Thread: Too fast and dangerous? 7mm Rem Mag, 180gr ELD-M, RL26

Hi Team,

I'm in need of some wisdom from the forum.
I have worked up a load for my 7RM that can shoot the hair off the nut of a fly at 100y (exaggerating a bit).
However the load is a lot faster than what the hornady reloading guide says. The test rifle from the book had a 2" shorter barrel and a slower 1:9 twist rate. Mines a suppressed 26" 1:8 twist.
From your wisdom, should I be concerned that my speed of 3070fps is a lot faster than what the book says I should be getting of 2900fps with a book max of 67.3gr of RL26?

Nosler Brass
Fed Match Mag Primers
Hornady ELD-M Projectiles
68gr of Reloader 26
COAL: 3.380
Average Speed: 3070fps (10 round test)
ES: 17fps (10 round test)
Average group size 0.27" (2x 5 round groups)

Primers are not showing signs of flattening, and no sticky bolt, a single case of 10 showed a faint extractor mark.

The load of 68gr is .7gr above hornady's book max which is at 67.3gr of Reloader 26.
The COAL of 3.380" is longer than the hornady COAL of 3.290.

I'm keen to hear what your thoughts are, should I be concerned and back off my load back to where the speed aligns with the book recommended speeds?

That's fantastic!
Book max loads are very Conservative so I wouldn't be concerned.
Job done. Go out and shoot some shit!

Originally Posted by Gkp

That's fantastic!
Book max loads are very Conservative so I wouldn't be concerned.
Job done. Go out and shoot some shit!

Thanks Gkp, that is what I was thinking too.
I have read Nathan Fosters reloading books and he mentions the same, though I know there is more experienced people than I on this forum so I thought it best to check.

How much jump are you giving the 180's out of interest? I'm finding them a bit finicky in my 284.

Originally Posted by Pommy

How much jump are you giving the 180's out of interest? I'm finding them a bit finicky in my 284.

Around .030" jump, which is a lot but my Mag can only accept a COAL of 3.4 so I stick below that.

Aye, job done go hunting & enjoy.

Greetings Kiwiazonic,
If you are getting more velocity than Hornady then you are getting more pressure. I assume that with an eight inch twist it is not a factory barrel. If so this could account for part of the difference. Your additional two inches of barrel would add about 60 fps so the remaining extra velocity would equate to about 2 to 3 grains of extra powder. The max pressure for the 7 mm Rem Mag was reduced about 25 years ago due to erratic pressures in the cartridge. In my opinion, at least, primer appearance and bolt lift are worthless as pressure indicators but I would be concerned about the light ejector mark. To me this would indicate that the elastic limit of the case is near. To an old and cautious Fudd like me it is more risk than I would take but you must make your own decision. A round 3,000 fps sounds doable, You may wish to check how much flatter trajectory the extra 70 fps makes.
Regards Grandpamac.

Originally Posted by grandpamac

Greetings Kiwiazonic,
If you are getting more velocity than Hornady then you are getting more pressure. I assume that with an eight inch twist it is not a factory barrel. If so this could account for part of the difference. Your additional two inches of barrel would add about 60 fps so the remaining extra velocity would equate to about 2 to 3 grains of extra powder. The max pressure for the 7 mm Rem Mag was reduced about 25 years ago due to erratic pressures in the cartridge. In my opinion, at least, primer appearance and bolt lift are worthless as pressure indicators but I would be concerned about the light ejector mark. To me this would indicate that the elastic limit of the case is near. To an old and cautious Fudd like me it is more risk than I would take but you must make your own decision. A round 3,000 fps sounds doable, You may wish to check how much flatter trajectory the extra 70 fps makes.
Regards Grandpamac.

Thanks Grandpamac, that's some pearls of wisdom there.
That small amount of brass flow into the extractor port defiantly has me questioning the limit I'm pushing, and the days at the range were mild so maybe a hot day is all it takes to push it over the limit.
70fps does not add much if anything to the drop, though it just the point where my velocity and accuracy tightened up, nothing else in my ladder test compared to this sweet point, so it's a real head scratcher form me.

Wow that is great performance alright, 180gr 7mm at 3000fps, with great accuracy, that will work on a bit of stuff !

What chronograph please and/or has the velocity been compared to any drop data yet?

Originally Posted by Puffin

What chronograph please and/or has the velocity been compared to any drop data yet?

Hi Puffin, Chronograph is a Shooting Chrony - Master Beta. My speeds were tested over 2 days, 2 x 5 shot groups. Day 1 group averaged 3072fps, day 2 group averaged 3071fps.
I have only tested over the chrono, no long range validation yet as I wanted to talk to this group first before taking the development any further.
If I could get my hands on another chronograph to validate the speed the would probably help, but as you say a drop test would prob be the best way to confirm.

Originally Posted by kiwiazonic

Hi Puffin, Chronograph is a Shooting Chrony - Master Beta. My speeds were tested over 2 days, 2 x 5 shot groups. Day 1 group averaged 3072fps, day 2 group averaged 3071fps.
I have only tested over the chrono, no long range validation yet as I wanted to talk to this group first before taking the development any further.
If I could get my hands on another chronograph to validate the speed the would probably help, but as you say a drop test would prob be the best way to confirm.
Attachment 145564

Greetings Kiwiazonic,
That's a nice rig. A couple of things to consider in your deliberations. First fast barrels give more velocity because they develop more pressure. Second you are working up your load in mid winter. I don't know how temperature sensitive R26 is but the pressure you get on a mid summer day in the Kaweka's could be considerably higher. Perhaps a bit of testing in hot weather may be wise before you load too many.
Regards Grandpamac.

Originally Posted by grandpamac

Greetings Kiwiazonic,
That's a nice rig. A couple of things to consider in your deliberations. First fast barrels give more velocity because they develop more pressure. Second you are working up your load in mid winter. I don't know how temperature sensitive R26 is but the pressure you get on a mid summer day in the Kaweka's could be considerably higher. Perhaps a bit of testing in hot weather may be wise before you load too many.
Regards Grandpamac.

Thanks grandpamac, at this point I am thinking I will reduce the load. I have a wife and kids to think about so playing risky with loads is not something I am keen to do.
Thanks for all your help. I see you are Hawke's Bay as well, hope to see you on the hills sometime.

I have always been able to achive book max at least. However.... the other day I loaded up a pet load I have of 51.7gr 2209 with 140 Interlock for my new Kimber, this load has shoot really well in every 270 I have had, it shot well in the Kimber also, but... I loaded up a couple at the book max of 52gr 2209 (only .3gr more than the pet load) and fired off the first one, it was wildly off target compared to the lower load and the bolt was very very stiff, primer was super flat. This makes me a bit nervous about using the pet load now in this rifle so I will start again or possibly just back off to 51gr and see if its still nice and accurate. Amazes me how it can go from fine to crazy with .3gr more powder

Originally Posted by Ryan_Songhurst

I have always been able to achive book max at least. However.... the other day I loaded up a pet load I have of 51.7gr 2209 with 140 Interlock for my new Kimber, this load has shoot really well in every 270 I have had, it shot well in the Kimber also, but... I loaded up a couple at the book max of 52gr 2209 (only .3gr more than the pet load) and fired off the first one, it was wildly off target compared to the lower load and the bolt was very very stiff, primer was super flat. This makes me a bit nervous about using the pet load now in this rifle so I will start again or possibly just back off to 51gr and see if its still nice and accurate. Amazes me how it can go from fine to crazy with .3gr more powder

Hi Ryan, yes I agree it does not take much for a boarder line load to go from good to bad. This is why I thought I better check with the wisdom of the group. Even a temp change could push it over the limit.