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Old 10-25-2012, 11:24 AM   #2101
EvilGenius
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Quote:
Originally Posted by Fire Escape View Post
I can't say that I understand the theory well. Somehow I missed studying much about sound and supersonic speed. Does a plane only create a sonic boom at the moment it passes into supersonic flight or is it continuous and we only hear it when we are at the 'appropriate' distance? My guess is the latter but I really don't know, it is purely a guess on my part.

In many years of pulling targets during competition (you stand behind a large earthen 'wall', directly below the target and pull it down into the 'pits' after (usually) each shot to mark the location and value of the hit, It was necessary to wear hearing protection because of that 'crack' (sonic boom?) as the bullet passed overhead. In long range competition (1,000 yds) there would still be a crack from the magnums but a standard .308 (which usually went subsonic at about 900 yds) would only make a slight noise as it went through the target. The actual 'bang' from the gun firing would come along about a second after the bullet at that range.

I can say that after shooting a suppressed 5.56 yesterday, in company with 3 others that were not suppressed, it is much quieter but still maintains a 'crack'. A kind of apples to oranges comparison is that my suppressed .22lr is virtually silent other than the bolt clicking back and forth. No doubt the much smaller capacity of the .22lr is partly responsible but the projectile being subsonic also plays a part (or so I have always been told). The two projectiles are close in diameter and weight but differ greatly in velocity.


Bruce
The "boom" is a shockwave of compressed air that builds up on the leading edges of the aircraft and when it surpasses that speed it essentially breaks through that sockwave, however that shock wave still follows behind the aircraft. So it continually makes a "boom" so long as it stays supersonic.

Imagine the airplane making a constant "whoosh" sound that lasts about a second as it's moving by, as it gets closer to the sound barrier the volume of that whoosh increases and the period of time the sound occurs over is shortened. Once it breaks you're essentially taking a really loud second long "whoosh" and compressing it into a fraction of a second. So it sounds like a boom, bang or crack depending on the size of the object and how fast it is going. We hear it when the sound created by the aircraft reaches us.

Most .22lr is right on the verge of being super sonic (it usually depends on what you're barrel length is). So some of them make a crack as well although not a super loud one, but a lot of them don't and they have a tendency to be real quiet.

Same reason that a lot of "special" groups prefer suppressed .45 acp handguns, because it carries about the same energy as 9mm, but is much slower. Well below the speed of sound, in some cases not even in the trans-sonic zone.


Edit:

Maybe this will help. (let me also define "whoosh" as any sound coming from the aircraft be it engine noise or any other sound)



#1 is the "whoosh" the plane makes as it's moving through the air if it were observed from a chase plane moving at the same speed.

#2 is the same "whoosh" as observed by someone in a fixed position relative to the plane. It's also a good example of the doppler effect, the sounds waves on the front are compressed slightly and make a higher pitch sound and vice verse with the waves behind.

#3 is in the trans-sonic zone as you approach the speed of sound. The sound waves coming off the front are being compressed into a shorter space (period of time) and also their pitch is increasing.

#4 is supersonic. The aircraft is moving so fast that the sound coming off the front (and any other surface as well) can no longer propagate forward in front of the aircraft because the sound itself moves at a slower speed than the aircraft does. It has been compressed into a nearly instantaneous point in time and is now just a loud crack or boom. However, it does propagate radially outward from the aircraft at the speed of sound so the best way to represent that is to use a cone instead of a bubble like the other three.
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EvilGenius screwed with this post 10-25-2012 at 11:49 AM
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Old 10-25-2012, 03:21 PM   #2102
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Originally Posted by McNeal View Post
the reason why small bore targets have 10 individual targets on a piece of paper. One for each round!
Yep, the 10 "ring" on the old Army target is a .020 dot.

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Old 10-26-2012, 05:41 AM   #2103
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Originally Posted by kioti View Post
Yep, the 10 "ring" on the old Army target is a .020 dot.

mine never look like that.
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Old 10-26-2012, 07:48 AM   #2104
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Quote:
Originally Posted by McNeal View Post
mine never look like that.

Yeah, he missed all that other black area!
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Old 10-26-2012, 02:00 PM   #2105
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mine never look like that.
Get one of these and burn up about 80,000- 100,000rounds.

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Old 10-26-2012, 02:10 PM   #2106
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Refinish?

Quote:
Originally Posted by kioti View Post
Get one of these and burn up about 80,000- 100,000rounds.


Did you refinish that? My 1813 sure doesn't shine like that gun does.


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Old 10-26-2012, 02:24 PM   #2107
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Originally Posted by Fire Escape View Post
Did you refinish that? My 1813 sure doesn't shine like that gun does.
Bruce
Refinished it a few years ago,'68 1413 barrel/action,Fajen blank my dad and I carved that same year,butt plate is off a Walther.
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Old 10-26-2012, 03:41 PM   #2108
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Quote:
Originally Posted by kioti View Post
Get one of these and burn up about 80,000- 100,000rounds.
This is what I've been using.



What's that scope you've got on yours? Are you shooting at 50 meters?
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Old 10-26-2012, 05:22 PM   #2109
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This is what I've been using.
What's that scope you've got on yours? Are you shooting at 50 meters?
I started with a 340B Mossberg then a 52C Win. next a Anschutz 64 then the SuperMatch 54.

Back in the day I shot indoor gallery at 50 ft, outdoor 50 yrds. and 50 meters and 100 yards.

The pic I posted earlier was prone position at 50 ft a year or so ago, my fat belly now is a tight fit in the old 10X leather coat.

The telescope is a Redfield 3200, 20X boosted to 24X.

Here's the factory test target that came with the rifle.
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Old 10-26-2012, 08:00 PM   #2110
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Originally Posted by kioti View Post
Yep, the 10 "ring" on the old Army target is a .020 dot.

Do I see powder burns on that paper?

Just kidding man. Nice shooting.
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Old 10-26-2012, 08:17 PM   #2111
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Quote:
Originally Posted by Signal View Post
anyone got a suppressed .17 HMR-

How quiet

I prefer to not shoot mine without hearing protection. I have been around suppressed 17HMR's enough to say that they are quiet enough by a good deal to shoot without hearing protection. A proper suppressor will take almost all of the muzzle blast out of the equation leaving only the crack of the bullet. It's a small projectile therefore it leaves a small sound signature.

They are much more pleasant to be around when suppressed.
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Old 10-27-2012, 11:15 AM   #2112
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i see in my local gun store flobert/9mm rimfire shotgun rounds are still available, anyone use these "garden guns"?
(although at now over 1/$1.50 per cartridge, i bet you dont very often!)
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Old 11-06-2012, 05:10 PM   #2113
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I bought one of these Savage .22s last week and broke in the barrel by shooting all kinds of ammo rapid fire through it.

Anyway it shoots best with CCI Blazer, even better than with SK Standard Plus. Tried Federal Match and a couple of others, but glad it likes the Blazer, my favorite cheap ammo. At the end I was getting 1/4" groups at 50 yds with it about 2 out 3 times, with one or two flyers ruining the group that didn't make it. Also the Accutrigger was still too heavy for me screwed down to the minimum (2.5 lbs), so I cut a couple of layers of the spring off to bring it down to about 1.25 lbs and will try that today. Love the tac bolt and the composite stock which provides the lil gun with great balance, much better than the Mk II BVT, which probably shoots a little better.
Here are two 5-shot groups shot with CCI Blazer today. The bottom is four shots in one hole and one off to the left a little:

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Old 11-07-2012, 03:36 PM   #2114
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Quote:
Originally Posted by doc_ricketts View Post
I bought one of these Savage .22s last week and broke in the barrel by shooting all kinds of ammo rapid fire through it.

Anyway it shoots best with CCI Blazer, even better than with SK Standard Plus. Tried Federal Match and a couple of others, but glad it likes the Blazer, my favorite cheap ammo. At the end I was getting 1/4" groups at 50 yds with it about 2 out 3 times, with one or two flyers ruining the group that didn't make it. Also the Accutrigger was still too heavy for me screwed down to the minimum (2.5 lbs), so I cut a couple of layers of the spring off to bring it down to about 1.25 lbs and will try that today. Love the tac bolt and the composite stock which provides the lil gun with great balance, much better than the Mk II BVT, which probably shoots a little better.
Here are two 5-shot groups shot with CCI Blazer today. The bottom is four shots in one hole and one off to the left a little:

Impressive groups Savage makes good stuff
Is that stock, stock??

My savage hates blazer, loves the CCI mini mags.
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Old 11-07-2012, 06:44 PM   #2115
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Impressive groups Savage makes good stuff
Is that stock, stock??

My savage hates blazer, loves the CCI mini mags.
That is a stock stock on the MKII TR. The nice thing is it is very well balanced and actual composite/wood. It seems to be a Boyd .22 stock and I am thinking about ordering one for my 10/22 Ruger. I just got back from trying to get some good scores on a USBR target and found that I can still improve my trigger pull on the MKII. Probably will lighten the pull up some more to less than 1 lb.
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