I am very dissapointed with Berger bullets regarding the 338 hybrid bullet.

[Chas1]

+1 w/GreyWolf, I was in the Corps too and was taught one thing...kill the bastards.

 

[Eric Stecker]

When at the Williamsport 1000yrd comp, one shooter said that most guys that are serious about shooting LR target jump VLD's .080" to .100" from the lands.

Tank,

You make an excellent point and for clarification we encourage those who shoot the VLD to try our bullets with a jump as much as .120 (4 COAL Test on how to get VLDs to shoot).

My comments about freebore make the assumption that the freebore length is quite a bit longer than .120. As I mentioned I support the process of discovery and will encourage anyone to pursue such a test. Even if it tells us nothing new that is still something (confirming existing knowledge).

My suggestion that it will not be implemented is based on the idea that one would need several hundred thousandths of freebore to achieve such a result (if it helped at all). This will not be a popular solution if the freebore needed is excessively long especially if we make a bullet that doesn't slump under high pressure regardless of jump length.

Something else to consider is that nose slump is the result of the material forward of the bearing surface realizing launch g-forces that exceed their ability to maintain their shape. Think about a pilot in a plane being pressed into his seat during a launch off of a carrier. In high pressure loads the bullet realizes something like 800 Gs which is more than the material can take. I am having a hard time understanding how freebore can lessen this launch pressure but until a test is conducted this is specualtion.

Regards,
Eric

 

[montana_native]

Without reading this entire thread, I will ask a question that has probably already been addressed...

Is the nose slump the reason the bullets are not living up to the projected BC? If I shoot them out of a gun that can only acheive 2780 fps, would they maintain their shape and G1 BC of 0.891?

Thanks.

 

[GMBshootingclubM60]

What kind of bullets did the Germans and others shoot in the very high velocity experiments? Like 5000fps plus? This was during WW2, I think.

Seems like the nose would burn up, like a reentry vehicle!

 

[Broz]

Without reading this entire thread, I will ask a question that has probably already been addressed...

Is the nose slump the reason the bullets are not living up to the projected BC? If I shoot them out of a gun that can only acheive 2780 fps, would they maintain their shape and G1 BC of 0.891?

Thanks.

I have some solid info for this question MTN. I have got my dial ups to a nats behind. With 100 down range. The 300 hybrids are 1/2 moa at all ranges for me.

I am using Exbal with this info.

MV= 2785
G1 BC= .820

Spot on dial ups and 1/2 moa or better at 802, 995, 1177, 1395, and 1500 yards.

Jeff gun)

 

[Eric Stecker]

Is the nose slump the reason the bullets are not living up to the projected BC? If I shoot them out of a gun that can only acheive 2780 fps, would they maintain their shape and G1 BC of 0.891?

Montana Native,

There are two seperate situation regarding this bullet. The first is that our original calculation of .891 was inaccurate. Jeff's analysis is accurate and matches Bryan's more thorough calculation of .818. This BC is higher than any other 338 cal bullet in existance but it does fall short of our originally published number.

The second situation is that in high pressure situations this bullet will drop an amount that is consistent with an even lower BC. It has been measured to shoot with a drop that is consistent with a BC as low as .700. The high pressure loads that produce this result are well above SAMMI spec and so far all occurances were reported as being shot in the 338 Lapua Magnum.

We believe this results is due to the high pressure causing the nose to slump which will change its shape to a less aerodynamic profile.

There is a thorough explaination of this situation on our website. Go to the first article on our blog which is located on the left hand side of our home page.

Regards,
Eric

 

[Broz]

The high pressure loads that produce this result are well above SAMMI spec and so far all occurances were reported as being shot in the 338 Lapua Magnum.
Regards,
Eric

Hey.... I wish you would quit saying stuff like this. They are shooting awesome out of my 338 Lapua Magnum, and I just bought 250 more. I am stocking up!! So quit scaring me like this.

I am hoping to do an expansion test at 1000 yds soon. If they work like I think they will, I was hoping to get you guys talked into keeping this design and adding another for the cannons. Not everyone shoots a .338 that is maxed out or over bore you know... Ha ha!

So has anyone checked to see if they are working for more people than not??

Might be interesting to see what the ratio is. Then design a thicker jacket for those who have higher acceleration, velocity and case capacity.

Just my 1 1/2 cents.

Jeff

 

[royinidaho]

Eric & Broz,

They are working more perfectly that perfectly in my lowly RUM. Only going maybe max of 2750 most probably a little less than that. I don't trust my Chrony and have shot to only 700 yds. But at that distance the 0.819 worked great.

Broz,

Regarding expansion tests. Check out my 3rd shot post. (Still processing pics) Maybe later tonight.

All I can/will say at this is, don't try to contain the media in any fashion. Leave a lot of flexibility for expansion. Make the media fixture as flexible as possible. I don't recommend wet phone books.

If the results of my tests are representative of the Hybrid, who in the heck would give one iota of care to a loss of a few bc points.

 

[Eric Stecker]

They are shooting awesome out of my 338 Lapua Magnum, So has anyone checked to see if they are working for more people than not?? Then design a thicker jacket for those who have higher acceleration, velocity and case capacity.

Jeff

Jeff,

You got it right (so to speak) again. The slump result is realized when these bullets are pushed very hard (way over SAMMI spec). I'm not trying to pick on the 338 Lapua Mag but this is the only case that has produced this result when these bullets are pushed very hard.

So far no other case has been reported as shooting our bullets with more drop than expected (based on a .818 BC). We are getting ready to test several cases at very high pressure so we can define the issue more clearly so we will have more thorough information soon.

We are working to determine if the pressure limit that the bullet can take now is fixed and specific or broad and more random. One result that has been surprising is that even when drop exceeds predictions due to nose slump (working theory) the precision is not as bad as we expected under these circumstances. These shooters still achieve roughly 1 MOA accuracy as far out as 1,500 meters.

Sure 1 MOA is not what you should expect from a Berger but consider that this bullet may be reshaping itself inside the barrel under extreme pressure. This is hardly what I would call a controlled result. If you asked me to estimate dispersion under these conditions I'd have guessed that they would shoot all over the paper. This isn't the case.

The good news is that if the line between slump and no slump is thin then it is likely also fairly stable. If we can clearly identify this line I can assure you that we will never make a bullet again that crosses over it. We will also be able to help many shooters sort out a problem that may be plaguing others who aren't even aware of this potential result.

Most 338 cal shooters will not have to worry about the slump issue at all especially hunters who don't typically shoot extremely high pressure loads. We are waiting for some specific experiments but early indications are that this is an effective bullet on game and is shooting more precisely and accurately than other options in its class. We do not have any intension of discontinuing the bullet you are shooting now.

For those who want and/or need to shoot at the highest pressure levels to achieve the flattest possible trajectory we are coming up with a version that will hold up to this specific application. You don't need to save the 300 gr Hybrids you have now for a special occasion because we'll make more.

Regards,
Eric

 

[Airgunner7]

I may be a bit of a rookie here but, when u change the seating depth velocity changes as well- correct?

What I have learned from my light weight sporter is that it vibrates differently with velocity and impact location and group size changes.

I can't understand why seating depth plays a roll in accuracy when all that is changing is how much gas gets ahead of the bullet.

 

[Broz]

Jeff,

Most 338 cal shooters will not have to worry about the slump issue at all especially hunters who don't typically shoot extremely high pressure loads. We are waiting for some specific experiments but early indications are that this is an effective bullet on game and is shooting more precisely and accurately than other options in its class. We do not have any intension of discontinuing the bullet you are shooting now.

You don't need to save the 300 gr Hybrids you have now for a special occasion because we'll make more.

Regards,
Eric

This is great news! Thank You Eric, and all the folks at Berger!

Jeff

 

[Eric Stecker]

Airgunner 7

It has been my experience that seating depth is one of the two critical and most common adjustments (the other being powder charge). Seating depth changes the amount of pressure inside the case. If you move the bullet further into the case, pressure will increase because you are reducing the volume of space in which the powder will burn.

If you are away from the lands some gas will escape which will affect velocity but your initial pressure spike will be higher if your COAL is made shorter with the same charge.

Changing seating depth also affects when the bullet will exit the muzzle. When the powder ignites your barrel will whip. The best precision is obtained when the bullet exits the barrel during a dwell or said differently when the barrel is whipping the least.

It is possible to have a higher velocity ammo configuration impact lower at a fixed distance due to barrel whip and when the bullet exits the muzzle during this whipping action. The higher velocity load will drop less over a distance but if you were shooting a higher velocity load at say 300 yards and you switch to a slightly lower velocity load don't assume your gun is broke if the shots print slightly higher at that same distance.

"Tuning" your rifle is the pursuit of every precision oriented shooter. When guys say this or that load "shoots little wads in my gun" what they are saying in different words is that their rifle is tuned as well as it can be with XYZ load combination. This combination is usually achieved by adjusting powder charge and seating depth (not at the same time by the way). Neck tension, case prep and chamber configurations can play a role but it is to a lesser degree as long as they are not completely out of whack (this includes scopes).

Regards,
Eric

 

[Chas1]

For those who want and/or need to shoot at the highest pressure levels to achieve the flattest possible trajectory we are coming up with a version that will hold up to this specific application.

Eric, great news. Thanks.

 

[Pdvdh]

If you move the bullet further into the case, pressure will increase because you are reducing the volume of space in which the powder will burn.

If you are away from the lands some gas will escape which will affect velocity but your initial pressure spike will be higher if your COAL is made shorter with the same charge.

Regards,
Eric

Well... This would be a great time and place for Bryan Litz to provide some internal ballistics insights and technical information/education. Since it's a topic commonly discussed that results in completely differing conclusions.

I'm not certain I understand your statement on seating depth versus pressure Eric. You may be confining the comments on pressure to the instantaneous initial pressure at the moment the primer flashes, rather than peak pressures. The comments hint of conflict with my own findings and on-line research. Which are; increased seating depth produces reduced muzzle velocity,with a constant powder charge. And if MV is reduced with increased seating depths, then how can increasing seating depth result in increased pressures? Anyhow, the first 17 Posts in the following recent Thread takes us to the heart of the matter fairly quickly: http://www.longrangehunting.com/forums/f28/ql-v3-6-just-arrived-its-conflicting-info-57160/

The thread is a discussion of the affects bullet seating depth has on cartridge pressures and muzzle velocities, which is currently on-topic.