280 AI and IMR 4831

[wolfhunter]

I had a real nice 280AI traded it to my brother for his wife . the caliber is very accurate but if you want to shoot heavy bullets. (175) a 30-06 with 180 is a good choice .

 

[Albert GRANT]

I had a real nice 280AI traded it to my brother for his wife . the caliber is very accurate but if you want to shoot heavy bullets. (175) a 30-06 with 180 is a good choice .

"traded it to my brother for his wife"
That must make for awkward family gatherings!

 

[Ray B]

Some would say your brother got the better deal.

 

[Nevada Mike]

Sometimes there is a breakdown between writing and reading!

 

[Albert GRANT]

Sometimes there is a breakdown between writing and reading!

Indeed! This one could go either way, but reading it quickly, it sure made for a good laugh!

 

[Areaonereal]

Best laugh I have had in a while….

 

[wolfhunter]

that was wrote kinda funny it was a 7mmstw for the 280AI my brother is very happy with his wife and I like her to

 

[Donnstar]

What are you trying to achieve? Distance, speed, accuracy, lethality? Perhaps I missed your goal in this thread? 7 anything is my happy place!

 

[Donnstar]

4350 & 4831 with a 165 ish hunting bullet in a 1/8

 

[Inline6]

Powder is new, less than 2 years old.

I'm not concerned about the powder, only what GRT is showing relative to what I can infer from Nosler's and Hodgdon's load data.

Hodgdon is showing 55 gr of IMR4831 under a NP 175 as generating 61K PSI, but that's using a Nosler case, presumed water mass of 74 gr (that shows 64.9 gr of usable space under the bullet in GRT, which tracks with what Nosler shows).

GRT is showing that same load at 49K PSI

Pretty sure the issue is with GRT.

With the 160 gr A Frames, I started at 55.7 gr IMR 4831 and progressed up in .2 gr increments to 58.5, COAL of 3.33 (which I think is too long by a little). GRT says I should have been around 2825 at the top end, but my magnetospeed showed me right at 3K fps on the highest load. No signs of pressure on the brass or anything.

I'm not too concerned about over-pressuring on the 175s, will take the same baby steps to progress up, just seems odd to me the disparities I'm seeing.

One thing for certain with 160 gr SAF....my rifle seems to like pushing them pretty hard. Both of those 4 shot clusters are over 2900 fps, one almost 3K fps.

View attachment 518302

Did you true up your info after you measured velocities? It will get you much closer in GTR and should help you find your node. It is scary accurate with the loads I use.