doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Needing Low Pressure load for 12 Ga AA

Powder and primers are important, but don't overlook the wad. My 12 ga. target loads (American Select, Win 209, Win AA) drop 700psi if I use a Rem TGT wad instead of a Win AA wad. With my 20 gauge target loads, switching from WinAA to RXP20 wads drops the pressure by 2100 psi.

It would seem to me that anything at or below the 8,000 psi black powder levels would be fine. As long if the gun was in good shooting condition, and having the action bedded in case of wood shrinkage due to age. In guns that have not been bedded, dropping around 20% of psi, or to around 6400-6500psi seems prudent in order to take it easy on the old girl's wood. The exception would be a very light English gun, perhaps even lower...

"The Wood" would much prefer a 1oz load moving 1150 FPS @ 9K PSI than a 1�oz load moving 1250 FPS @ 7K PSI. PSI is not a factor in figuring recoil nor is it much of a factor in what the wood feels.

I'm with Stallones, 18 gr Green Dot, 1 oz shot

I have found that about 7000psi is the proper low pressure.. Lower than gives irregular ignition and irregular results on birds and clays

Ok, If it's not a matter of PSI, then what is the major factor involved in determining recoil and consequential effects on wood? Is it FPS? Is it a relationship between load weight and FPS? Is anyone able to explain the actual physics? That way we can avoid merely asserting opinions.

Recoil is the factor. Heavy loads, at low velocities, still put a lot of stress on wood. It has been suggested that light loads, at low pressure and most often low velocities, generate low recoil and hence less stress on wood. It all comes back to simple vector physics, for every vector, action or force there is an equal and opposite vector, action or force. If you push a payload out the barrel a force is thrust into and against the stock.

Ok, but I'm trying to understand the reasoning behind what 2-Piper alluded to, that a 1oz/1150FPS/9000PSI load would be easier on the wood rather than the 1oz/1000FPS/6500PSI load that I have been using.

Ken61, 2-piper was merely restating the free recoil formula, where mass and velocity are the only determinants of same. Since your load is equal in mass and lower in velocity, he would be most accepting of it, even if it had higher pressures...which it doesn't.

Ken;
I made absolutely no comparsion to the 1oz/1150FPS/9KPSI to a 1oz/1000FPS/6.5KPSI load. Quite obviously that load would be still easier on the wood than the load I stated.
I in fact stated that 1oz/1150FPS/9KPSI was easier on the wood than a 1�oz/1250FPS/7KPSI load which it is in spite of the later load having a lower PSI.
Indeed I stated to use the same factors used for calculating Recoil when considering the wood, PSI is not one of the factors of Recoil.
Indeed PSI is necessary to cause the movement of the load down the barrel, but the amount of weight moved & the speed at which it is moved are the factors of recoil. We too often get hung up on pressure as being "Only" the peak pressure. If you accelerate 1oz of shot out the muzzle to 1150FPS you have done a given amount of Work, irregardless of the peak pressure of the load. If you compared the Average pressure (Area under the pressure curve) over the entire length of the barrel of two loads moving the same amount of shot to the same speed you would find them for all practical purposes identical, even though they may have a widely varying Peak Pressure.