Load Data for 8mm Mauser w/ IMR 4166?

M

Mosin-Marauder

New member
I'm looking for load data (if such data exists) for 8x57 IS using IMR 4166 Enduron under a 200 grain bullet. I wanted to get Varget but I figured I would try this before buying another can. If you guys could find some somewhere for that bullet weight, I would really appreciate it, as I looked on hodgdons website, nosler, and on steves reloading and couldn't find anything. Thanks in advance!
 
My IMR-4166 velocities in 300WM 125 gr 3200 fps and 6.5-06 120 gr 3200 fps match predictions in Quickload estimates for the same powder charges in H322.

I cannot say enough good things about that powder. It fights temp and Copper.
I am trying to get to the range this week with 4166 in some rifles I built in 6mmBR, 25-06, and 7mmRM. I will be using my H322 model.
 
CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

Maybe my post doesn't do you any good.
I would expect to hit SAAMI max 35 kpsi at 37 gr
I would expect to hit CIP max at 56.56kpsi at 44 gr
I would expect to find the edge of loose Boxer primer pockets at 72 kpsi at 48 gr.

I should warn you that this is an estimate based on an estimate by an amateur.... But it may give you some starting point. If you back off 10% from 37 gr and work up, it should be plenty safe. My guess is that 200 gr 8mm kicks so hard you will never make it to the top of a work up. I have not done that with 8mm since 2002.
 
Both posts are a huge help, as this powder is extremely new to me, and if it works I intend to continue using it, I may load something like 38 or 40 grains and see how pressure is. Thank you very much for your help, Clark!
 
IMR4166 is listed as one step faster than 4064 and four steps slower than 4895.

The Hodgdon data for a 200gr bullet in 8x57 is 39gr for 4895, and 40gr for 4064. Starting velocities are a sedate 2,100 fps range. Max charge is 44.5gr for 4064, and 45gr for 4895, both a hair over the 2,400 fps range.

Max pressure for each is 48k CUP, which is going to be safe in any large ring Mauser, but not something I'd use in a small ring Turk.

Anyways, if I were going to estimate charges for IMR4166, I'd split the difference between 4895 and 4064, which would be a starting charge of 39.5gr and a max charge of 44.7gr. This lines up pretty well with Clark's Quickload simulations although slightly higher on the starting charge. I'd expect a 37gr charge to be around 1,950 fps to 2,050 fps out of a K98.

As always, be as safe as you can in your reloading practices, watch for pressure signs when you work up. Just because something works in someone else's rifle doesn't mean it will work in yours. A well worn K98 isn't going to show pressure signs in a load that would lock up a Yugo M48 with almost new throat and bore.

Jimro
 
CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

I fired a round of IMR-4166 today in 25-06.
I got 0.016 inches of extractor groove expansion, the bolt had to be yanked open, and the primer fell out.
In 2003 I H335 308 worked up to a 0.011" extractor groove expansion at 90kpsi QL with a Mauser case head in 1 gr increments.

If that charge were 4064 it would be 94 kpsi. H322 would be 118 kpsi. Jimro's 4064 model seems more accurate.
 

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  • 25-06 115 gr Nos bal tip moly 3.31 in 54 gr IMR-4166 pre 64 M70 Shilen barrel 0.016 in groove ex.jpg
    25-06 115 gr Nos bal tip moly 3.31 in 54 gr IMR-4166 pre 64 M70 Shilen barrel 0.016 in groove ex.jpg
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This is probably a good time to point out for posterity that generally rifle load data within the normal range of bullet weights follows a linear approximation of the pressure curve created by adding more powder. Clark's H322 data is both useful, but not complete.

Pressure isn't linear, it really is a curve. As you add more powder, you get less internal volume, and more solid turning into gas in a given amount of time. So the two things that matter most are burn rate and load density. You can approximate for an unknown powder if you can find analogs on both sides of the burn rate, loaded in the same cartridge, and pushing the same bullet. If you don't have all those things, just use a powder that you have good data for.

But, you need to realize that as you get to either end of starting OR max charge, the shape of the pressure curve should be treated as a complete unknown. You can get pressure spikes that cause detonations, you can get pressure wave resonance that cause random secondary pressure spikes.

I point this out because Clark's data is a great example of one powder having the same "linear approximation" in normal charge ranges having a significantly different pressure result beyond normal charge weights. The software is only as good as the programmer, and a linear approximation of pressure versus charge weight will always underestimate an overcharge overpressure because it isn't mapping an appropriate upward curve (with an eventual leveling off at 100% detonation).

Hope this helps

Jimro
 
As Jim says, sometimes these approximations are way off. Fishing in the fog the 1970s the big boats had Lornan C and maybe radar. In my little boat had a compass, a watch, and I knew the approximate speed of my boat. Sometimes I came out of the fog right back at the harbor. Sometimes not. In the 80s I had a depth sounder and could follow a shoreline I could not see. Now we have GPS and we always know where we are way out at sea.

I think me having Quickload, a chronograph, and reading the brass, I am about as sure of myself as salmon fishing in fog the 80s. Ok and long as I don't get too far from shore.

CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

Today I shot some more IMR-4166. This time in 6mmBR with CCI450s. This is brass that is tougher than the primer, and this is the toughest primer I know. It is right at the limit for primers. QL thinks it is 86 kpsi if 4166 were 4064. I can't go any higher in charge weight to find the threshold of primer pierce, it is powder to the top of the case mouth and then tapped down and then compressed. For a safety margin for hunting I will shoot a big batch of this into targets and then if I have no pierced primers, I will back off a grain for hunting.

From previous experiments, I expect no primer to get much past 85 kpsi in QL.
 

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  • 6mmBR 95 gr NBT 1.21 in 32 gr 4166 CCI450 rem700 9-18-2016.jpg
    6mmBR 95 gr NBT 1.21 in 32 gr 4166 CCI450 rem700 9-18-2016.jpg
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CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

Using Jimro's suggestion to interpolate the Hodgdon Burn chart I can fix the 4166 as one step faster than 4064 and 4 steps slower than IMR4895.
Doing that I get 77 kpsi and 79 kpsi QL for these two pics with a microscope.
The CCI 450 primer did not pierce with a 0.3 gr increase, that is good [even with cratering], but I can see I had some Rem700 ejector hole in bolt face swiping on the brass at 77kpsi and some increase at 79kpsi. This is at 114% fill factor, and these cases take some effort just to get where I compress the powder.
 

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  • 32 gr IMR4166 95 gr NBT 1.21 in 6mmBR 77kpis QL 9-21-2016.JPG
    32 gr IMR4166 95 gr NBT 1.21 in 6mmBR 77kpis QL 9-21-2016.JPG
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  • 32.3 gr IMR4166 95 gr NBT moly 2.21 in 6mmBR CCI 450 79kpsi QL 9-21-2016.JPG
    32.3 gr IMR4166 95 gr NBT moly 2.21 in 6mmBR CCI 450 79kpsi QL 9-21-2016.JPG
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Way Cool on the microscope. Cheap junk is sometimes all you really need. Would we all rather have stereoscopic Leitz? sure. Would the difference be apparent in the pixels we can jam into a board post? Not likely. Especially not the stereo part.

CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

I took another approach. In 30-06 and in 308 Win, for a 180 grain bullet (about same sectional density as a 200 grain 8 mm bullet) that the 4166 and 4064 min and max loads are within 0.1 grains of one another and the velocities are also fairly close. The 30-06 has about 10% greater case capacity than 8×57 Mauser, and the 308 about 10% less. The corresponding expansion ratios also in between for the 8×57. As a result, it is very likely that the 4064 load levels that Hodgdon says are safe for the 8×57 with a 200 grain bullet are going to be within a a tenth of a grain or two of what is safe for it with 4166 with a 200 grain bullet. Those 4064 loads are 40 grains to 44.5 grains. Knocking them down another 5% until you get your sea legs with it is perfectly reasonable to do.
 
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