280 AI

[cajun]

Theres a youtube video out there where a guy cuts a 308 down. I want to say it's around 25 fps per inch giver or take. When looking at load data and trying to figure out a shorter barrel thats what I use.

 

[RAGGED EDGE]

FPS per inch is a fluid exercise. I think 25 is a number that will serve as a usable average.

 

[Rocketeer77]

I did some more homework and study taken from all the tests others have done, on average the 25 fps per inch is light. Often as not removing 2" reduced velocities between 80 to 100 fps. That's at a critical area & the velocity changes were NOT consistent by any means?

 

[Buttermilk]

Berger Bullets manual has the velocity increase or loss per inch of barrel over there published data. I don't have my Berger manual handy or I'd look it up. I do believe it's in the 23 fps range for the 308...

 

[Ernie]

30 fps per inch is my typical guess, so I typically say, "25-35" fps per inch.

 

[eoperator]

I went from a 24"proof to a 20" bartlein 162eldm same powder/brass/charge weight & lost 90fps
280ai

 

[Rflshootr]

Thanks. This project is going to be a poor boy build lol. I have an old savage 30:06 that is about a 2 moa shooter. Rebarrel, glass bed, refinish stock, new trigger. Biggest decision now is barrel taper,length. If threading for a can that will dictate min contour. The plan is a 7 1/2-8 # rifle. Already have a 9+ # custom 7 mag.

A Shilen #3 is pretty close to the factory barrel. You would only have to do a small amount of fitting in the barrel channel in front of the action. Plus, you can end up with a shouldered barrel and also up to 25" long if you desire.

Welcome to Shilen Rifles, Inc.

 

[Ekupp]

Real world speed with a 22" and 140's 160's. Wanting to build a lighter shorter rifle ( already
have a 9# 7 mag) and will be running a can.

Thanks

K m kppjppkpkkkpkjp

 

[Mike Matteson]

Are you going back to a 30/06 or something different? A 280AI case is about .1 longer than a 30/06 of other cases on that line. (25/06,270,7mm). So powder can be added to the mix. Otherwise if changing out barrels which require a reamer anyway. I ran into a problem here awhile back in COAL with my 6mm/280AI. I got 500 case in 280AI from a brass supplier here last year. A lot of case were shorter that what is shown by several thousands.
There has been talk about your chamber and where the neck of your case fits into the chamber. That case can't be to long or real problem can happen. The other is the case doesn't want or need to be to short either. Within couple of thousands or so. Cut down on problem with your lands, and carben build up.
So this time I am having a reamer built that is shorter in COAL by several thousands to get around that possible problem.
The reamer cutters should match your count on rifling. if your have a 6 land barrel, the cutters on the reamer should be 6. If 5 them it should be 5 cutter.
Otherwise have a smith use his reamer and set up for chambering your barrel. It all depend on what you want out of it.
It's a rabbit hole!

 

[msauce1]

Not to change things but I just got into the 280 AI game. All due to a friend and have a Shillen barreled browning A bolt 2 that shots better than I thought it would under .5 moa. It is a low round count barrel 80 ish when does one see a barrel speed up??

 

[manitou]

They all vary, depending on: Inside barrel finish/quality, bullets used and "witchcraft". Lol.
My last 280ai took 200 rds, which was more than average, and it was a Bartlein barrel.
Most folks say at about 100 rds.

 

[Ernie]

Not to change things but I just got into the 280 AI game. All due to a friend and have a Shillen barreled browning A bolt 2 that shots better than I thought it would under .5 moa. It is a low round count barrel 80 ish when does one see a barrel speed up??

Depends...Every barrel is different.
75-150 is when it is probably going to do it.
Some might not be done till around the 200 mark though.
Don't worry about, just remember/consider it

 

[Rflshootr]

If all of the sudden your groups open up, most likely, it changed. If your groups stay consistent, don't let it worry you.

 

[john k]

Not to change things but I just got into the 280 AI game. All due to a friend and have a Shillen barreled browning A bolt 2 that shots better than I thought it would under .5 moa. It is a low round count barrel 80 ish when does one see a barrel speed up??

Be careful or you will end up in the .280AI cult like me. Shot/hunted/loaded with .280 for 20 years and 5 years ago I tried P.O.'s version of .280 and now I'm still hooked. Great, efficient, and good looking cartridge.