In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.
25-35winchester load/powder?
ern98
Member Posts: 1,725 ✭✭✭✭✭
Hello all, I'm working with a recently rebarreled (24") falling block works actioned rifle chambered in 25-35win. My first choice of powder to try was imr 4320 under a Sierra 90g hp. At 28g it did 2550fps, at 29g it did 2625fps. But at 29g the case was almost totally full and ejection was starting to get sticky. I was hoping for something more like 2700fps so my question is what you all might recommend for the next powder to try. I'm thinking something like imr 4895, but am open to suggestions. I intend to stick with the Sierra 90g hp as the projectile unless the rifle really shows that it doesn't like them. Thanks.....
Comments
I don't mean to be rude, but that's where I'd find any load I might quote you, and you might as well not trust my typing to report that load correctly.
Tailgunner1954, are you suggesting that I increase the throat length like the Weatherby chambers or something like that?
Bhavin, thank you for the suggestion.
My understanding is that H380 is slower then IMR 4320, but then isn't it normal to have to use a larger measure/weight then with the faster powder? With 29g of 4320 the case is darn near full, so there isn't much room to increase the charge....
Tailgunner 1954, I hear you about the chamber. The last resort idea is to convert it to the 25-35 Ackley improved version. As far as volumetric density, yeah on that also. Unfortunetly the IMR 4320 granual is very small, not a ball, but small. That's one of the reasons I started there. The only ball powder I have any experience with is H335 in my .223rem reloads. And my take on it is that it is about the same as IMR 4320. Is H380 a ball powder and is it enough slower to be a good match up?
BTW, the problem is not so much the manual data, but YOUR rifles chamber tolerances. Small differences in throat dimentions can make large differences at the muzzle.
Edit
No, I'm not suggesting you jack up the freebore (ALA Weatherby). In fact I'm suggesting that you may not be able to get the velocity you want, due to the internal dimentions of your existing chamber.
I've gained/lost (depending on perspective) 270 fps due to a throat being just .003 larger in diameter than it should have been (fixing it cost me an inch of barrel off the breach end)
As far as getting more of a slower powder into a case, it comes down to the "bulk denity" of the given powder. IE: going from a given "stick" powder to a slower "ball" powder will take up less space in the case and yield a larger volume of gas for the same peak pressure.
IOW find a load that groups well, in your rifle, and be happy.
Thank you again Rocky, I will be starting on the very conservative side and working up in 2g intervals. By using data from the 250sav, which has all kinds of modern data, I am estimating the relative volume/pressure of IMR 4895 as compared to IMR 4320. And no I am not using the actual 250sav volumes. I will then back off my previous 4320 attemt to get a starting place for the 4895. I'm not sure what I will get, but it will be interesting......
The Lyman/Ideal loads for 4895 with the 87 JSP began at 25 grains for 2275 fps up to 29 grains for 2700 even. Do be aware that back then they estimated pressures right along with velocities!
BTW, if you find any equally old data for the 25 Remington Rimless round, you can use it also. Case capacities were identical to the 25-35 even though case shapes were not.
In your falling block rifle, be sure to try some Nosler 85 Ballistic Tip as well as Hornady 75 VMax bullets for varmints. Data for 87/90 bullets will work fine for either.
First of all, the burning rates and pressure profiles of powders do change over time as manufacturing methods and raw materials change. Did you ever notice how even for modern calibers, the "maximum" load in the latest edition of a manual may differ from that listed in an earlier edition? Or, compare the "maximum" listed in the latest edition of several manuals and you will often find significant differences due to different lots of powder, different lots and brands of bullets, different chamber dimensions, etc. Never, never take as gospel any load from a single source, especially from an old manual.
Second, the variations in chamber dimensions, bore diameteter, etc. from gun to gun is a lot greater for old guns in old calibers than it is in modern guns with modern calibers. Just because a particular load works well in one doesn't mean it will in another.
This one may throw ya a little.... Starting load of 27.5 gr. of AA2520 and possibly to work up to 30.8 gr. On the low end you should be around 25-2550. Depending on your rifle (YMMV) you could possibly go as high as 2800 fps. Stop with any sign of pressure. If the lever sticks then back off.
This load was interpolated from a 6.8 SPC load, allowing for the increased pressure of the decreased diameter of the .257 bullet.
Let us know how that works.
That's a good thing. If you ever do get a chance to try the AA2520 load let me know. I was flat out impressed with it's ability to produce velocities and not show pressure signs in several small medium sized cases.