7mm Rem Mag Powder Question

[Radosilver]

I’m just recently getting started with reloading so I apologize in advance if this is a dumb question. But, I am trying to work up a hunting load with 160 grain Accubonds in a 7mm Rem Mag. I’m trying to be as skimpy as possible with bullets since Accubonds are non-existent at the moment and have been for the better part of a year. So, I’m trying to save enough for a hunt assuming I get the load dialed in half decent, and am trying to shortcut as much as possible without doing optimal charge weight tests, extensive seating depth tests, etc. because I simply can’t get enough bullets to do the testing I’d like to do. Figure I’ll do more testing once I can get the bullets again. That being said, I got the results in the pics with IMR7828-SSC and H1000. The 7828 had a smaller group size, but the H1000 seemed to have a more uniform pattern. Based on this small bit of data would you who are more experienced move forward with the 7828 and do more testing or would you play around with the H1000? Also, am I better off adjusting powder charge or seating depth next? The velos are in the photos. Currently I’m sitting at 15 thousandths off the lands. Or is this simply not enough data to know?

 

[christian1]

Not sure what to tell you. Interesting that the H1000 has lower ES and more speed. Personally I am using IMR 4831 in both of my 7 mags and getting fantastic results.

chris

 

[ktm450]

4831 or 4831SC are tough to beat in the 160 class bullet’s. I get sub MOA from a bone stock Browning Hells Canyon and 162 Hornady ELD-X.

There may be better options but the gun shoots too well for me to switch

 

[Radosilver]

Not sure what to tell you. Interesting that the H1000 has lower ES and more speed. Personally I am using IMR 4831 in both of my 7 mags and getting fantastic results.

chris

Thanks. I noticed that too. That’s what made me second guess just going with the powder that produced the smallest group.

 

[Radosilver]

I’ll have to look at my notes. Can’t remember if I tried IMR4831 or not. Don’t have any H4831.

 

[Raghornklr]

following

 

[30338]

I had great luck with H1000. I'd take your best load and seat .03 deeper for a few 5 shot groups. I'd imagine one of those will impress.

 

[A382DWDZQ]

What was your starting load with H1000? 66gr is Hodgdon published max and when your group starts to scatter, that can be a sign you’re too hot. Maybe shoot a few at 66 and see how they do.

 

[Radosilver]

What was your starting load with H1000? 66gr is Hodgdon published max and when your group starts to scatter, that can be a sign you’re too hot. Maybe shoot a few at 66 and see how they do.

That’s interesting. The manuals I am using list max loads at 68.5 to 69.0 grains (Hornady & Sierra if I remember right). I’ll back it off some and see what happens. Thanks.

 

[toddh]

Mine likes 4831sc or R23 with the accubonds. I can usually get sub 1" groups. I'm thinking I run about .020 off the lands.

 

[Tberg]

R23 Accubond Mag length in a T3X. A little over Alliant book max. Took a coues at 640 yards in 2021.

 

[amassi]

What was your starting load with H1000? 66gr is Hodgdon published max and when your group starts to scatter, that can be a sign you’re too hot. Maybe shoot a few at 66 and see how they do.

Nosler lists 70.0gr max of h1000 with a 168

Sent from my SM-G991U using Tapatalk

 

[mmac]

RL22, Retumbo, 7828SC, N560 all seem to work well for me.

 

[Radosilver]

UPDATE: I shot groups again with both powders. Both provided good group sizes. Here are the details for those who are curious. Shooting conditions were very close to the same as when the targets above were shot--maybe a few degrees hotter but not by much, no wind and relatively how humidity both times:

IMR 7828-SSC (same 63.0 gr. powder charge but shortened the COAL by .004" to 2.749" to the ogive): group size got smaller (.951" to .707"), extreme spread went from 18 fps to 12 fps & standard deviation went from 8 to 5. Speed also increased from an avg. of 2,895 fps to 2,977. So, overall a nice improvement.

H1000 (decreased powder charge to 67.0 gr. from 68.0 & shortened the COAL by .004 to 2.749" to the ogive): group size got dramatically smaller (1.384" to .621"), but extreme spread went from 17 fps to 50 fps & standard deviation went from 7 to 21. Speed decreased from an avg. of 3,046 fps to 3,012.

All this data needs to be confirmed again, because I'm using small sample sizes due to a lack of bullets and wanting to keep enough in reserve for hunting season. However, assuming this data holds true I interpret this as meaning I should likely just stick with IMR 7828-SSC at the current 63.0 grains and length. This is a hunting rifle so anything 3/4" at 100 yards or lower makes me happy.

I'm curious if anyone would play around more with the H1000? I don't quite understand why velocity increased by shortening the COAL on the IMR powder but decreased when I shortened COAL with H1000. I would assume chamber pressure changes would have the same impact on velocity regardless of the powder but maybe I'm off base on this assumption.

 

[30338]

I'd be tempted to shorten it a bit more yet. That said, I'd also see loading up a bunch of either and going long and not looking back. Since supplies are short, I'd load a bunch of either and be done.

 

[Radosilver]

I'd be tempted to shorten it a bit more yet. That said, I'd also see loading up a bunch of either and going long and not looking back. Since supplies are short, I'd load a bunch of either and be done.

Thanks. I'm a newbie to this so I'm not questioning your logic, just curious on your thought process. Why would you consider going shorter? Also, would you be worried about the high ES and SD on the chrono readings at 67.0 grains of H1000? If I can get my hands on more bullets I am curious whether my velocities would stay consistent at 68.0 grains of H1000 if I shorten the length by .004 or more.

 

[amassi]

Both loads are sub moa
Stop worrying about sd/es and go shoot. Seriously
Shoot more
Shoot bigger groups than 3-5 rounds.
Don't chase your tail

Sent from my SM-G991U using Tapatalk

 

[30338]

Thanks. I'm a newbie to this so I'm not questioning your logic, just curious on your thought process. Why would you consider going shorter? Also, would you be worried about the high ES and SD on the chrono readings at 67.0 grains of H1000? If I can get my hands on more bullets I am curious whether my velocities would stay consistent at 68.0 grains of H1000 if I shorten the length by .004 or more.

Have had a few loads that kept getting better the shorter I seated the bullets. In your case, you reduced length and accuracy improved. Go ahead and reduce it a bit more and see what happens. But as has been stated, if I only had a limited number of components I'd call your groups with either powder good and load up a bunch. Good luck. If components ever come back in any quantity, you can fine tune things later.

 

[Super tag]

I run 70.5 gr H1000 in Nosler Brass with 168 VLD 3.4 COAL and shoot 1/2” groups, carefully worked my way up to this load, no pressure signs, no issues.

 

[roymunson]

I could not get 150 grain bullets together on my 7 mag with N160 or H4350, at least not to my liking

I got some H4831 and my 150 ttsx tightened up significantly. I think I now have a load and a COAL that can work with when it comes to putting together a hunting round.

I'm shooting a Tikka T3 with a vortex on top. Not a super high end gun, but enough to kill what I aim at.