Guess you got ripped off??????
I have four CZ's and four Annie's and have ordered many times from Pete at J N P. All the replacement bolts had the hex head, are you saying you got the standard slotted head??
As for the springs there is no comparison, just have to look at them!
And as for the shipping @ $7, I have never got anything from them for $7, it has also been the standard $20, maybe a little more.
You must have been in the wrong country!!!!!!!!!!!!!!!!!!!!!!!
Wayne
Wayne, they are simply dishonest in some of their marketing and products. For the 455 action screws CZ changed the angle on the lower side of the screw head to a standard 90 degree from the previous 120 degree screws that the 452 uses. They also changed the chamfer on the thin trigger guard to match this angle. Manufacturing tolerances on these are +2 degrees because it is important that they match... a 30 degree difference is a nightmare. J&P are claiming on their advertising that the new screws are correct on the underside yet they are simply the same old 452 head design. They are relying on would be buyers not knowing the difference, and even if they eventually find out, it costs them 12$ in shipping costs to get refunded for a $10 screw, that is pure BS. Worse than this, they made the screw heads to small in diameter and only a small sharp edge contacts the chamfer about half way on the diameter because of the angle difference....it deforms the chamfer over time and galls the metal with the poor fit. BTW, CZ will not honor a warranty replacement on the trigger guard from damage caused by this and they are aware of the mismatch. Here are a couple photos explaining the problem...
J&P 455 screw...
CZ stock 455 screw...
Lousy fit can be seen here...
Another issue with the screws is that CZ uses a hexelobe (torx) drive because it is 30% more shallow than a hex drive, this allows the drive to fit in the head properly and allows the top to remain flush with the trigger guard. Torx is a licenced drive system which J&P did not want to pay for so they made the heads stick out of the top of the trigger guard, this is not very appealing, and its because they cant make a shallow head for a deep hex drive, not because they are making a stronger screw as they claim.
As for the springs, just read their advertising on the 452/455 replacement spring. It is hokey and BS. They claim their spring is 10% stronger. Its a 29 active coil (longer) spring made out of thinner wire than the stock CZ (26 coil). I had them both tested at a spring co. in Toronto and the CZ spring is stronger in its complete range of compression in the bolt.. At 1.5" compression (mid stroke) the CZ spring is 20.3 lbs, the J&P spring only comes in at 18.6 lbs. Also, silicon chrome (J&P) is only typically used on high heat applications like auto valve springs and ASTM spring steel is superior for several reasons over it....
http://forums.1911forum.com/showthread.php?t=232087 Contrary to what J&P claims, neither spring will take a set over time, springs for these are made in a "preset condition", they are cycled a dozen times to full compression (closed coils) before shipping. Any extremely small loss in strength over time is called "residual creep" and it is less than 3% of the spring strength.
The CZ are over springed to begin with because the bolts are drilled for the striker in the same position for all calibers, 22LR, 22WMR and .17HMR. The magnums rim is .025" larger in diameter than 22LR so CZ moved the pin strike zone outwards to compensate. On 22 LR the pin actually hits off the edge of the rim slighly and ends up with a smaller footprint and also wasted energy going into the actual rims edge, than just inside it. Take a look at where the exit hole for the pin is on the bolt... it actually sits partly outside of the containment lip for the rim of the larger magnum round....
The proper way to accurize the 452/455 for better ignition on the 22LR is reshaping the pin tip to get a larger footprint just inside the rims edge. This requires honing a 5 deg bias to the bottom of the pin tip. With this better location on the strike, a 14 lb spring can be put in. This lighter spring puts less impact into the rifle on a strike and reduces barrel vibration/movement before the bullet has exited. 22 LR only needs ~ .015 strike depth in the brass on Eley ammo and up to .018" on Lapua/CCI.
