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I need some help... I think I'm right, but some others say I'm wrong...

RELOADERS!!! Help me out!

Take a 12 gauge single shot, break action shotgun with a 28" barrel and a fixed Modified choke.

I've loaded a 1 and 1/8th ounce load of lead shot in a Winchester AA hull with a 209 primer and an R12L wad. 11,100 PSI at 1580 FPS. using 37.1 gr. of Hodgdon LongShot powder.

I've also loaded a 1 and 1/8th ounce load of lead shot in a Winchester AA hull with a 209 primer and a Red PC wad. It runs at 7,900 PSI and 1090 FPS using 16.3 gr. of Hodgdon Clays powder.


My questions to you are these...

Are these two loads not perfectly acceptable loads according to the Hodgdon ballistic tables?

Other than the type of powder and wad the only basic difference is that one is much faster at a higher PSI while the other is slower at a lower PSI, correct?

OK here's the real point of this post...


Shot out of my aboved mentioned gun, what effect will the difference in velocity/pressure have on the patterns that these two loads throw?

What I'm interested in finding out is if velocity/pressure has an effect on pattern size when fired through the same choke.

I say a slower/lighter load will pattern slightly larger than what a standard modified choke would ordinarly pattern with standard velocity loads, and that if you fired the hotter load out of the same gun, the "modified" choke would pattern tighter than the gun would pattern with standard velocity loads.

What does Greener have to say on the matter?


This is to help explain some things to either myself or two a couple of other board members... we'll find out which soon enough! Please, educate me.

The first load may bloody your nose, depending on how the stock might fit. The second load will have much less recoil and be easier on the gun and on you. I'll let someone else argue the patterns, I would never consider the first load, period.

Conventional wisdom (or old wives tales) would lead one to believe that the lower pressure slower shot charge would pattern tighter because of less pellet deformation on initial setback would throw the tighter pattern but because each shotgun barrel and load combination are entities unto themselves the only way you are going to know for sure is to shoot and compare some patterns.

My take on it is this...the closer you get to the speed of sound,the more open a pattern will be.
Bullet shooters call it wind drift.
Pellet shooters call it blowing your pattern.

hope Im half right.

A projectile that leaves the muzzle supersonic will often do some odd things as it goes transonic and then drops to subsonic velocities.

If you never exceed supersonic velocities you never have to deal with passing through that range as the shot slows down.

Speed of sound in air is published at 1,125 ft/s.

The faster the speed of the pellet the faster the pellet flattens out. The more the pellets deform the wider the pattern. Burrard deals with this in his books,though,patterning is the only way to really know what's what.

Yes. At sea level and (I think) 70*F. Change the elevation, temperature, relative humidity and the speed of sound changes, but for conversation that is a good number.

According to Wikipedia

In the standard atmosphere:

T0 is 273.15 K (= 0 °C = 32 °F), giving a theoretical value of 331.3 m·s−1 (= 1086.9 ft/s = 1193 km·h−1 = 741.1 mph = 644.0 knots). Values ranging from 331.3-331.6 may be found in reference literature, however.
T20 is 293.15 K (= 20 °C = 68 °F), giving a value of 343.2 m·s−1 (= 1126.0 ft/s = 1236 km·h−1 = 767.8 mph = 667.2 knots).
T25 is 298.15 K (= 25 °C = 77 °F), giving a value of 346.1 m·s−1 (= 1135.6 ft/s = 1246 km·h−1 = 774.3 mph = 672.8 knots).

Elevation most definatly effects pattern or bullet trajectory.
I have a bunch of shotguns that will not shoot "hot" loads. Good for them, and good for me.

I have pushed steel shot to 1800fps, and the patterns were beyond horrible. Steel shot is not known for deformation. I believe the combustion gases expanding into the normal atmosphere were the source of the erratic flights.