CZ 457 touched to the extremes of machining and precision

adamg

CGN Ultra frequent flyer
Rating - 100%
91   0   0
Location
Saskatoon SK
Very interesting video from Kenny at DPG. He's giving out a TON of information here and I think it's really impressive how he starts with factory metal and touches all the important spots.

 
"REDIDISLY ACCURATE" (I apologize if he has a speech impediment)

"(the cz 457) Limits you on stocks and chassis"
>one of the most accepted footprints in all chassis and stocks

"mill turn these threads" - I guess technically correct, but not how we describe it where Im from.

"ground within one ten thou" - im just nitpicking

I would never use a parting blade to make a square shoulder where it matters as much as this. He would be a lot better finishing with a 35* diamond insert, turning from the ID outwards.

Something funny about running a Lynx but using Fowler to actually measure.

WHY IS HE UPDATING HIS TOOL OFFSETS WHEN THERE IS A WEAR COLUMN? - Must be a self-taught thing! I hope he does learn about this wear column.

"my c access" (I apologize if he has a speech impediment)

I hope one day he can just include the 30* offset in his code, anything left up to the operator will be forgotten to be done at some point in time (maybe he just programmed this all in Conversational?)

I'd flip that endmill to be axial and cut the flat with the entire flute length.

I know Im nitpicking, but if you want me to watch a 50 minute video like this I'm gonna comment. Something tells me this guy is self taught?
 
Last edited:
For all the tech, time and effort, you can't outshoot your ammo (so yes, be VERY picky about your ammo). As was shown, big flyer out the bottom in the 2nd group. I suspect, another flier will show up in the next group or two.. and again... and again.

I count every shot cause every shot is counted in competition. And when you count the fliers... I bet, this is a sub 1" at 100yds rifle with that lot of CenterX - I am being generous in assuming the fliers will always drop in the same direction and amplitude.

Which is the same result you would get with a range of quality rifles both custom and factory.... like my $225 bolt rifle and custom 10/22.

It is a pity that it was suggested 'any' match ammo can be run through this CZ with excellent downrange results. I think that is going to lead many customers to poor scores cause they think lower grades of ammo will work in competition.

YMMV

Jerry
 
For all the tech, time and effort, you can't outshoot your ammo (so yes, be VERY picky about your ammo). As was shown, big flyer out the bottom in the 2nd group. I suspect, another flier will show up in the next group or two.. and again... and again.

I count every shot cause every shot is counted in competition. And when you count the fliers... I bet, this is a sub 1" at 100yds rifle

Indeed, one cannot discount the fliers just because they are inconvenient towards one's narrative. They may well be a result of the ammo, though they could just as easily indicate some issue with the barrel. I have not seen Kenny talk about slugging barrels, lapping them, or even re-shaping the firing pin of the CZ for better ignition. Being capable of stacking some number of rounds tight means nothing if this cannot be achieved consistently. Diagnosing issues with .22LR is somewhat like voodoo witchcraft, there's only so much that what is non-destructively measurable can tell you.

Bill Calfee, Aug 19/2017:

"The 95% rule, and, a spearment to try

CYA friends:

As we discuss advancing rimfire accuracy here on CYA, always keep the 95% rule in mind.

____________________


We stumble over the first 90% of rimfire accuracy.....

With a sound barrel blank, and, a Class A contraption, you could try to mess the chambering up and you'll still extract at least 90% of the barrel's potential. ( provided the barrel is properly mated to the action..)

_________________________

But, if one uses reasonable care in chambering, one can extract up to 95% of the barrels potential.

________________________


It's that 1 or 2 percent above that 95%, that we pay all the money for, plus our sweat, that produces Big National winners and sets world records."


Bill's words give insight into how a person such as Kenny can produce some good shooting rifles by most person's standards. I don't think he has what it takes to set records in Big League Benchrest, however. I don't either, for the record, lol, though who knows, in time I may get there. I note that Kenny often uses incorrect terminology in attempting to explain things. This is either because he truly does not know what he is talking about, or he does not know how to properly express what he has in mind. He is an example of an experienced person who is perhaps not all that knowledgable. He knows, through trial and error, that if he does certain things, they work, but he does not understand why (lack of knowledge). A person can be conversely very knowledgable, as there is a wealth of information available in this day in age, but perhaps has not yet had the opportunity to put that knowledge to the test and gain experience. When one can combine knowledge and experience, great things are possible.
 
Back
Top Bottom