tell me about current 7mm bullets.

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RDavies
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Re: tell me about current 7mm bullets.

#16 Postby RDavies » Tue Apr 02, 2019 3:47 pm

bruce moulds wrote:rod,
how much freebore is required for the 183 copperheads in a 284 chamber?
bruce.

I am not sure yet as I hope to receive my Copperheads soon. Their bearing surface is a little shorter than the Berger 180 VLDs and Hybrids.

bruce moulds
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Re: tell me about current 7mm bullets.

#17 Postby bruce moulds » Tue Apr 02, 2019 4:42 pm

thanks rod.
that would suggest that 0.2" would suffice, as it is minimum for berger vld.
any update on that gratefully received.
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880
http://youtu.be/YRaRCCZjdTM

GSells
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Re: tell me about current 7mm bullets.

#18 Postby GSells » Sat Jul 27, 2019 9:12 am

This was a few weeks ago with 180 eld’s . Wind was coming at 1-3 o’clock. With some wind in my face. 9 twist Lilja. 280 ai at about 2910 FPS . It’s very weird as I have two beautiful waterlines and it happens from shot to shot ! Shot 5 is on one waterline shot 6 is on another! But it tells me rifle is going well otherwise it would be random elevation! I had a theory of dynamic stability with the headwinds coming off the mounds at Belmont. Which could very well be contributing to the effect. But it’s so uniform ?

Earlier in this week I was just checking velocities I had my old glasses on and shot acceptable groups at 100 m’s . Thought I would put my new glasses on which are slightly out of focus up close . But are very sharp out long . To my amazement both loads I was working with developed close to 1 moa elevation at 100 m’s . And the cross hairs were blurry and I was at times seeing double sort of thing for a second .

At the time I put it down to the mag speed moving after so many shots but I didn’t really know ?
Then I was looking at the et plot again afterworlds and it dawned on me! I shot that day with my new glasses.
And I believe my new glasses may have caused parellex errors. Which may explain the strange group of below . I certainly don’t have 80 FPS difference in loads !! Sd is usually around 5-6 FPS .

Yep so until proven otherwise I’ll put those glasses away .
As for the eld 180’s in a 9 twist. KHGS did well a few weeks ago with them at Malabar . I’m only using them at club for now . But they do seem to have potential!
CFC28165-D6D1-41AF-968B-6C0A98B56C4E.png
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bruce moulds
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Re: tell me about current 7mm bullets.

#19 Postby bruce moulds » Sat Jul 27, 2019 9:51 am

graham,
do you have astigmatism?
I do.
my optician told me that you can refocus a scope to suit glasses for your eyes.
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880

http://youtu.be/YRaRCCZjdTM

GSells
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Re: tell me about current 7mm bullets.

#20 Postby GSells » Sat Jul 27, 2019 9:57 am

bruce moulds wrote:graham,
do you have astigmatism?
I do.
my optician told me that you can refocus a scope to suit glasses for your eyes.
bruce.

Yes I do !
Ok I’ll try that and refocus the scope on my new glasses. But after the Qld Queens.
Thanks !

pjifl
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Re: tell me about current 7mm bullets.

#21 Postby pjifl » Sat Jul 27, 2019 10:13 am

Technically, eyepiece and spectacles have no effect on Parallax. Parallax adjustment takes place in front of the Graticule. But any poorly corrected astigmatism usually results in reduced resolution across the target in one specific direction.

I am beginning to wonder if the progressive lenses becoming more common in spectacles these days could be a problem for scope users. I have no experience of them.

GSells
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Re: tell me about current 7mm bullets.

#22 Postby GSells » Sat Jul 27, 2019 12:30 pm

pjifl wrote:Technically, eyepiece and spectacles have no effect on Parallax. Parallax adjustment takes place in front of the Graticule. But any poorly corrected astigmatism usually results in reduced resolution across the target in one specific direction.

I am beginning to wonder if the progressive lenses becoming more common in spectacles these days could be a problem for scope users. I have no experience of them.


Hi Pete , this is getting of topic , but this happens ! Thank you for for comments , always appreciated.
I know with taking my glasses off I’ll shoot 1 moa higher as my astigmatism is in the vertical.

I’ve refocused the Reticule for my new glasses . But Pete is there a chance that a poorly focused reticule could cause errors in the plain of the correction for ones glasses ? In that trying to focus the reticule with the side focus knob can like fight against each other?

I’ll try again with a known load tomorrow at My home range in a fly shoot .

GSells
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Re: tell me about current 7mm bullets.

#23 Postby GSells » Sat Jul 27, 2019 5:52 pm

Question has been moved to spectacles and eyesight thread .

pjifl
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Re: tell me about current 7mm bullets.

#24 Postby pjifl » Sat Jul 27, 2019 6:10 pm

Focusing the Graticule for the eye is via the eyepiece and is done first. And ideally this is best done with no target image in the scope - just a bright background. Unfortunately it changes with your state of health and hydration and if you have been reading a lot before the shoot.

If for some reason this is not done properly first, and you later adjust the side for best clarity rather than parallax, you can introduce some parallax in error.

It is possible that because of poorly corrected astigmatism you may be focusing the graticule with eyepiece poorly to begin with. My concern is that with progressive lenses, something similar may happen but that is just a sneaking suspicion in my mind. I know that because of falling public demand, many spectacle lens makers will not make simple lenses these days and Opticians find it hard to have them sourced and will push you towards progressive lenses.

Strangely enough, it is young shooters who are at most risk of ending up with parallax problems with a riflescope. Their eye is so flexible its focusing muscles can change in such a way that when they initially focus the eyepiece and when they actually shoot, their eye falls into a different setting.

Perhaps this should go in the new thread - it developed in this thread almost accidentally.

I think it is far more important than most think.

BTW, carefully centering the eye behind the scope eliminates any parallax problems even with a poorly adjusted scope. It is more important than getting a full wide view in the eyepiece and you can always fall back onto this.

If you have very slight astigmatism, as long as you use very high magnification, seen astigmatism actually has less of an effect and more or less 'goes away' with no spectacles. Apart from protection, you may actually be better off using no spectacles. Long and Short focus is perfectly compensated by refocusing the eyepiece as long as it has sufficient range.

With people with moderate astigmatism, it is hardly an option although you may be surprised. I have moderate astigmatism and am envious of those without any.

The classic way to detect astigmatism is to view a well printed circle without spectacles. At different distances from the eye, different parts of the circle will appear in better focus. Or view a well printed line directly with the eye. By rotating the line, it will go in and out of focus.

Fascinating subject and since people are different, there is no simplistic cure.

bruce moulds
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Re: tell me about current 7mm bullets.

#25 Postby bruce moulds » Sat Jul 27, 2019 7:06 pm

good post peter.
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880

http://youtu.be/YRaRCCZjdTM

GSells
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Re: tell me about current 7mm bullets.

#26 Postby GSells » Sat Jul 27, 2019 8:55 pm

pjifl wrote:Focusing the Graticule for the eye is via the eyepiece and is done first. And ideally this is best done with no target image in the scope - just a bright background. Unfortunately it changes with your state of health and hydration and if you have been reading a lot before the shoot.

If for some reason this is not done properly first, and you later adjust the side for best clarity rather than parallax, you can introduce some parallax in error.

It is possible that because of poorly corrected astigmatism you may be focusing the graticule with eyepiece poorly to begin with. My concern is that with progressive lenses, something similar may happen but that is just a sneaking suspicion in my mind. I know that because of falling public demand, many spectacle lens makers will not make simple lenses these days and Opticians find it hard to have them sourced and will push you towards progressive lenses.

Strangely enough, it is young shooters who are at most risk of ending up with parallax problems with a riflescope. Their eye is so flexible its focusing muscles can change in such a way that when they initially focus the eyepiece and when they actually shoot, their eye falls into a different setting.

Perhaps this should go in the new thread - it developed in this thread almost accidentally.

I think it is far more important than most think.

BTW, carefully centering the eye behind the scope eliminates any parallax problems even with a poorly adjusted scope. It is more important than getting a full wide view in the eyepiece and you can always fall back onto this.

If you have very slight astigmatism, as long as you use very high magnification, seen astigmatism actually has less of an effect and more or less 'goes away' with no spectacles. Apart from protection, you may actually be better off using no spectacles. Long and Short focus is perfectly compensated by refocusing the eyepiece as long as it has sufficient range.

With people with moderate astigmatism, it is hardly an option although you may be surprised. I have moderate astigmatism and am envious of those without any.

The classic way to detect astigmatism is to view a well printed circle without spectacles. At different distances from the eye, different parts of the circle will appear in better focus. Or view a well printed line directly with the eye. By rotating the line, it will go in and out of focus.

Fascinating subject and since people are different, there is no simplistic cure.
so short answer Pete is possibly “ Yes” it could have an effect?

Throw in 1000 other things that can cause vertical and it makes things difficult to try and find a fix !
I’ve even seen when I’ve been training in the paddock late afternoon three different elevations but perfect water line on all three groups but as I said about an inch apart for the 3 groups . My guess is differing temps or layers of air and refraction. I’ve seen and not every time , 5/8 moa in elevation from light to dark eg cloud and sun .

This game can be challenging lol!

Thanks again Peter .

Rich4
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Location: Chinchilla

Re: tell me about current 7mm bullets.

#27 Postby Rich4 » Sat Jul 27, 2019 10:52 pm

That is exactly my problem, many variables to diagnose without experience, training alone can be frustrating at times, I also would like to thank Peter for his generosity with his knowledge and time and many others on this forum giving information freely, I have been reading for ages and there’s still more to go, so a big thank you to all =D>

GSells
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Location: Qld

Re: tell me about current 7mm bullets.

#28 Postby GSells » Sun Jul 28, 2019 5:48 pm

Rich4 wrote:That is exactly my problem, many variables to diagnose without experience, training alone can be frustrating at times, I also would like to thank Peter for his generosity with his knowledge and time and many others on this forum giving information freely, I have been reading for ages and there’s still more to go, so a big thank you to all =D>

Hi Rich Great shooting with you today !

Well the results are in , refocused reticule and got a nice group at 900 yds on a 500 m fly target! Funny thing was I didn’t check for parellex! I can hear J Hausler words ringing in my ears “ Process Process Process “! I’m normally pretty good at my setup procedure that I never miss that lol! Well today I did ! Anyone that knows me , knows I tend to be a Gas Bagger and talk lots especially at club level when the pressure is off !
There is some relevance to the thread in that it was shot with 180 Berger’s . Which are just so reliable!
I guess I’ll put the pic up of the group . It’s shot with no flags , shot blind only reading mirage . There is 2 12 o’clock shots which I’m not sure as it was blind . But could have be me , parellex or there was a couple of shots that I shot in a weird boil ? So dunno !

But new glasses worked when focused.
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Pablolig
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Re: tell me about current 7mm bullets.

#29 Postby Pablolig » Thu Aug 01, 2019 8:29 am

Hi guys,

What about the Lapua Scenar L 180 gr???

Elwood
Posts: 18
Joined: Sat Aug 22, 2015 4:19 pm
Location: Great Britian

Re: tell me about current 7mm bullets.

#30 Postby Elwood » Fri Aug 02, 2019 4:04 pm

Pablolig wrote:Hi guys,

What about the Lapua Scenar L 180 gr???


Allow me, the Scenar L is a serious contender, it's just not as sexy as a Berger in BC terms. It is a much more uniform bullet which eliminates any having to sort, and the new Scenar L comes ready pointed, it's still not as pointed as a Berger Hybrid or VLD but you have to have a good look to notice the small difference.
In three different rifles, .284, 7mm Saum and 7/270 WSM they have all shot somewhere between 5 to 15 thou off the lands. You will need a free bore of around .250 and they work very well in a 1-9 twist.

Oh and they are nearly half the price of the Bergers!


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