Having some blown primers in 280 Ackley. I am using 59 grains of VVH 550 and a 140 Accubond out of a 24 inch barrel and would appreciate it if someone with a program which estimates pressure would run this for me. I feel it must be a chamber problem or case length issue, but want to eliminate the pressure issue first. I am not happy as the rifle will not pass a no go guage test, but still it will not close on a field reject guage, so though headspace is not ideal, it should not be dangerous.

Thanks.

Quickload says you are between 64-66,000 PSI, guesstimating because they don't have a 140gr Nosler bullet in their database. The low figure is for a 139gr bullet and the high figure is for a 150gr. Ballistic Tip.

550 is a vey peaky powder. It is way too fast for your application. Use 160 or 560, as it will fill your case better and give a better pressure curve.

I looked in all my sources and found no data for that powder for either the 280 Rem. or 280 AI with 140's. I use RL22 in my 280 AI, and it works great. Case capacity will limit you before pressures get too high. But, velocity and accuracy are great.
There is not really a "standard" for the AI dimensions. I found this out with my gun. I had to modify my size die, and had Quality cartridge run me some brass made to my chamber dimensions. Once I got past those issues, it's awesome.

Thanks a lot guys. With the headspace a little iffy, 64-66,000psi is too, too much for sure. I will load another few powders and find one that works I bet. I'll try Re22 and VVH560 as I also like and load 6.5x55 and they should work for that round too.

Any advice as to a starting point for the powder amount?

Thanks again.

***USE AT YOUR OWN RISK***

I'd start at 61 grains with both (2900 FPS w/150gr BT), R22 will fill the case better.

I would like to know where you came-up with that loading.

I found that from 49.7 grains to 56.0 grains with a Remington 9-1/2 primer was the useful range.

My copy of QuickLoad indicates taht pressures are in the 73,000 PSI to 74,000 PSI range.

And my Load From A Disk doesn't recommend N-550 as a suitable powder (and neither do I).

What I would suggest is:
IMR-4350 From 48.6 grains to 59.0 grains
Remington 9-1/2 Primer

QL is not 100% reliable nor is it idiot proof, but for what it is worth here are some more QL estimates. I used a 140 NBT and the default QL parameters for the cartridge.

59 gr. VV550 = 60 ksi, 3090 fps

QL suggests a 59 ksi limit for the 280 AI. The following loads are slightly under 59 ksi.

59 gr. WW760 = 3073 fps

62.1 gr. RL19 = 3091 fps

64.8 gr. RL22 = 3129 fps

Befus, when you say "blown" primers, do you mean the primers are pierced? Or do you mean the primers are falling out of the cases? A pierced primer points to a mechanical problem more than a pressure problem. On the other hand, if primers are falling out of the cases, then pressures are too high for your gun regardless of what any load reference says.

quote:

Originally posted by popenmann:
Befus, when you say "blown" primers, do you mean the primers are pierced? Or do you mean the primers are falling out of the cases? A pierced primer points to a mechanical problem more than a pressure problem. On the other hand, if primers are falling out of the cases, then pressures are too high for your gun regardless of what any load reference says.

Thanks, and yes the primers on two of the last 10 shots ,fired using the load I indicated, were completely blown out of the case. It may be a tight chamber issue, but I agree the pressure is too great.

quote:

Originally posted by ricciardelli:
I would like to know where you came-up with that loading.

I found that from 49.7 grains to 56.0 grains with a Remington 9-1/2 primer was the useful range.

My copy of QuickLoad indicates taht pressures are in the 73,000 PSI to 74,000 PSI range.

And my Load From A Disk doesn't recommend N-550 as a suitable powder (and neither do I).

What I would suggest is:
IMR-4350 From 48.6 grains to 59.0 grains
Remington 9-1/2 Primer

This is what my QL calculated for a 150gr. NBT

I agree with you that 550 is inappropriate.

quote:

Originally posted by popenmann:
QL is not 100% reliable nor is it idiot proof, but for what it is worth here are some more QL estimates. I used a 140 NBT and the default QL parameters for the cartridge.

59 gr. VV550 = 60 ksi, 3090 fps

QL suggests a 59 ksi limit for the 280 AI. The following loads are slightly under 59 ksi.

59 gr. WW760 = 3073 fps

62.1 gr. RL19 = 3091 fps

64.8 gr. RL22 = 3129 fps

Befus, when you say "blown" primers, do you mean the primers are pierced? Or do you mean the primers are falling out of the cases? A pierced primer points to a mechanical problem more than a pressure problem. On the other hand, if primers are falling out of the cases, then pressures are too high for your gun regardless of what any load reference says.

How didn you use a 140gr NBT if it is not present in the QL bullet list?

The 7mm 140 gr. Nosler Ballistic Tip is in my Quickload library. I have the latest powder and bullet update disk from Neco.

The brand of bullet isn't going to make much difference to QL, except that it will adjust the seating depth slightly to account for differences in bullet length. The QL parameters were never customized for Befus' gun anyway, but that shouldn't make much difference in this case, either.

I don't know what to tell Befus. His load sounds reasonable, but if primers are loosening, then there is definitely a problem.

I just bought mine and it doesn't have it

I have two 280 Ackley Improved rifles, both with 26" barrels. I've tried just about every powder/bullet combo you can think of, and the best load I've come-up with is 66-67 grs. of Re25 with a 150 gr. NBT. However, Nosler partitions and Swift Scirrocco bullets work well too - NBT is the most accurate. The new Retumbo powder from Hodgdon also looks promising. Velocities with the Re25 are ~3225 fps with acceptable PSI and NO blown primers - although I've been there with faster burning powders and STIFF bullets like Lost River Ballistics. (LRB makes a very high BC 140 gr. solid copper bullet, although very expensive.) I'd suggest you try Re25 and/or Retumbo with 150 or 160 gr. bullets. In my opinion, the 280 AI is just about perfect bore for 7 mm bullets.

But, if you like that 140 gr. bullet, here's some loads in a 280 AI with 26" barrel. They are accurate and reach MAX in my opinion.

NBT=Nosler BT
LRB=Lost River Ballistics
SBT=Sierra Boat tail
SFB=Sierra flat base

R25…66.0 140 NBT 3274 OK Pockets
R25…66.0 140 LRB 3314 OK Pockets
R25…66.0 140 LRB 3335 Pres OK
R25…66.0 140 SBT 3211/3256 Accurate
R25…66.5 140 SBT 3205/3271 Accurate
R25…66.5 140 LRB 3287/3257
R25…67.0 140 LRB 3334 accurate(MAX!)

R22… 63.0 140 SFB 3241
R22… 64.0 140 SFB 3300
R22… 64.0 140 NBT 3342
R22… 64.5 140 SFB 3318
R22… 65.0 140 SFB 3340 (MAX!)