7 mm mag /180grain berger

[Canadian Bushman]

That's a stout load. I'd be really surprised if it was only running 2950 fps. Most guys arent' runnng that much Retumbo with 168s let alone 180s.

2975fps is what the mag had as his velocity.

 

[Dick Tinsley]

That's a stout load. I'd be really surprised if it was only running 2950 fps. Most guys arent' runnng that much Retumbo with 168s let alone 180s.

I also agree. I could be wrong, but my vote goes to either his crono is not tellin the truth or he has a very slow barrel, or somebody is pullin somebody's leg in the artical. Just my 2cts.

DT

 

[Wile E Coyote]

Correction

His load was a 180 vld in front of 73gr of retumbo with a remington 9-1/2 with .330" free bore.

Guns and ammo march 2010.

I've tried 75 gn of Retumbo behind a 168VLD and 71 gn behind a 180VLD. Both of those were near or at max when I did the ladder test on them.

Flattened primers on both. Bolt lift was getting stiff and they recoiled severely from an un-braked 26" barrel.

Won't be doing that again.

Settled on 70 gn of H1000 for the 168VLD and 68 gn for the 180VLD. The rifle and load shoot under 1/2 minute... shooter, not quite that good.

Have come to the conclusion that if I can't get it with those loads, I'll be getting a rifle bigger than a 7RM outa the safe and I'll try to get a little closer.


Pete

 

[sendero72]

I've tried 75 gn of Retumbo behind a 168VLD and 71 gn behind a 180VLD. Both of those were near or at max when I did the ladder test on them.

Flattened primers on both. Bolt lift was getting stiff and they recoiled severely from an un-braked 26" barrel.

Won't be doing that again.

Settled on 70 gn of H1000 for the 168VLD and 68 gn for the 180VLD. The rifle and load shoot under 1/2 minute... shooter, not quite that good.

Have come to the conclusion that if I can't get it with those loads, I'll be getting a rifle bigger than a 7RM outa the safe and I'll try to get a little closer.


Pete

What were the MV's for the 168 and the 180? I'm getting ready to test the 180 Hybrid in my 7 mag with a 26" barrel.

 

[Canadian Bushman]

Im not a personal friend of mr burns or have i ever spoke to him. He participated in an article for G&A providing information on long range hunting and shooting and grey bull precision and their rifles in 2010. This was the data provided on the 7 mag that he built and was using for the article.

I dont know why the imformation wouldnt be accurate and why mr burns would have motive to provide false info.

With the endless combinations of chamber dimensions, lead angles, bullet jump, and freebore who knows what his rifles can do with said amount of powder.

 

[Wile E Coyote]

What were the MV's for the 168 and the 180? I'm getting ready to test the 180 Hybrid in my 7 mag with a 26" barrel.

168s are 3019fps with an ES of 7. I arrive at that ES after firing 30 + rounds and ignore the single highest and lowest value.

The 180s if I recall are just short of 2900. I've only fired about a dozen of these to date; saw they were grouping well and just haven't gotten back to them to test and do the math any further.

Pete

 

[brentc]

With the endless combinations of chamber dimensions, lead angles, bullet jump, and freebore who knows what his rifles can do with said amount of powder.

True. But, if I was using that much Retumbo in my 28" 7RM to only get 2950 fps I'd consider those chamber dimensions a failure and start over with something that is known to work.

 

[sendero72]

Any difference in burn rate of the IMR 7828 and 7828 ssc? Is there a difference in the load for the 180 Berger with these two powders?

 

[7magcreedmoor]

67.6 grains of Retumbo over CCI BR2, 26" PacNor 3 groove 9 twist, 2905 fps. COAL wouldn't be meaningful as I measure and write my measurement using a comparator on the ogive, and I don't recall the dimension of the comp off the top of my head. Velocity derived by shooting 300, 600 and 1175 yards, then running the observed drops back through the ballistic calculator's trajectory validation tab. My COAL is longer than SAAMI spec for sure.

 

[Canadian Bushman]

True. But, if I was using that much Retumbo in my 28" 7RM to only get 2950 fps I'd consider those chamber dimensions a failure and start over with something that is known to work.

And mr burns would sell it for more than its worth along with a box of ammo and a calibrated elevation knob. Takes different strokes to move the world.

 

[MudRunner2005]

Any difference in burn rate of the IMR 7828 and 7828 ssc? Is there a difference in the load for the 180 Berger with these two powders?

7828 and 7828 SSC should be identical burn rates. The SSC is just a Super Short Cut grain powder allowing you to fit more in a given space due to settling. But that doesn't mean you SHOULD cram more in there, since it is the same burn rate as regular 7828.

 

[Deleted member 46119]

7828 and 7828 SSC should be identical burn rates. The SSC is just a Super Short Cut grain powder allowing you to fit more in a given space due to settling. But that doesn't mean you SHOULD cram more in there, since it is the same burn rate as regular 7828.

My experience with 7828 vs. 7828SSC is that going from 7828 to SSC will see reduced velocities at the same charge. I blame this on lowered case density but it could be lot to lot variation but it was a 150fps spread. 3 different powder lots at this point.

I really like 7828 in belted magnums. Regular and SSC depending on chambering, projectile and charge needed to achieve an accurate load.

 

[MudRunner2005]

My experience with 7828 vs. 7828SSC is that going from 7828 to SSC will see reduced velocities at the same charge. I blame this on lowered case density but it could be lot to lot variation but it was a 150fps spread. 3 different powder lots at this point.

I really like 7828 in belted magnums. Regular and SSC depending on chambering, projectile and charge needed to achieve an accurate load.

7828 SSC is my go-to powder. I use it for everything from my .25-06 AI up to my 7mm STW's, and even my big .300 Ackley.

Reason being, if I can use 2 powders for all my rifles, then stocking up will be alot cheaper and easier. It's called planning ahead for when the SHTF.

 

[steeltraps]

I bouht 8lbs of 7828 sc the other day! I hope it works out! At least you can find it! To tell the truth avalibility is why I bought it!