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Red Rabbit

Lighter vs Heavier Bullets?????

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Now that we have all drawn December tags :rolleyes: and are working up new loads, trying new factory ammo, new wonder bullets and new thunder sticks, thought I would share some observations.

 

Many think that one gets less recoil with lighter bullets in the same gun. Having done some checking for my 300 WSM, and a 7 RUM, the recoil changes a negligible amount. In the 7 RUM, 140 grainers at 3300 fps gave 32 ft-lb, and 160's at 3200 fps also produce 32 ft-lb recoil, using max loads with the same powder with a 9 lb rifle.

 

My 300 WSM produces 30 ft-lb with both 150 and 180 grain bullets in an 8 lb rifle.

The recoil from a lighter bullet is offset by its higher velocity and greater powder usage.

 

Link to recoil calculator:

http://benchrest.com/sst/recoil.html

 

Trajectory favors the lighter bullet by 2-6" less drop at 600 yards with a 200 yard zero.

10 mph wind drift favors the heavier bullet by about 2" less drift at 600 yards.

the heavier bullet has 13-15% more energy at 600 yards.

 

So for long range coues, I would say to choose the non-varmint bullet that is most accurate, since any advantages of heavy vs. light are slim (recoil and energy) and opposing (drop vs. drift).

 

But it sure is fun to tinker and experiment :D .

 

Doug~RR

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Most of the good loading manuals have drop and wind drift tables for each of the bullets they make, with muzzle velocities shown at 100 fps intervals. If you know the ballistic coefficient of the bullet you are shooting and the muzzle velocity, you can find a bullet in the tables with a similar B.C. and get a pretty good idea what you can expect. Most of these tables are calculated with a few known points determined by shooting and the rest of the information is extrapolated from ballistic programs on a computer, so it is always best to confirm the expected results by shooting your load in your rifle.

 

I have a PACT chronograph that includes a ballistic calculator program and the resulting drop tables are almost always right on. Of course, I use the actual muzzle velocity of my loads that are obtained by chronographing five rounds and calculating the average. This program lets me adjust for ambient temperature and altitude (I beleive that the manuals assume sea level and 75 degrees F). All of this is probably only important to a rifle "looney" like me, but it makes my hobby more enjoyable! So far it hasn't cut into the money that I spend on booze or permits...

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Ben~rifle looney,

 

Has JB at the Campfire given you a label too :rolleyes: . A good one to have. I have been using the Point Blank program.

 

Doug

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Guest Ernesto C

Excellent post and excellent observations Doug. That's why I love my 150gr on my 30-06 and specially at long ranges. On my 270 I use 130 or 140s. Often while coues hunting you may shoot way over 300 yards so I personally dont like lighter bullets.

What will you be using in 36C? your 300 WSM or 7 RUM? 150,180's or how many grains?

 

Ernesto C

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Interesting, not much difference at all between the 7 RUM 140 and 160 grain. The 7 RUM 140 grains for coues and the 300 WSM 180 grain for your elk look good. Good luck and get some biggins this year!

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The 7 RUM belongs to someone else, but somehow I have four 300 mags that all want to go hunting.

In the 300 WSM, I am trying to find an accurate 150 grain load with the Nosler Accubond. I have one with 150 TSX's, but I like to tinker. Will use 180's on the elk and may on the coues also, depending on whether I find an accurate one with Nosler 150's.

 

RR

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180s and a 300 mag are hard to beat for ANY game in AZ. Buck the wind and arrive with authority out to quite a bit farther than anyone has any business shooting... I gave up on 150s in the 300 after one application on coues. (The 150s were ballistic tips though, which I've also given up on. I like to eat the animals I harvest.)

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Great info guys!

I also shoot the 7mm RUM. I use the 140 grain and a 26" barrel and I love it for everything. But I would like to mention that it wouldn't be the gun that it is if I didn't take advantage of it with a Burris 3x9 full field 2 with balistaplex (not sure on spelling) This scope is awesome! Without it, it would be like putting one 10 yard pin on a Mathews bow and calling it good. Of course you gotta have a range finder to take full advantage of it. I have used other scopes and they don't compare in a hunting situation. Like I said I use this load for everything so I always know where it hits. I used to change grains around with my old 30-06 until I asked myself what would have killed that critter better? A new 180 gr load in the dirt or my old 150 gr in the lungs? After I answered this my "old 06" became my "trusty old 06" until it was stolen. Now I have my "new trusty ultra mag"!

 

Keep the wind in your face!

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