Ongoing 300wm testing, first 1moa group

Im shooting accurate 220LG 1.5-1.5-97 alloy, two wraps tracing paper, LLA and sized .3097
3 powders with 1gr dacron equalized to 1900fps on all, at 2k i wasnt able to get anything impressive but usable, tried 2200 once and was about 40moa give or take a few, im not sure where they all went. But gun is a 26" 10 twist, consistently getting confetti floating away 6 feet infront.
Attachment 238351 just confused why the bigger groups seem to be flyers rather than a bigger group, is that normal for dialing a load in ? still kinda new to cast rifle. I took good care making the ammo the powder should be the only variable. My 2000 fps 4831 group was about 1.5" but was evenly spread not 3 touching in center. So im guessing accuracy goes from big to small with fliers to small, perhaps.

Feel like life would be easier if it was a 30-06 maybe 12 twist, but this gun was won from a show so i make due

Thanks for the report. I haven't PP for the 300 Win Mag (yet), but if I were to I'd probably be looking at even slower burning powders. That's where I got the best velocity with very good accuracy in the 30-06. I'd think that IMR7828, W785, H450 or something similar might be worth trying.

Not sure how much bullet deformation you might be getting when the pressure spikes. You might want to try a few dozen linotype bullets to see if it helps...assuming you are not working up hunting loads. And like AZ suggested, a slower powder. That is a big case...adding Dacron may help. If Larry Gibson does not comment on this thread PM him. Not sure if he loads for the .300 WM but he has done a lot of work with Dacron and could have some suggestions.

Good luck.

I did make this alloy for hunting, did testing with it at 1700 impact speed and it seems exactly what I want correcting from the last deer a bit, so launching at 1900 is pretty much where im happy. I could try harder lead just to see how they group.

I am using 1gr of polyfill, it seems enough to hold the powder in place.

I would buy some slower powder to try but I just bought 4 cans recently so my wallet might not like a 5th. really if the 4895 results are fairly repeatable im good, deer wont notice a difference with anything under 2moa at my hunting distances, and much faster just be damaging meat more. I should probably check at 100yd tho just to make sure they don't destabilize at 51 yds.

guess my first post was a bit misleading sounding like im focused more on pushing speed

I'll add that it's quite easy to get to 1900fps with very good accuracy without paper-patching, even in a 1/10 twist barrel. I have a 300WM load that gets 1900fps with the Lee C309-170F bullet and 5744 powder, that will shoot MOA at 100 yds. The PP though, can be used to obtain significantly higher velocities even with a soft alloy such as yours. The slow powders give the boolit a "gentle shove" out the barrel, as opposed to a more violent smack that you would normally get with a faster powder. In addition, with the slow powders the case can be nearly filled to capacity, eliminating the need for any fillers. This has been my experience anyway, YMMV.

No affense but I’d try it again at a 100 yards and see it keeps MOA. I’ve had groups like that open up at a 100 yards. But I’m impressed with the 300 WM holding a tight group with that big case.

So H4831 is a fast powder and getting rifles to shoot cast 1moa is easy, is it opposite day? i dont understand

To clarify things a bit, H4831 is a pretty slow powder, but I don't consider SR4759 or even H4895 as slow powders. And I never said getting 1moa with cast is easy. I said getting to 1900fps with good accuracy is easy. I hope that helps.

turns out it was a fluke anyway. of the load that shot good I tried 5 more at 50yd, 5 at 100yd, and 5 at 50yd powder coated gas checked and there all averaging 3 moa like the previous testing with my range of rifle powder speeds, mostly 4831. realistically that's enough for my hunting spot where I cant see past 100 anyway but might as well just practice with the 44 levergun with aperture sights if I don't beat 3moa

Yeah, the 300WM can be a bit of a booger with cast. The short neck doesn't help things much with long boolits. That's probably one of the biggest reasons I have never attempted to PP with it. The 30-06 is probably better suited for PP IMHO, but I'm sure the 300 can be made to work too. I may get around to it one of these days.

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Originally Posted by bmortell

turns out it was a fluke anyway. of the load that shot good I tried 5 more at 50yd, 5 at 100yd, and 5 at 50yd powder coated gas checked and there all averaging 3 moa like the previous testing with my range of rifle powder speeds, mostly 4831. realistically that's enough for my hunting spot where I cant see past 100 anyway but might as well just practice with the 44 levergun with aperture sights if I don't beat 3moa

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I would tell you to weigh your boolits and separate them within a grain or even less and retest. I messed with my 77/44 last year and have two different loads that shoot sub MOA at 100 yards with a Lyman devastator. But it was after a lot of tinkering with acraglassing the bedding area, lightening the trigger, installing way too much power optic...14x, switching to smokes clear PC since it coats thinner, more even, and smother, made sure my GC seated perfect, shot off a lead sled, and messed with crimp pressure and styles. I tested four different alloys and about a good four to five hundred plus rounds. Once in a while Murphy’s law still plays a role and your going to have a mystery flier imo. Before I started messing with my bedding the best group I had was 2moa and the average was 4 MOA.

You had something going right for a few rounds so don’t give up yet. I tried j words and trail boss in my 375 rum a few years ago and couldn’t hit a barn if I was locked inside it at a 100 yards. Once I got up to 2700 FPS the groups tightened which defeated the purpose being it was busting my shoulder almost as much as a full throttle 3000 plus FPS load.

The way I look at it if I’m shooting cast and wanted to shoot a certain diameter bullet (.308) and I have a smaller caliber rifle for instance a 308 versus a 300 RUM I’d pick the lesser of the two rifles since you’re only going to shoot a max of 2000 fps out of both guns with cast so you might as will pick the smaller caliber case and save on your powder and imo it will probably be more accurate with more of a case to powder fill ratio. Maybe I’m wrong? I’m sure someone will chime in. I realize you can shoot cast in anything but from my experience and the posters who have tried cast in the bigger bottleneck cartidges(larger than 30-06’) seem to never get acceptable group sizes.