Home Forums Hunting & Shooting Ask The Gunwriters Mule Deer; Why the Disparity?

Also keep in mind that the same technician, using the same equipment, drawing cartridges from the same lot of ammunition, with the same test rifle, on the same day can easily produce 10 shot averages that differ by 1,000 PSI. It gets worse as you move from lab to lab.

I imagine if there is a lab in Denver, technician's results could vary even more...:)

Not trying to be "smart", but based on what empirical data do you suggest that? Is it assumed: a) That they don't know what they're doing?, or b) They're pushing things beyond SAAMI psi?, or c) They're guessing?, or d) Their equipment is broken?, or e) Their bullets go faster at the same psi?, or d) Your experience doesn't match theirs in MV?

Just like to know what you're thinking.

Bob

www.bigbores.ca

I'm with Vic on this one. No offense to Mule Deer. His post is, as usual, excellent and makes sense. However, when I look in the Nosler manual, the velocities just seem high.I find the 270 WSM data to be particularly optimistic.

FWIW, I have found the Lyman data listed on Loaddata.com to typically be pretty close to what I see on my chronograph.

405wcf

Nosler uses wiseman barrels for most of their data testing, tight bores with minimum spec chambers give higher pressure with higher velocity. I've used their data in factory rifles and get 100 to 150 feet slower than nosler book says. Also seen those same loads used in a tight bore and tight chamber in a custom barrel and they pretty much matched what nosler book says.

Bushrat nails it.

Yep, and thanks JB for the excellent information.....

Thanks JB. Your post cleared some things up for me.

Sure thing.

I'll take (D). I have complete confidence in Nosler as a manufacturer, but "D" is the standout.

I have noticed, in .243, that a couple of loads had velocity listed with the 75 grain bullets and IMR4895 that I was never able to duplicate, not even come close. About 200 fps difference.

I noticed in a couple of instances in other cartridges that velocity fell short IN MY RIFLE. I thought nothing of it figuring well, it's my rifle.

It's when I heard others stating the same thing that I thought that there may be something to it. I was able to get within a reasonable difference between their manual and my results with a .223 load and IMR4198/50 grain bullet, accounting for the difference in barrel length.

I have nothing against their bullets and am revisiting the .243 after a number of years without one. One of the bullets I want to try is the 95 grain Partition. I will look at their suggestions for this bullet and see how it works out. If their bullets show a tendency to land fairly close to one another, field testing will begin in November.

And I suspected that the explanation would be something as simple as this.

My experiences have been the same as above, 100-150 fps differences between my custom chambered rifles and factory rifles of same caliber with the vels of the customs being more in line with Noslers data.

I'm a little late to say this as I just saw Mule Deer's post, but WOW!!

Well said! Should be required reading/sticky!

Russ

Agree. Thanks MD.

Glad so many people liked it, but that "post" originally appeared here on the Campfire as one of my monthly columns when I was writing them for Rick. We have talked about getting the column started up again, but I have to find an opening in my schedule, which is pretty full for the next several months.

It also appeared as a chapter in my book RIFLE TROUBLESHOOTING AND HANDLOADING, and in the Berger handloading manual, so it's been around for a while.

thank you for sharing what you've learned and experienced. looking forward to the resumption of your columns here on the 'fire

If you liked his post, you'll love RIFLE TROUBLESHOOTING AND HANDLOADING. I bought it for myself as a Christmas present and was never happier with a technical book. It's like getting a master's degree in rifles and shooting.

I got your book "RIFLE TROUBLESHOOTING AND HANDLOADING" about 6 months ago and just haven't had the time to read it (yet). I had total knee replacement surgery last week and once the misery factor subsides, I'll have the time to read it as I recover.

Thanks, MD.

All of us who read 24HC are in your debt.

That's why I rely on Lyman's manuals and Ken Water's "Pet Loads" as my first point of reference. Lyman's manuals have always been the standard and they have the most experience of anyone in the loading business. They also pressure test every load.

OK, but shouldn't a given pressure yield approx the same velocity no matter what rifle?