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slow barrel

Underperforming ammo is a known thing in 6.5 PRC, especially in Hornady. Too bad you aren't interested in reloading, you could gain back the performance that the cartridge is capable of.

Your method of establishing dope is fine, and better than most guys take the time to do (not counting us geeks of course), kudos to.you for.making the effort.

The chronograph your buying will give you very accurate velocities at the muzzle. This will highlight the next problem with ammo manufacturers......their BCs are often overstated too!. Atleast you will know exactly what to adjust in your ballistics app.
 
In my experince, ballistic software algorythms are approximations, especially when you are trying to true your data out to 1000 yds and beyond. My 6.5 PRC is shooting 160 gr. Matrix VLDs at 2,950 fps. This has been verified over two different chronos. However, when I "trued up" my data input with actual results I was seeing on the targets downrange, the program automatically dropped my muzzle velocity by nearly 200 fps to make the software results fit my actual downrange experience. It could have left the initial velocity input of 2,950 fps alone and adjusted the bullets BC, but I guess it is just easier for it to adjust the velocity. Don't worry about it. Your barrel is most likely not slow, but rather your ballistic software is compensating for its algorythms not quite matching actual results.
 
Chronos are nice tools to have but as mentioned above, targets don't lie. Consider conducting your trajectory validation test a second or even third time. If you get the same drops three times in a row and have shot at to your maximum range, it really doesn'tmatter what the chrono says.
 
Before I had access to a chronograph ( I now borrow a buddy's ) I did what you did. Except I zeroed for 100yds then moved out 100yds at a time recording bullet drop. That built a real-time ballistic card. Gravity will never change and hopefully your loads won't either. When I got the chronograph and jumped into the calculations they were somewhat close to what I had shot. Close enough to put a good shot on a deer sized animal out to 500yds. The chrono speeds caused me concern though when I saw a large spread of differences shot to shot. I thought 30 to 40 fps was alot. Anyways, every shot went exactly where I aimed it so I ignored the chrono data chalking it up to "pilot error" setting up or using the chronograph.
 
You are doing it just fine and the most accurate way. Even after shooting over a Chrono you still need to verify the drops at distance. I don't play with BC as I figure the manufacture must be close enough....so I change speed ....you can do it either way, both work fine.
.
 
kylcan2510 said:
so I have a browning xbolt speed LR 6.5 prc with 26" barrel. I was verifying my dope without shooting through a chrono. I haven't shot through a chrono because I don't have one, and I dont live close to anyone that does. I zeroed my rifle at 200, made sure my scope height was correctly plugged into my 2 shooting apps that I use (Shooter and Hornady), and then entered the muzzle velocity that was listed on the boxes. (Hornady ELDX and Berger 156 EOL). At 500 yards I was grouping low with both bullets. When I plug in the numbers to the mv to get my dope matching my point of impact im about 200-250fps slow with each ammo type. Im somewhere around 2750 with the Bergers and 2850 with the Hornadys. I know this isn't the best and most precise way to build a dope card, but it has worked well for me in the past. How much is not knowing actually velocity actually hurting my accuracy? This is a hunting rifle only. Any ideas here? Barrel sound really slow? Am I missing something. On the apps that I use I made sure that scope height, G7 BC's, all environmental factors etc are correct. Maybe BC's arent true?
Click to expand...
In my opinion, you are better off developing your DOPE from actual shooting at several distances than from measuring MV with a chrono and plugging it into an app.
 
Brathany said:
I doubt you have a slow barrel. It's just likely the box velocities are over exaggerated, or shot in warm weather with a 30" test barrel and so on an so forth. Hornady is pretty spot on with their listed BCs.

You don't need a chrono if you are drop testing the ammo to the ranges you intend to hunt. Where those bullets hit is what you record for your range card.

Make sure you are using station pressure and not the local weather station pressure report. There can be a big difference there.
Click to expand...

I'm guess'n this is the answer. There's been a lengthy conversation pertaining to some factory ammunition being far below advertised velocities! memtb
 
emp1953 said:
Before I had access to a chronograph ( I now borrow a buddy's ) I did what you did. Except I zeroed for 100yds then moved out 100yds at a time recording bullet drop. That built a real-time ballistic card. Gravity will never change and hopefully your loads won't either. When I got the chronograph and jumped into the calculations they were somewhat close to what I had shot. Close enough to put a good shot on a deer sized animal out to 500yds. The chrono speeds caused me concern though when I saw a large spread of differences shot to shot. I thought 30 to 40 fps was alot. Anyways, every shot went exactly where I aimed it so I ignored the chrono data chalking it up to "pilot error" setting up or using the chronograph.
Click to expand...
As said above, a 100 yard zero is preferable here as it's just much easier to know your zero is true. Half inch low on zero can really start to mess with your groups at longer ranges. Shoot a 10 round group at 100 to know where your true zero is, not one or two shots.
 
med358-boise said:
Chronos are nice tools to have but as mentioned above, targets don't lie. Consider conducting your trajectory validation test a second or even third time. If you get the same drops three times in a row and have shot at to your maximum range, it really doesn'tmatter what the chrono says.
Click to expand...

And……..while you're at it, attempt to duplicate your temperature and elevation expected on your hunt! memtb
 
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Jakeweb09 said:
As said above, a 100 yard zero is preferable here as it's just much easier to know your zero is true. Half inch low on zero can really start to mess with your groups at longer ranges. Shoot a 10 round group at 100 to know where your true zero is, not one or two shots.
Click to expand...

Or, a few shots at 100 to verify the "dog will hunt"……then shoot 10 or so @ let's say 300. Assuming the group is a good 300 yard group, adjust to place the group where it should be" @ 300………that should make you very comfortable to make those 500 yard shots!

This may also help with differences in temperature and elevation differences, at least within somewhat normal shooting distances …..not the super long stuff! Those shots "open a whole new can of worms"!😉

I may be wrong with my method……but, I'm comfortable with it at my maximum shooting distance! memtb
 
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