7MM Berger Conundrum

[kc0pph]

168 vs. 180 berger bullets?

I have been playing with Load From a Disk with a 7x300 Wby Mag. I have 1 box of 168 and 1 box of 180gn. I will be using H-870 powder (Over 100FPS gain over other powders).

The picture attached shows bullet drop of Load From a Disk's MAX loads for the caliber. It goes out to 2000 Yards. The 168 shoots flatter even out to those distances. The Energy is pretty much the same.

So those of you shooting the 180's why are you shooting them? What Am i Missing? The ability to buck the wind should also stay consistent with Bullet drop as that is Velocity and BC.

It shows 54 MOA drop of the 168 at 2000 yards vs 57 MOA drop at 2000 Yards, so they seem identical. But do you want to spend the extra powder in the 168's to get a slightly flatter shooting bullet?

 

[Booney]

were is your graph on wind?

 

[Stumpm2]

I have shot the 168s and this weekend loaded up some 180s to try and I was surprised by the increase in felt recoil with the 180s. I also did not lose as much velocity as I thought I would by going up to the 180s. When I was looking at drop figures, the 168s were slightly flatter, but the 180s had slightly less wind drift. I was assuming a 100 fps drop in velocity for the 180s and my actual lose in velocity was only around 70 fps. I think I will be sticking with 168s for shooting ease unless I find the 180s shoot a lot better. This was out of a 7mm Dakota.

 

[Booney]

that was my next ? witch ones shot better.

 

[kc0pph]

231 inches with 168 and 228 with 180 so the 180 will buch a 10mph wind slightly better, but 3" at 2000 yards is not much.. The Graph for the wind is attached.

 

[Stumpm2]

that was my next ? witch ones shot better.

Conditions were not the greatest, so I did not get a great feel for how they are going to shoot compared to the 168s. The 168s are definitely more pleasant to shoot and I was not expecting to notice a difference.

 

[BryanLitz]

Here's some further information on those two bullets:
http://www.appliedballisticsllc.com/index_files/7mmNumberOne.pdf
http://www.appliedballisticsllc.com/index_files/7mmNumberTwo.pdf

The analysis focuses on NRA style target shooting but the ballistics are the same regardless of the target.

-Bryan

 

[kc0pph]

Just the person I wanted to chime in.

Btw. I got a chance to skim through your book, Look forward to buying it here soon.

What i got out of reading *Most* of your 2 articles is (At a much lower velocity) the 168 and the 170 are very similar and not enough difference between them to really care which one ins being launched (excluding Energy for hunting). This is what i found in my simulations.

Big question now, if they preform almost identicle then what is the purpose for having 2 bullets the same. I would think it would be cost effective to drop the 180 and go for just the 168, develop a 190 or something that would have a ballistic advantage?

For anyone who wants quick reference the 2nd link he posted scroll down to where you see targets it summs it up pretty good i feel.

 

[BryanLitz]

...Big question now, if they preform almost identicle then what is the purpose for having 2 bullets the same. I would think it would be cost effective to drop the 180 and go for just the 168...

Some rifles 'tune' better with one or the other. In other words, they may be practically the same performance-wise, but if your rifle shoots one in 1/2 MOA groups, and the other in 1 MOA groups...

That's the same reason there are so many .22 cal varmint and target bullets in such a small weight range. 50 grains, 52 grains, 55 grains, 60 grains. All flat base hollow points. Not that there's much (if any) ballistic difference, but some rifles like certain weights better than others.

Take care,
-Bryan

 

[rscott5028]

I would think it would be cost effective to drop the 180 and go for just the 168, develop a 190 or something that would have a ballistic advantage?

What Bryan said.

...plus, he/they are working on a 195 that should have even more of an advantage if you have a rifle/cartridge capable of exploiting it.

-- richard

 

[kc0pph]

Yeah that would make sense. Well just loaded up 20 of the 180's and we will see how well they do at the range tomorrow. Hoping 1/2 MOA out of them. Ill let you guys know how they do.

Do we have a estimate on the B.C of the 195 gn bullet? Just a rough guess??

 

[elktaxi1]

please post your results i shoot a 7mm 300wby and would like to see if you get them to work. i have not been able to get them to work.

 

[kc0pph]

Well I somehow lost my micrometer and so can not measure the OAL of the loaded rounds but I loaded 20 with 75gn H870 (Light load) and seated them pretty far in. The rifle i am shooting them out of will get here tomorrow, plan is to clean it, scope it and head to the range. The rifle has a .180 freebore in it so not sure if that will help or not. Ill post pictures of my targets.

 

[rscott5028]

Do we have a estimate on the B.C of the 195 gn bullet? Just a rough guess??

http://www.longrangehunting.com/for...e-7mm-195-gr-eol-hybrid-hunting-bullet-85792/
"It has an estimated averaged G1 BC of .794 and a G7 BC of .406."