Ladder test 6 x 47 Lapua

aaronraad · Post by **aaronraad** » Sun Mar 10, 2013 6:27 pm

ecomeat wrote:
aaronraad wrote:Tony

Between the Broughton, March and the MagnetoSpeed I'm surprised you have purchased the complete RSI Personal Ballistics Lab
...the upgraded version has been out all of 5 minutes!

I look forward to hearing about the barrel.

Good luck.

Aaron

Smart arse !!
I am just back from our Club day, but did manage to get some photos early thismorning. I will try to get them on here as quickly as I can.
Now Aaron, you of all people should be able to understand what it is like to really really want to understand ballistsics !! eg WHY did i just shoot a 4 ?

Be patient Tony I'll stick my neck soon enough and give evryone a fair hack :wink:

Forget about the '4', just focus on making sure everything feels right to shoot the next '6'. The 4 has been and gone the 6 is still there to grab!

I've actually come to the conclusion that understanding ballistics is pretty much a self forfilling prophecy. Most of the mathematics is empiracal based and you end up with the same result. I'm happy enough with the G7[sub]L[/sub]'s that they work so it's time to bring some more radical designs to make some signifcant increases in BC.

CED screens are very light sensative. Setting up to minimise light changes is the tough part, even indoors. I think both CED(et all) and the MagnetoSpeed still have their roles to play.

johnk · Post by **johnk** » Sun Mar 10, 2013 8:36 pm

Bruce,

Stop that. It'll turn you as blind as the ladies you're referring to.

John

ecomeat · Post by **ecomeat** » Sun Mar 10, 2013 9:39 pm

Bloody Chronographs......can't live sanely with them and can't live without them . Does that seem familiar from somewhere ..........
What about the KURZEIT PVM 21 chronograph ? Has anyone had any experience, good or bad , with these. They read as though they are in the same category as Oehler and are a neat $1000-00 here from an appointed Australian Distributor.
My main concern is that all of their PR and marketing blurbs seem to blur the difference between PVM 08 Model, and the newer, improved PVM 21 model.
They have a remote control unit, and it interfaces with the Quickload/quick target software. Sold and promoted by Neconos in the US , who own the fancy software.
There is certainly a big place for the MagnetoSpeed Chrony in the F Class world to check velocities , but given developments and commonsense, I think there is a huge requirement for an accurate conventional chronograph.
I hate my Shooting Chrony Beta Master more than anyone should ever hate an inanimate object. Just an absurd waste of money and time, and never worked more than 5-10% of the time.
Our Clubs Pro Chrony was cheap, and worked every time I used it..even seems to be accurate when compared to a MagnetoSpeed. But it's budget price tag would nearly indicate that it "should" have the inherent weakness of the Shooting Chrony type of reader, whereby variations in light cause enormous variations in the velocity readings
CED M2........many stories about inaccuracies under certain conditions, including our own Webmaster.
Does anybody know anything about this PVM 21 ??
Also, I have never researched it, but what about Quickload itself ? Any or many here in Oz with good or bad experiences ?
The US forums have many posts with tight arses asking others to run certain loads/pressures/velocities etc for them looking for results, but I don't think it's actually that expensive (maybe $160-00 or so) Even well respected forums like Accurateshooter.com have many requests for Quickload assistance. Quality shooters like Erik Cortina from Team Lapua and Steve Blair make a lot of postings on there, right beside the many requests for someone to run XYZ load combination please.
I would love some feedback on the PVM21 if anyone can contribute
Rgds
Tony

aaronraad · Post by **aaronraad** » Sun Mar 10, 2013 11:09 pm

Maybe a phased array doppler radar doesn't seem so silly after all.

jcinsa · Post by **jcinsa** » Mon Mar 11, 2013 5:33 am

I've had a CED for 5 years now.

Bought the Infra Red Screens when I moved my shooting position on my home range to the back of a shed, about 2 years ago.

I've had no roblems whatsoever with the CED.

Well worth considering.

Post by **AlanF** » Mon Mar 11, 2013 8:29 am

I read somewhere that Oehlers are available again after a few years absence? They have a good name, but I'll betcha they're not perfect. I think the key is to learn the limitations of what you have (unless its a real lemon). I've done that with my pair of CEDs and F1 Chrony. If I want maximum accuracy it has to be done near the middle of the day with a clear sky, with all 3 chronos in series (no IR on CEDs). This is when I test powder/primer/seating combinations looking to minimise velocity spreads. I usually reload the same case to eliminate that as a variable, and just fire into a hole in a bank. For ladder testing at 500yds, which I usually do in late afternoon at the range when the mirage has gone and wind has abated, I just take the F1 chrony or a CED with IR, because accuracy of velocity is less important to me for that purpose.

Alan

bruce moulds · Post by **bruce moulds** » Mon Mar 11, 2013 8:43 am

when i shot my old chrony with a 9.3 x 64 brenneke it slowly fell over backwards like something out of a clint eastwood movie.
tha ced that replaced it has never missed a beat when supplied with adequate batteries.
no chronograph is dead accurate, being a guide only. (not sure about the barrel mounted ones)
each kind has its strengths and weaknesses, and should be used accordingly.
my first chrono had silver screens that broke a circuit, and had to be replaced each shot. you had to turn a little dial till a light came on 3 times, and then get the vel from a chart. very modern in its day! i think a guy called ralph bone sold them.
we used to extend the screen life with alligator clips and wire, not always successfully.
john,
i was semi blind by the time i was 18.
keep safe,
bruce.

daj · Post by **daj** » Mon Mar 11, 2013 9:02 am

Tony,

A mate and I both have CED chronographs that track well within a few fps when they are daisy chained in the bullet flight path. That was not the case originally.
We found that the factory folding bases varied in length by a few millimeters and this caused noticeable differences in our velocity measurements. When we machined rigid aluminium bases to separate the sensors by exactly 2', the differences disappeared.

My MagnetoSpeed constantly reads 10fps faster than the CEDs and causes the POI to be higher when it is attached at 6 o'clock on the muzzle. Lately, I only use the CED when checking loads on full bore rifles with the front sight attached or on rifles with 1.25"+ muzzles.

Regarding QuickLoad, yes, it really is that good - provided you feed it good information. Using a chrony and QuickLoad helps find the best loads in the least time. I use the Optimum Barrel Time (OBT) method and it is usually spot on predicting the node once I have established how a particular barrel performs (ie its muzzle velocity) with a particular powder and bullet combo.

bruce moulds · Post by **bruce moulds** » Mon Mar 11, 2013 9:12 am

daj,
your post poses the question.
how much does 10 frs matter in the real world?
i would suggest not 1 iota.
keep safe,
bruce.

Post by **AlanF** » Mon Mar 11, 2013 9:58 am

daj,

Here are some recent figures from my two CEDs (no IR screens) in series (no IR screens). The first group (with 168VLDs) was with clear sky and high sun, the second (with 180Hybs) was with sun lower. As you can see the differences vary more in the second session.

Also of interest to you will be the Moly vs hBN comparison. With the 168s, the HBN gave velocities about 20fps higher. This was reported by John K also. It suggests that moly is more slippery. Both Moly and hBN gave about the same degree of copper fouling, although there were more shots (8 vs 5) with hBN.

From this, I'm not totally convinced that hBN is the way to go, with its only clear advantage being less messiness. Admittedly, I've never experienced the moisture or "ceramic" issues with moly talked about elsewhere.

I'm going to do more testing with the 180 Hybrids and hBN just in case the "CED a" figures with 5fps ES were accurate. Those 4 shots were increasing from 58.0 to 59.5gn of 2217.

Alan

daj · Post by **daj** » Mon Mar 11, 2013 12:33 pm

Bruce,
I agree. (and I am not loosing any sleep over it)

Alan,
regarding the CEDs, we also found that our different units responded differently to different bullets. eg Scenars would read faster on one CED than the other whereas Amaxs would be the reverse. Different light sensitivity would be my guess. That's one of the features I like about the MS, no lighting issues.

I too found my velocities to be higher with hBN. Web proponents claim it is more slippery than moly. If it is, then my coating must be thick enough to cause extra friction. However, provided my ES and fouling rate stay low, I don't really care about the friction one way or the other. I am going to try the cleaner (?) "wet moly" method next to compare.

I am most interested to hear how your next test goes with the 180 Hyb. That's a very broad V node you have if it is real. How was the POI change?

David

johnk · Post by **johnk** » Mon Mar 11, 2013 12:52 pm

David,

I have had the same outcome. I concluded that it meant that HBN had less lubricating effect than Moly. I should have shot bare projectiles too, but I couldn't be bothered. What I have found & it supports my supposition is that I get copper fouling with HBN where I didn't with moly.

Hey, that suggests that there might be a deleterious reaction, doesn't it?

John

daj · Post by **daj** » Mon Mar 11, 2013 1:50 pm

John,

I started coating with hBN last year as an experiment to see if I could resurrect an old shot-out 308 F/C barrel for hunting. It was so badly fire-cracked for the first few inches that naked bullets would leave chunks of solid copper in the cracks and accuracy was only a memory. hBN changed that dramatically. I can again shoot long strings under 1moa - which is just fine for my hunting needs. Borescoping reveals a burnishing of Cu under the hBN but no large chunks. From your observations, perhaps moly might perform even better in that extreme situation.

Reaction? My understanding is that hBN is inert.....(?)

David

johnk · Post by **johnk** » Mon Mar 11, 2013 5:00 pm

Reaction to heat from combustion.

Ben F · Post by **Ben F** » Mon Mar 11, 2013 8:19 pm

Your velocities are too low.

6x47L works very well at over 3200 with 105 vld.

I run two 6x47 barrels chrony on last rechamber by Matt Paroz who witnessed chrony test goes 3211 average, sd & es both single digit.

As you say you will need to treat barrels as a cosumable, rechamber @ 800-900 rnds.

Ben