250 Ackley Barrel Length?

[AROKHUNTER]

I need some advice about the barrel length on the 250 Ackley. I'm going to put one together and would like to know what type of REAL gain or loss in performance the 2" will make. Does anyone have any actual experience with this? What should velocity difference be in these barrel lengths with this chamber? What powders would be top performers? I plan to run 80-100 grain bullets, mostly 100 grainers, in a 1 in 10" twist. I've not been around a 250 Ackley, but I'm eager to see what it's capable of. Any and all advice is greatly appreciated.

THANKS!

[darkker]

As far as REAL info on that cartridge, I can't help you.
What I can tell you is based off of Pressure testing in a few other cartridges.

the kicker in your post is the bit about "I'm eager to see what it's capable of". Specifically what do you mean? If you are talking absolute possibilities regardless of pressures, then you can get a few hundred fps. If you are talking about staying within the parent cartridges SAAMI spec, then the gain will be very minimal.

What most people either don't know or ignore, is that pressure and velocity are tied rather closely.
Those that use a Chrony, typically start at least in the middle of the load data; and if things are fast make the false claim of "hey! my super-awesome barrel is fast!!"; not true.
Remember that book data IS pressure tested, in SAAMI minimum spec testing equipment. Production firearms are looser tollerances than that, so you will have more gas by-pass and lower velocities. Also NO data outside of the now very old A-Squared manual, listes powder/primer lots tested. All powder tells you to drop 10% when switching lots... That means if you don't start low and chrono going up, you don't know where your lot of powder falls, compared to tested; nor how much slower your barrel actually is.

I hope you like the gun, and tell us how it performs for you!

[AROKHUNTER]

I intend to work up a load starting with a minimum charge and continuing up until signs of pressure begin to show, OR accuracy begins to fall off drastically. That is how I work up a load for all of my guns. This will be no exception. When I say that, "I'm eager to see what it's capable of", I mean just that. I've read many times of the potential gain of 200fps-300fps over the parent cartridge. I'm hoping that I will be able to reach the upper end of the gain in fps and still get the accuracy that the 250 Savage is known for. Barrel length is a factor that I always like to hear about from experienced shooters. It does make a difference, as well as other factors. I would just like to hear what loads and barrel lengths are being used to obtain certain velocities and then compare for my own final decision.

[darkker]

"Signs of pressure" aren't accurate and generally show up around 70,000 psi.
Barrel length on short actions don't amount to as much at people wish they do. From pressure testing the Creedmoor and a few others; 10-15,000 psi additional will gain you around 75-100fps.

[yobuck]

I think even 200 fps might be on the high side of any velocity gain with an Ackley chamber.
Ive often thought about trying an Ackley chamber in my 25/06. But my mind always recovers
when i remember a few more clicks on the scope is another option.

[darkker]

But my mind always recovers
when i remember a few more clicks on the scope is another option.

Might steal this and put it in my signature, buck.

[stomp442]

The 250 Savage is one of the cartridges that benefits most from improving. My brother has one and it will literally do anything the larger 25-06 will do only much more efficiently and in a short action. As with most Ackley chambers there is more to them than a little more velocity and clicks on a scope. He is running a 26" Hart on his and it is absolutely devastating on deer with a 115 Berger.

[yobuck]

The 250 Savage is one of the cartridges that benefits most from improving. My brother has one and it will literally do anything the larger 25-06 will do only much more efficiently and in a short action. As with most Ackley chambers there is more to them than a little more velocity and clicks on a scope. He is running a 26" Hart on his and it is absolutely devastating on deer with a 115 Berger.

Well i wont argue that the shoulder angle helps with brass stretch. But a guys got to do alot of shooting to really appriciate that.
As for the claim that one cartridge benefits more than others, by how much is still the question. 150 fps wouldnt be enough for me
to go to the expence of rebarreling. Frankly if i were starting from scratch building a gun for (performance) it wouldnt be in 25 cal.
If i were ever going to seriously consider rebarreling my 25x06 to ai, id go up to 6.5 not 25.

[stomp442]

This is not a discussion of what caliber is better or why you would choose something bigger it's about the merits of the .250 Ackley Improved.

Brass stretch is the one thing about an Ackley chamber that I care about the least. Yeah, it's nice not having to trim very often but what I like most about them is their efficiency. The extra velocity is awesome, but it's even cooler when you get the extra velocity using the same powder charge as the parent case. Take my .260 Ackley for example 42gr of H4350 gives me just over 2800fps in a standard 26" .260 and the same powder charge gives me 2950 out of a 26" Ackley version. This is literally the same performance achieved by the larger 6.5-06 or 6.5-284 only using 6-8 grains less powder to do it. Whats not to love about that. It's true one could simply pick a factory chambering that produces the same performance but where is the fun in that. The nice thing about guns and the shooting sports in general is that there is something for everybody and more than one way to skin a cat.

[foxx]

Actually, Stomp, (though I like your post) the OP's question was whether some one experienced with the 250 AI believes there is a viable, real world difference in performance when comparing two barrels with a 2 inch difference in length? My GUESS is there is a point where the difference is worthwhile (20 inches vs. 18, for example, but not 28 vs. 26). Clearly, at some point, add'l length no longer contributes to speed and can actually hinder it. So then you ask, short of that point, when does ease of handling out weigh the advantage of bullet speed? To determine that, you gotta consider what type of shooting you will be doing? Here in Michigan, I have shot and killed a lot of running bucks while walking to and from my stand. Therefore, I really appreciate the merits of a true, well-balanced carbine over a long rifle. Once I am in my stand that might be overlooking a bean field, however, I prefer a longer and heavier barrel. Also, I do not own a 250 AI, but, based upon some of the other posts within this thread, I might wanna get one. :) So... I don't know the answer. Maybe someone else does.

[yobuck]

Actually, the shape of the case has very little bearing on velocity. And im not implying it has zero. Its the powder charge within that creates velocity
and not case shape. There is no doubt its possible to achieve more velocity by using an Ackley improved case as opposed to a standard version.
But the addittional velocity comes as a result of addittional case volume and more powder, and not as a result of a more efficent case.
As for whats not to love, i guess nothing so long as your happy with what youve got. As for barrel legnth it need only be long enough to burn the powder.
With todays powder choices shorter barrels are being utilized more successfully.

[BillPa]

I'm hoping that I will be able to reach the upper end of the gain in fps and still get the accuracy that the 250 Savage is known for. Barrel length is a factor that I always like to hear about from experienced shooters.

24" sporter barrel, RL-15, Fed 215, Win brass, 24" barrel throated to seat a 100 Nosler Solid Base to the base of the neck @2.75X" COAL. 3200+ a bit. I don't list the charge weights I use because its like the three bears, some say its to hot, too cold or just right.
I'll only say the Sierra manual lists 41.0gr/RL15 as both the max velocity and accuracy charge weight, a few tenths of the predicted performance using LFAD and my chronograph.

Bullet Type = .257 100-GR SBT GK SIERRA Bullet Weight = 100.0 grains
Bullet Diameter = 0.257 in Bullet Length = 0.990 in
Bullet BC = 0.355 Sectional Density = 0.216
Case Type = 250-3000 Ackley Impr. 40 deg. Case Length = 1.912 in
Full Case Capacity = 50.943 grains water Est. Overall Cartridge Length = 2.750 in
Net Case Capacity = 48.953 grains water Bullet Seating Depth = 0.152 in
Rifle Type = Savage Barrel Length = 24.0 in
Effective Barrel Length = 22.24 in Barrel/Case Volume Ratio = 6.9
Cartridge Temperature = 70.0 °F
Powder: RL-15
Calculated Powder Charge = 40.0 grains
Load Density = 81.7%
Charge/Bullet Weight Ratio = 0.4
Estimated Muzzle Velocity = 3106 ft/sec
Estimated Chamber Pressure = 48382 CUP
__________________________________________________ ________________________________

Load Table
-------------------------------------------------------------------------------------
% grs Wt. Ratio ft/sec CUP Notes
-------------------------------------------------------------------------------------
75 36.7 0.367 2850 40399 OK
80 39.2 0.392 3044 46446 OK
85 41.6 0.416 3231 52252 High Pressure
90 44.1 0.441 3425 58300 High Pressure

The numbers compares favorably with the 25-06/100s but burns roughly 15 grains less powder in the process.

Bill

[stomp442]

The numbers compares favorably with the 25-06/100s but burns roughly 15 grains less powder in the process.

Bill

Isn't that awesome!

[yobuck]

Depends on how you interpet what you read i guess.
My interpetation of what Bill said was 3044 fps was max for his gun
using a 100 gr Sierra with 39.2 gr RL 15.
Thats pretty much exactly what my Sierra manual says it would be
although they used a 26" barrel which apperently isnt necessary according to Bills data.
Although my manual dosent show a load using RL 15 it does show 3000 fps being a max load
with several powders using the same bullet (in the standard version).
So based on Bills testing, and comparing that with my Sierra manual my advise to the op would be to save your money.
Comparing the 250 Savage and also the 257 Roberts to a 25/06 in my opinion would be a better argument.











9.

[foxx]

I still don't see what you guys are talking about, in relation to the OP's question. Yobuck, what money are you suggesting the OP could save and by what means?

He is asking for advice on meaningful changes in velocity with various barrel lengths when loading 250AI. Are 24" barrels cheaper than 26"? Other than horn rattling, what is all the chatter about?

[AROKHUNTER]

Thanks foxx. My thoughts too.

BillPa---
What is the twist rate in the barrel you're shooting?

[BillPa]

BillPa---
What is the twist rate in the barrel you're shooting?

10.

[yobuck]

I still don't see what you guys are talking about, in relation to the OP's question. Yobuck, what money are you suggesting the OP could save and by what means?

He is asking for advice on meaningful changes in velocity with various barrel lengths when loading 250AI. Are 24" barrels cheaper than 26"? Other than horn rattling, what is all the chatter about?

Save your money is an old expression meaning dont do it.
In this case my remark was my opinion on wether the op should
spend money changing from a standard 250 Savage to an Ackley version.
My opinion was not based on (personal) favorites but simply on what i gathered
by Bills results and my own observation of my Sierra loading manual.
Im actually glad this topic was brought up because my interest has been so low on the 25 cal
cartridges that i wasent aware how the 25/06 (which i own) compares to others. NOW, a fair question
might be (well why do you own one)? Well in answer to that i never planned on that. But the gun was in
nice condition, has an aftermarket barrel with no nut, was priced very reasonably, and the clincher was it
had an old Redfield scope on it that i thought would go well on a classic 88 Winchester i have. By the way,
im not really a big fan of 88 Winchesters either. But this was a gift from my oldest friend so im sorta stuck
with it. Anyway the 25/06 wouldnt be the worst thing i can think of owning, and it might be handy if i ever
decide to go antelope hunting again. Ive got a couple short action 700s kicking around and the page on my
Sierra manual for the 257 Ackley is still open on the table. Did i explain what i meant clear enough Foxx? lol

[foxx]

Yes, Yobuck. Thank you.

I did not mean to be a jerk or offend anyone, I never mean to do so. But sometimes I do because I say things in a smart alecky way hoping you all know my intentions. I also enjoyed the discussion about 250's and am interested in trying them myself now.

I was just trying to get the thread back on track with regards to the OP's original question. I think Bill was trying to give specs for his 25 so others could offer what data they have with regards to all that.

Anyhow, its all for fun.

Maybe there isn't anyone out there who can add credible data to compare with Bill's. It was a good question, though.

[yobuck]

Absolutly understand Foxx. I tend to be smart alecky myself and i know its sometimes missunderstood.
Even when sitting across a table from someone it can be difficult communicating at times.
Some areas of PA are well known to have populations of people who seem hard to joke around with.
Chust vy are you laughin at me for throwin the horse over the fence some hay?

[scope eye]

What it boils down to is, it is not worth it or cost effective to rebarrel just to go to an AI version, on they other hand a setback or rethroat at 1/3 the cost is worth it. and as far as barrel length 24" is more than enough for a case that holds 40gr of powder, especially if you are going to lug it around.

Dean