What I have found out while reloading and reading is too much wad pressure can cause the column of the wad to collaps. Some people also do this in order to make a improper wad/payload work. This can usually be detected by a bulge in the center of the crimp.
As far as too little wad pressure, I haven't had any problem reloading with 0 wad pressure. I only load newer style powders (Hodgdon's Titegroup and Longshot), so I think this is a null and void point. An educated guess is that wad pressure is for single base powders that need to get a proper seal in order to get an effecient burn. Just my observation, not to be taken for the Gospel.
With modern wads, plastic hulls, and appropriate usage, I've never applied more than enough pressure on the wad seating to exceed the slightest movement on the MEC guide on the seating die mechanism. Never more than +/- 10 lbs....breakemall....Bob Dodd
My friend said with AA cases, red dot powder, cci 209 primers and AA wads that he is just running the wads down tight. Is this a problem or not. He said that on his pacific reloader that when he was running them down tight that it was showing 60-70#'s on the gage. We would like to know if its time to stop or keep reloading with set up.
Tonight, out of curiosity I took apart a Federal shell to measure the components of it. I was rather surprised when I found that after careful removal of the wad the powder was greatly compacted into the base, the bottom half so tightly compacted I had to tap the shell on edge on the table a bunch to get it to loosen up. I don't know what wad pressure they are using at the factory, but with that shell it was a bunch!
This question keeps comming up periodically, Again, Wad pressure was a product of the old days ( for us that remember) when we had to use fiber disc over the powder, these fiber disc were somewhat compressable, but not as much as the modern day plastic wad, so wad pressure was to ensure a good seal between the powder and shot, You should use just enough pressure on the plastic wad to insure that your removing the air, for reloaders that have a wad pressure gauge, a slight deflection is sufficent, if you use high wad pressure you will collaspe the wad causing concave crimp and later on a shell the has been reloaded numerous times, the wad will straighten out causing a convex crimp and possibly opening. hope this answers your question. smokum, Big Jim
Big Jim - I remember the days of fiber wads. Wad pressure was important then.
The key to the question of "how much wad pressure" now is not how much pressure is applied to the wad but how much pressure remains applied to the powder after the wad ram is lifted and the hull moves to the next station. The answer is almost none. It is easy to grasp a seated wad and lift it from the hull with very little pressure. It makes little difference if the wad was seated with 1, 10 or 50 pounds of pressure. They will all lift out easily.
Also, when the primer fires in a loaded shell, the internal pressure against the wad reaches 8,000 to 10,000 pounds per square inch in around 5/10,000 of a second. An additional 5-10 pounds caused by seating the wad with 50 pounds of wad pressure would be irrelevant.
I've always followed the directions that are printed in my PW manual. Their instructions are to seat the plastic wad using only enough pressure so that the hull cannot be lifted in the die. The goal is to gently compact the powder and eliminate any air space between the powder cup and the powder without collapsing the wad. Once that has been accomplished, more pressure is unnecesary and counter-productive. I can spin the hull, feeling only slight resistence, with my thumb and forefinger, while the wad ram is still in contact with the bottom of the shot cup.
Interestingly, I have an article coming out in a summer issue of Shotgun Sports that addresses this topic. As others have said, wad pressure is unimportant today with one exception - the new-style AA hulls. I've never used AA ammo but understand that the wad has to be seated with an obscene amount of pressure to avoid the over-powder cup hanging up on the hull's basewad (or something).
I load with as little pressure as I can get away with. In some cases, that's none and my loads work fine and have done so with Clays, International Clays, Green Dot, TiteGroup and PB powders and Claybuster CB-4100 "Lightning" and CB-4118, WTW Windjammer and Remington FIG-8 and TGT-12S wads.
Some folks with more expertise than I have tell me that too much wad pressure can cause the cushion section of the wad to be collapsed in the hull instead of collapsing during the powder ignition process. That can lead to more deformed pellets and increased felt recoil. If the wad is severely collapsed, its base can "cock" in the hull. If that happens, velocity can be lost through gas leaking past the over-powder cup and patterns can be compromised because the wad's base is not in line with the rest of it and is caught by the air it is rushing through.
All that makes good sense and I believe it but if it's accurate, how do those new-style AA hulls produce good patterns? I'll stay with minimal wad pressure just the same.
Maybe my results aren't typical or maybe I have hit a lucky combination of components, but I've loaded amny thousands of the new AA hulls and have used basically the same wad pressure for them that I use for Remingtons. I've never had a wad hang on the insert, nor have I ever had a bad shell could could not be traced to a stubborn Federal primer. I use 16.6 to 17.5 grains of Clay Dot and either genuine Remington Fig 8 or TGT wads, or genuine Windjammers. The powder cup doesn't even touch the inner walls of the hull until it gets past the lip of the insert, and that lip is well tapered. I have always figured that if the factory wads don't hang on the insert at the rate they are loaded, my replacements shouldn't either.
I AM careful to watch the shot height on each shell as it cycles through the loader so I can spot any that are abnormally high, but I've only ever spotted 1 in those thousands and that was due to an insert that was raised when the wad was seated.
I remember many years ago loading with one of the old Lee Loader hand dies in paper cases with fiber wads. We used a bathroom scale to set the wad pressure. Talk about sore hands hitting 30 pounds with that thing!
These are Annie/Protection loads. The recipe is as follows:
Tapered Remington hull (STS, Gunclub, Sport load)
28.5 grains Longshot
Fig. 8 or Blue Downrange wad
1 1/8 oz of 6's
Remington 209 primer. (Winchester 209 primers can be substituted but you can feel a bit more bite).
I know this load is not in the book! So don't go flaming me to death. This load has been checked out and doesn't come anywhere close to being dangerous. Several people that I shoot with has started to load this shell because of its effectivness and lack of recoil. The PSI is sub 10,000. This load will yield 1350fps +/- from a 30" INV+ barrel.
On a MEC, just enough wad pressure to stop the shell from turning with light finger pressure at the bottom of the downstroke. Might be just a slight movement on the indicator. On the 2 piece Win AA hulls, I use the same low pressure with good results, unless using one of the fast and dense powders like WST or Titegroup and then I just bring it up another ten pounds or so to be sure. Just enough to seat the wad without distorting it. I only use wads designed for tapered hulls with the vents down the sides of the over-powder cup. Straight wall wads might create some issues. I don't get bloopers or off sounding loads with the above practices, even in cold weather. Basically, just enough pressure to seat the wad on top of the powder without distorting the wad. If there is a need to compress the wad severely in order to obtain a good flat crimp, then you need to select components that will fit better.