double_pedro

Just an FYI - the roll pin in the slide actually stops the forward travel of the FP if there's nothing that the FP contacts in the chamber (like a snap cap)....Sigs are the same way (and can be prone to similar problems when dry-firing without a snap cap). Also, the snap caps that CZ includes quickly get a hole worn into the green "primer" and may no longer prevent the FP from contacting the roll pin when dry firing....that's why CZ gives you a bunch of extra green "primers". Do you dry-fire a lot without a snap cap or with a "worn" snap cap? It looks like the groove of the outer roll pin may have been getting hit/caught on the ledge of the FP that makes contact with the roll pin if you let it (e.g. when dry-firing without a snap cap). When re-installing everything, make sure the groove of the outer roll pin is facing up. Regarding the perfect alignment of the two parts for a CZ75 to work...I can think of a few things that need to be aligned but none that are particularly prone to misalignment or problems in normal use. I would also like to hear what that was in reference to. Good luck.

Spanky - Those look like fun. If you don't do them at EAPS, we could try a couple at CAS in January and work any bugs out at set-up.

Great post....and in a twisted sort of way, what you describe is one of the things I like about CZ's, you have to give 'em a little love in order to make them your own.

That sounds encouraging. Do you have a rough guess at your "typical" stopage rate (other than to refill primers, powder, or brass) - is it 1 per 100 rounds, 1 per 1000, somewhere in between? Thanks.

I am thinking about getting a Super 1050 with a P/W AutoDrive and a KISS bullet feeder. I want to crank out large quantities of 9mm using Federal primers and mixed range brass. I've been doing this on a 650 with a KISS bullet feeder and Lee FCD in station 5 to deal with any bulged brass I may pick up. I'm not unhappy with my 650 but I seem to run into more than my share of jams (maybe 2% on average when well set-up), usually associated with primer seating, primer indexing or brass slightly mis-aligned at station 1. The point is, I can't imagine it being worth the effort to autudrive my 650 (even if there was an autodrive available for a 650) because jam frequency is too high (possibly being exacerbated by Federal primers and mixed brass). I am wondering if the 1050 is that much more jam-free than my 650. The idea of an almost fully automatic 1050 is very appealing if it would run reliably using mixed brass, a Lee FCD and Federal primers. Has anyone had experience using mixed brass, federal primers and a Lee FCD on an automated 1050? I am concerned by some comments I have read that brass "preparation" is very important for an automated 1050....exactly what does that mean? I can see having to use clean, reloadable brass of a single caliber, no residual polishing media, etc. but does it have to be single headstamp, non-bulged as well? Thanks for any advice/experience.

Perhaps shooting faster (i.e. fast clicks) helps your brain run faster so you "see more". It would be interesting to see studies done in the context of shooting. Full article

Sweet! Way to go.

Stages are posted here.

This resurrected thread caught my eye.....I recently tried their 9mm 147 grain FP. unfortuntately, I found they fouled my rifling and some key-holed (1 or 2%). Otherwise, I liked them....very clean to load and handle, not too smoky (but a little more than FMJ's). Reading the tips on their website, they caution against using a Lee Factory Tapper Crimp Die - which I am using - so that may be the culprit. Oh well, I like the Lee die so I'm reluctant to see if it is actually the cause or if it is inherent in the bullets themsilves for my loads. FWIW, I was loading 3.2 gr N320 to an OAL of 1.100" and getting 880 fps from a CZ Shadow.

Cincinnati has a gentrification problem with its many old neighborhoods. Younger, upwardly mobile families are choosing to live in new construction in what used to be the sticks (e.g. West Chester - I have a sister in West Chester :-)) but now is suburbia. Those closely spaced, old houses in what used to be wonderful neighborhoods no longer suit the wants and needs of many of today's home buyers. As a result, tax revenues and property values plummet, crime moves in and you have a downward spiral. Who's to blame? If only we knew how/wanted/had to re-adapt our cities to changing wants and needs rather than just abandoning them like slash and burn farming. End of rant.

Are cash transactions (i.e. not credit card) still free?

I believe they are both about 18 lbs (coincidentally).

Let me add another round of congratulations to John Heiter and the entire crew for a great match - truly a "Classic"! Also, count me as another satisfied Squad 4 member - you guys were great to shoot with.

...Here's a little more thought regarding geometric details. It may shed some light on the reasons for popple holes, side ports, finding the "right" load, etc. Geometry Considerations Each partition of the gas (x, y, z) will carry the same momentum. Depending on where the gas molecules exit the muzzle and the angle at which they exit, some gas molecules will encounter (collide with) the compensator and some won't. The resulting compensation, depends on the specific (geometric) details of how the exiting gas molecules collide with the compensator. If the angular distribution of the exiting gas molecules is (approximately) known, it would be fairly straightforward to use a computer simulation to follow the bouncing gas molecules to determine the expected compensation for a given compensator design. Rather than going into such a full blown analysis, let's take a look at some back-of-the-envelop estimates of the most critical features. Taking the z direction as the barrel axis, the x and y components normally cancel out and the exhaust gas carries a net momentum in the z direction. As in the above example, we will parameterize the z-momentum of the exhaust gas as a fraction, f, of the bullet's PF (f will primmarily depend on the bullet weight and burn rate of the gas). Now, depending on the geometry (mostly the length and caliber) of the compensator, only a fraction, F, of the exhaust gas will encounter the compensator, the rest will exit through the muzzle of the compensator and have no effect. Vertical Compensation (muzzle rise/flip) One of the primary objectives is to compensate for muzzle flip. Muzzle flip arises from the torque produced by the accelerating force of the gas acting along a line of action (the barrel axis) that is off-set from the axis of rotation of the recoiling. Exactly where this axis of rotation lies is a matter of debate and depends on the shooter, grip, etc. For this discussion, it will be taken to lie just under the beaver tail. In this case, the lever arm yielding the torque produced by the accelerating gases is about 1 cm (vertical distance from the bore axis to just under the beaver tail); the lever arm yielding the compensating torque from the exhaust gases is about 20 cm (distance from just under the beaver tail to the compensator). The longer lever arm of the compensating exahust gases is important because it enables a small fraction of the exahust gases to more fully compensate for the torque produced by all of the accelerating gases (acting via a shorter lever arm). For simplicity, we will use a relative lever arm of 20, but this may vary somewhat depending on the pistol, shooter, grip, etc. The simplest way to compensate for muzzle flip is to port the top of the compensator but not the bottom (or use something like an AK47 muzzle brake where the entire top is milled off). It is worth noting that a large initial port allows the higher angle components to escape vertically - these carry more of the off-axis momentum and most effectively compensates muzzle flip. In the limiting case, we end up with a net fraction F of the exhaust gas exiting upwards. As before, the vertical (y) momentum carried by the gas is the same fraction f of the bullet's PF resulting in a compensating torque of 20 * f * F * PF relative to that produced by the accelerating gases of (1+f) * PF. To perfectly compensate for muzzle flip, we need to have: 20*f*F = 1 + f or f = 1/(20F - 1) This is just a "ballpark" relationship to illustrate the balance between the load and the design of the compensator. As mentioned above, f will primarily depend on the bullet weight and burn rate of the gas, while F will depend on the geometry of the compensator. The relationship above amounts to "finding the right load" (bullet and powder) to achieve the best compensation for muzzle flip. Using rough numbers, if F is 30% (i.e. 70% of the exhaust gas exits through the muzzle of the compensator), we find f needs to be about 20% to achieve full compensation for muzzle flip. This is a reasonable value for the momentum fraction carried by the exhaust gases of a slow powder. If a different compensator design was able to encounter (i.e. use) a larger fraction F of the exhaust gas, a faster powder would be required. Note that the design of the compensator may be such that it selectively captures a certain fraction of the exhaust gas for vertical (flip) compensation and a different fraction of the exhasut gas for horizontal (push) compensation (e.g. by using side ports as well as top ports). Horizontal Compensation As discussed above, muzzle flip should be possible to completely compensate due to the larger (20x?) lever arm of the re-directed gases (distance from the comp to the beaver tail versus the distance from the bore axis to the beaver tail). When it comes to horizontal (rearward recoil impulse) compensation here is no such "mechanical advantage" for the effect of the re-directed gases. Therefore, relatively speaking, horizontal compensation (rearward recoil impulse) is going to be less effective since the gas only carries a fraction (10-30%?) of the bullet PF to begin with, and only a fraction of that gas (less than 50%?) will encounter the compensator. By re-directing all of the encountered gas rearward, you may be able to reduce horizontal recoil by roughly 5 - 15% of the bullet PF - e.g. reducing recoil to 145 PF for a 170 PF bullet. Further, since the pistiol requires a certain amount of recoil to operate reliably, there will be a practical limit not far below this. It is worth noting that the longer the compensator, the better it will compensate horizontally because it will encounter (use) more of the low angle near-axis directed gas. This would be my guess as to the idea behind "popple holes" in the barrel - the comp sort of starts way back in the barrel. What does it all really mean? Having now thought about the details a little, I can imagine some designs may achieve a little more horizontal compensation than others, but that probably has relatively little practical effect. I think the biggest difference you may encounter is more likely to be in how well a load is matched to the requirements of that particular design to eliminate muzzle rise. Since the choice of bullet weights and powder burn rates are limited, there is no guarantee that you can find a "perfect" load for every compensator design. Hopefully there are enough options to be able to get close enough.

Here's my approach to the "physics" of the problem (the rest is "engineering"): When firing a projectile: 1. Linear momentum is conserved which means something (the bullet + exhaust gas) goes one way and something else (barrel, slide, frame, shooter and re-directed exhaust gas) goes the other....think equal and opposite. 2. Angular (rotational) momentum is also conserved. This comes into play in two ways....the first is the spin of the bullet imparted by the rifling will cause the pistol to twist the opposite way. The second is a little harder to conceptually grasp, but there is also angular momentum associated with the linear motion of the bullet + exhaust gas (relative to some reference point). Offsetting this is the angular momentum imparted to the barrel+slide+frame+shooter which is perceived as muzzle flip. Re-directed exhaust gas will also carry angular momentum and this may reduce the rotation of the pistol due to recoil. So, the way a compensator fits into all of this is that the without a compensator, the exhaust gas can only work against you (which is why loads using a heavy bullet and fast powder use less gas for a given bullet power factor and this yields less recoil in a non-compensated pistol). If you have a compensator, the ports re-direct some of the gas backwards, upwards and sideways). Gas that is re-directed backwards, can impart up to 2x its momentum to the thing (compensator) that re-directed it - this results in a net redcution in the recoil momentum of the barrel+slide+frame+shooter and ends up as more momentum in gas molecules that are now directed backwards (which is why someone felt the need to invent blast shields). Similarly, by re-directing some exhaust gas upwards and sideways, you end up with exhaust gas off-setting the angular momentum carried by the bullet - as a result twist and muzzle flip is reduced. Now, all of the above essentially allows you to make gains on the contributions to recoil from the gases themselves. For example, suppose the residual gases carry 10% of the bullet's 170 PF. In this case, uncompensated you'd have a 170 PF bullet + 17 PF of gas going one way and the net recoil of the pistol would be 170 + 17 = 187 PF going the other. If all of the exhaust gas could be re-directed backwards, it would impart a momentum kick forwards of 2 x 17 = 34 PF, reducing the net recoil of the pistol to 187 - 34 = 153 PF (you'd have a 170 PF bullet going forwards offset by 17 PF of gas that has been re-directed backwards; the net recoil of the pistol would be 153 PF). The last point to make is that by using a slow powder you end up with gas generated after the bullet leaves the barrel. This results in a larger fraction of momentum carried by the residual gases which allows you to gain more from the compensating effect of the compensator.