Published reloading data??

[double_a85]

I recently picked up a box of 270 140 grain accubonds and have been researching published loads. I plan on starting with Ramshot Hunter and stumbled across something I thought interesting.

In Noslers loading data book, they have a max powder charge of 56.5 with a MV of 2971.
Ramshot's loading data has a max powder charge of 53.7 with a MV of 2999. Both seemed to have 24" barrels used in their test. I guess what caught my attention is 3 grains difference on the max loads seem pretty significant.

Anyone have ideas on the variance between Nosler and Ramshot? Both using the same bullet, powder, and barrel length?

 

[jryoung]

In general there are always variances in reloading data depending on who is publishing the data. Additionally, you could put two 270s, side by size and shoot the same load out of both rifles and get different results.

There are always a variety of factors at play, which is why it's best to start low and work your way up and let your rifle/load tell you where max is always taking into account what data is published.

 

[Southwind]

Yes, you can see a wide discrepancy between published data. Just had this conversation on the 270 and H4831 where there was a 6 grain difference in max between manuals.

I guess the lesson is start low and work up cautiously. It helps have a chronograph and a buddy with "load data"

I have had my best luck with my 270 win with Reloader 22.

 

[double_a85]

I hear ya guys on starting low and working up... I reload for 4 different 270's and found a sweet spot for all the guns with 150 grain ballistic tips with 50 grains of H4350. Not even close to the fastest load or even pushing the max charge but all the guns shoot the load great.
I haven't done much "testing" or research of different bullets or powders because the first load has worked so well... guess thats why the difference caught my eye.

I really like the way Ramshot Hunter meters (use it in my 243) and have a pound of it on the shelf... so availability and ease of use is why I want to try it with these 140 accubonds.

 

[1_pointer]

Was the brass the same in both the Ramshot and Nosler data? If different could easily explain the discrepancy.

How different, if listed, are the max pressures? I assume they are close seeing how close the reported velocities are.

 

[double_a85]

Was the brass the same in both the Ramshot and Nosler data? If different could easily explain the discrepancy.

How different, if listed, are the max pressures? I assume they are close seeing how close the reported velocities are.

Different cases, different primers. That would seem to explain a lot. Nosler didn't publish the pressures--- at least not on the website load data.

 

[1_pointer]

I could easily see a different brass & primers being responsible for that level of difference. If at all possible, I use the bullet manufacturers data and follow the recipe exactly. That said, a bit of cross referencing is easy enough if you are changing components. Now if I could just afford a chronograph...

 

[double_a85]

....Now if I could just afford a chronograph...

A friend of mine has one and keeps telling me I need to use it to see what velocities I am really getting... Maybe I should take him up on the offer this year. Kinda curious what my ballistic tip loads do versus a load with the accubonds.

 

[jryoung]

A friend of mine has one and keeps telling me I need to use it to see what velocities I am really getting... Maybe I should take him up on the offer this year. Kinda curious what my ballistic tip loads do versus a load with the accubonds.

If you're going to reload, to me, it doesn't make sense not to have one. They are relatively cheap and can give you another great point of data when determining the quality of a given load.

 

[sbhooper]

There are many variables in reloading. I have never seen much difference in primers and brass. Bullets can be different from one maker to another, but usually not too much, except for all-copper bullets. EVERY rifle is different. Each barrel can be a new adventure.

Generally, I have found that max loads from the powder manufacturer is usually pretty good with THAT bullet. There again, not every bullet is the same. I trust specific data from the bullet people, as they are using their particular bullet. Powder companies are using a bullet that will be close to what you want, but not necessarily just right. I usually cross-reference several different sources of data before I make a load, but generally, with any data, I will start about a grain under max and go from there. I have had real good luck with one grain under max with any load and seating the bullet to the bullet manufacturers test length. From there you can adjust.

As an example, I did a load for a 300 wsm. I used Nosler data for seating depth and one grain under on the charge. I thought the bullet was seated too deeply and called Nosler. The guy that I talked to, said that he was not part of testing that particular bullet, but that it did seem pretty deep. He doubled checked the data and said that is what works. Guess what-IT WORKED! The first load that was put through the rifle was sub-minute and on the money to 800 yards.

The bottom line is that there is no absolute in reloading. There are too many variables for exacts. Good logic and common sense goes a long way.

As far as velocity, it is not as important as accuracy. First develop a safe and accurate load and then worry about velocity. A chronograph is necessary when it comes to figuring ballistics, unless you are going to shoot targets at every possible range. You also need velocity figures to determine exactly whether or not the bullet is within its performance range.

A chronograph can be had for a reasonable amount of money. I bought a Pro Chrono over 30 years ago and it is still going strong. The current model looks just like mine, only with the big sky screens and more bells and whistles. The new one costs $125 or so, which is less than what I paid for mine 30+ years ago.

 

[danr55]

greatest thing about using a chrono when you load is measuring the standard deviation of the loads. If you can keep the SD under 10 FPS you are doing well.

 

[BuzzH]

I would use any published velocity data as suspect, and a rough idea of where you're at velocity wise. It can be right on, low, or high...even with the same barrel length.

We have 2 7-08's, both model 700's, both with pacnor barrels. My wifes rifle has a 23 inch barrel and shoots 43 grains of varget at 2930 FPS with a 140. Mine has a 24 inch barrel and with the exact same load I get 2850 FPS. Same brass, powder charge, primers, OAL, etc.

Whats more important than velocity is knowing how to read pressure signs. Unless you make a major mistake, your rifle isnt going to blow up by using listed maximum loads.

 

[1_pointer]

The reason I want an accurate chrony is to be able to have somewhat of an educated guess as to pressures. If I use the same components and recipe as the Nosler book (for example) is a very safe guess that pressures are quite similar. If I'm lower the pressure is lower and vice versa. The one I really want to get is the Magnetospeed...

Dan- How many shots are you using to calculate SD? I know most folks don't clock enough rounds to get a statistically adequate sample size... Yes I'm a nerd!

 

[double_a85]

The one I really want to get is the Magnetospeed...

That is one fancy gadget!

 

[double_a85]

Maybe I should start a new thread for this... but how hot is too hot when working up a load to test for hunting season? I was wanting to do some reloading this weekend, but with temps in the mid 90's I don't think that would be the best time to be out shooting and checking the loads out.

 

[Ben Lamb]

Maybe I should start a new thread for this... but how hot is too hot when working up a load to test for hunting season? I was wanting to do some reloading this weekend, but with temps in the mid 90's I don't think that would be the best time to be out shooting and checking the loads out.

I've seen pressures rise significantly between extreme temp swings. Loads that are safe in guns when it's 40-50 degrees become bolt stickers at 90.

Best thing to do is shoot when it's cooler out like early in the morning.

 

[double_a85]

I've seen pressures rise significantly between extreme temp swings. Loads that are safe in guns when it's 40-50 degrees become bolt stickers at 90.

Best thing to do is shoot when it's cooler out like early in the morning.

Thats kinda what I was thinking as well Ben. Guess I needed "reassurance." Maybe I will load up a few tests with everything labeled so when it gets cooler I will be good to go.

 

[Biscuit Hunter]

Down here in AZ, it's generally pretty hot when I do most of my off season shooting practice, so I don't settle on a load until I've tested it when temps are in the 90s. Come to think of it, 80-90 degrees is probably when I do most of my load development. I like knowing that a load will be safe in whatever ambient temp I want to shoot it in. I don't shoot long range, so I'm not worried about losing a bit of velocity on a cold morning during hunting season. I haven't noticed any POI changes with my loads developed and sighted in on a hot day, and confirmed later on when things cool down.

If you're really concerned about temperature, Hodgdon's "Extreme" line of powders is supposed to be very temp stable. H4350 is one of them, and you mentioned having worked with that before. Might just stick with it.

 

[Gunner46]

Ok Double ...... It's just me and you, sitting at some dive joint. A couple (14) brews down the hatch. Ya with me Bro ? Come on, keep up, drink like a Marine (or a Sailor if need be) this is serious $hit !

Plublishhhetted ballisticks are Crap. Crat... Crabt........Oppiess.... Sblit de b#er .... CRAP !!!! (Xuse me Mam)

It's Legalize, Marketing. TAA DAA.

Get a cheap Chrono, burn a few rounds, and when you find a load that will do "good enough", just go hunting.

When you get back, a pic would be nice.

 

[1_pointer]

Some testing results I've read about show that most all powders are affected above 70º, just some less than others. Like Biscuit said, if the load's safe at 90º it'll be safe at all temps below that. It'd be a good idea to recheck POI in cooler temps to make sure that hasn't changed. With some thought, there's no reason not to shoot if you want to.