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Brewster11
PostPosted: Sat Aug 14, 2021 12:52 pm  Reply with quote



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

Interesting that you should mention this Mark. When I first noticed this at the range, there happened to be an instructor nearby. He observed my shooting and we discussed the issue. He said “it can happen sometimes” and suggested a fitting. I wasn’t about to modify the nice little 20ga I was using, so that was the end of it.

V/R
B.
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MSM2019
PostPosted: Sat Aug 14, 2021 5:28 pm  Reply with quote



Joined: 04 Mar 2019
Posts: 1819
Location: Central ND

Brewster11,

Well, that's about all I have.

Never heard of it, but I believe you.

Have a great rest of your weekend.

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Mark...You are entitled to your own opinion. You aren't entitled to your own facts.
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MaximumSmoke
PostPosted: Sat Aug 14, 2021 9:02 pm  Reply with quote
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Joined: 01 Dec 2005
Posts: 1550
Location: Minnesota and Florida

Don't you just love it. It's always the equipment; it's never the shooter.
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John Singer
PostPosted: Sun Aug 15, 2021 4:20 am  Reply with quote



Joined: 03 Sep 2014
Posts: 398
Location: Rochester, MN

Brewster11 wrote:
Quote:
Therefore unless you have the superhuman ability to swing a shotgun at a speed exceeding that, a shot charge is the same if fired from a moving or stationary shotgun.


John, that is true only if you eliminate muscular response, which is different between a static and moving gun, and reaction time. As Fred Etchen discusses exhaustively in his book, a motor reaction time of 200 milliseconds irrespective of decision time can amount to an enormous shift in POI when swinging on a moving target. As such, I’m not sure what a pattern board POI is telling me.

And Mark, a remount should not be needed for doubles if the POI changes with the upper barrel; only a different firing picture is needed.

Notwithstanding the objections noted above, I suggest that this can be readily demonstrated by going to the range, set up on station 3, and firing a dozen or two rounds with an identical choke in both upper and lower barrels and prove to yourself whether or not your hit quality can be improved by adjusting vertical POA.

I have performed this test multiple times now with different o/u guns and have demonstrated to my complete satisfaction that this is absolutely the case, albeit to varying degrees with different guns. “Registering” my barrels on station 3 has not only improved my scores, but erased years of frustration with the different POI of my various guns, and also loads for that matter.

V/R
B.


Brewster,

I apologize for the difficulty of conducting this conversation over this forum rather than face to face over morning coffee or evening beer.

I reread your OP and want to offer a couple of observations that may offer insight into your observations.

1. Several years ago, I was "building" smooth bore slug guns for deer hunting in Southern Michigan. I was purchasing older bolt action shotguns, cutting and crowning the barrels, machining and installing scope mounts, installing recoil pads and trigger jobs. My goal was to get these guns to shoot 4" or smaller groups at 100 yards. In my first prototype, I cut the barrel at 24". I then zero the gun to shoot 2" high at 50 yards. At that range most smooth bore slugs are supersonic and group well.

I then moved back to 100 yards. I immediately noticed that the groups printed 6" higher at that range than they did at 50 yards.

I also recalled a police officer friend tell me that "slugs fly" or impact higher at long range. After doing some reading on the subject, I learned that this phenomenon is caused by the shooter experiencing the felt recoil before the slug can exit the barrel. I then started cutting 1" off the barrel at a time until the effect disappeared. I found that the effect disappeared at a barrel length of 20". I then started cutting all these slug gun barrels at 19.5". This gave me a stiffer, shorter barrel that tightened the groups and eliminated the effect of barrel rise at recoil. I built about 7 of these guns. I still have one.

2. My second observation involves the Benelli Super Black Eagle 3. If you Google it, you will find a number of people complaining that it impacts too high for them. I have had customers trade in the SBE3 for an SBE2. We have measured the stock dimensions, rib heights, etc on these guns and can find no discernible differences.

The most plausible explanation is that the SBE3's Comfort-Tec stock is flexing during recoil before the shot charge exits the barrel. I think that Randy Wakeman has written about this. The stock is polymer. There are chevrons cut into the bottom and a cheek pad cut deeply into the top of the comb. There is only about 3/4" between the first chevron and the cheek cut. Upon firing and recoil, this stock flexes at this point causing the barrel rise.

Your observations described in the OP are very perceptive. Almost nobody notices the subtle differences in the quality of target breaks between the top and bottom barrel on a trap field.

You very well could be experiencing the subtle differences in POI due to the differential recoil of the upper and lower barrels.

BTW: I think the pattern board would confirm this too.

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Two Pipe Shoot
PostPosted: Wed Aug 18, 2021 5:56 am  Reply with quote
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Joined: 25 Jun 2008
Posts: 1863
Location: Wisconsin

With open chokes like cyl and skt, beads on a gun are helpful when leaning it against a soft barked tree; useless when gunning for moving targets. The key to breaking targets and knocking down birds lies on either side of your nose. If you can learn and then trust the relationship between your eyes and hands, you’ll find that your brain uses your eyes to tell your hands what to do. The ability to focus hard on a target gives your brain the data needed to guide your hands moving those barrels. I’ve never started but have finished many gunners’ grasp and mastery of this concept and the times I have watched a level III instructor start a shooter of any age the use of a BB gun and ping pong balls on the ground at five yards was the key to beginning a shooter and starting them on the path to true gunning.

Most of us started out plinking with rimfires and relying on sights and then beads to aim and graduate to point. Beads on a shotgun with open chokes are useless. If you can learn to trust your eyes and hard focus to the extent that the target seems slower than usual, you are on your way to becoming a true gunner; someone who has developed an instinctive relationship with swing and flight path. Fine tuning after that includes minor adjustments of stance and mounts. Beads on my guns are handy when applying tighter chokes on turkey heads when my heart is thumping and my butt is numb or painful or when I have several mosquitoes making withdrawls and my gnat blowing skills are challenged.

When you learn with beads the above suggestions are counter intuitive, but I promise you that the journey is worth the flats of shells required to break old habits. When you find the groove you will know it, and illumination is akin to the sun creeping out of the clouds after a spring rain. I wish this revelation on all of you.

Reno

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double vision
PostPosted: Wed Aug 18, 2021 6:50 am  Reply with quote
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I own two O/U guns. I took the beads completely off one, and blackened the bead on the other. O/U's tempt me to aim, but my SxS's are always instinctive.
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