Search

Extractor Engagement 45vs9mm

Why are there different ways to fit an extractor? I recently fell in to a debate regarding extractor case engagement so I wanted to share some insight about the topic. The extractor on a 45 acp was designed to engage the rim of the case by the flat area behind the claw, the claw simply grabs the rim to pull it out of the chamber, but does not apply radial pressure on the case. It is very important that the claw does not come in contact with the case bevel, as this will prevent the case from sitting flat against the breechface, this was the way the gun was design because it was designed around the 45acp cartridge. But what happens when you are fitting a 9mm? The gun was not designed around the 9mm cartridge so what accommodations must be made to make this work consistently. The 9mm case at the rim is 0.100" smaller than the 45acp. The rim itself is also 0.025" vs 0.040" (0.035 act.) in depth. If you fit the 9mm extractor in the same manner as the 45, not only would your claw get reduced to about 0.020" to ensure clearance on variety of cases, it also has to move radially towards the center of the bore to make up for the difference of 0.050" per side case diameter... meaning bending at a greater angle AND removing more material from the fitting pad for clearance in the extractor tunnel to achieve a proper amount of deflection since the extractor tunnel is in the same location on 45 slide and a 9mm slide. As a result of this, many smiths, including myself, have decided that engaging the case with the claw in the extractor groove would allow for maximum contact with the claw on the rim, since you can maximize the entire 0.025" depth, while maintaining less of a bend in the extractor to make contact which is more difficult to tension properly and exacerbates the 90 degree claw angle itself. The 9mm case pressure is around 15,000 psi greater than 45 so the additional expansion in the chamber could use the additional claw contact. Someone mentioned that the claw contacting the case would cause degradation to accuracy but I simply ask how so? Both 45acp and 9mm require similar tension, so as long as the tension is radial it does not matter where the contact occurs, HOWEVER, it is still very important that neither 45 or 9mm claws contact the case bevel in the extractor groove, as again, this will prevent the case from seating square with the breechface. This can cause issues with both feeding and accuracy. I also take this one step further and add a slight bend down on the extract because just as the case is further in radially, it drops further axially as well when the barrel drops out of batt

A majority of my builds are 9mm these days so I wanted to look at the actual numbers to decide on what would be the best approach to a very important part of the 1911 platform... so here it is.



Difference between 45 and 9mm case

45acp Extractor engagement

9mm extractor engages the case with the claw in the extractor groove.

315 views

Mailing Address:

11121 Daybreak Glen

Parrish, FL  34219

Phone:

941-545-0820

 

Copy Right @ 2015  Bunker Arms Custom TM

Bunker Arms Proudly created with Wix.com