CZ Czechmate Recoil Spring tuning

[chapo]

Ok, so today I went back to the range for another round of tests. Seems like I'm spending so many bullets and powder just in testing!! It's crazy. Ok, to the point, I used my Czechmate with AA7 in all loads and loaded up to 1.165". Mixed brass.

124gr CMJ: I tested 9-13lb springs on loads of 9.7gr, 9.9, 10, 10.2.
115gr CMJ: Tested same springs with charges of 9.8 &10g.

Attached a video I made of the results even with slo mo. I will chrono the best combinations of powder and recoil spring at a later date.

Please please provide me feedback as to what you think the best combination is, based on the video. I am too close to it and have begun to think they are all the same!! lol

 

[mike mccormick]

First things first.....do not use mixed brass with high end loads. Just asking for trouble. Serious impediment to accuracy also. Case volume varies greatly from one manufacturer to the next.

 

[chapo]

Yeah. Most of my inconsistency is from the mixed brass. It’s just expensive to keep buying new brass and to separate fired brass by headstamp is super tedious.

 

[mike mccormick]

Yeah. Most of my inconsistency is from the mixed brass. It’s just expensive to keep buying new brass and to separate fired brass by headstamp is super tedious.

Maybe so, but running major PF in a 9mm is way above normal pressures. The difference of case capacities can be a lot bigger pain than a little sorting. I buy used brass, already sorted to one brand, for $30/1000.

 

[chapo]

Where is this? Would like to buy

 

[Leadpilot]

It’s been several years since I owned my Czechmate but 10.5gr of shooters world major pistol powder, Montana gold 115rn at 1.165”, and a 10# recoil spring was the sweet spot.

 

[mike mccormick]

Where is this? Would like to buy

Several people , one is Calvin Hirsch. Calvinhirsch399@gmail.com