Home Forums Reloading Big Game Rifles loading data velocities

I have found over the years that loading manual velocities should not be taken seriously,but a trip to the range today demonstrated just how much velocities can vary.My rifle is a factory 280AI.According to the Nosler web site, 59gr of IMR 4831 behind a Nosler 140gr Accubond in a Nosler case should produce around 3160fps-3170fps,however in my rifle,the identical components were only producing 2970fps.The maximum powder charge listed on the Nosler site is 60gr,and the velocity listed is 3222 fps,so there is no way that I will reach 3200fps by only adding one grain of powder.What I will do is work up to 60gr,and if there are still no signs of case web expansion,I will work up to 61gr in the hope of at least reaching 3100fps with good accuracy.

I've noticed that the tightness of the chamber and several barrel factors have a lot to do with how close you can get to the loading data. In the tight chambers in my custom rifles, I commonly exceed published max velocities with loads under max, but my rifle shows pressure signs when I use max loads, sometime severe.
In my factory rifles, I often had velocities slightly below the book, but could safely load them much stiffer than published.

My experience matches exbiologist on this one.

Lou

I have found that owning a chronograph is an eye-opening experience. Some of my loads make right at book, some never get anywhere near and one rifle I bought after I got the chronograph makes near max velocity on starting loads, with almost all powder/bullet combinations.

A slightly different spin here.
What I load for is accuracy exclusively, and whatever velocity come along with that is good enough for me. The only thing I would actually need the exact velocity for is bullet drop data. If I sight in an accurate load at 100 yards, then shoot that load at 200 yards, I really have all of the data I need for that load. I can then make an accurate drop chart from those two points on the graph. It's always going to be a parabola; close enough anyway.
If I lived and hunted in places where really long shots are routine, I'd get more interested; like Prairie Dog huting, or Antilope hunting, etc. But, the swamps here only offer short shots.
My point here is I'm really uninterested in exact velocity numbers.
YMMV of course.

Don

Don,

I tried to PM you about some 250 Savage data you might find interesting but it turns out you are ignoring me. If we got really crossthreaded about something I'm sure it's a simple miscommunication. My take is you're a reasonable man so if we disagreed about something and I hit a nerve I assure you it was unintentional.

I know you can't see this but maybe someone can shoot Don a message for me.

m

I load for accuracy as well. With the latest rifle, I used the chrono to find out where I hit max velocity, so I could use that as a basis on where to work from there. The interesting thing was, this 25-06 hit max velocity with some book starting loads. Sooo, working down from there, I was able to find a load that was safe and accurate. I have a 22-250 that is pretty dang accurate, and it runs about 300 fps slower than what the book shows that it should be running. I am not gonna change it, but nice to know it isnt going as fast as I thought as far as trajectory goes. I love tinkering, so it was interesting to see what all my different loads were doing. The loads I had before the chrono that were accurate havent been messed with since they were all showing safe velocities. The new 25-06 could have proven to be a little interesting with out the chrono.

I've always found it tough to meet Noslers vel with the listed charge....do-able but with more powder(when safe). The one cartridge it was spot on for was my 257Roy.

My chrono is mainly just another safety measure when developing a new load.

Brett

........It just goes to show that each individual rifle has its own ballistic fingerprint; tighter chambers, slower bores, faster bores, powder likes and dis-likes, bullet likes and dis-likes, primers, individual rifle tolerance for max loadings,,,the whole 9 yards.

For hunting loads, I load for accuracy while trying for the best possible chrono`d velocities as well. The rifle itself determines what works good and what doesn`t work so great.

+1..........for the most part.

MM

The only rifle I have that matches the manual is my M70 in .243. It is lock step with my Hornady manual because they used a M70 to develop the data. All others are slower. The only time I pushed it, I was able to reach the target velocity, and it was accurate, but brass life was 1 shot. All for 100fps. Not worth it IMHO.

You have to remember, most manual data is worked up in 26 in. test barrels. You will never match those numbers without serious pressure.

IIRC, SAAMI-spec test barrels are 24" for most common cartridges. There are those which are some other length, but most are 24.

I have a 243 which matches Nosler speeds with Nosler charges. I can't get QuickLOAD to tell me those loads are safe, though, no matter how hard I try.

In some manuals yes,but in other manuals that is not the case.The 280AI for example is listed with a 24" barrel in my Nosler manuals.

I have found the Nosler book velocities very difficult to match. The max loads always provide matching pressure indications, however. I am no longer surprised or depressed by my inability to meet their advertized velocities. Their recommendations for most accurate powder combo usually saves enough time and resources to make amends.

I have a couple of rifles that show different velocity than what the manuals say. My 270 wsm is the worst, with a grain more powder I am getting an average about 50 fps less velocity than what the manuals say I should get. My 300 wsm is the opposite, with 165 gr swift sciroccos and 67.5 gr of IMR 4831 I am getting 3110 fps, swifts loading manual shows a max charge of 71 gr and 3070 fps. I also have a 7.7 jap rifle, the seirra manual shows 2700 fps with 48.8 gr of IMR 4320 using their 150 gr bullet, I am getting 2804 fps with 47.5 gr.

Keep in mind that velocities between different powder lots (of the same type of powder) can vary significantly...

I've had them both high and low compared to load manuals.. strictly why I believe they are strictly that, reference manuals..

I've also had rifle barrels not even make the max load before they are blowing primers...

we all know each rifle is an entity unto itself, as explained by ex biologist and Montana Man having the same results.. along with other guys...

seafire is right (again)

Even the various book writers agree with this. They all state somewhere in their pages the result they found in their lab might not be what you`ll find, start low & work up........