7mm Rem Mag 168 and 180 Bergers

jmcarrol

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Oct 31, 2010
Messages
280
Location
NW Arkansas
I have a R Bros 7mm Rem mag. Throated for 180 Bergers and RE 26. Was just wondering if anyone has tried RE26 with 168 Bergers? I hate muzzlebrakes, so I prefer not to use mine and try the 168s for less kick. Do you guys think there will be much difference in recoil? Have you tried RE26 with a 168 Berger? I have RE26, Retumbo and H1000.
 

jmcarrol

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Joined
Oct 31, 2010
Messages
280
Location
NW Arkansas
I’ll probably just use the load Travis sent for the gun. Just curious about difference in recoil between 168 and 180s.
 

Scott E Ames

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LRH Team Member
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Dec 25, 2012
Messages
350
SHOW OFF stating you have Retumbo! Kidding aside here is my 7mm RM target with RL 26. ( it says
"7 Bean" because this one was built by Jon Beanland and lets me know which 7 mm RM I was shooting that day)

7Bean:RL26.jpeg
 

Scott E Ames

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Dec 25, 2012
Messages
350
"Thanks for the replies. I’m down to 4 lb of retumbo so I’ll try the 26."

Forgot to include that my rifle doesn't have much recoil at all but with the big Nightforce scope it weighs right at 11#.
 

KaSH0508

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Joined
Feb 27, 2017
Messages
38
Location
Utah
I have been running the Berger 168 Hunters and RL26 in my 7mm mag for the past 5 years or so. I run them around 3050 FPS and i can consistent 1/2 - 3/4 inch groups if I do my part. They hammer deer though that’s for sure!
 

Tiny Tim

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Jan 26, 2015
Messages
837
Shouldn't be much difference at that weight. On a lighter unbraked rifle, there is a noticeable difference between a 140 and 160 class bullet.
 

BallisticsGuy

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Joined
May 8, 2016
Messages
1,176
Location
Heck
There will be essentially no difference at all. This should be generally obvious but I guess without the math people just don't see it. Simple physics.

recoil energy = (MV*((bullet weight in grains/7000)+1.75*(powder charge weight in grains/7000)))^2
weapon inertia = 64.348*rifle weight in pounds
recoil force remaining = recoil energy / weapon inertia

Recoil is a function of the mass of the powder, the mass of the projectile, the mass of the gun and the velocity of the projectile. Unless you can make a BIG bloody difference in what any ONE of those numbers is doing WITHOUT THE OTHER NUMBERS INCREASING are you will not appreciably affect recoil.

So if you have 180 grain bullet and 77 grains of powder at 2900fps in a 10lbs gun there's total kick of 26lbs/ft/sec. No surprises there. Thing is, smaller bullets tend to be a good bit faster and energy comes from squaring speed not mass so mass changes aren't as helpful as speed changes. So, you can't just go a little lighter to get a noticeable drop in recoil energy. If you drop to a 168gr bullet and pump the speed as it will naturally tend to do, to say 3050fps, then the recoil force actually goes up to 27lbs. If you don't change the velocity upward and leave it at 2900 then you see 24lbs of free recoil. This means that you've made a difference which you will not be able to detect. The small difference is because of the small change in projectile weight. The difference in bullet weight has to be a lot to make a noticeable change. So if you were to go with say, 90gr bullets even though they might be running something silly fast like 3600fps the recoil force would be reduced noticeably to something like 21lbs, as noticeable as the difference between a .308 and a .30-06 with equal weight bullets.
 
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