need Need more experienced help

[Bassnbow]

Not sure what to try next!

I have a 280 Ackley with 26" barrel using Nosler brass. Started load development after firing brass one time with cheap bullets. With once fired brass and CCI L/R primers I was getting very good accuracy with a couple different loads using 143 HH and 145 Barnes long range ttsx. Using H4831sc (59.5 -60.5 grains) (Barnes book max charge is 60.9, but I'm not getting any signs of pressure). I had several groups with the Barnes from 3/8-5/8" with velocities from 2950-3037. When I loaded the same loads again with twice fired brass the velocities increased some (2980-3070) but the groups also opened up to 1"+. I'm now at three times fired brass and still not getting the consistent smaller groups. Seeing similar results with the Hammer Hunters, but I didn't get quite as good a groups to begin with. I also tried H4350 and RL23 powders with L/R primers. The 4350 was decent, but velocities were lower than I wanted. The RL23 was promising with the higher velocities around (3100-3130) but the groups weren't any better. I have annealed the brass after each firing. Is this normal as the brass gets more firings, and if so what should I try to get back to the smaller groups, increase or decrease load charges, try magnum primers?
For info, I have gone over rifle to make sure nothing has loosened up an the rifle has been thoroughly cleaned between range trips. Any suggestions would be greatly appreciated. Thanks in advance
Pat

 

[L.Sherm]

Not sure what to try next!

215 primer with the RL23, ive helped couple guys that weren't happy with just a LR primer untill they switched to a 215 primer.

 

[L.Sherm]

You should be knocking on the door of 3200 fps also or better with 140 class bullets and atleast a 24" tube and RL23

 

[ShtrRdy]

When firing new brass the first firing expends some of the energy forming the case to the chamber. When you fire it the second time the energy is used to make to bullet go faster.

Try reducing the powder charge so that the velocity matches what you were originally measuring.

 

[Koda_]

Is this normal as the brass gets more firings, and if so what should I try to get back to the smaller groups, increase or decrease load charges, try magnum primers?

Is your rifle brand new?

It is normal if the barrel has not settled in yet.

Whats interesting is Im in the middle of load development doing the same thing:280AI, with the same brass, with the same barrel length, and using H4350 and IMR4831, except Im using a 140g Absolute Hammer. Velocities have not been impressive but Im pushing about 3100fps safely. My rifle is brand new. Ive read not to load dev a new barrel until its settled in.

 

[Bassnbow]

215 primer with the RL23, ive helped couple guys that weren't happy with just a LR primer untill they switched to a 215 primer.

Thanks I will try that

 

[Bassnbow]

When firing new brass the first firing expends some of the energy forming the case to the chamber. When you fire it the second time the energy is used to make to bullet go faster.

Try reducing the powder charge so that the velocity matches what you were originally measuring.

Great thanks

 

[Bassnbow]

Is your rifle brand new?

It is normal if the barrel has not settled in yet.

Whats interesting is Im in the middle of load development doing the same thing:280AI, with the same brass, with the same barrel length, and using H4350 and IMR4831, except Im using a 140g Absolute Hammer. Velocities have not been impressive but Im pusing about 3100fps safely. My rifle is brand new. Ive read not to load dev a new barrel until its settled in.

It's not new, probably 250 rounds down the tube

 

[Koda_]

It's not new, probably 250 rounds down the tube

Then I dont know, I would guess that by 250 rounds any barrel would be settled in.

 

[codyadams]

Just for a reference, in a 24" 7 mag with H4831sc and ADG brass, I am running the 143 @ 3250 fps, pressure signs showed up a little over 3300 fps. The Barnes will be noticeably slower due to bearing surface design, and Nosler brass is not near as tough as ADG, however in a 26" 280ai, I would expect the 143 to run 3150ish with H4831sc, and likely a little more with rl23. However, different rifle/ammunition components could make that vary.

Assuming all possible rifle/optic issues are addressed....

I would do a primer test at a charge weight you know is safe and was accurate in the past. I would start with CCI 200, CCI 250, Federal GM210M and GM215M. Do 5 shot groups of each, in decent conditions, and I prefer to do this at a minimum of 200 yards. Check velocities while doing this. E.S. isn't necessarily important at this point, you may be outside of a charge node, however you will get an idea how the primers affect velocity.

Choose the best one, then (if you haven't already) do a rough max pressure work up (in that cartridge, I would do one shat at each charge, increasing .5 grains at a time) so you know where pressure signs start to appear, also documenting velocity, and look for flat spots. Next is either a seating depth test if accuracy isn't very good (i start coarse, .015 jumps, then if needed, fine tune with .002" adjustments), or if it's doing well, a ladder.

In that cartridge, I would do 2 rounds each at .2 grain increases, surrounding the velocity range I want to be in, and shoot them at 600-800 yards. I shoot the two rounds of the same charge as quickly as I can accurately and consistently, so they are shot in similar conditions, let the barrel cool between 2 shot groups for hunting rifles.

If I don't find a good load doing this, I switch components. But if I start with good components, I rarely have to do that. H4831sc is a great powder for consistency in my experience, so is H4350. I have heard good things about rl23, but haven't tried it myself.

 

[Tiny Tim]

Sounds like you may have left a stable node. Try backing off to the same velocity and see what happens. You may also be able to go up to a higher node. Nosler brass is softer than other premium brands and brass life may suffer if you choose to increase charge weight.

 

[ResearchinStuff]

You're chasing your tail because of small sample size errors from 3 shot groups, or something mechanical has changed (loose action screws, lose scope mount, scope failed internally, stock bedding breakdown).

 

[30378wbymag]

Have you considered StaBall 6.5? Hodgdons data lists really good velocity for the .280AI this was with a 140gr. Nosler BT.

58.1 gr.

3,113 fps

61,000 PSI

I've read good reports on this powder, I picked some up to try in the .243. Looks promising! I'm going through primer trials with my 6.5 PRC...

 

[Buckys]

Are you resizing your brass after firing and, if not, is this purposeful?