WHATS YOUR C.O.L.? I KNOW YOURS WILL BE DEFERENT THAN MINE BUT I'D BE INTERESTED TO KNOW WHAT EACH IS WITH EACH BULLET AND LOAD.

i rechambered a 700 action and barrel 280 to the ackley. ive only been able to get 140 grain noslers to shoot.
imr 4350 54.5 grains
c.o.l. 3.192 - 3.200
210m primer
remington brass
note: the groups are 1 inch
the c.o.l. range all shoot the same. whats funny when fireforming for brass all my old reloads in 280 shot under .5 inch. the 150 nosler part. and 139 gr. sst's i can't get under 1.5 inches. they shot great in the 280 before. i tried different powders such as rl 19 and h4831sc with no success. in the original 280, it loved imr 4350 and rl 19. can someone guide me here. the action has been trued and the stock fit is perfect. the trigger is at 2.5 lbs. i can go back and load up some rl 19 at 57 grains in old 280 brass and seat at 3.240 and they'll ring a hole at 100 and 200 yards. after fireforming i can use this load and it will not shoot under 1.5 to 2 inches. case specs check out perfect.

Snider700,
How much have you varied the the O.A.L on the cartridge? I have a 25-06 AI and I messed around a good bit to find out what length of cartridge the gun wanted to shoot. In my case the rifle really liked 3.395". Everything less than that it really did not like. I would focus on the O.A.L. After that, you can try different powders but my expierence here tells me that this matters less than the O.A.L of the round.

Is the barrel contour light? Is the barrel free floated? In either case a forward pressure point might sort it out. In most cases the AI round is faster than the original round. Sometimes the barrel harmonics get out of whach when you speed things up. I have an 8mm Mag that needed a pressure point right up near the forend. Went from 1.5" to 0.75". All I did was put some silicone rubber shims between the barrel and stock. Screwed it back together and the same load just pulled right together.

I hope this helps. There can be many things really. Loose scope mount, action screws too tight, action screws too loose, bad bedding job, etc. I hope it sorts out but once I dialed in my 25-06AI it became pure happiness to hunt nad shoot with. Good Luck!

Cheers,
Jason

If the barrel was previously bedded and the rechamber included the necessary setting back of the barrel you may need to re-bed the barrel or float it. I would try seating bullets to be variations of 0.01" to 0.05" off the lands. You may find there is COAL sensitivity.

I guess I was lucky. I rechambered a Weatherby Mark V Lightweight Synthetic to 280 Rem AI and it shoots just about anything well. It especially likes the 154 grain Hornady Interbonds right now.

I have a 280 ackley and imr 4350 is the powder that I use and this rifle is a ruger action. It is a tack driver with this powder. Here are some of the loads that I use.

145gr. speer bt 59gr imr 4350, 139gr. sst 59gr. imr 4350, 154gr spire point hornady 54 gr. imr 4350, 154gr spire point hornady 48gr imr 4350 154gr spire point hornady 51gr. imr 4350. I try to keep the trim length at 2.530. WATCH your pressure. These loads work for my rifle but be careful. 59 grs. are ok but show some pressure. I may be able to go a few more grs with them but WATCH the pressure. Work up to the 59grs.
Good shooting
farmboy9