Ballistics question to the long range experts

bummer7580

Lil-Rokslider
Joined
Oct 9, 2017
Messages
128
Location
minnesota
I have been hunting with a 7mm Rem Mag forever. I practiced out to 600 yds. and was confident that if I was presented with the correct opportunity I could kill a bull at that distance. Though ready I was always able to close the distance to within 400 yds. I like my 7mm but have decided I want to shoot a lighter kicking rifle. I am looking at a 7mm-08 with a brake. My 7mm magnum shoots 160 gr. bullets at 3060 and I see I can load the same bullet to 2650 in the 7mm-08. That makes the 7-08 13.3% slower than the 7mm mag. Now the question- will the 7-08 have the same energy at 520 yds.(600yds-13.3%) that the 7 mag has at 600yds? Also if both are sighted in to hit point of impact at 200 yds. would the inches drop for the7-08 at 520 yds. be equal to the inches drop of the 7mm mag at 600 yds.? Thanks for any insight guys. Hopefully I still won't have to shoot over 400.
 
OP
B

bummer7580

Lil-Rokslider
Joined
Oct 9, 2017
Messages
128
Location
minnesota

Overdrive

WKR
Joined
Aug 10, 2018
Messages
494
Location
Earth
Why not just put a Muzzlebrake on the 7mag? I have one on my 7 mag and 300 Wthby and the recoil on the 7 mag is like shooting a .223 but it is also a fairly heavy rifle. The 300 Wthby is a little more but reduced way down that I can shoot 50 rounds a day with no more bruised shoulder. Just a thought.
 

blkqi

WKR
Joined
Aug 21, 2017
Messages
433
No, that's not how it works. Energy scales with the square of the velocity. E = ½mv^2
 

mwf008

Lil-Rokslider
Joined
Mar 19, 2020
Messages
191
I agree with the above. My CA Mesa 7mag has about the same recoil as my heavy ass RRA LAR-8 in .308. Maybe even a touch less. It’s actually pretty pleasant. I have no problem shooting it all day.
 

W1bowo

Lil-Rokslider
Joined
Aug 24, 2019
Messages
104
I agree with the above. My CA Mesa 7mag has about the same recoil as my heavy ass RRA LAR-8 in .308. Maybe even a touch less. It’s actually pretty pleasant. I have no problem shooting it all day.
+1
BB.jpg
 
Joined
May 4, 2020
Messages
38
Location
Canada
calculators will answer all of your Kinetic energy questions, I believe someone posted a good one above.

In regards to changing your rifle. You are taking a massive step backwards going to a 7mm-08. This is a great rifle caliber but if your goal is to get into long range hunting or shooting there is no benefit in shooting the same bullet slower. If recoil is a concern 100% brake your 7mm rem mag. All of my hunting rifles are braked. I am 6'4 and 240lbs and am not sensitive to recoil. I have military training when it comes to long range shooting so form is no concern either. But I brake every rifle because if I am going through the trouble of measuring grains of powder to the thousandth of a grain, trimming brass and seating bullets to the thousandth of a inch, millions of dry fires and rounds down range to perfect my trigger pull and cheek weld. If am going to do all of that to shoot a group that is a thousandth of a inch tighter, why wouldn't I remove the effect of recoil on the rifle. Can you shoot well with recoil? Of course you can. Can you shoot better with absolutely no recoil? Hard to argue that you can't.

My 300winmag Fierce Edge is my go to work horse for hunting. It is a light rifle, I think 7lbs out of the box. But I upgraded the brake it came with to a nice side ported unit. My 9 year old daughter can shoot 50 rounds through it on a hard bench no problem. ohhhh and I am running 212 grain ELD X through it as well. So I could tame the rifle even more by choosing a smaller bullet.
 
Joined
Jul 18, 2019
Messages
2,051
I have been hunting with a 7mm Rem Mag forever. I practiced out to 600 yds. and was confident that if I was presented with the correct opportunity I could kill a bull at that distance. Though ready I was always able to close the distance to within 400 yds. I like my 7mm but have decided I want to shoot a lighter kicking rifle. I am looking at a 7mm-08 with a brake. My 7mm magnum shoots 160 gr. bullets at 3060 and I see I can load the same bullet to 2650 in the 7mm-08. That makes the 7-08 13.3% slower than the 7mm mag. Now the question- will the 7-08 have the same energy at 520 yds.(600yds-13.3%) that the 7 mag has at 600yds? Also if both are sighted in to hit point of impact at 200 yds. would the inches drop for the7-08 at 520 yds. be equal to the inches drop of the 7mm mag at 600 yds.? Thanks for any insight guys. Hopefully I still won't have to shoot over 400.

I'd be inclined to check out a 280 AI as well for what you're looking to do, though the guys above make some great points on the brake. I've got a 7 mag too and it's not nearly as nice to shoot as my guns with brakes or friendlier cartridges.
 
Joined
Dec 30, 2014
Messages
8,168
I'll be contrarian. 7/08 is fine to 600 yards and you'll enjoy shooting/practicing with it more to that range, it will cost less, you will spot impacts easier than you would a RM, it will be less sensitive to proper recoil management, and the barrel will last longer.

A RM wins in the ballistics department but functionally a 7/08 isn't a bad choice.
 

1shotgear

WKR
Rokslide Sponsor
Joined
Jun 8, 2015
Messages
1,256
Location
Denver, CO
If you are jumping down to a lighter recoiling round, you might want to think about going with a 6.5 PRC or 6.5 Sherman Short mag. Both of those cartridges can push a 156 grain Berger EOL between 2900-3000 with a 24 inch barrel. You would be able to use about the same bullet weight as you are using in a 7-08, but you can push it a few hundred fps faster. Also, the 6.5 mm 156 grain Berger has a higher B.C. than a 160 grain 7mm bullet which will result in higher retained energy and velocity at distance. Recoil would be similar or less than a 7mm-08. Also, don't worry to much about your inches of drop. It really isn't much of a factor now that we have ballistic calculators that tell us our exact drop in different conditions. You should pay more attention to wind drift. A cartridge/bullet combination that does well in wind will allow more room for error when making wind calls. Have fun with your new rifle!
 

Formidilosus

Super Moderator
Joined
Oct 22, 2014
Messages
7,992
I have been hunting with a 7mm Rem Mag forever. I practiced out to 600 yds. and was confident that if I was presented with the correct opportunity I could kill a bull at that distance. Though ready I was always able to close the distance to within 400 yds. I like my 7mm but have decided I want to shoot a lighter kicking rifle. I am looking at a 7mm-08 with a brake. My 7mm magnum shoots 160 gr. bullets at 3060 and I see I can load the same bullet to 2650 in the 7mm-08. That makes the 7-08 13.3% slower than the 7mm mag. Now the question- will the 7-08 have the same energy at 520 yds.(600yds-13.3%) that the 7 mag has at 600yds? Also if both are sighted in to hit point of impact at 200 yds. would the inches drop for the7-08 at 520 yds. be equal to the inches drop of the 7mm mag at 600 yds.? Thanks for any insight guys. Hopefully I still won't have to shoot over 400.




With an appropriate LR bullet, in this case a 162gr ELD-M, there is 290’ish yard difference in expansion range at SAC (ft-lbs of energy is a useless metric for killing) between your two stated velocities. All the way from 980 yards at 3060fps MV, to 690 yards at 2650fps MV....

The difference in wind drift is a whopping 1mph- from 7mph bracket at 3060, to a 6mph bracket at 2650fps MV.


Unless you are planning to shoot big game past 700-800 yards, the 7mm-08 is fine. Due to recoil, as 1shot wrote above, dropping down to 6.5mm, though I see no reason 600 and in to use a 6.5 PRC or SSM, will increase effectiveness and decrease recoil.
 
Joined
Mar 28, 2020
Messages
527
calculators will answer all of your Kinetic energy questions, I believe someone posted a good one above.

In regards to changing your rifle. You are taking a massive step backwards going to a 7mm-08. This is a great rifle caliber but if your goal is to get into long range hunting or shooting there is no benefit in shooting the same bullet slower. If recoil is a concern 100% brake your 7mm rem mag. All of my hunting rifles are braked. I am 6'4 and 240lbs and am not sensitive to recoil. I have military training when it comes to long range shooting so form is no concern either. But I brake every rifle because if I am going through the trouble of measuring grains of powder to the thousandth of a grain, trimming brass and seating bullets to the thousandth of a inch, millions of dry fires and rounds down range to perfect my trigger pull and cheek weld. If am going to do all of that to shoot a group that is a thousandth of a inch tighter, why wouldn't I remove the effect of recoil on the rifle. Can you shoot well with recoil? Of course you can. Can you shoot better with absolutely no recoil? Hard to argue that you can't.

My 300winmag Fierce Edge is my go to work horse for hunting. It is a light rifle, I think 7lbs out of the box. But I upgraded the brake it came with to a nice side ported unit. My 9 year old daughter can shoot 50 rounds through it on a hard bench no problem. ohhhh and I am running 212 grain ELD X through it as well. So I could tame the rifle even more by choosing a smaller bullet.

wow
 
Last edited:

Jardo

WKR
Joined
Aug 7, 2017
Messages
468
Location
Hawaii and Utah
Get a 280ai and handload. It matches up with 7mm mag without the recoil or blast.

I’ve killed elk at 600 yards with mine.


Sent from my iPad using Tapatalk
 
OP
B

bummer7580

Lil-Rokslider
Joined
Oct 9, 2017
Messages
128
Location
minnesota
I agree with the above. My CA Mesa 7mag has about the same recoil as my heavy ass RRA LAR-8 in .308. Maybe even a touch less. It’s actually pretty pleasant. I have no problem shooting it all day.
I admire your taste in rifles. The 7mm-08 I am looking at is the CA Mesa. I suspect it should be pleasant to shoot and I do like its fit. I haven't bought a new rifle for awhile- about due.
 
Top