7mm rem mag 7828

[tyeager2964]

So I bought a magneto speed sporter and finally got to play today. I have an accurate load for my 7 mm RM with 160 gr Sierra but I knew it was slow with only 60.5 of 7828 behind it. I calculated it at 2700 fps with drop data and the new toy confirmed 2681 avg with an sd of 9. It shoots great but what's the point of a 7 mag at that velocity.

Long story short I loaded up my final 6 bullets at 65 and 65.5 grains of IMR 7828. They both shot close to half MOA which is all I'm looking for really but I dont have any more to load to chrono. I dont have any pressure signs but that's 1 grain over book max (depending on book).

Can anyone with quick load give me an estimated velocity guess. If its linear I can simply do the math but I'm guessing pressure curves aren't (hence curves).

Sierra SPBT 160 gr model #1920
IMR 7828
Federal 215 large mag primer
Hornady cases
Loaded CBTO is 2.726 (fit in Tikka mag)
24" barrel

I dont want to buy more 7828 if I cant get to 2950 or so

Any advice on my next powder? Its likely going to be 4831sc or the newer enduron 7977. I'm ideally looking for 3000 give or take with a 160gr pill

 

[keithcandler]

I don't think that your rifle can read a book.

Your next powder should be Retumbo, start off at 69.5 and shoot three shot groups to 71.0g. Velocity will be 3000+ at the accuracy node, just shy of max pressure.

 

[Shortmagman]

I have had good luck with H1000 and RL-22. Both can get you 3000/sec.,however RL-22 is not temperature stable. From what I read IMR-7977 or RL26 are great choices. I have loads worked up with both but I just have not had time to test them.

 

[300stw]

ive run many pounds of 7828 160 accubonds at 2997 ave, with 67 grains,,, in 2 diff rifles, im using r26 now, 3000 is easy and 25 below to 75 above 0 has been very stable ,

 

[300stw]

Cartridge : 7 mm Rem. Mag.(SAAMI)
Bullet : .284, 160, Nosler AccuBond 54932
Useable Case Capaci: 72.296 grain H2O = 4.694 cm³
Cartridge O.A.L. L6: 3.290 inch = 83.57 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 7828

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 82 53.20 2404 2053 30900 10548 89.3 1.600
-18.0 84 54.53 2466 2161 33002 10908 90.7 1.559
-16.0 86 55.86 2529 2272 35250 11256 92.1 1.519
-14.0 88 57.19 2592 2387 37654 11591 93.3 1.476
-12.0 90 58.52 2655 2505 40228 11911 94.5 1.430
-10.0 92 59.85 2719 2626 42985 12213 95.5 1.385
-08.0 94 61.18 2782 2750 45940 12497 96.5 1.342
-06.0 97 62.51 2845 2876 49108 12761 97.3 1.301
-04.0 99 63.84 2909 3006 52510 13003 98.0 1.261 ! Near Maximum !
-02.0 101 65.17 2972 3137 56166 13221 98.6 1.222 ! Near Maximum !
+00.0 103 66.50 3035 3272 60099 13415 99.2 1.185 ! Near Maximum !
+02.0 105 67.83 3097 3408 64333 13582 99.5 1.149 !DANGEROUS LOAD-DO NOT USE!
+04.0 107 69.16 3160 3547 68899 13722 99.8 1.114 !DANGEROUS LOAD-DO NOT USE!
+06.0 109 70.49 3222 3687 73828 13834 100.0 1.080 !DANGEROUS LOAD-DO NOT USE!
+08.0 111 71.82 3283 3830 79141 13916 100.0 1.048 !DANGEROUS LOAD-DO NOT USE!
+10.0 113 73.15 3344 3974 84854 13985 100.0 1.016 !DANGEROUS LOAD-DO NOT USE!

 

[jjmp]

Don't have quick load but ,I figure your 2930 ish or a couple fps minus . I'd skip h4831 ,Peroid !!! I don't think Retumbo can't beat Imr 7977 . Best compromise buy a pound of each and let your rifle tell you ! Cheers

 

[MudRunner2005]

So I bought a magneto speed sporter and finally got to play today. I have an accurate load for my 7 mm RM with 160 gr Sierra but I knew it was slow with only 60.5 of 7828 behind it. I calculated it at 2700 fps with drop data and the new toy confirmed 2681 avg with an sd of 9. It shoots great but what's the point of a 7 mag at that velocity.

Long story short I loaded up my final 6 bullets at 65 and 65.5 grains of IMR 7828. They both shot close to half MOA which is all I'm looking for really but I dont have any more to load to chrono. I dont have any pressure signs but that's 1 grain over book max (depending on book).

Can anyone with quick load give me an estimated velocity guess. If its linear I can simply do the math but I'm guessing pressure curves aren't (hence curves).

Sierra SPBT 160 gr model #1920
IMR 7828
Federal 215 large mag primer
Hornady cases
Loaded CBTO is 2.726 (fit in Tikka mag)
24" barrel

I dont want to buy more 7828 if I cant get to 2950 or so

Any advice on my next powder? Its likely going to be 4831sc or the newer enduron 7977. I'm ideally looking for 3000 give or take with a 160gr pill

Books are just guides... Keep working up slowly with 7828 looking for pressure. I'm at around 3115 FPS MV with 67.0 of 7828 SSC with a Berger 168 VLD, just before pressure signs, but I have a match chamber that doesn't allow the brass to expand much, so it creates more pressure (velocity) at lower powder charges. Factory chambers, like in your rifle should allow more expansion of the brass, so you might be able to safely go higher in charge. I say "might", because every rifle is different, you just have to work up to find out. But always do so slowly and carefully.

7977 is another good option.

 

[tyeager2964]

At 69.5 of Retumbo is that being compressed?

 

[MudRunner2005]

At 69.5 of Retumbo is that being compressed?

I wouldn't mess with Retumbo...It's a very picky and finicky powder. I tried it in about 4 rifles and couldn't get it to shoot consistent at all. It shot good in my buddy's .300WM, but it didn't shoot good in any of my rifles that I tried...Including two 7mmRM's, a 7mm STW, and my .300 Ackley.

 

[jasonco]

Loading manuels are just a guide, SO YOU DON'T BLOW YOUR FACE OFF, not a hard fast, set in stone commandment of laws. Find your path to speed, accuracy & precision. And asking for advice here is a great start! Yes, you are in a lower accuracy node, let the 7MAG breathe!

 

[jasonco]

Retumbo would be on the too slow side with 160's. Get a little bit faster burning powder?! I was always partial to H4831 and H1000 in my 7Mag.

 

[Creedmoor shooter]

If you can find it rl-26 is where it's at in 7mm mag. My last 7mm ran 69 grains of rl-26 at 3146. I ran up to 70.5 grains. I'm guessing that had to be 3200 or better. 67.5 grains ran a 180 at 2975 fps.

 

[keithcandler]

That is BS about Retumbo being too slow for 160's, as we shoot it with 160g accubond, 160g Sierra, 162g sst, and 168g Berger, fed 215's.

In Remington 700's, around 71g is our load with the 162g SST at 3100 with a 26" barrel. The 160g Sierra btsp has more bearing surface and will build pressure sooner than the 162g sst, which is why I suggested that you start off with 69.5g and work up.
705.g of Retumbo with the 215 is what I shoot with the 168g Berger HUNTING vld =3050fps.

R#25 with a win mag primer is another powder that works excellent with the 160g class bullet with extremely low SD.

R#26 is going to be one heck of a powder in the 7 RM with 160-180g bullets, I have not tried it so can not give first hand experience with it.

 

[MarkA]

That is BS about Retumbo being too slow for 160's, as we shoot it with 160g accubond, 160g Sierra, 162g sst, and 168g Berger, fed 215's.

In Remington 700's, around 71g is our load with the 162g SST at 3100 with a 26" barrel. The 160g Sierra btsp has more bearing surface and will build pressure sooner than the 162g sst, which is why I suggested that you start off with 69.5g and work up.
705.g of Retumbo with the 215 is what I shoot with the 168g Berger HUNTING vld =3050fps.

R#25 with a win mag primer is another powder that works excellent with the 160g class bullet with extremely low SD.

R#26 is going to be one heck of a powder in the 7 RM with 160-180g bullets, I have not tried it so can not give first hand experience with it.

I agree Retumbo works great in the 26" and longer barrels but if you want top speed without a compressed load just can't beat RL26 with in 24" barrel with IMR7977 a VERY close 2nd! OP's barrel is 24" that is in the wheel house with RL26.