Sizing Bottle-Neck Cartridges

[Lee Q. Loader]

Is it more difficult to full length size cartridges with a sharp shoulder?
Specifically is sizing a 280 AI more difficult to get right than a 280 Rem because of the shoulder?
Maybe it's more difficult, less difficult or maybe same.

I'm considering a rifle in one or the other of these and I would most definitely reload all ammo.
The answer to the above question could sway me one way or the other.
Maybe I'd also consider a 7mm-08.
Let's not have this turn into a discussion on which of these is better in performance please, I really just want to know about sizing the brass.

Oh yeah. I also wanted to ask if the difference in the shoulder causes one or the other to need trimming more often than the other?
What about life of the brass?

 

[.308 Norma]

Those are some good questions, and even though I can't answer them, I do hope you get some good answers because I'm interested.
That said, you also mentioned you're considering a 7mm-08. You don't think a 7mm-08 has a "sharp" shoulder, do you? I load for a couple of 7mm-08 rifles, and IMO the 7mm-08's shoulder isn't all that sharp. It's a little sharper than a 308 Winchester's shoulder all right, but still not what I think of as "sharp," and I haven't noticed it being any harder to full length resize than a 308 Winchester - probably a little easier than a 30-06 because it isn't as long.

 

[Grumulkin]

Is it more difficult to full length size cartridges with a sharp shoulder?

No.

Specifically is sizing a 280 AI more difficult to get right than a 280 Rem because of the shoulder?

No.

Oh yeah. I also wanted to ask if the difference in the shoulder causes one or the other to need trimming more often than the other?
What about life of the brass?

Brass life is related to how often a case needs to be trimmed. A more tapered shoulder, i.e., a less sharp shoulder, will cause the case to lengthen a bit more with each firing so will result in a lessened case life. If you're referring to the 280 Remington vs the 280 AI, the difference in case life probably won't be much and will be more related to how precisely your handloads fit the chamber. The main advantage of the 280 AI will be a larger case capacity and a little gain in velocity.

 

[Lee Q. Loader]

Those are some good questions, and even though I can't answer them, I do hope you get some good answers because I'm interested.
That said, you also mentioned you're considering a 7mm-08. You don't think a 7mm-08 has a "sharp" shoulder, do you? I load for a couple of 7mm-08 rifles, and IMO the 7mm-08's shoulder isn't all that sharp. It's a little sharper than a 308 Winchester's shoulder all right, but still not what I think of as "sharp," and I haven't noticed it being any harder to full length resize than a 308 Winchester - probably a little easier than a 30-06 because it isn't as long.

No, that's not what i meant. I'm just considering a one of these three chamberings and I'm leaning toward the 280AI. Looking at that cartridge gives me pause because I've never loaded anything like it. So I thought, well if 280AI is difficult to load then I would be fine with 280 Rem or 7mm-08. Thank you for your response.

 

[Lee Q. Loader]

No.



No.



Brass life is related to how often a case needs to be trimmed. A more tapered shoulder, i.e., a less sharp shoulder, will cause the case to lengthen a bit more with each firing so will result in a lessened case life. If you're referring to the 280 Remington vs the 280 AI, the difference in case life probably won't be much and will be more related to how precisely your handloads fit the chamber. The main advantage of the 280 AI will be a larger case capacity and a little gain in velocity.

Thanks for your responses! I think I was just intimidated by the appearance of the 280AI case. I don't know why. But I just wanted to be sure it wasn't too difficult to work with.

 

[jmorris]

It can take more force to reform, than just resize but it you are talking about regular brass turned into “AI” that work is done upon firing and the case is “blown out”. After that it’s lube and size as normal.

 

[edwardware]

A competently applied lube reduces sizing force so much, that everything else is practically non-existent in comparison. I've done some case forming that really needed an iron Rockchucker (originally invented for swaging jackets), but everything else can be done in any decent aluminum press.

The shoulder angle makes no difference.

 

[Bfh_auto]

Use good lube and you won't notice the difference.
I tried imperial sizing wax on 280AI and struggled to size. Went back to the lube pad and haven't had an issue since.
BTW I'm a huge 280 AI fan. It's straddles the line of Magnum performance while still recoiling light enough my 11 year old niece shoots it.
She has been shooting rifles since she was 4 though.

 

[Chuck R.]

A competently applied lube reduces sizing force so much, that everything else is practically non-existent in comparison. I've done some case forming that really needed an iron Rockchucker (originally invented for swaging jackets), but everything else can be done in any decent aluminum press.

The shoulder angle makes no difference.

That's kinda how I ended up with my Redding "Ultra Mag". Bought a new BPCR for silhouette matches in a custom chambering; 40-70W. Also bought 500 pieces of Starline .45-90 brass to form. Tried with my regular old Rockchucker and two weeks later a new Ultra-Mag arrived and a BC1000 case annealer. I've never been shy at throwing money at a problem.

I load for a couple of the sharp shoulder cases and as the other guys said there's no apparent difference in the force required.

 

[Blue68f100]

Annealing the brass may have been all that was needed. I've seen many times work hardened brass would not size down till annealed, then it was very easy. Besides when you anneal you pretty much eliminate all spring back.

 

[edwardware]

. . .and two weeks later a new Ultra-Mag arrived and a BC1000 case annealer. I've never been shy at throwing money at a problem.

Yeah, I'll agree to that. Nice setup!