What do you guys think about a slightly heavier recoil spring assembly? Logic says if the high velocity 125 gr .357 sig projectiles develop 600 lbs-ft of energy, the recoil impulse versus the .40 S&W cartridge has to be more slightly intense.
The calculation of recoil is complex and involves weapon weight and the effects that the shooter has on absorbing the recoil impulse. But assuming everything else is held more or less constant while looking
only at the ballistics of the rounds being compared, the greatest contributor to the recoil impulse calculation is the
momentum of both the bullet and the propellant gases. Concentrating only on the effect from the bullet, bullet momentum is proportional to
bullet mass times bullet velocity. That is very different from bullet
energy, which is proportional to
bullet mass times bullet velocity times bullet velocity. Judging recoil from the muzzle energy figures leads to grossly incorrect results because the momentum calculation is
proportional to the velocity, while the energy calculation is
proportional to the velocity squared.
It is very common to have a loading whose light bullet at high velocity has much higher energy, but less momentum imparted to the bullet when compared to another loading with heavier bullet and lower velocity. In that case, the second loading will likely have the greatest recoil impulse even though it has the lower energy, because its imparted momentum is greater.
Let's use a couple of examples with data from the
Ballistics By The Inch Website, using data from a 4-inch barrel.
.357 SIG, 125 gr. Corbon:
Muzzle velocity 1468 fps measured (Muzzle energy 598 ft-lbf)
.40 SW, 180 gr. Federal Hydra-Shok:
Muzzle velocity 1022 fps measured (Muzzle energy 417 ft-lbf)
The ratio of muzzle momentum for these two cartridges is calculated very simply as:
(velocity of .357 x mass of .357) / (velocity of .40 x mass of .40) =
(1468 x 125)/(1022 x 180) = 0.997
If both rounds have the same muzzle momentum, the ratio above will be 1.0.
The actual result indicates that the momentum of both of these rounds from a 4-inch barrel is essentially identical (almost a ratio of 1.0). If we split hairs, in fact the .357 bullet has slightly less momentum (and therefore, slightly less recoil) than the .40 bullet.
This is in spite of the .357 SIG bullet having 43 percent greater muzzle energy than the .40 SW bullet!
Is there options for the recoil spring assembly for my G27? I see glockmeister sells/references the same recoil assembly for the models 26,27,33, and 39.
You presume to understand the engineering design requirements for the Glock subcompacts
better than Glock! For me, even though I've been an engineer for 40 years, I would not be as bold.
Maybe my thinking is off but if you're developing 450 lbs-ft energy with a .40 round, versus 600 lbs-ft with a 1500 fps 125 gr .357 sig round.....surely the sig recoil is markedly greater, or more recoil energy to absorb. Instead of battering the slide. Maybe try a recoil assembly for the 29, 30, 36 group of pistols?
As shown earlier, any reliance on muzzle energy as a measure of the recoil impulse or velocity is incorrect and
will lead to very wrong conclusions.
As an aside, you are not going to see 1500 fps from a 125 gr .357 SIG bullet coming out your G27's 3.4-inch barrel, or even the G32's 4-inch barrel. But from the full-size 4.5-inch barrel of a G31 it's certainly possible. I get 1565 fps from my G31 with Underwood ammo.
Trust that Glock's engineers know what they are going. The subcompact Glocks (non-10mm and non-.45) have been around for almost 18 years, all of them using the same RSA without requiring customer enhancement for safe and reliable and durable operation.