Chronograph

[WampusCat]

I would imagine 15 feet per second is it going to make a huge difference overall.

Not Lance but you got it right. They difference would be tiny if measurable at all with so many other factors in a long shot.

 

Your velocity will get you close enough to make fine adjustments when confirming drops at distance. Applied Ballistics has an accurate measurement of the BC for your 180's (G7 - .345?). Using that BC and your actual drops at distance to work backward on a ballistic calculator will help determine the most accurate velocity data. Adding current environmental conditions to your calculator during confirmation will make your data even more solid/repeatable.

[PowellSixO]

For the money you can't beat the MagnetoSpeed or MagnetoSpeed V3. They're easy to use, and very accurate when comparing bullet drops to measured fps readings. What ever you do, don't buy a shooting chrony f1. I've had 2 of them, and I don't trust them at all. I've seen 100-300 fps swings with them. They're junk imho.

 

 

https://www.midwayusa.com/product/628777/magnetospeed-v3-ballistic-chronograph

 

https://www.midwayusa.com/product/896627/magnetospeed-sporter-chronograph

[KaibabHunter]

I'm trying to get my rifle ready for a dec hunt. I shot my 300 win mag thru a chronograph yesterday when it was about 100*. It gave me 3 speeds on a 3 shot group: 3180, 3194 & 3198 (avg 3190). The box says 3120 from the manufacturer. My dec hunt the avg temp will probably be 45-50*, maybe as low as high 30's and as high as 70*. Avg elevation of say 2500. Zeroed for 200.

 

I want to order my CDS dial from leupold, would it be safest to just use the 3120 from the manufacturer or should I use the avg from yesterday of 3190?

[lancetkenyon]

If you have your chrono at 15' or so, plug in your numbers to your ballistic program and use that as your muzzle velocity. Look at what you lose in the next 15', (probably around 22fps) and add that number to your number to get a very close true muzzle velocity. I doubt you will see much of a difference except a few inches at distance.

[rossislider]

I'm trying to get my rifle ready for a dec hunt. I shot my 300 win mag thru a chronograph yesterday when it was about 100*. It gave me 3 speeds on a 3 shot group: 3180, 3194 & 3198 (avg 3190). The box says 3120 from the manufacturer. My dec hunt the avg temp will probably be 45-50*, maybe as low as high 30's and as high as 70*. Avg elevation of say 2500. Zeroed for 200.

 

I want to order my CDS dial from leupold, would it be safest to just use the 3120 from the manufacturer or should I use the avg from yesterday of 3190?

Use your average. Do not use the manufacturer's numbers! Those numbers are averages from different rifles with many factors coming into play that are going to be very different from what you are shooting. They offers those numbers to give you an idea, but will never be true to every, or even most, rifles.

[PowellSixO]

I'm trying to get my rifle ready for a dec hunt. I shot my 300 win mag thru a chronograph yesterday when it was about 100*. It gave me 3 speeds on a 3 shot group: 3180, 3194 & 3198 (avg 3190). The box says 3120 from the manufacturer. My dec hunt the avg temp will probably be 45-50*, maybe as low as high 30's and as high as 70*. Avg elevation of say 2500. Zeroed for 200.

 

I want to order my CDS dial from leupold, would it be safest to just use the 3120 from the manufacturer or should I use the avg from yesterday of 3190?

Maybe try keeping your ammo in an ice chest, and pulling a single round out at a time and immediately firing through the chronograph? I've heard of guys doing this while working up loads in the summer, to simulate fall hunting conditions.