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7mm Rem. Mag and Winchester Supreme 780

Discussion in 'Handloading and Reloading' started by ojibweindian, Oct 10, 2009.

  1. ojibweindian

    ojibweindian Well-Known Member


    Just thought I'd post data I've collected; I've been roaming to and fro on the 'net and have noticed that there's not a lot of data concerning 780 and the 7mm Rem. Mag.

    Powder: Winchester Supreme 780
    Bullet: 150 grain Remington Core-Lokt
    Primers: CCI 250 and WLR

    Shot strings consist of 5 rounds.

    Using a WLR:
    59.0 grains - 1.34"
    59.5 grains - 1.63"
    60.0 grains - 3.02"
    60.5 grains - 1.47"
    61.0 grains - 2.56"
    61.5 grains - 2.86"

    Using a CCI 250:
    63.9 grains - 1.83"
    64.3 grains - 1.71"
    64.7 grains - 2.75"
    65.1 grains - 1.44"

    I've a few more loads with the CCI 250; 65.5 grains, 65.9 grains, 66.3 grains, and 66.7 grains.

    Anyway, I'm pretty happy with the 65.1 grain load as 1.44" for a 5 shot group using a Core-Lokt bullet is pretty good. A Core-Lokt has a great reputation as a hunting bullet, but it's not a Match King by any stretch of the imagination. Anyway, I might start playing with seating depth to see if I can tighten things up a bit, but there's no hurry. And I'd like to see how my final four loads perform first.

    So, there ya go. As I learn more about 780, I'll dump the data on this thread.
  2. ants

    ants Well-Known Member

    Thanks, Ojibwe

    So you figure that the higher performance is due to the magnum primer? Or the higher powder charges? Or both?

    Using a rifle rest of some sort?

    I'm waiting for more reports on Supreme 780 for 30 caliber magnums. But keep reporting your findings in 7mm. I am certainly interested. Do you have a chronograph? It would be interesting to compare to other powders. And are your groups similar with other powders, or is 780 outperforming the others?
  3. ojibweindian

    ojibweindian Well-Known Member


    Actually, I get better accuracy results from 60.7 grains of RL-19, touched off with a WLR primer. I'm using a different bullet, though. The bullet is a "blemished bullet" I bought from MidwayUSA a few years ago. Bought a couple of thousand because they were REALLY cheap, about 10 buck per 100. Using that bullet and RL-19 gives me a 5 shot group of 0.712" at 100 yards, but it doesn't open up on deer like the Core-Lokt does. Every Core-Lokt I've sent towards a deer has dropped it on the spot, with a pretty good sized exit wound.

    For hunting purposes, I'll give up a bit of accuracy for a bullet that drops them right then.
  4. ants

    ants Well-Known Member

    Me too!
    RL19 works well in 300 Weatherby mag, RL22 works even better.
  5. ojibweindian

    ojibweindian Well-Known Member

    Well, I've completed more load testing with Supreme 780. 65.5 grains and 65.9 grains of 780, with a 150 grain Remington Core-Lokt, and a CCI 250 primer gave groups of 0.55" and 0.59", respectively. Groups really starting opening up with charge weights greater than 65.9 grains.

    I'm going to shoot several more groups using those two powder weights to gather more data points for analysis.
  6. ants

    ants Well-Known Member

    What's the velocity at 65.5g?
  7. ojibweindian

    ojibweindian Well-Known Member


    I don't have a chronograph, so I have no idea. The 65.5 grain and 65.9 grain loads are a few grains below the max of 68.0 grains. I'm assuming that velocities for these two loads are in the neighborhood of 2,900 fps. Maybe a little more than that.
  8. ojibweindian

    ojibweindian Well-Known Member

    Well, spent a few hours at the range today and shot some more of my 65.5 grain load of 780. Was really checking for zero on the rifle as opening day of Alabama's deer season is tomorrow.

    Anyways, shot one group, just to make sure all was well, and it was. A 1.18" group sighted in a 2" at 100 yards. I must say that 780 and my Weatherby seem to be getting along rather well together :D
  9. ojibweindian

    ojibweindian Well-Known Member

    Took the Big 7 out to the range this past Sunday for grins and giggles. A few 3-shot groups with my 65.5 grain load of Supreme 780 averaged 0.59" at 100 yards.

    It was a good day, as the Big 7 performed a bit better than normal.
  10. ojibweindian

    ojibweindian Well-Known Member

    It's been a while since posting anything concerning my experiences with Supreme 780 and my 7mm Rem. Mag. Anyway, I went to the range a few weeks ago to dial in the Vanguard for Alabama's upcoming deer season. My load, to restate, is a 150 grain Remington Core-Lokt over 65.5 grains of 780 touched off with a CCI 250.

    I first zeroed the rifle at approximately 25 yards (paced off). I then moved the target stand to 100 yards (again, paced off). The load, at 100 yards, printed close to 3" high, give or take 0.1". Groups were a bit bad, at 1.8", most likely because of the variable winds blowing at around 5 - 15 mph. I don't do well at reading variable winds.

    When I got home, I used an online ballistics calculator (JBM) to get some sort of an idea of the load's muzzle velocity, energy, and trajectory out to 300 yards. As an aside, a 300 yard shot at a deer here in Alabama is a rare thing; all my deer have been shot at less than 150 yards. The foliage at Skyline and the Bankhead are pretty dense, and the terrian is rather steep.

    To continue, I plugged in the 25 yard zero, the BC, weight, diameter, and wind speed, then played with the velocity parameter until the results displayed a 3" high point of impact at 100 yards. According to the results, my 65.5 grain load is roughly pushing 3150 fps at the muzzle. A bit faster than I expected.
    Last edited: Nov 5, 2011
  11. ojibweindian

    ojibweindian Well-Known Member

    Oh, I did the same thing with another load, 60.9 grains of RL-19, a WLR, and a 150 grain blemished bullet (I guessed the BC). Again, it was zeroed at 25 yards, and printed about 2.6" high at 100 yards. This load seems to have a muzzle velocity of around 2750 - 2800 fps.
  12. NCsmitty

    NCsmitty Well-Known Member

    Thanks for posting your experience with the 7mm ReMag, ojibweindian.
    I'm a firm believer in using magnum primers in workups, with large doses of ball powder.

    Your load of Rel-19 appears a little low, and you seem to have room to improve on that one, should you so choose.

    The 7mm Remag is a great cartridge and works well at 40yds or 400yds, especially when you're using a quality bullet.

  13. gamestalker

    gamestalker member

    What distance are those groups from?

    I've been using RL22 with excellent results, but I'm as well always interested in a potential substitute or addition to my 7 mag world. Currently I'm getting consistent Sub MOA groups at 100 yds using just about any bullet with RL22 in generous amounts. So far the only bullet that has never performed well for me is the 100 gr. Seirra HP, even at low velocities it won't hold a group of better than 1.77" @ 100 yds. In comparison a varmit bullet that is really shinning for me is the 115 gr. TNT, at velocities below 3400 fps though.
  14. Blue68f100

    Blue68f100 Well-Known Member

    I started reloading for the Rem 7mm Mag in the 70's. Back then you did not have a lot of selection as you do now. The load I developed with IMR4350 and Serria 160gr SPBT produced 1 ragged hole at 100 yrds in my Rem 700 BDL and by brother's M77. Factory ammo back then was not near as good as it is today. Back then if your got 1 MAO you were lucky, normally it was around 1.5 MOA. I have never shot any other bullets or powder so it's nice seeing what others are doing. I prefer ball powders but the 4350 has proven it was good choice. Since I'm near max I weight out all of my loads so dispenser accuracy does not come into play. I have about shot up all that I loaded back then and will need to be reloading some more in the near future. Shooting 1 round a year a box lasts a long time.... I may be using this gun for the wild hogs. I want have to worry about under penetration with it.

    A MAG Primer is a must when it comes to lighting off large amounts of powder and slow burning powders.

    Keep up the good work, you will find that magic load that works with your gun.
  15. ojibweindian

    ojibweindian Well-Known Member

    You're welcome.

    Yeah, that RL-19 load is a bit weak for the Big 7, but it really does perform well on paper. I generally get right around an inch with it, sometimes a bit better, sometimes a bit worse. Essentially, it's a rough equivalent of a 280 Remington load. It does a pretty good job at dropping deer, too.
  16. ojibweindian

    ojibweindian Well-Known Member

    100 yards.
  17. ojibweindian

    ojibweindian Well-Known Member

    Just got back from the range today, both to reconfirm zero on my "goto" deer loads, and to do a bit of work-up on another bullet.

    This time around, I used the 150 grain blemished bullet I bought from Midway eons ago, a CCI 250 primer, assorted cases (fully resized), and graduated charges of Supreme 780

    I started off at 63.9 grains of 780, and worked up to 65.5 grains, in 0.4 grain increments. I shot 5 three shot strings at a distance of 100 yards, on sandbags:

    Date Powder Charge Wt. Bullet Bullet Wt Primer Case Group Distance

    11/05/11 Supreme 780 63.9 Blemish 150 CCI250 Assorted 2.66 100
    11/05/11 Supreme 780 64.3 Blemish 150 CCI250 Assorted 2.38 100
    11/05/11 Supreme 780 64.7 Blemish 150 CCI250 Assorted 0.84 100
    11/05/11 Supreme 780 65.1 Blemish 150 CCI250 Assorted 1.91 100
    11/05/11 Supreme 780 65.5 Blemish 150 CCI250 Assorted 0.99 100

    I think the 64.7 grain load shows a bit of promise. Also, I find it interesting that 65.5 grains is roughly just as accurate as the 65.5 grain Core-Lokt load.
  18. gamestalker

    gamestalker member

    Yes, 100 yds. is where I start with all new bullets and loads so I don't waste components. Once I'm certain of a bullets worthy groups at 100 yds. I then step out to 300 yds. But once I've determined the POI at 100 yds., I ultimately zero at 300 yds. because that is where my velocity begins to best corespond with the BDC program in my RX-IV.
  19. ojibweindian

    ojibweindian Well-Known Member

    More fun with my Weatherby 7RM and Supreme 780. I think I've confirmed a pretty good load using a 150 blemished spire point (from Midway). Load consists of 64.7 grains of 780, a CCI 250, and assorted cases. Three shot groups at 100 yards are averaging 0.79". I'm going to wring this load out a bit more, with 5 shot groups at 100 yards. I'm also curious to see how this load performs at distances out to 300+ yards.

    Also, I've been expirimenting with a 162 grain Hornady SPBT. So far, no good. I started out at 61.6 grains of 780, moving up in 0.5 grain increments. Last load I was able to test was 62.6 grains of 780. There are some encouraging signs, though. As I moved up the ladder, groups shrank. The 62.6 grain load, the best so far with the 162 grain Hornady SPBT, printed at 2.17" at 100 yards. I've got another three loads (63.1, 63.6, and 64.1) to test, and I'm hoping that one of the three give me a sub-MOA result.

    Another thing. Hodgdon's PDF data shows that I should be using a WLR primer with 780 in developing loads for the Big 7. If my remaining three 162 Hornady loads, which will be touched off by a CCI 250, are disappointing, I'll switch primers to WLR or CCI 200 and see what happens.
  20. Skyshot

    Skyshot Well-Known Member

    That's some good info, my 7mag shoots it's best with a load of 63. grains of IMR7828 and a federal 215Macth primer and a 160 gr. Nosler Accubond it's always sub 1/2 MOA with 5 shot groups. As far as 150 gr. bullets they seem to be at thier best IMR4831 or N160 and likes most 150 grain bullets I just can't get the 1/2 MOA like the 160 does.

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