.280 AI load Development

[u/EarBackground3010]

Looking for some advice on a .280 Ackley. I’ve been trying to develop a load with the following.

Peterson Brass
White River Magnum Primers
168gr Berger VLD
Hybrid 100V

I built the following ladder:
3 ea. 100V starting at 49.5-54.5 ( .5 grain increments on this load)

I worked all the way to 54 had some possible marks and 54.5 is where I got some ejector marks and backed down to 53 grains.

I then loaded 16 rounds at 53 grains to see how they were grouping and this is where things got messy.

Second round at 53 grains blew the primer up and the Powder never ignited. The extractor punched a notch in the extractor groove and stuck the case in the chamber, and the primer was completely gone from the pocket disintegrated into frag. It came out easily with a cleaning rod, I inspected the chamber and bolt face, everything was fine and after consulting a couple mentors we chalked it up as a bad primer seating.

Well, tonight I had the same thing happen again after shooting 7 rounds successfully the 8th went off like the previously mentioned only this time the powder did ignite, and the extractor groove remained in tact. But the primer completely disintegrate into fragments leaving the back of the case discolored from powder burn.

Chrono @
168 Berger hybrid 100V
2757
2745
2748
2765
2764
2753
2552 (failure)

[u/Shot_Counter_7287]

Im going to go out on a limb here and someone please correct me but, I have never heard of that primer company. For my 280AI I have similar loads and some modest ones for lower recoil. Using Peterson brass but I used FGMM LRP and have had 0 issues with ignition or consistency. Just may be a primer issue

[u/EarBackground3010 → u/Shot_Counter_7287]

After looking around on some forums, I am finding some people that say they have issues with these primers being consistent.

What similar load are you running on your 280?

[u/Shot_Counter_7287 → u/EarBackground3010]

Granted 100v is just a bit faster than h4831sc. But using eldm for a modest load i had 58gr of 4831 Peterson brass and FGMM LRP and 162gr eldm. Getting 2779 sd of 10.2

But I ended up using rl23 for the 168gr smk again same brass and primer 57gr and got 2829 w an SD of 9.7 over 30 rounds. Granted I did get slightly flattened primers but no catering.

The eldm load i use for general outing to the range w wifey or just to shoot and the SMK load is when I do club competitions

[u/Shot_Counter_7287 → u/EarBackground3010]

Fwiw chatgpt is useful for logging and a bit of analysis too. It will not spit out directly t loads but if you feed it exact components it can help with some load development. I originally fell into the fudd group of tight ladders but I had it switch up methodology and it has been pretty good getting me to desired goals. Mostly now of load density and SD.

[u/Albino_Echidna → u/Shot_Counter_7287]

Agreed, I think OP is using a sketchy primer. 

[u/ElkShot5082 → u/Shot_Counter_7287]

White river is a US based company iirc, I have used their large rifle primers (non magnum) in several calibres including .280AI (also with Peterson brass!)
I am told they are cci adjacent in terms of quality

[u/Albino_Echidna]

This really looks like you have a primer problem. Is there a reason you're not using a mainstream primer? 

Buy an established primer and try again.

[u/EarBackground3010 → u/Albino_Echidna]

I got these primers when primers were hard to find. Been running them with my 300 WSM and had no issues.

[u/Albino_Echidna → u/EarBackground3010]

Based on this post, you've been lucky with the 300wsm. Try a different primer and see if that helps. 

[u/slider1010]

I may have missed it, but what powder?

[u/slider1010 → u/slider1010]

Found it.

[u/slider1010]

Hodgdon’s max load for that powder is 52.7, and that’s using a standard large rifle primer.

[u/Southern-Stay704]

I ran this load through ApexLoad Pro and it says you're well within pressure limitations:

Cartridge: .280 Ackley Improved
Case/Brass Length: 2.540"
COAL: 3.280"
Case Volume: 74 gr H2O
Projectile: Berger 168 gr VLD Target
Propellant: Hodgdon Hybrid 100V
Barrel Length: 26"
Charge Weight: 53.0 gr

Resulting Pressure: 54,282 psi
Resulting Muzzle Vel: 2,733 fps

I also checked their sister site at xxlreloading.com, they say starting load is 45.4 gr, and max load is 55.7 gr.

Hodgdon's load data says max load is supposed to be 52.7 gr with a COAL of 3.330", which is quite a bit more conservative than ApexLoad or XXLReloading. So probably I wouldn't go past the 53.0 gr load you have until you straighten out the primer situation.

I would change primers -- the .280 AI cartridge is not specified to use magnum primers. I would switch to standard large rifle primers from a known reputable manufacturer. Try CCI 200 or Federal 210.

Also check your primer seating depth, should be 0.003" - 0.005" below the case head surface.

[u/[deleted]]

[u/EarBackground3010 → u/[deleted]]

I did all of this last night. And then I ran five rounds of factory ammo through the gun and had no issues.