Loading Manual Discrepancies?

[duurmeehr]

I have been shooting 45 grains of IMR4895 behind a 150 grain .308 ballistic tip bullet for ten years. The load came from the #3 manual (I never bothered picking up a new version) and is right in the middle of the 43 grain minimum and 47 grain maximum. When the accubonds came out I just converted over to that bullet with the same charge. I have never experienced any pressure signs with either bullet.

Last night for some reason I looked at Nosler's online load data. The minimum and maximum for the 150 grain bullet there is 40.5 to 44.5 for IMR4895. What happened to the 43 to 47 in my manual???

Anybody got any knowledge of this?

 

[Elkman]

I have no technical knowledge of changes in the powder over a number of years. But do see a change in manuals. I think its our lawsuit culture catching up with the loading manuals. I have a couple of rifles where I am now according to the new online manual's are 3 grains over max. Nosler has gotten more consertative as years go by. Thats my take on it.

 

[DrMike]

Lot-to-lot differences account for some of the change; better testing methodology accounts for some of the change. The latest data is closest to the powder you have recently purchased. Some of the older guides and manuals should be approached with caution with current powders.

 

[Antelope_Sniper]

Also look to see if they changed brands of brass. That can have a large effect as well.

 

[30-338]

Your data is from Nolser # 3 manual which list a 1/12 twist barrel. They changed data with #4 and used a 1/10 twist barrel plus differnt barrels manufactors. Nolser doesn't list # of grooves and that can effect loads also.

 

[JD338]

Lot-to-lot differences account for some of the change; better testing methodology accounts for some of the change. The latest data is closest to the powder you have recently purchased. Some of the older guides and manuals should be approached with caution with current powders.

Exactly! Better test equipment and liability are the main reasons.

JD338

 

[1Shot]

NO TWO RIFLE BARRELS WILL SHOOT THE SAME VELOCITY OR GIVE THE SAME PRESSURE. These are loading guides. With any load data you should start at the min load and work up watching for pressure signs in you specific weapon. I have had some weapons that you could go way over what is listed as max loads with no problem. Others I have not even been able to get close to the max loads before the pressure was too high. A chrono is you best friend when working up loads. It will let you know by the velocity you get when your pressure is getting up there. My hunting load for 150's in my 308 that has a tight neck match chamber Heart barrel is 44 grs IMR 4895. I have switched to 125 ballistic tips with 46 gr IMR 4895 for whitetail deer. It really hammers them in their tracks.

 

[duurmeehr]

Lot-to-lot differences account for some of the change; better testing methodology accounts for some of the change. The latest data is closest to the powder you have recently purchased. Some of the older guides and manuals should be approached with caution with current powders.

Exactly! Better test equipment and liability are the main reasons.

JD338

Finally got through with Nosler tech support today. They said, guess what, better test equipment and liability.

He did say that if I had been using that load all this time and didn't show any pressure signs good chance there wasn't a problem.

Thanks for the feedback.

Great forum.

 

[spires5d]

Well with you should be able to load IMR4895 powder from 42.6 to 47.3C max in a .308 rifle. This data comes from the Imr Manual dated 2006 using a 150 gr. Nosler BT to acheive 2920 FPS. At the present,I'm loading IMR 4895 powder ,46.5 grains with 150 gr. Hornady SP in my grandson's .308 winchester. This load works good in his Browning A-bolt.





7Mags forever and a 30 cal. will "Slam Dunk UM"

 

[Greg Nolan]

All the above. I had come to the opinion that Nosler's attorneys were writing the manuals untill one day a new 22-250 loaded 2.5 grains below the Nosler max broke the extractor and jammed the ejector. I had to use a 2x4 to open the bolt. Once it was fixed I found I could reach full velocity with 4 grains below max. Huh!!!
I still have several calibers that are 2 to 3 grains over max at their best accuracy and velocity compromise with no pressure indicators. So it seems that each chamber and barrel combination is different so needs to be worked up slowly. Besides all the differences in test barrels, twist rates etc. the chamber reamers are used within tollerences of wear. The first time used it cuts a max size chamber. The last time it's used before discarded it has warn down and is now cutting a minimun size chamber. And then there's the difference in brass thickness. I got my 30-378 load perfected using a bunch of Norma brass. I got a deal on some Weatherby brass (also made by norma) and with the same load I was back to the 2x4 to get the bolt open. I pulled and checked powder weights. Loaded one more and tried it. Same problem. I went back to the Norma brass and shot a 3.5 " group at 500 yds with no pressure. Lots and Lost of variables and I don't know a tenth of what the other folks on this forum know.
Good Luck
Greg

 

[Antelope_Sniper]

The 22-250 is a good example of why you should always start low and work up. I've seen several reports of the 22-250 producing high pressure with mid-level loads. I think part of the reason is the 22-250 is such a great prairie dog gun, and they may get shot alot under hot conditions. A coulple years back I was shooting a near max load, but still within book. It performed well in the spring while I was working it up. I was shooting the heck out of prairie dogs on a 100+ degree day, up unitl about round 50, when the case decided to implant itself onto the bolt face. It took a block of wood to open the bolt and remove the case from the bolt face. The gun was fine, but needless to say, the load has been backed off.

 

[JD338]

The above stories are exactly why Nosler calls the load book the Reloading Guide and why we all need to start low and work up. It is sometimes tough to take the time and cost of components to start from the low point and work up to a max load. What I have done is load "proof loads". Starting low and working up 1 gr increments to get to where I want to be. Doing this saves time and money getting to the upper end safely. Each fired case is carefully inspected and if any high pressure signs show up, I stop right there.
This may not work for everyone here but it has worked for me.

JD338

 

[jmad_81]

I'm finding the same thing with my 280 AI that Greg had with his 22-250. I used to just start out with the max load and load a few half a grain under and a few half a grain over the max and test those three loads. Sure don't do that any more! Had to rebuild the bolt on my 280 AI the other day.

[b]WORK UP!!![/b]