface area, they need more surface coatings in this respect and this increases the total kernel's non-combustible weight as a percentage of the total, all other things being equal. (One reason too why ball powders were often 'dirty' as non-combustibles mostly remain in the barrel as fouling - but manufacturers seem to have found ways of mitigating this in modern versions.) A simplistic view would therefore be that as a slower burning powder has heavier / thicker deterrent coatings than a fast-burning grade, it will therefore have a correspondingly reduced specific energy value given the increase in non-combustible percentage of total weight. (I suspect that this is being over simplistic though given the sophistication of powder manufacture and chemical behavioural modifications these days.)

The old IMR 'legacy' grades of the postwar era right through to the end of US based DuPont Corporation production all had identical nominal specific energy values as quoted by the manufacturer and burning rate was determined almost entirely by the shape / size factor similar weights of deterrents used. This obviously doesn't apply to the modern versions with IMR-4895 having one of the highest ratings around, much higher than most in the range. It is also obvious that the ADI manufactured Hodgdon brand grades see large variations in specific energy values. What I have long wondered, but never seen an explanation for is how some ADI / Hodgdon grades, specifically H4895 and VarGet (plus IMR-4895) have specific energy values of well over 4,000 K Joule / Kg way up with double-based or nitroglycerin infused 'high-energy' types such as the Viht N500 series. Do they use 'purer' nitrocellulose than others that generates more energy, or one with more hydrogen and oxygen atoms in the molecules, or is there a higher percentage of combustible to non-combustibles in the finished product? Or what?

In any event, it has nothing at all to do with burning rates in themselves. This is one of several reasons why it is often a poor strategy to treat propellant properties and applications as being solely characterised by the various grades' quoted positions in burning rate charts. Not only does this practice sometimes see apples compared to oranges, but there are various other factors such as specific energy values and specific densities that affect overall performance, behaviours in any given cartridge and/or bullet weight, and optimal or even suitable applications.

 

[Pigdog]

thanks for the replies and laurie for your very detailed reply that is a little above my knowledge. I have asked this question to hodgdon but yet to receive a response. I also noticed on the barrel life prediction formula the heat potential for H4350is listed on that table as 3990 not 3760 as listed on other places so not sure which one is correct. I think I will send ADI an email to ask them as well.

 

[Stralyanshooter]

Wow that's a big difference. Let us know which is correct.

 

[Zero333]

RL-22: 3,990
RL-25: 3,810
RL-33: 3,900
RL-50: 3,820

This is irrelevant to most folk for many reasons. If you look at those #'s it looks like RL-50 & RL-33 are FASTER than RL-25 but we all know this is not the case

 

[kvd]

Do they use 'purer' nitrocellulose than others that generates more energy, or one with more hydrogen and oxygen atoms in the molecules, or is there a higher percentage of combustible to non-combustibles in the finished product? Or what?

Nitrocellulose is polymeric in nature and linked molecule chains can be quite large. It may be that larger molecules are used, packing more combustible material in each kernel.



Ken

 

[Sheldon N]

I also noticed on the barrel life prediction formula the heat potential for H4350is listed on that table as 3990 not 3760 as listed on other places so not sure which one is correct. I think I will send ADI an email to ask them as well.

Quickload has H4350 listed as 3760.

 

[Pigdog]

ok well I'm not sure why the barrel life excel sheet chart shows H4350 as 3990. This makes a fairly significant difference in barrel life if you change it to 3760 vs 3990 so I would like to get to the bottom of it. Looks like hogdgon wont respond I will give ADI a try as this is where it comes from.

 

[Sheldon N]

@Bart B. Do you know where the number for H4350 came from? I think this was originally based on your table, from your prior posts on the subject.

 

[Laurie]

Burning rates are determined by the combination of two methods - kernel form and dimensions, the surface area being the key factor of the first element - the greater the kernel's area, the faster it burns initially.

I should say that that is kernel surface area in relation to kernel weight. Traditionally (as in black powder for instance which has no chemical burning rate modifiers), the smaller the grain size, the faster burning it is. That is because a say 100gn weight charge made up of X number of small size particles has a greater aggregate surface area when burning starts than a coarse grain version where 100gn weight = X divided by 2 or 3.

So traditionally, slow burners had longer extruded kernels than fast burners; ball powders had larger diameter balls - but particularly in the case of extruded (tubular) types, this conflicted with the user's desire to have small kernels that metered and flowed easily in mechanical powder measures, same in the case of industrial users who measure large numbers of charges on multiple cavity volumetric devices. (That is one reason why many military purchasers specify ball powders as this form as a general rule produces more uniform charge weights across cartridge production lots and therefore not only more uniform MVs and peak chamber pressures, but crucially more uniform gas port pressures which makes semi and full-auto weapon actions more reliable.) Propellant manufacturers starting with ADI / Hodgdon have become very adept now at producing short-cut versions that still produce a slow initial burn - eg H4831 original and H4831sc which have somehow squared this circle so well that ADI and Hodgdon quote identical loads data for the pair.

 

[Pigdog]

Just to follow up on this neither ADI or Hodgdon responded to my email about this topic

 

[Pigdog]

finally received a response from ADI Australia who make these powders and they have said the heat/energy potential data floating around has not come from them. Hodgdon hasn't replied back. So unsure as to where these figures have come from