6.5 x 47 - 4500 fps possible?

[tarsiernyc]

Went to the range today. with lighter loads I was getting around 3,000 fps with hot loads as much as 4500 fps. Can I believe the Chrony or is it lying to me?

Time to buy a new chrono?

Thanks,

Paul

 

[Kenny474]

What weight bullet were you using? Sounds a bit fast.

 

[paulnyc]

pretty light stuff 100 lapua and bergers, 108 lapuas and 123 lapuas. The fastest obviously were the 100s.

 

[Kenny474]

I did a little research, I don't think the 6.5X47 has enough boiler room to push 100's to 4500fps.

4500 is just too fast. I doubt the bullets would have even stayed intact, and likely would have exploded before ever reaching the target from over-rotation.

My 6-284 won't even come close to that with 55 grainers.

 

[paulnyc]

so throw out the Chrony?

 

[Mark Walker in TX]

4500 is not going to happen, not even close.

Probably just a light issue, or you didn't have the chrono opened all the way, I've seen that happen before.

 

[RonAKA]

My .264 WM can't get 87 grain bullets up to 4000, even though it has nearly double the powder capacity. Suggest your chronograph is being a little optimistic.

 

[RDavies]

Ir was probably a combination of the crony picking up the unburnt powder particles, and bright sun. If I shoot over the crony in bright sun, I often get way high readings, but for 4500 fps, it is probably the unburnt powder.

 

[M14AMU]

Me thinks there's a 'screw loose' somewhere! The location is conjectural...at best! You ain't gonna get 4500 fps! Do ya own stock in a barrel making company by chance??

 

[TX65]

I was able to run 81 grain flat base bullets at 3800 fps in a 30 inch barrel. If you ran a 100 grain at 4500 fps, you probably need to carefully measure the cases because they are either trash or your chronograph is.

 

[spclark]

How far from your muzzle was the first screen on your chrony? I typically use a steel tape measure to make sure my set-ups are consistent over time with the first screen placed 10' down range. 15' might be even better but that makes alignment more time-consuming & so far my results have been satisfactory.

Do you have a small bore rifle you can use to verify whether the chrony is working properly for a given range set-up? Using known-velocity small bore ammunition to "boot-strap calibrate" a chronometer at least gives you the benefit of doubt when you get readings like this.

4500 fps from a 6.5x47 shooting 100 grain bullets is hard to fathom. I doubt you could get even an 85 grain moving that fast & not destroy cases, or your rifle.

 

[BoydAllen]

Return the chronograph for repairs. No, 4,500 is definitely not possible, not even close.

 

[15Tango]

Return the chronograph for repairs. No, 4,500 is definitely not possible, not even close.

Maybe there's a 30 grain .264" bullet we're not aware of?

Wayne

 

[paulnyc]

went to the range again today - same readings - I am throwing out the chrony - which one do I buy next?

 

[jack1k]

The best chronograph imo is the Ohler 35/35P. I have the 35 and it works just fine.
Battery life is longer than the printer version, if you don't mind writing the information in your log book. The 35P is great if you want a print-out.
You can find a used one if you look around. I'm not sure if they will start making them again, but parts and repair Ohler was still doing the last time I looked.
Jack1k

 

[spclark]

Oehler is doing another batch of 35P's this year, for sale on a first come first served basis:

http://www.oehler-research.com/model35.html

I have no idea how they plan to distribute them so you're best advised to contact them IMMEDIATELY to get your name on a list... if there is one:

http://www.oehler-research.com/cgi-local/SoftCart.15.exe/online-store/scstore/p-M35-P.html?L+scstore+tcvp5437ffc7abc7+1292864693

Probably the BEST chronometer - pricey though - is the PVM-21 from Neconos:

http://www.neconos.com/details12.htm

CED has a pretty good reputation too, while being a great deal less costly:

http://shootingsoftware.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=RSI&Category_Code=CED

PACT has a range of products depending on your needs and budget.

http://pact.com/index.php?option=com_content&task=category&sectionid=4&id=14&Itemid=66

I hear them less spoken of & as such don't know whether they have anything to recommend them over the others mentioned above.

 

[TonyR]

I have the PVM-21 and like it very much. IMO, infra-red screens are the key to consistent chrono readings. The PVM-21 has them and I believe that there are less expensive chronos that have them as well.