Ever use a PVM-21 Taliv? I know you’re around lots of shooters, so I figure you’d be a good one to talk to about it.
I spent a few thousand bucks on chrono’s over a period of years. None worked.
I bought a PVM-21 and have enjoyed accurate FPS readings to within 2 fps ever since. I too have trouble trusting chrono’s… but I trust my pvm-21. If I were to pick 2 pieces of equipment that have made the most difference in my first-round hits… it would be the pvm-21 and vectronix LRF. 
I don’t even know what this thread is about anymore, but all I can tell you is this - I’ve never failed to have Shooter get me to within 0.1 or 0.2 MILS of actual POI with 5.56, 7.62, 300WM, or .50 (my experience is admittedly limited to those calibers). And it’s been without fudging anything. Good input - good output, with the help of an Oehler 35P.
And yes, I DO input environmental data when zeroing. I have no idea why you wouldn’t. I’m sure Litz has an explanation if he actually does suggest what you’re saying. So I’m not dismissing him in the least. But when all is said and done, the bullet is the truth - and I won’t argue with 0-0.2 MILS out to the maximum effective ranges of 4 calibers.
I’m not a competition shooter and there are certainly people here who probably have more experience and knowledge on the technical side of things than I do (Taliv and Orkan). But on the applied side, I really know what works, and applying environmentals for the zero works. YMMV.
orkan, actually i don’t recall ever hearing about it before. i googled it a bit before responding. interesting unit. it’s not currently worth $800 to me but it looks like a very curious sensor setup and at first glance i like the software they include, which would save me the step of manually collecting the data and dumping it into xcel to process.
re: environmentals, how does shooter know what powder you’re using? some are notoriously more temp-sensitive than others. i wonder if it assumes you’re using a single or double base powder. i don’t doubt that it gives you very accurate info, i’m just curious how it does it.
Not sure about shooter and powder. I know it has a function to put a velocity spread in it based on powder temp, but I’ve never used it.
As a matter of practice, I never select temp sensitive powders. My main powders are varget and retumbo.
I’m going to drop the dough on a PVM-21. I think a lot of my headaches in the last few months have been chronograph-related. There’s no fucking way I’m getting the ESs that my chronograph has been giving me, with the results I’ve been getting at extended ranges. Plus the initial MV I was getting has to be wrong, because using the Litz G7 for my bullet in Shooter gives me perfect results once I dick with the input MV to make it match what I got when I shot the ranges indicated.
Check out the PVM-21 when you get a chance. You can get it through neco. It was worth the money to me. Inputting the exact velocity in the condition you are zeroing for is one of the main things that have led to my shooting solutions being dead on to the tenth of a mil.
It doesn’t. You have to establish what the correlation is between 1 degree powder temperature variations and the corollary effect on MV. So if 1 degree equals +/- 4 FPS, bumping the temperature up or down 1 degree will simply alter the MV by 4 FPS. The powder temperature function just makes it easier to adjust MV based on temp and to come back to baseline. It takes a lot of time behind a chrono and isn’t generally worth it, especially with the more temperature stable powders. Plus, it’s not always a linear function. The difference in a 20 degree variation will not be the same for 20-40 degrees as it is for 80-100 degrees. When there’s huge swings in temperature I just manually input MV changes based on data rather than relying on the powder temp tool.
That’s probably the way I’d do it. I’ve never had to do it with either varget or retumbo though. I’ve shot in -10f to 110f, and my solution has been dead on.
If I were using shitty powders that have huge velocity swings like reloader or something… then I might be inclined to give it a try. Why anyone would ever want to use a powder like that when there are much better options is beyond me.
heh, well, reloader 17 is what i have used exclusively in my 260AI. year before last when i was working up my data with the jbm program, the temp changes in that calculator were accurate enough i went from the typical 30-60-90* cards to 30-50-70-90* cards because i could see the difference at distance. i was a little surprised. in any event, the extra velocity is worth the hassle for me.
When you’re so damned good… sometimes you have to make life hard for yourself to stay challenged.
Reloader powder is for the challenged.
lol.
I almost quit reloading because of Alliant’s crappy powders.
My very first load was 45 ACP, and their powder was flinging soot and crap everywhere… :fie:
why spend it at all?.. as Orkan
said, the bullet dont lie, you get accurate drop info, no crono is needed…
the “math” way is more accurate…
the basic “math” is
known good BC
“average FPS”
= drop
now go out to 3 or 400y and get “real world” drop…
compare that to you predicted drop…
adjust FPS up or down to match …
if you have access to 600 and 800 and 1k, do the same…
example, i “guess” my MV is X… i input that in shooter, shoot at some clays at 600 and tune till i hit, put that drop in shooter, and it will tell you your true MV
spend the 800 on ammo and classes and it will be better spent then on a crono…
the only thing a crono can do for you is ES to see how good your loads are, and a 100$ crony will do that.
Dang ring why didn’t I think of that before?
edit: should have added /sarcasm tag. read post 19
Just because your drop at one certain distance is correct on one given condition, does not mean your curve is correct for all conditions.
Getting an exact velocity at an exact condition allows the ballistic computer to work precisely at all conditions and all distances. (as close to it as you can get)
Obviously you should prove your dope at as many distances and in as many conditions as possible… but no one is going to convince me that accurate data collection is a waste of money.
Allow me to say it again for the cheap seats. The PVM-21 and PLRF05 allowed me to achieve DEAD ON firing solutions in any condition I’ve shot in at any distance I’ve tried them when using Shooter. Prior to having BOTH pieces of equipment… my ratio was way lower than it is now. Quite literally… the wind is the only variable I work on when I go shooting. When my 375CT gets here… that may change, but for now that’s the way it is.
Does anyone sell the PLRF05 for anything less than full retail?
Not that I’ve seen. They can’t keep them in stock at $2000.
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=3231447&nt=7&page=1
MagnetoSpeed Chronograph Review
Neat option. I’ll stick with my PVM-21.
I know this is a little old but I am so happy to read this I’m grinning ear to ear.