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<  16ga. Ammunition & Reloading  ~  need help with chronograph results
kennedy756
PostPosted: Mon Apr 10, 2017 11:18 am  Reply with quote



Joined: 30 Sep 2015
Posts: 637
Location: NEW SALISBURY INDIANA

16 ga
18.5 gr universal
209 primer
1 0z shot
claybuster wad
Rem game load hull

Hodgdon says it should go at 1165 fps, I used my Ithaca 37, mod choke, caldwell chronograph and it reads 1300 fps, second shot 1308, tested a hotter round and it was 1338, and should have been about 1200. any ideas? muzzle was 9 foot from it. Am I testing too close?

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jschultz
PostPosted: Mon Apr 10, 2017 11:53 am  Reply with quote



Joined: 07 Apr 2007
Posts: 1624
Location: northwewst Wyoming

You didn't specify the 209 primer that you are using.
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kennedy756
PostPosted: Mon Apr 10, 2017 12:13 pm  Reply with quote



Joined: 30 Sep 2015
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Location: NEW SALISBURY INDIANA

winchester primer, I called hodgdon, and they said -no way-said it must be picking up the shock wave.

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16ga Marlin 90 1939
16ga browning citori lightning grade 3 2003
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Lon
PostPosted: Mon Apr 10, 2017 12:55 pm  Reply with quote
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Joined: 27 Dec 2010
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Location: Spokane, WA

Most people start with the shotgun muzzle two, three or four feet from the closest chronograph sensor. Check your chronograph owner's manual for their recommendation.

Also, you might try a few rounds of factory ammo and see what you get for velocities. I've found the one ounce Federal and Herter's factory rounds produce velocities pretty close to their listed velocities. At least this would give some sort of baseline.

I always shoot three or four rounds of Federal factory loads over the chronograph at the beginning of each session to make sure everything is working correctly.

Also, I've had several reload recipes that produced a lot more velocity than what is published. Sometimes it can be explained by different lots of components and other times it leaves me scratching my head!

Hope this helps.

Lon

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AmericanMeet
PostPosted: Mon Apr 10, 2017 1:19 pm  Reply with quote



Joined: 26 Apr 2010
Posts: 3172
Location: NCWa

Your chronograph may be registering the front or first few shot of the load which may be going faster (for a few yards) than the bulk of the load. so your load may be similar to the printed load but the first speedsters at the front are giving a false reading.
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Brewster11
PostPosted: Mon Apr 10, 2017 10:02 pm  Reply with quote



Joined: 08 Feb 2009
Posts: 1301
Location: Western WA

Very likely you are picking up the shock wave or debris. If anything you are too far from the muzzle. 3 ft from muzzle should be no problem but make sure you are at least 6 in or more above the sensors.

I was having the same frustrating problem with bogus readouts from my Chrony F1 but was able to eliminate it entirely by removing the sky shields and rods. Open sky (not overhead light bulbs) is needed but clouds don't seem to affect it. The data was much more repeatable and consistent with reference tables afterward.
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16GAwaterfowler
PostPosted: Tue Apr 11, 2017 4:20 am  Reply with quote



Joined: 15 Dec 2005
Posts: 287
Location: missouri

Look at your manual Caldwell recommends five feet from the muzzle for shotguns
12. For shotguns stand only 5 feet away. Shotgun blast may affect the projectile
readings. Watch out for flying wads that might damage the chronograph
.
At that keep in mind many chronographs are made for single projectiles and not shotgun loads, I've seen some that were off by 150 fps from where it was supposed to be.
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kennedy756
PostPosted: Tue Apr 11, 2017 4:32 am  Reply with quote



Joined: 30 Sep 2015
Posts: 637
Location: NEW SALISBURY INDIANA

thanks everyone, as usual you have gave me ideas to work with, I am going to start over with my factory ammo and move closer, also try with out the rods.

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3crosses
PostPosted: Tue Apr 11, 2017 5:52 am  Reply with quote
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Love the watch out for flying wads. Yea and just how the hell is that done! Laughing
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16GAwaterfowler
PostPosted: Tue Apr 11, 2017 8:50 am  Reply with quote



Joined: 15 Dec 2005
Posts: 287
Location: missouri

3crosses wrote:
Love the watch out for flying wads. Yea and just how the hell is that done! Laughing

After putting a few steel BB's straight through mine and having to replace it I built a shield out of aluminum angle and 1/2" thick Lexan that attaches to the front of the chrono, for the most part problem solved.
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Dogchaser37
PostPosted: Tue Apr 11, 2017 1:04 pm  Reply with quote
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Shotguns and chronographs.......

To start out, set the muzzle 3 feet from the center point of the two skyscreens. For Pact or Oehler chronographs. 2 feet from the start screen. Long distances from a shotgun muzzle cause problems with chronographs. Chronograph in the shade or on a cloudy day, a cloudy day is ideal.......ALWAYS use the diffusers.

Shock waves are rarely an issue. Shock waves and a chronograph is like blaming bad patterns on chamber pressure......maybe sometimes almost never but then again once in a blue moon on the 6th Sunday of a January 3 years after a leap year.

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kennedy756
PostPosted: Tue Apr 11, 2017 1:15 pm  Reply with quote



Joined: 30 Sep 2015
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Location: NEW SALISBURY INDIANA

ok, so I set up about 3 ft from it, shot a 1200 fps factory rem game load, and got 1211 fps, shot my reload and got 1345 fps. so now what?

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16ga browning citori lightning grade 3 2003
16ga Francisque Darne 1920
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16GAwaterfowler
PostPosted: Tue Apr 11, 2017 2:14 pm  Reply with quote



Joined: 15 Dec 2005
Posts: 287
Location: missouri

A--Your scale may be off, but I doubt that much
B- You got a hot lot of powder, I would go with B myself.
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kennedy756
PostPosted: Tue Apr 11, 2017 2:59 pm  Reply with quote



Joined: 30 Sep 2015
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Location: NEW SALISBURY INDIANA

scale is good, checked it with weights, powder is from various batches including some from Australia and some from Canada. could I be compressing the powder when I seat the wad?

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16ga 3-Win 37
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16ga Marlin 90 1939
16ga browning citori lightning grade 3 2003
16ga Francisque Darne 1920
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wellshooter
PostPosted: Tue Apr 11, 2017 3:15 pm  Reply with quote



Joined: 03 Feb 2014
Posts: 325
Location: West Texas

Now ypu know that 6' of distance is worth 45 fps. Other than that ????

But I have to agree with you I couldn't match up with Hogdon data when I was working up my 2 1/2" 7/8 oz load with Universal. I just kept dropping the powder charge 1/2 grain at a time and retesting until I got in the range of velocity I wanted. I also shot a few factory Herters to check my chrono and bumped the charge up and down until I was pretty durn sure my data was consistently repeatable.

I suspect most of the loads on the Hogdon site are extrapolations from tested loads. Just don't know which load was tested.

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