Max loads and pressure question...
I cannot seem to find ANY loading data for the .300 Win Mag AI. PO Ackley's Reloading Manuals say to use .300 Weatherby loading data in the 300 AI. There is a significant difference in the load data for the 300 Mag and the Weatherby. We all know that Weatherby calibers are designed around the freebore concept. I'm currently seating my bullets .01 into the lands. The Weatherby calls for a max load of 78 grains of RL-22 for my particular bullet and the Mag calls for a max load of 74.3 grains.
I just loaded up some VLD's at 73 grains and 74 grains of RL-22...this is still 4 grains under the max load for the Weatherby. Do you think this will be a safe load? Keep in mind that I'm seating into the lands...there's no freebore here.
I've found very little data on line...Thanks!
I just loaded up some VLD's at 73 grains and 74 grains of RL-22...this is still 4 grains under the max load for the Weatherby. Do you think this will be a safe load? Keep in mind that I'm seating into the lands...there's no freebore here.
I've found very little data on line...Thanks!
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Eric,
Welcome to the land of experimentation. If anyone on these boards would be able to help you, it would be Nononsense, JustC, or Sandwarrior, for the best answer's. But one question they are going to ask, would be, what are your pressure signs telling you? Primer flatness, case head expansion...measured before and after firing, etc. We try not to grow the case head by the web any more than 0.002-0.003". Are you fire forming with these loads , or are these the subsequent loads using the fire formed case? unless fire forming, most fella's I know, try to stay off the lands.
Best
EDIT 1
quote:but if PO Ackley's book is right, I should be good...I'm just a little unsure.
Eric,
PO Ackley's book may be correct for the rifles he was using, but you will not know if it was right for your's, unless you fire it. I would would not rely on the pressure signs you seen while fire forming, as you are bound to loose some pressure there. I would e-mail one of the big three I listed if I were you...especially the wildcatter...Nononsense.
One last thing, which 300 mag AI are you talking about? There are several 300 Mags...H&H, Winchester, RUM, WSM, SAUM, and Weatherby.0 -
like tsr said you are kinda on your own in this area. I think case head expansion is the best method but at .002/3" you will have loose primer pockets in 2/3 firings (not good). I had a .300 Weatherby mk 5 in the shop that was unsafe with factory ammo, it was a custom barreled rifle by McMillon with no freebore. Primers would 'fall out' after one firing. I have a .300 h&h a.i. that I do use .300 weatherby data for and this has a larger case than your .300 win. mag. a.i. (weatherby data is on the 'warm' side for this case!). 0 -
quote:Originally posted by tsr1965
Eric,
Welcome to the land of experimentation. If anyone on these boards would be able to help you, it would be Nononsense, JustC, or Sandwarrior, for the best answer's. But one question they are going to ask, would be, what are your pressure signs telling you? Primer flatness, case head expansion...measured before and after firing, etc. We try not to grow the case head by the web any more than 0.002-0.003". Are you fire forming with these loads , or are these the subsequent loads using the fire formed case? unless fire forming, most fella's I know, try to stay off the lands.
Best
This is fire formed brass and this rifle likes the bullets in the lands. I have yet to see any pressure signs b/c I haven't shot these loads in it yet. These loads are close to max for the parent cartridge and I'm seating into the lands (which is what makes me nervous)...but if PO Ackley's book is right, I should be good...I'm just a little unsure.
When I was fire forming my brass, my groups started tightening up with the hotter loads.0 -
Hello ECC---I've done a fair amount with various ack. imp. cartridges, but don't hold myself out to be an expert. Every thing stated above is reasonable to me. However, I would not try to deal with two variables at the same time. First I would start with the max std load given in your manual, WITHOUT THE BULLET BEING TIGHT AGAINST THE LANDS, seat bullet to SAAMI overall lenght. I would work up in 1/2 - 1 grain increments looking for pressure signs. Usually I can go 5 - 7 % above parent cartridge load. When I find the max load that appears safe, I would then start seating the bullet farther out, again looking for pressure signs. Some where in this process you should find a safe load for YOUR rifle. Just don't do both at the same time, as they both will affect pressure. Good luck, Be safe
HAWKSHAW0 -
Ackley is dead. His personal advice to me on his .219AI caliber and loads for a BSA Martini were wrong, ringing an expensive chamber.
I have his correspondence both before and after the fact.
Work up to your max loads and spacing off the lands progressively.
Measure case diameters at the extractor groove with a caliper, not a micrometer, for growth.
Stop at any growth as being over max. as primer pocket looseness is the most reliable indicator of maximum loading.0 -
ECC,
you say "I can't seem to find - -"
With an empty 300 Win Mag & an empty 300 Wby plus your empty formed case, weigh them & then fill with water & weigh again to compare volume.
If your "wildcat" is in between, use caution but interpelate your starting load between the two tables.
The title of your post says you seek "max" load.
Reloading is a science. There are MANY variables, each has it's "max". The only "max" that is the end of your search sould be the maximum accuracy at the range you expect to work.
max pressure
max seating depth
max velocity
max powder charge
These are all starting points, time to back up & start over!
You state "seating my bullet .01 into the lands"
This is not possible! The force of chambering a round will not broach your bullet into the rifling before it simply seats the bullet deeper.
Back up your seating depth to clear the rifling by .015. After you find optimum accuracy with a powder charge & bullet, then vary your seating depth by .005 to see if you change velocity without serious loss of accuracy.
Hope you have a strong shoulder, Jim0 -
Eric,
I've found something very helpful over the years with various Ackley cartridges. Everybody I know who shoots them don't shoot them for extreme performance, they shoot them for better case life, which adds to consistency of accuracy. I generally see a lot of improvement from the Mauser and .250-3000 based cases. Mostly because the biggest jump believe it or not is in the case wall expansion not from blowing the shoulder forward to 40 deg. In most of those cases improved performance is necessary simply because you've gone to a much increased case volume. In the .300 WM to the .300 WM AI you're not jumping all that much in volume.
Then:
The second thing I will recommend is running a ladder from known mid-level loads up to about 4-5 gr. over max published for the .300 Win Mag. I suggest basing all interpolations off the Win Mag case. Don't use the WBY case as it has different flow dynamics. My favorite powder in my .300 was H1000. It pretty easily got my 208 A-max's and 210 Bergers up to the prescribed velocities I wanted.
Now, when I say ladder, this is what I suggest. I just read the whole thing by TresMon over on Snipers Hide forums. I believe he posts here as well.
Anyhow, Load one shell at mid range load for .300 WM. The next 1 gr. more and so on until you get to max for the .300 WM for that powder. Then proceed in .5 gr. increments. Normally for this you load in 1% increments of the max (.8 gr.) but since you are down a ways it's going to run a little faster at the bottom end. And get you to where you need to be without wasting bullets.
Assuming you mean Berger 210's I went with the Sie. 220 RN load off the Hodgdon website. they use 73-78 gr. So load the first @ 75 gr. the second, 76 third, 77 fourth 78 (max), fifth 78.5 (above max) sixth 79, seventh 79.5, eighth 80, ninth 80.5, tenth 81, eleventh 81.5, etc, up to 85 if you want to go that high. In this case you know you are going to pull a couple so might as well go up.
Now for shooting them:
TresMon strongly suggests 600 yds. Not all that easy to get that far in a lot of places. So, if you can, 300 will suffice, 200 if you have no other choice. But go out as far as you can, whatever range. What you'll do is shoot these bullets from the low end to the high end. On one large piece of paper so that you can track the bullets upward POI's. At some point the bullets tend to cluster at one elevation. This is the accuracy node you are looking for. At any sign of too high of pressure, stop. Save all the hotter loaded bullets for pulling at home and then reloading them.
Note: I used to chase this on a chronograph. I would find the velocities that sometimes tended to run closer. That gave me good accuracy at long ranges. But, I think this physically seeing the harmonics in action is really the way to do it.
Also Note: You can bring the chronograph, but just record velocities. It'll save bullets when using a rough calculator to determine drops later on. Don't think you need to use the chrono as a tool to set which load. That is done by watching the harmonics in action.
To explain this, as the barrel sends a shot downrange and aborbs the released energy it vibrates. That vibration is just like a wave in the water. The barrel moves along in a sine wave. That accuracy node is where your barrel (muzzle) tends to hit top of the sine wave...literally. The sine wave the barrel creates is to a degree, limited by the materials natural flex. Meaning within a certain band any 3-6 or even seven bullets will bring that barrel up to the top of its sine wave then stop at the natural flex of the barrel. Anything lower or higher may have the bullet poi's coming back down. Or going increasingly left and right. In summary what you are doing is timing the barrel harmonics.
When you find the right load range verify it by loading three bullets each in .5 gr increments starting one grain under the middle of the groups and ending one gr. over. That's fifteen more bullets. Shoot those at three targets, one of each weight at each target. remember to mark each hit. Evaluate which ones grouped the best and that's your load.
I tried to get through this without being too long. e-mail me if you have questions or stay on. You can get some more good answers.0
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