@tonykharper
Tony, this is interesting. I have asked before and never really got an answer.
"A point of argument SAP vs PAS, is a spring isn't as reliable driving a light pin to an exact speed as it is in moving a heavier pin to an exact momentum."... This in theory makes sense.
You also mentioned there are other points as well. Can you please elaborate?
Thank you,
Gjmen22
There is a little bit of BS and lots of misinformation in the whole PAS/SAP discussion in the BR world. The only place where it happens to any amount is on CYA. Calfee is a big proponent of PAS ignition systems and an even bigger opponent of anything or anyone else. All of this PAS superiority must be taken with a big grain of salt due to the source. Calfee has made up lots of terms and claims about different aspects of both designs in addition that are misleading at best. In addition, not all SAP actions are the same. Calfee basically states they are all just like the 40X, which is far from the truth. Lets look at the facts first.
MD: This whole "momentum dependent" term is suspect at best. Energy is the basic measuring stick, not momentum. Whether its fast and light, slow and heavy or maybe both, equal energy is equal hit. In order to ignite priming compound, a certain amount of speed is needed to create the internal friction in the material or it "doesn't go bang". Hitting the primer with a truck and squeezing it over 5 seconds will just smash everything and not go off. Lots of position guns have lighter/faster systems and have worked for years. Friction hurts all of the designs, PAS included. Just see how a little bit of lube in the system slows it down and it no longer works. BTW, the PAS design requires lube in all the wrong places and with all the surface inside the pin area is ripe for a lube related ignition inconsistency. Most 40X based designs have nearly equal mass and similar spring forces at cock as the PAS Turbo design. IF MD is good in the Turbo, its basically the same in the 40X, 2500X and Vudoo too. All you really want is a system that consistently hits the primer hard enough and fast enough to light it off without being excessive.
SPRINGS: The statement that springs die a little bit every time and only have the right force for a short time is not inherently accurate. A PROPERLY designed spring will never change its characteristics. After millions of actuations within its limits, a PROPERLY designed spring will still be the same. Go one step down and get a spring that is designed such that it exceeds tensile stress in outer layers, but not by much. That spring will not last for millions of cycles without fracture, but once it takes its initial set, it will not get shorter or loose force. One more step down and now you have a spring that reaches tensile stress limits in all of its layers. THAT spring does continue to degrade. The major contributor to overstress is the OD being smaller than you really want. Guess which design has the smallest OD? I'll jump to the end, PAS. That is one of the biggest drawbacks of this design. There just isn't enough room for the spring to get a properly designed unit in there, so you have to contend with springs that fail. Most SAP design are on the hairy edge. When I did all my centerfire actions, I sent Remington springs to Sterling for analysis and recommendations for my actions. IN the end, I have a design in my actions that are as close to PROPERLY designed as possible in the space inside a bolt. MY springs will not take a set after the initial sizing and keep consistent tension from then on. I am not sure about Vudoo, maybe Mike can add something here. One thing for sure, any 40X type of SAP design has a better spring design then any PAS. That is one of the main reasons I didn't do PAS in the first place.
SLOP and FRICTION. This is very dependent on the designs. I won't speak to all of them here. IN my 2500X design, the shroud is rigidly attached to the bolt and the shroud is bored such that there is never any interference or inconsistency. The 40X is not that way. There are misalignments and slop in the 40X shroud. I minimized surface area inside also, I have about 10% of the surface area that the Turbo does that can cause friction inside the firing pin design. In the 2500X, the spring is installed such that there are no sharp edges that can rub on moving parts as the slide. In the rear spring mount on the Turbo, the edge of the spring will rub on the inside of the firing pin as it drops.
There is so much to go into here that I can't do it all at once. Go look at the equipment lists and make your determination, just look at all of them. Calfee loves to point to the ARA indoor results. Turbo equipped guns did pretty good. HOWEVER, he conveniently jumps over one day earlier on the PSL where 2500X SAP actions dominated.
ANY good action set up properly does a few things right. It has to interface to the stock correctly, hold the barrel firmly and light off the round. All of these customs can do that. Don't let a few mouthpieces try to convince you otherwise.