Am I getting resonable velocity?

[tittlet]

I have a Browning A-Bolt II chambered in 280 Rem with a 22" barrel. I can't seem to get close to the published load data velocities. I'm using 150 gr Nosler Ballistic tip bullets and IMR 4350 powder. Using Nosler's load data I worked my way up to max. Their published data shows 2865 fps with a 26'' barrel. I'm getting an avg of 2605 fps. Does this seem reasonable? I know I'm going to be losing some speed due to a 4 inch shorter barrel, but I wasn't expecting 260 fps loss in speed.

I also tried Ramshot Hunter. Nosler's load of 52.5 gr went 2815 fps mine was 2602 fps avg.

I have been pretty anal about measuring my powder too. I use a Dillon beam scale made by Ohaus and a digital scale by Hornady. I don't dump powder in my cases till both scales agree with each other. I have check weights that I use on both scales so I am pretty confident my powder weights are accurate.

Any suggestions or insight on this?

 

[starnbar]

4 inch barrel difference is A LOT I would not try to make up the difference be content with what you are getting

 

[AJC1]

You definitely have a shorter barrel, what I can't tell you is if they had a fast or slow barrel. Two exact same barrels can easily be separated by 100fps.

 

[243winxb]

Loss per inch can be 20 to 50 fps.

Nosler data is generic. The different bullets will NOT produce the same velocity..

Brand of brass can make a difference.. Are you using Nosler brass?

Different powder lots when compared to slowest & fastest can be as much as 10%

Accuracy over velocity for me.

 

[AJC1]

Accuracy over velocity for me.

View attachment 1077591

Yesssssss

 

[GeoDudeFlorida]

Is Nosler using the same chronograph? The same rifle? Is Nosler even using a rifle? Odds are they’re using a universal receiver and test barrel. The data is there as a guide. The point of the guide is to provide pressure tested data so the Handloader knows where the safety margins are, and that is about it. You’re not going to get the exact same results, even with the exact same setup because of lot-to-lot variables. Go for accuracy and safety. Leave performance to the wildcatters.

 

[n2omike]

Are you at max? Have you looked up other sources of load data? Some list max a lot lower than others. You may have some room to play with. I'm assuming you are looking for signs of pressure. You will lose a little velocity (see the above posts) but what you are losing seems a little much. May even double check you powder scale.
Good Luck

 

[tittlet]

Loss per inch can be 20 to 50 fps.

Nosler data is generic. The different bullets will NOT produce the same velocity..

Brand of brass can make a difference.. Are you using Nosler brass?

Different powder lots when compared to slowest & fastest can be as much as 10%

Accuracy over velocity for me.

View attachment 1077591

I agree with accuracy over velocity too. My best accury was well below max. I only went to max to test velocity. It's just that I was so far off the published data I was concerned something was wrong.

I'm using Federal brass and as for different bullets I will try that.

 

[tittlet]

Are you at max? Have you looked up other sources of load data? Some list max a lot lower than others. You may have some room to play with. I'm assuming you are looking for signs of pressure. You will lose a little velocity (see the above posts) but what you are losing seems a little much. May even double check you powder scale.
Good Luck

I have checked other sources and Nosler is conservative on its max charge of IMR 4350. I didn't find the need to chase the other published max loads. I'm just concerned with being 200fps slower than Nosler data.

 

[Bcwitt]

Nosler data is a bit optimistic, generally.

 

[Slamfire]

4 inch barrel difference is A LOT I would not try to make up the difference be content with what you are getting

You are right, and I would like to add that Corporate marketing departments use magic to make the bullets go faster!




I don't have a feel for velocities with a 280, so I don't know what I would consider maximum loads. However, I cannot push a 150 in a 270 Win much above 2700 fps before I start blowing primers. I am keeping below 2900 fps with 130's, and everything I read in print, I should be getting 3000 fps with 130 grain bullets.



A lot of those published numbers need to be taken with a grain of salt. For me, does the rifle shoot well with the load, and are you experiencing any pressure issues. If the first is yes, and the second is no, the shooter does not have a problem.

 

[stillquietvoice]

From looking at several calibers of different nosler data, most of the test guns are match barreled rifles with tighter chambers.

load data I worked my way up to max. Their published data shows 2865 fps with a 26'' barrel. I'm getting an avg of 2605 fps. Does this seem reasonable? I know I'm going to be losing some speed due to a 4 inch shorter barrel, but I wasn't expecting 260 fps loss in speed.

 

[kalielkslayer]

It’s been hinted at.

You can push it until you start seeing pressure signs.

I load my .280 with nickel plated brass. I have gotten sticky ejection and pretty severe primer pressure signs. Both of those made me go back down. But the accuracy was still tightening up until those signs showed up.

If you want more velocity with the same accuracy, you might try RL19.

I chase accuracy, not velocity. But different than a previous post, my .280 shot better the hotter it got.

The 1st time the groups grew was the first time I saw severe pressure signs. Prior to that I had flattened primers and the headstamp was noticeably flattened.

One gun, one experiment.

Go up slowly and use caution.

 

[Bcwitt]

Manufacturers tend to publish data/velocities that showcase there products. They might have selected the fastest barrel out of over a dozen barrels that gave the best paper ballistics. Often good barrels give lower velocities then shot out sticks. When VV entered the US market place, there published velocities were some 200 to 300 fps above what proved attainable. Unbiased pressure tested data practically doesnt exist.

 

[Chuck R.]

Like other's I've never gotten published velocity with published loads.

I don't lose sleep over it either. Each barrel/chamber is a rule onto itself. I do find some of the published velocities "close" as as long as they're using a barrel length that makes sense for the cartridge. One of the best methods to "get there" that I've found is the OCW method:

http://www.ocwreloading.com/about.html

3. Consult at least three load data sources for maximum charge weight for the powder you've selected. Powder manufacturers are the most reliable source. You must then decide on what your maximum charge will be. I use an average of the 3 max charges.

4. Back away from the maximum charge by 5 to 7 percent, and load one test round with this charge. Add 2% to the charge weight, and load another cartridge with that charge. Load a third test cartridge with the next 2% graduation. You will use these three cartridges for sighters, and more importantly to determine pressure tolerance in your individual rifle. They will also "season" the barrel with the powder that you're testing--always a good idea.

5. Add another 2% or so to the charge level used in cartridge #3 of step 4, and load three rounds with this charge weight (you may want to load four rounds, in case you pull a flyer, and need an extra). Add .7% to 1% to this charge, and load three more. Add that same graduation again, and load three more. Continue adding the chosen graduation until you have moved ONE increment above your chosen maximum powder charge. If I'm working with a .223 in the 20 grain powder charge area, I move in .2 grain increments. With the .243 and .308, I like to move in .3 grain increments, and with the 270 and 30-06 I might use .4 grain increments. The larger the cartridge, the larger the graduation.

I basically made a spreadsheet that captures the above. I simply find the 3 max charges by load books/sites and enter it. The calculations then spit out what my load steps should be. You'll note that by following this, the last 2 "steps" will be slightly above the average of the load book max charges. I've yet to run into a pressure issue with this.
Just for a reference, not that it matters, in 24" .270 I get 3170 with 130s and 2950 with 150s using H4831SC.

 

[jmr40]

I have data from one source saying 55 gr of H4350 is a max load @ 2895 Fps and yet another source saying 49.7 @ 2700 fps. Both of these use 24" barrels. Nosler says 51.5 which seems like a pretty small charge. I'd work up to 55 gr with caution. At any rate, you should be able to get close to 2800 fps even with a 22" barrel. While accuracy will trump a little velocity, 2600 fps is insanely slow for that rifle. You can get 2800 fps from a 22" 7-08 shooting 150's.

If you start with a certain barrel length and a known velocity it will shoot slower as THAT barrel is cut shorter. Real world is 10-25 fps per inch for most cartridges. The most I've ever seen documented when cutting down a barrel was around 30 fps from a 300 magnum.

But when comparing 2 different barrels it is impossible to predict. Somewhere between 25-50 fps variance between 2 different barrels with the same length is common and more than 100 fps isn't unheard of. I've seen 20" barrels 25-30 fps faster than another 22" barrel, and I've seen 20" barrels 150 fps slower than another rifle with a 22" barrel.

Some barrels just shoot faster than others which may be the key to your issue. High quality custom target barrels have closer tolerances than common factory production barrels and tend to shoot faster. Those are often the type of barrels ammo manufacturers use to test their loads. That is why it is often not possible to quite reach those speeds with common guns even with barrels of the same length.

 

[tittlet]

Thank you everyone. I do appreciate all your help.