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Hey you 7mm Mag guys. I just bought some Hornady 139 grain SST bullets from Sages. I have never loaded them before. I have IMR 7828SSC, IMR 4350 and H4350 on hand. I see that Western Powders has Ram Magnum as well. Anyone have experience with this bullet and any of the powders that I have listed. I am not looking for load data as I have that info already, just advice. I will be shooting them out of a Savage 111.
I have got 50 of these loaded and ready to go for today. I ended up buying a pound of Hodgdon H4831SC. I have 25 loaded in .5 grain increments with the H4831SC and 25 loaded in .5 grain increments with IMR 7828SSC. Taking the gun out this morning to see if they will shoot well or not.
Shot these loads today. The Hodgdon H4831SC shot like crap. The IMR 7828SSC loaded at 60.2 Grains shot a 0.75" group. I think this will be the load that I will be using. I did shoot one prairie dog at about 100-110 yards. It removed the back half of him. I had to go shoot it again with my 40 S&W to finish him off.
One of my hunting buddies runs 150 grain TSX with 63 grains of IMR4350 in his 7mm Rem Mag. Groups under half an inch. Velocity is around 3,050 fps best I can remember. This is a load he worked up, so don't use that as a starting point.
The gun is capable of shooting tighter groups than I am able to shoot. I am very impressed with the 0.75 inch that it produced.Sent from my SM-S903VL using TapatalkQuote:
Originally Posted by SouthernCoyote
I think you’re way low. I run h4831 with 162s and am at 63.5gr I load 140gr Berger bullets and lid at 64 even.
I used the data in the Hornady manual for the 139 SST's. I don't recall the advertised velocity for the IMR 7828SSC powder. I will look it up tonight and post it here. The next time I get to go and shoot the gun I will chrono the load.Quote:
Originally Posted by tabascoman
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What charges did you try for the 139 and h4831? I didn’t get very good accuracy with mine loading low charge. My rifle shoots great with a high charge. I haven’t changed my load in 9 years with the 162 or 140 unless it was trying a different powder. You may also want to try some rl19 or rl22. Depending where you are they do get kinda finicky when it gets hot.
With the H4831 I started with 63.5 grain and ended around 67 if I remember correctly. The best group I got the the H4831 was just under 2 inches.
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Wow. That’s high. What’s your seating depth? Im
at mines 3.280 with the 140 bergers
Please remember this is from memory. I have everything writen down at the house. If I remember correctly. I am seating to 3.265. That is 0.025" from the lands.
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Totally understand. I’d try backing them up some. Not all bullets want or need to crowded to the lands. All mine justo. I’ve not found any hat needed to be close to the lands in my rifle
The book says to load them to 3.290". I made a dummy round to test that length. I could not even get the bolt closed. That is when I measured the max length and seated 0.025" deeper. The IMR 7828SSC shot great with the same seating depth. This round is only going to be used to shoot Antelope, coyotes and prairie dogs. If I get to go for elk next year I will be using the Barnes TSX 160 grain.
I only use IMR 4350 for my 7mm mag.... I am always in the mid 60's..... I'd have to open my book to get specifics....
So, here are the correct numbers for the IMR 7828SSC and Hodgdon H4831according to the Hornady book. H4831 starting load is 55.5 grains with a max of 65.0. I started at the 55.5 and loaded 0.5 grain increments up to 62.0. None of the shot well. The IMR 7828 starts at 60.2 with a max of 68.1. I started at the 60.2 which shot the 0.75" group, and loaded 0.5 grain increments up to 63.2 grains. The heavier the load the bigger the group got. The 60.2 and 60.7 was the best loads. It look like my gun doesn't like the hotter loads.
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Maybe try a different powder, or bullet, or seating depth. If the 2700fps velocity is on par with your 60.2gr load, then that would amount to a very expensive to shoot 7x57 Mauser. Definitely adequate for killing whatever game your after, just not what I would want or expect out of a 7mag.
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Hornady is also very conservative. I’d do a good ladder test and find the max load for your rifle. When I started all I had was a lee book I got with my loading kit. You should be upward of 3300fps with 65gr load. I’m running just over 3200 with my bergers at 64gr. And 2985 there about with the 63.5gr charge with my 162 amax
Got to go shoot this load of 60.2 grains of IMR 7828 SSC behind the Hornady 139 SST through the Chrono this morning. The Chrono was set at 10 feet in front of the muzzle. Here is the results:
Average 2830 fps
Standard Deviation 23.71
True Muzzle Velocity 2836.61
Spread 54
FPS Ft-Lbs Power Factor
Shot #1 2796 2413.26 388.64
Shot #2 2833 2477.56 393.79
Shot #3 2850 2507.38 396.15
Shot #4 2841 2491.57 394.90
This should work for any Antelope and coyotes that I run across.
Yes it should.
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