Berger 7mm 190gr long range hybrid

[davidjoe]

A decrease in velocity of 120 fps would be huge in terms of load development.

One would tend to think so, Ned.

 

[lawrence97]

David,
What’s your muzzle velocity with the 190’s and the 184’s ?

Looks like your 184’s are arriving on target faster but need to know muzzle velocity to compare.

The 184’s seem tighter but neither of those groups at 600 has great vertical.

 

[davidjoe]

David,
What’s your muzzle velocity with the 190’s and the 184’s ?

Looks like your 184’s are arriving on target faster but need to know muzzle velocity to compare.

The 184’s seem tighter but neither of those groups at 600 has great vertical.

I didn’t chrono today. SD’s were about double normal due to wind. Very strong angling gusts.

 

[lawrence97]

I’ve never experienced double the SD due to wind. Mine stays in the single digits for 25-50 rounds no matter what. You must be experiencing some strange stuff if SD is affected by wind.

 

[davidjoe]

From Sunday. Lesser headwind than today, but still primarily headwind. Single digit.

 

[davidjoe]

Same box of bullets. Shorter barrel.

 

[lawrence97]

View attachment 1164051 Same box of bullets. Shorter barrel.

Same rifle?
I see the caliber as .308 for your etarget.

Your average velocity isn’t far off from both sessions which could be the particular temp, density altitude or environment for given day.

The SD points me to think there’s some load work that needs to be done and the vertical for your 600 yard targets is not great.

*”same box of bullets shorter barrel”*
With this being said how can you compare apples to apples such as SD or bullet performance between 184’s or 190’s ?

Did you compare 190’s to 184’s out of the same gun?

 

[Ned Ludd]

One would tend to think so, Ned.

I pointed that out because anyone running the 190s will likely already be dealing with a loss of velocity relative to the 180 or 184 Hybrids due to the increased bullet weight. That is just simple physics and the inherent pressure limitations of a given cartridge. In light of that fact, minor load velocity variance in the range of +/- 50 fps or less isn't going to have much of an effect on wind deflection for a given BC bullet. Assuming equal precision, using a bullet with higher BC will generally provide more gain in terms of wind deflection than is possible by increasing velocity.

 

[davidjoe]

Same rifle?
I see the caliber as .308 for your etarget.

Your average velocity isn’t far off from both sessions which could be the particular temp, density altitude or environment for given day.

The SD points me to think there’s some load work that needs to be done and the vertical for your 600 yard targets is not great.[/QUOTE

Same rifle?
I see the caliber as .308 for your etarget.

Your average velocity isn’t far off from both sessions which could be the particular temp, density altitude or environment for given day.

The SD points me to think there’s some load work that needs to be done and the vertical for your 600 yard targets is not great.

*”same box of bullets shorter barrel”*
With this being said how can you compare apples to apples such as SD or bullet performance between 184’s or 190’s ?

Did you compare 190’s to 184’s out of the same gun?

Today’s targets were the same gun. The Sunday target was to show SD in calmer conditions.

 

[davidjoe]

I pointed that out because anyone running the 190s will likely already be dealing with a loss of velocity relative to the 180 or 184 Hybrids due to the increased bullet weight. That is just simple physics and the inherent pressure limitations of a given cartridge. In light of that fact, minor load velocity variance in the range of +/- 50 fps or less isn't going to have much of an effect on wind deflection for a given BC bullet. Assuming equal precision, using a bullet with higher BC will generally provide more gain in terms of wind deflection than is possible by increasing velocity.

I agree. That’s why the 195 H has been my preferred bullet. All current 7mm Berger hybrid bullets group better than 1/6 moa at 600 yards in the calm.

 

[davidjoe]

Lawrence, JBM says:

184 = 3,150
190 = 3,060


I have a simple chronograph but it put them both so much lower that either it, the ShotMarker or JBM are very incorrect:

184 = 3030
190 = 2982

 

[No i deer]

From Sunday. Lesser headwind than today, but still primarily headwind. Single digit.

Out of curiosity what's the SD at the muzzle..
I wondered how much it changes at the target..
I'm not used to seeing these figures

 

[davidjoe]

It’s typically very close. I have seen the SD both somewhat lower and higher at the line. I don’t see a divergence of a whole order of magnitude much. Today, without a line chrono I came close to that, because I didn’t wait out the wind. I shot into gusts as well as during let offs. Made only mild, quick calls. The 190’s are new to me and I wanted see how they moved, as opposed to slowly shooting the prettiest target. I also wanted to see if they would blow up. Not so far.

 

[F Class John]

FWIW everyone does realize the Shotmarker ‘at target’ data is not reliably repeatable right? Adam will freely admit that those numbers are subject to any number of discrepancies that make the data non-correlatable to actual muzzle SD or ES. It’s not a reliable chronograph unless you’re in a wind tunnel.

 

[rardoin]

FWIW everyone does realize the Shotmarker ‘at target’ data is not reliably repeatable right? Adam will freely admit that those numbers are subject to any number of discrepancies that make the data non-correlatable to actual muzzle SD or ES. It’s not a reliable chronograph unless you’re in a wind tunnel.

My findings also. Some target frames/sensors/sensor hubs are better than others it seems. I take the at target velocity data lightly.

 

[lawrence97]

Lawrence, JBM says:

184 = 3,150
190 = 3,060


I have a simple chronograph but it put them both so much lower that either it, the ShotMarker or JBM are very incorrect:

184 = 3030
190 = 2982

David,
The shot marker is by no means a replacement for a chronograph. It simply allows you to compare data and it should not be used to extrapolate velocities back at the muzzle. I don’t consider JBM to give good calculations either unless you input every variable and these variables need to be accurate. The data at the target can vary a lot based on environmental conditions more than you would see at the muzzle on a given day. Density altitude is a major factor for down range velocities.

The only way to see what’s happening at the muzzle is with a good chronograph at the muzzle such as a Magnetospeed or a Labradar.

If you have been basing your muzzle velocity from on target velocity approximations that the shot marker provides you will be lost and not have a true velocity at the muzzle.

 

[davidjoe]

David,
The shot marker is by no means a replacement for a chronograph. It simply allows you to compare data and it should not be used to extrapolate velocities back at the muzzle. I don’t consider JBM to give good calculations either unless you input every variable and these variables need to be accurate. The data at the target can vary a lot based on environmental conditions more than you would see at the muzzle on a given day. Density altitude is a major factor for down range velocities.

The only way to see what’s happening at the muzzle is with a good chronograph at the muzzle such as a Magnetospeed or a Labradar.

If you have been basing your muzzle velocity from on target velocity approximations that the shot marker provides you will be lost and not have a true velocity at the muzzle.

I follow. Also, while I tried to “square up” with these two screens, I was standing and shot from the shoulder - with the imperative being that I put these rounds into the yard (sandy loam, ~3 miles to property line), so I may have shot these rounds through it at enough of a down angle that it read them as going slower than they were.

That thought occurred to me when the difference between each was not particularly similar, but they were both lower.

I should have shimmed up the front of the chrono to closer match my angle. But now I cleaned the barrel already.

 

[lawrence97]

I follow. Also, while I tried to “square up” with these two screens, I was standing and shot from the shoulder - with the imperative being that I put these rounds into the yard, so I may have shot these rounds through it at enough of a down angle that it read them as going slower than they were.

That thought occurred to me when the difference between each was not particularly close, but they were both lower.

I should have shimmed up the front of the chrono to closer match my angle. But now I cleaned the barrel already.

“I was standing and shot from the shoulder - with the imperative being that I put these rounds into the yard”

you are standing with an fclass rifle? More power to you.
The shot marker works fine if you are pointed in the general direction. If you go outside it’s limits of approx 20° then it may register a miss/crossfire. The shot marker also registers the quality of each shot and the stability of the frame being used. If you click on “Sensor Monitor”, it will display the quality and rate it from 1-5 stars with 5 stars being excellent.

I think you should stop guessing and invest in a good chrono or stop playing with the 195’s that you seem to blow up in the worst of moments and stick with what’s winning such as 180’s-184’s running from 2750-2850 out of straight 284’s or shehanes.

 

[davidjoe]

Yeah it sucks that 195 blew up although I really pushed the temp. But these 190’s look very promising. Those practice targets, the bullets were box to brass for range practice. The ShotMarker was earlier today. (20 feet over sea level here.) Running multiple guns and twists simultaneously in each of several calibers... I don’t chase an exact velocity, per se, but load (200 plus, 100 ct MTM boxes stay full ~50 with 195’s in .284 and in 30 Saum) to a very healthy/safe pressure that does turn out to be close in actual velocity (30 FPS) regardless of which gun uses it. Even if I stopped using a certain load in big matches, it’s already there on my industrial looking shelves in mass quantity, and will have get used somewhere, if I have to shoot very slowly.

Chambers are cut so close together that I can take a piece of used brass and the bolt will drop by itself on four .284’s, four Saums and three .338’s - all same Surgeon SSXL actions. I just wanted to see at home how close the chrono, (an old cheapie one), was to that estimate. My buddy’s got a Labradar we do use from time to time. The JBM estimates today are close to the last Labradar session and also they do match the actual come ups I’ve used at 1,000. But when they are off, and sometimes have been, JBM estimates are “optimistic”.

 

[No i deer]

The target SD's are interesting but not a reliable source of info then..
It was worth me asking the question..!!
There is so much more info on accurate shooter than you find over here..
It's a wealth of info..
I think my 1 in 8.25 barrel has a .220 freebore so probaly not long enough for the 190s..
I've 1500 of the 184s to use up first anyway..
As this coronavirus is beginning to stop big gathering of people these bullets may last quite a while the way it's heading .