Question on 7mm RM and 180gr. Bergers

[6.5x300 WBY]

Shoot the Bergers. You're getting great, confidence building accuracy. Load up on HSM ammo and work on your drop validation. The Bergers will work for you.

Thx I will load up on them for sure. Nice stable awesome accuracy. Can't wait to get a buck in my crosshairs this August in SC. Or a hog with would be great.

But I won't be able to shoot at any range beyond 100 yards. Not in my area. It's unfortunate but true.

 

[MudRunner2005]

I have seen bullets shoot strait that I KNEW couldn't be stable, such as a Berger 170 EOL out of a standard 10 twist .270, at about 4000 ft elevation.....shot surprisingly well, but I think I would be hesitant to use this for hunting, simply due to a test that a member did on here showing ballistics of MANY bullets, and Berger and matrix bullets consistently would banana if they were not stable. Would it still cause damage? most definitely, tumbling bullets will mess **** up, the downside is that they tend to be unpredictable and probably will not penetrate as much. It is very interesting however, that an unstable bullet can still be so accurate.

Mine is same Sendero but regular 7mag. It's lights out so we are stable at like 100 feet at NJ shore. Go figure got to find what your gun likes

Yeah, it almost makes you wonder in reality just how stable bullets are in twists that are slower than what the manufacturers say is necessary. Because for years Berger claimed a 1:10 was stable for the 168's, and a 1:9 was stable for the 180's, but a couple years back, they tweaked the BC's of their bullets, and now they claim that you need a 1:9 for the 168's, and a 1:8 for the 180's...

That being said about them changing required twist rates, even on Berger's own twist rate calculator, with my 9.25" twist, and 180 Hybrids going 3,000 FPS MV (mine are actually closer to 3,100, just using 3000 as a static), is showing a 1.48 SG...Which is so close to stable, that I'd consider it stable. A 1.5 SG (or higher) is ideal, and considered fully stabilized.

 

[martinakl]

Yeah, it almost makes you wonder in reality just how stable bullets are in twists that are slower than what the manufacturers say is necessary. Because for years Berger claimed a 1:10 was stable for the 168's, and a 1:9 was stable for the 180's, but a couple years back, they tweaked the BC's of their bullets, and now they claim that you need a 1:9 for the 168's, and a 1:8 for the 180's...

View attachment 98112

That being said about them changing required twist rates, even on Berger's own twist rate calculator, with my 9.25" twist, and 180 Hybrids going 3,000 FPS MV (mine are actually closer to 3,100, just using 3000 as a static), is showing a 1.48 SG...Which is so close to stable, that I'd consider it stable. A 1.5 SG (or higher) is ideal, and considered fully stabilized.

View attachment 98113

Does it show something different for the 180 Hunting VLD? If I remember correctly, the HVLD has a lower BC and just a fraction of a hair shorter in length.

Berger site is blocked at my work

 

[MudRunner2005]

Does it show something different for the 180 Hunting VLD? If I remember correctly, the HVLD has a lower BC and just a fraction of a hair shorter in length.

Berger site is blocked at my work

In reality, the HVLD vs. the TVLD should be 100% identical, other than jacket thickness. The Hybrid, has a hybrid shaped Ogive, and originally showed a higher BC than the 180 VLD bullets. I don't know if Berger didn't re-test them or not, but I have several older boxes of Bergers in both the 180 VLD and 180 Hybrids, and just looked at them.

The original 180 VLD bullets (target & hunting versions) had a .659 G1 BC, .337 G7 BC, and recommended a 1:9 twist. And the 180 Hybrid bullets had a .674 G1 BC, .345 G7 BC, and recommended a 1:9 twist.

 

[6.5x300 WBY]

Yeah, it almost makes you wonder in reality just how stable bullets are in twists that are slower than what the manufacturers say is necessary. Because for years Berger claimed a 1:10 was stable for the 168's, and a 1:9 was stable for the 180's, but a couple years back, they tweaked the BC's of their bullets, and now they claim that you need a 1:9 for the 168's, and a 1:8 for the 180's...

View attachment 98112

That being said about them changing required twist rates, even on Berger's own twist rate calculator, with my 9.25" twist, and 180 Hybrids going 3,000 FPS MV (mine are actually closer to 3,100, just using 3000 as a static), is showing a 1.48 SG...Which is so close to stable, that I'd consider it stable. A 1.5 SG (or higher) is ideal, and considered fully stabilized.

View attachment 98113

Muddy. Glad you posted but I have to confess that stuff is way above me. I don't know how they come up with this stuff. Put numbers together make **** up and call it fact. Who knows. All I know is I get bullet holes and incredible accuracy at 100. I guess this stuff is for the more knowledgeable peeps than I. I just shoot what my gun likes and go from there. All of my rifles tell me what they like. Lighter bullets from many manufacturer don't shoot. Heavy bullets shoot in my Sendero. I guess I am not up to all this stuff. I am more old school and test to see what my gun tells me she likes. Your hurting my head. Need Tylenol now. : )

 

[codyadams]

Mine is same Sendero but regular 7mag. It's lights out so we are stable at like 100 feet at NJ shore. Go figure got to find what your gun likes

Do not confuse stability and accuracy, they are two different things. You can have accuracy without stability, and vice versa. You in fact are not stable at 100 ft elevation with a 9.25 twist and 2950 fps (only by a small margin), unless you are shooting over 75 degrees roughly. At 15 degrees your stability drops to 1.33 (a minimum number of 1.5 is needed for adequate stability) What will happen is your bc will be compromised, however slightly, depending upon variations in temp and altitude. They may shoot very well, but when you use them on game just keep a close eye on performance. They may not perform as advertised due to instability if you happen to shoot at a low temp. Run your numbers here: http://www.bergerbullets.com/twist-rate-calculator/ if you want, and you can see for yourself exactly what your bc will be at varying temps and altitudes. If you do not plan on shooting over 100 yards however, the BC loss does not matter at all. Just keep an eye on on-game performance and you should be golden!!

 

[6.5x300 WBY]

Cody thx for that info. It's a bit confusing to me how u can have one without the other. But I will be hunting with this ammo in SC in AUGUST. I EXPECT IT TO BE IN THE 90'S WHILE HUNTING. I HAVE SHOT MY TC contender with 77 grain pills and get tears and I know it's not stabilizing in that barrsl. Obviously to me. When I switched to 55 great pills bullet holes and great accuracy.

I do understand twist rate and relationship to accuracy depending on weights. But if my bullet shoots great and has clean holes at 100 no tumbling or tears I would feel like it's good to go.

Now you guys are saying not so fast???? ***. Why did I come hear in the first place. When I start to understand something there is 10 more things I never heard of and don't know. Is this true or someone just puts some numbers down and makes **** up saying it's fact. Now I have a headache and need a Vicodin. Tylenol no good anymore.

 

[codyadams]

Cody thx for that info. It's a bit confusing to me how u can have one without the other. But I will be hunting with this ammo in SC in AUGUST. I EXPECT IT TO BE IN THE 90'S WHILE HUNTING. I HAVE SHOT MY TC contender with 77 grain pills and get tears and I know it's not stabilizing in that barrsl. Obviously to me. When I switched to 55 great pills bullet holes and great accuracy.

I do understand twist rate and relationship to accuracy depending on weights. But if my bullet shoots great and has clean holes at 100 no tumbling or tears I would feel like it's good to go.

Now you guys are saying not so fast???? ***. Why did I come hear in the first place. When I start to understand something there is 10 more things I never heard of and don't know. Is this true or someone just puts some numbers down and makes **** up saying it's fact. Now I have a headache and need a Vicodin. Tylenol no good anymore.

Calm down now, no need to get all distraught. It's just knowledge that you have never learned before. We all learned it at some point. And no, it's not made up. People much, much smarter than you or I have figured this out and made it easier to understand, and if you practice enough it becomes apparent. I am going to explain this stuff, if your not interested than just skip the rest. Oh and please, don't do drugs.

There are different levels of instability, a bullet doesn't go from perfect flight to tumbling just like that. Think of an arrow in flight, if you have shot archery much...you have seen arrows that fly perfectly, they never really have any visible wobble, just perfect flight, and you have also seen arrows that have a slight back and fourth/up and down wobble when they fly, however they can still be accurate though their flight is not perfect. If your bow is far enough out of tune, or fletchings are messed up, or something else like that, arrows can veer off to a side or any other direction bad enough that all accuracy and consistency is lost. It is no different with bullets; there are varying levels of instability. An S.G., or gyroscopic stability factor, of 1.5 and higher is good stability, think of the perfectly flying arrow. A 1.35 is slightly unstable, think of the wobbly arrow, can still be accurate, but not perfect flight. Now say your at a 1.0, now you have the tumbling, arrow veering off target situation, your 77 grain bullet in your TC situation. Varying levels. My numbers aren't exact here, I'm generalizing to try to make it easier to understand. Hope that helps describe the stability part....

Now, if you are shooting in the 90's, according to Bergers bullet calculator you will be fine. However, I will try to explain why it is important with Bergers, Matrix, or most other hollow point hunting bullets with a small hollow point, to be stable for best terminal performance.

So say you are shooting, and your stability is 1.35 or so. We are in the wobbly, but still possibly accurate arrow region now. Your bullet is similar to the arrow, as in the bullet is a little wobbly going though the air, the point is not always perfectly strait forward. So, if it hits not pointing exactly strait forward, it CAN (not will, but can) begin to tumble instead of expand as designed.

 

[6.5x300 WBY]

Calm down now, no need to get all distraught. It's just knowledge that you have never learned before. We all learned it at some point. And no, it's not made up. People much, much smarter than you or I have figured this out and made it easier to understand, and if you practice enough it becomes apparent. I am going to explain this stuff, if your not interested than just skip the rest. Oh and please, don't do drugs.

There are different levels of instability, a bullet doesn't go from perfect flight to tumbling just like that. Think of an arrow in flight, if you have shot archery much...you have seen arrows that fly perfectly, they never really have any visible wobble, just perfect flight, and you have also seen arrows that have a slight back and fourth/up and down wobble when they fly, however they can still be accurate though their flight is not perfect. If your bow is far enough out of tune, or fletchings are messed up, or something else like that, arrows can veer off to a side or any other direction bad enough that all accuracy and consistency is lost. It is no different with bullets; there are varying levels of instability. An S.G., or gyroscopic stability factor, of 1.5 and higher is good stability, think of the perfectly flying arrow. A 1.35 is slightly unstable, think of the wobbly arrow, can still be accurate, but not perfect flight. Now say your at a 1.0, now you have the tumbling, arrow veering off target situation, your 77 grain bullet in your TC situation. Varying levels. My numbers aren't exact here, I'm generalizing to try to make it easier to understand. Hope that helps describe the stability part....

Now, if you are shooting in the 90's, according to Bergers bullet calculator you will be fine. However, I will try to explain why it is important with Bergers, Matrix, or most other hollow point hunting bullets with a small hollow point, to be stable for best terminal performance.

So say you are shooting, and your stability is 1.35 or so. We are in the wobbly, but still possibly accurate arrow region now. Your bullet is similar to the arrow, as in the bullet is a little wobbly going though the air, the point is not always perfectly strait forward. So, if it hits not pointing exactly strait forward, it CAN (not will, but can) begin to tumble instead of expand as designed.

Cody .thx so much I appreciate the efforts here. That makes sense to me. I love bow hunting be it compund or crossbow. Arrow in flight made it make sense to me. Now I do understand. Also going by the chart on Berger I am like 1.48 at worst when they say 1.50 sg is needed to be optimal. So it's so close I don't think I will worry. Now if I use this bullet combo in winter when it's 25 degrees it may be a different story.
Thx Cody I truly appreciate your time and help.

I am going to be purchasing some HSM 168 hunting VLDs. Bergers and see how they shoot. Again appreciate it.
Oh I don't do drugs. : ).

Appreciate everything

Brian

 

[codyadams]

Cody .thx so much I appreciate the efforts here. That makes sense to me. I love bow hunting be it compund or crossbow. Arrow in flight made it make sense to me. Now I do understand. Also going by the chart on Berger I am like 1.48 at worst when they say 1.50 sg is needed to be optimal. So it's so close I don't think I will worry. Now if I use this bullet combo in winter when it's 25 degrees it may be a different story.
Thx Cody I truly appreciate your time and help.

I am going to be purchasing some HSM 168 hunting VLDs. Bergers and see how they shoot. Again appreciate it.
Oh I don't do drugs. : ).

Appreciate everything

Brian

Excellent, those 168's perform excellently in the 4 different 7 mags I have used as well!! Identicle performance to the 180's.

 

[barefooter56]

This is true, my cousins rifle has a 9.25 twist, however we live at 6600 feet, and where we hunt in from that elevation up to 8000-10000 feet, and even at our lower elevation and a low temp of 15 degrees with a 9.25 twist we have an sg of 1.71, up that to our elk hunting average of 8500, at an average elk hunting temp of 30 degrees and the sg is now 1.90.

However, if your at an elevation of say 1000 feet, same 9.25 twist, and 30 degrees, you are not properly stable at 1.43...you need a minimum of 55 degrees with a 9.25 twist at 1000 ft to BARELY stabilize this bullet. What can happen in this situation is the bullet tip is not totally stable, and since it is such a small hollow point, if it hits not square on, the bullet tends to banana and begin to tumble. It can still do extreme damage, but does not perform as it should. Just something to keep in mind!!

Cody and all,
Thanks for the kind words about our bullets performance on game! However, there is a lot of misunderstanding about our TWIST RATE CALCULATOR. The two words "MARGINALLY STABLE" are the problem. For a bullet to be completely unstable the STABILITY FACTOR (SG) number has to be below 1.0 ( personally I fudge it to 1.1 to give me some cushion). The numbers 1.0 to 1.49 only indicate how much the BC of the bullet is affected. Those numbers are indicated by an adjusted BC value and a percentage the BC is also affected. What they don't mean is that the bullet will become unstable and start to tumble at a certain yardage down range. The bullet will be flying point forward until it hits the dirt. Out to about 600 yards you wont see much more effect on the bullet due to external conditions such as wind. From 600 yards on out you will notice more effect on the bullet by conditions due to the compromised BC . And if you were a TARGET SHOOTER trying to hit a target out where the bullet goes in to the TRANS or SUBSONIC stages of its flight you would lose the spin rate stability faster to help stabilize the bullet as it passes through these stages. http://www.appliedballisticsllc.com/Articles/ABDOC2.6 - Transonic%
20Effects%20on%20Bullet%20Stability%20&%20BC.pdf
ALTITUDE is the biggest factor there is in making up for lack of barrel twist rate. Velocity and Temperature help. But ALTITUDE is the big one. Always make sure you base your barrel twist rate on the LOWEST ALTITUDE you will be shooting at. In regards to our new Optimal Barrel Twist Rates. These are all based on a worst case scenario of 59 degrees at SEA LEVEL. We did this because we discovered that there were a couple twist rates we had listed that would not stabilize the bullet at 59 degrees at sea level so we changed them all so that now you know what you need from sea level on up to work. This will explain why the BC changes :http://www.bergerbullets.com/update-of-berger-bullets-performance-data/
Hope this helps make things clearer in regards to The TWIST RATE CALCULATOR ETC. If you have any more questions please let us know!
PS New phone number is 660-460-2802 8am to 4:30pm EASTERN MON thru FRI

 

[MudRunner2005]

In regards to our new Optimal Barrel Twist Rates. These are all based on a worst case scenario of 59 degrees at SEA LEVEL. We did this because we discovered that there were a couple twist rates we had listed that would not stabilize the bullet at 59 degrees at sea level so we changed them all so that now you know what you need from sea level on up to work.

Ahhh! That explains it. I never did read any explanation as to why the twist rates were changed. I thought it had more to do with the BC's changing from the new doppler radar testing, and was not really thinking that it was about "worst case scenario" as much as full stability.

 

[6.5x300 WBY]

Cody and all,
Thanks for the kind words about our bullets performance on game! However, there is a lot of misunderstanding about our TWIST RATE CALCULATOR. The two words "MARGINALLY STABLE" are the problem. For a bullet to be completely unstable the STABILITY FACTOR (SG) number has to be below 1.0 ( personally I fudge it to 1.1 to give me some cushion). The numbers 1.0 to 1.49 only indicate how much the BC of the bullet is affected. Those numbers are indicated by an adjusted BC value and a percentage the BC is also affected. What they don't mean is that the bullet will become unstable and start to tumble at a certain yardage down range. The bullet will be flying point forward until it hits the dirt. Out to about 600 yards you wont see much more effect on the bullet due to external conditions such as wind. From 600 yards on out you will notice more effect on the bullet by conditions due to the compromised BC . And if you were a TARGET SHOOTER trying to hit a target out where the bullet goes in to the TRANS or SUBSONIC stages of its flight you would lose the spin rate stability faster to help stabilize the bullet as it passes through these stages. http://www.appliedballisticsllc.com/Articles/ABDOC2.6 - Transonic%
20Effects%20on%20Bullet%20Stability%20&%20BC.pdf
ALTITUDE is the biggest factor there is in making up for lack of barrel twist rate. Velocity and Temperature help. But ALTITUDE is the big one. Always make sure you base your barrel twist rate on the LOWEST ALTITUDE you will be shooting at. In regards to our new Optimal Barrel Twist Rates. These are all based on a worst case scenario of 59 degrees at SEA LEVEL. We did this because we discovered that there were a couple twist rates we had listed that would not stabilize the bullet at 59 degrees at sea level so we changed them all so that now you know what you need from sea level on up to work. This will explain why the BC changes :http://www.bergerbullets.com/update-of-berger-bullets-performance-data/
Hope this helps make things clearer in regards to The TWIST RATE CALCULATOR ETC. If you have any more questions please let us know!
PS New phone number is 660-460-2802 8am to 4:30pm EASTERN MON thru FRI

Mud can you translate this into laymen's terms. I know he explained something but I need an explanation of his explanation. Man I feel like iiam in Astrophysic or something. Good grief. Does he mean I will be good shooting the 180bergers from my Sendero with 9.25 barrel? I am lost. Thx

 

[MudRunner2005]

Mud can you translate this into laymen's terms. I know he explained something but I need an explanation of his explanation. Man I feel like iiam in Astrophysic or something. Good grief. Does he mean I will be good shooting the 180bergers from my Sendero with 9.25 barrel? I am lost. Thx

If you input your data into their bullet stability calculator, and you get an SG (unit of measure for gyroscopic stabilization) from 1.0 to 1.49, then your bullet is considered "marginally stable", which means it CAN potentially still be accurate even out to around 600 yards before showing any signs of instability (like key-holing or poor accuracy).

And if you get an SG of 1.5 or higher, your bullet is considered "fully stabilized" even through the transonic (1,340 to 1,126 FPS) and down to subsonic (1,125 and lower) speeds.

So, as long as your input data gives you something above 1.0 to 1.49 SG, you can still be accurate, but it might not be 100% stable. If you get an SG of 1.5 or greater, your bullet will be 100% stable in your rifle in it's current load.

For example, my STW shooting the 180 Hybrids showing a 1.48 SG shows marginally stable, but it's so close to 1.5, I'd consider it to be fully stabilized (personal opinion), but with everything in this sport, it's always best to go shoot them at distance and check your drops and your targets to verify for yourself before shooting at game that far.