I am putting together a wildcat based on this, but will be using .243 brass instead of .308. I am thinking of Ackley -izing this round 40 degree shoulder, and straight walls, this wil give an extra couple of grains of powder, I am planing for a 24inch bbl 1:10 twist.

Do you think there will be added benefit to Ackley-izing this cartridge?

Thanks

Kind of like Ackleyizing a 45-70.

quote:

Kind of like Ackleyizing a 45-70

Sorry I do not get this, the 45-70 is straight walled , the .243 is not?

I must be missing something

quote:

Originally posted by roberti11:

quote:

Kind of like Ackleyizing a 45-70

Sorry I do not get this, the 45-70 is straight walled , the .243 is not?

I must be missing something

I think it's called artistic liscence. The geometry of the 45-70 allows you no ability To modify and the shape of the .243,.308 family allows you very,very little. It's an almost no gain situation.

Now a .257 PO improved would be something else. roger

He just meant it is fine like it is.....

If you go to my web page www.duanesguns.com and look at the data for my 257DGR you will have a good idea of what the Souper will do. Going to a 40 degree shoulder will only increase the chance of feeding problems and velocity increases will be minimal. The 257DGR has a smidgen less body taper than the Souper, but I also pushed the shoulder back a little to gain some neck length. It gives a little more room to play with seating depth.

NOTE: blow out the taper on the 45-70 and you have the .475 American. You can also do this and create the .450 American, a 45-70 with a 28-degree shoulder at about a 21% increase in capacity. They were quite popular here some twenty-plus years ago when Siamese Mausers were $50 and Fajen had $50 stocks for them.

Rich
DRSS

The 25 souper is a cool round.
But if you are looking for a little more powder room consider the Roberts improved.
I built mine on an FN supream action.
I don't know what action you are using but the Roberts works in most any.
If You are using a Remington short action, I would not AI the Roberts beacuse of posoble feeding problems. But the 250, 3000 AI might be about the same as the souper...tj3006

I always thought that the 25 Souper was one of the more interesting cats but improving it? I'm not so sure that there's any benefit to that.

What do I know though?

I had a discussion with a guy who wanted to Ackley a 300WSM. He claimed that improving any case will get him 100-200 fps.

He couldn't seem to understand that the amount of improved performance is determined by how much case capacity you add by blowing the body taper out.

I have a 25 Souper and think that it is in the same league as the 257 Roberts. If you want a faster short action .257" bore cartridge, you might want to look at the 25-284.

Jeff

If you are using a bolt go for it you can use the extra space to seat larger slugs deeper! I am building a 250 Humdinger which is an improved Souper necked down to 257. I will duplicate 25-06 velocities, with less powder and is short.

Dear Robert,
I have one of each. Both are great. Built on a Md 7 and a 722[AI]. If you are planning on shooting the heavier 117/120 then you might want to consider the AI. I shoot only the 100 in mine so the difference is neglible. With my standard Souper I have NO problems doing as good as or better than a 257 Roberts. With the 22.5" Shilen bbl on the standard I can get [verified] 3200 + with the 100s but have never tried the 117s. I did try the 117 Sierras in the AI though and it did better than my hunting partners 257 R. by about 110 fps. I attribute this to the great Lake City NM brass being so much stronger than the commercial stuff. I never really found a need to shoot any bullet heavier than the 100s in any 25 cal rifle. Proper bullet construction/placement did the trick. As stated--if you want to shoot the heavier bullets? Try the AI. Either one will make you VERY happy!
Aloha, Mark

Mark,
It is good to know that someone else has faith in the 100gr bullets. From what you said it sounds like your experience mirrors mine with the 25 cal. I shoot a 250/3000, a 250AI, a 257Rbts, 257AI, and the 257DGR. My only "beef" with the Roberts or the 257AI is they need a 3"magazine and I like 700's so a 308 based case is close to perfection, especially with a 100 gr bullet.

I do not agree that the Roberts needs a 3 inch magazine. Remington made many of them on the short action 722.
Although Ruger makes them with a long action , I took a couple dummy rounds seated to the lands on my Ruger long action to a hawk shop and they fit just fine in the magazine of a Ruger .243. I will agree that 3 inch is better for maximizing the preformance of the round with heaver bullets , but a short action Roberts should still push a 115 or 120 grain bullet as fast as a souper , or just as close, and faster than a 250-3000. ...tj3006

Load a 115 BST or a 120 Nosler BT to fit a remington 700 mag box without powder in the case, you will find that the bullet falls into the empty case because it is seated past the .257 diameter of the bullet (holding a bullet in the case from the pressure of the compressed powder does not improve accuracy potential), plus you are sacrficing powder space to the bullet. Just because a factory does something it doesn't mean it is the best way to go. I guess getting into a debate about performance is not worth wasting time due to the similarity of the two cartridges- the point being a 308 case is a better fit in a 2.8" SA 700 and the 3" box of a Ruger or a model 70 are perfect for the Roberts

Many years ago in Hawaii I built a 257 Roberts for a customer/friend. We discussed the SA VS LA in the Remingtons so decided to do an experiment. I loaded a 257 Roberts [722 Rem] with 117 Sierras and gradually worked up loads until max was attained. Accuracy was not the issue--only velocity. I forget the actual velocity but it was somewhere in the 2990 area. This was with the bullet seated back to function in a 722 mag [2.810] easily. Then we loaded some with the bullet out to the max where the base of the bullet was at the shoulder/neck juncture. I think we were able to get another 1.0 gr or so. This equated to a velocity gain of 19 fps in the old Remington. NOW! A lot of things might have been different IF we had used a new Shilen barrel of Douglas but we didn`t! I [personally] don`t think the difference is that great. As to bullet selection? The old MASTER himself--P.O. Ackley told me way back in the early 70s that NO calibre was meant to shoot the lightest OR heaviest bullets in that particular calibre and, in the case of the .25s, to shoot the 100s. I did just that and have never regretted it, at least not yet! Like Duane said-- he likes the 100s too. This is just my .02 for whatever it`s worth.
Aloha, Mark

I also have a 722 in .257 Ackley Improved and like some others I have never seen the need for bullets heavier than 100 gr. Magazine length has never been an issue.
The same can be said about the .244 Remington. For a mere 10-15grs. of bullet weight the .244 was a marketing flop. It seems that most people assume that more bullet weight is better, not necessarily so. We don't shoot 6m/m bullets heavier than 85's regardless of twist and they kill deer with authority.

Stepchild

Not long ago on another forum , Somebody posted a craig boddington article , and it said the 6mm required a long action.
I can't think of a factory rifle chamberd for the 6mm Rem witch was built on a long action.
Granted not many factory rifles on the 6mm anyway. But all I have seen , remingtons and Rugers were short actions.
My .257 Roberts are both long actions. A Ruger and an 03 springfield. My AI Roberts is a FN supream. I may build or buy another Roberts on a Short Rem or Ruger just cause I want to see what I can do with 120 grain bullets...tj3006

quote:

Originally posted by roberti11:
I am putting together a wildcat based on this, but will be using .243 brass instead of .308. I am thinking of Ackley -izing this round 40 degree shoulder, and straight walls, this wil give an extra couple of grains of powder, I am planing for a 24inch bbl 1:10 twist.

Do you think there will be added benefit to Ackley-izing this cartridge?

Thanks

You might gain 40-50fps at the same pressures, but you will need to trim cases MUCH less often. + ya gotta admit the Ackleys sure do look cool!

John

Thanks guys for all the input, after much deliberation I decided to go with the following.

Berger 115gn bullet, base brass Lapua 243, resized to .257 using the 25 souper die.
OAL 2.86, body taper removed, and shoulder comprimized at 34deg (after fire forming).

Should have 54.5gn of usable capcity. Once the reamer is made I will complete the project and post my results.