Quote:
Originally Posted by lclund1946
I think that we are all in agreement that small capacity cartridges are more sensitive to changes in primers, jump to the lands and differences in chamber/throat dimensions which must fall within the Saami Tolerances I mentioned.
Something we have not discussed is slight differences in bore/lands dimensions which is likely why CZ rifles usually run more pressure/Velocity/grain of powder than others. I had a 17 HMR, in a CZ, that got more velocity than a Savage with factory ammo. In fact I witnessed a case head separation in the CZ, with factory ammo, on a hot day in the gopher patch. My 17 cal. J. Dewey rod was tight in the CZ but worked fine in the Savage.
Fast burning/temp sensitive powders are also much more volatile than the slower ones which are much more forgiving. As an example Lil Gun is shown to generate 35 fps/1,200 PSI/0.1grain while CFE BLK generates 25 fps/800 PSI/0.1 grain according to Hodgdon's data. As well LilGun has a really high Nito glycerin content which I believe makes it more unstable under varying conditions. Another possibility is that the reduced load density sets up a situation where detonation comes into play with LilGun in the 17HH.
I did suggest that seating to manufacturers OAL would have bullets seated 0.080 - to over 0.100" in a 17 HH chamber. The 0.015" tolerance in FB/throat length will not have a significant impact on pressures in this case. The fact that all 17 HH minimum Saami Chambers have a 1 degree 30 Minute throat angle, 0.0502" FB and a 0.0859" throat +0.015" for Max Saami chamber seems to escape you. I have been trying to teach you this for longer than I care to mention but somehow ignorance always seems to prevail and you keep taking jabs at me??  |
I have had similar results between CZ and Savage. I bought the 97r? in Savage..results on gophers, were less then stellar..lots of walking wounded..and lack luster performance...not much better then my cz.22LR shooting CCI mini mags.
Sold the .17hmr in Savage..not impressed..swore I would not buy another .17hmr.....Well life being what it is I came across a really good deal on A CZ in .17hmr...WELL the difference between the two rifles is like night and day.. nearly zero walking wounded...better trajectory..better gun handling and accurate.
The CZ rifle is what a .17 HMR should be