The sweet spot for me almost aways seems to be the 3000 fps range in many of my cartridges using heavy for caliber bullets. Exception being smaller case cartridges.
Where's all the new 25 caliber bullets?
- Thread starter std7mag
- Start date
Orr89rocz
Silver $$ Contributor
Well the tipped gamechangers do seem pretty good out of a 10 twist. Shot two loads at 550 yrds in some gusty conditions. I should have waited for a better day but shot when it seemed calm. One load had good vertical but windage was broad, maybe some due to the load some me and the wind? Hard to say need to repeat. Other load had a nice group of 4 landing in a 4x3” rectangle. One off low left, again could be wind could be me. But seemed pretty consistent enough, its not a match gun by any means and only 14x scope. I guess if they were not stable they might be More inconsistent on hits?
They did seem to take .75 moa more elevation adjustment over predicted, which the app has worked well for other gun loads. So maybe thats what berger means by marginal stability may compromise bc
They did seem to take .75 moa more elevation adjustment over predicted, which the app has worked well for other gun loads. So maybe thats what berger means by marginal stability may compromise bc
Sierra states 10 twist (or faster exception is the 250-3000 cartridge). That cartridge is around 2800-2850 with the 110s. Your setup clearly is much faster putting you easily within the 10 twist category. I wouldn't completely rely on the Sierra BC published number or the calculator 100%. The MOA at every range is what it is. Be happy with the accuracy your getting at 550. IMO, your bullet is stable. 550 isn't really long enough range to make a difference in BC regardless of the numbers unless it's a heavy round nosed design.
Some get you very close and some close enough to fine tune better. It's definitely a great asset in shooting but nothing beats the time on the range getting the gun dialed exact.
Orr89rocz
Silver $$ Contributor
No doubt but when you have no data you gotta start somewhere and for me, atleast with a 308 and 300 wsm with two different loads, its been pretty close. This was abit further off than i was used to. Thats why i thought maybe something to this marginal stability bc thing. Never shot a bullet with this low a spin factor.
I dope sheet too, but mainly adjust my calc inputs to match reality, and then it will adjust again for change of weather altitude etc. cant always shoot in every condition known to occur and carry a book into the field. In my experience once you have the calcs dead onfor a given condition, its reliable in others within reason. Hunting temps seem to be 30-55 degs for me on average norms so only minor adjustments are needed. I verify the load in cold and warm extremes of that range. Anyways offtopic lol continue on
That’s rockin from a 20” tube. Re23/26 seem to be a good match for the Mauser length cartridges. As soon as I can find some, I plan to try It out. Same with Re17...
Wow, yes it is. I didn't read the 20" barrel part. Almost 3000 from a 20" barrel in a Roberts is cookin.
Yep I agree. I just don't think it's the twist that's causing your difference. I'm no rocket scientist so maybe someone else can add their opinion because you could be dead on. It's just my experience that the twist isn't your issue with the added elevation.
I ALWAYS use dope data( Ballistics calculator) after running velocities. It's a huge advantage when getting out to 600+ yards. No chasing bullets or guessing. At this point, after doing this stuff long enough, we all pretty much can get within a minute of bull out to 600 yards with most cartridges. There all very close really out to that range. BC doesn't really come into play until after 600 yards.
100 of what ?
Check out Blackjack bullets.
Where did you find them? Blackjack has been out of stock for a while.
Which cartridge? I would back off 2-3 full grains from a book starting load for a 115-120gr bullet. Also use data for the slowest powders mentioned
Just built one on a Remington long action switch barrel. You have any load data for the 131?
Your .257 Roberts AI is running the 131BJ at 3200 fps in a 25" barrel ? That's darn impressive if it is. How's accuracy at the 3200 mark ? I was kinda thinking that was a bit high for the 25-284 in the same length barrel. Maybe not.
Yeah I hit a big pressure spike around 3250 (MRP). Accuracy is still sub 0.5moa at that speed for me, but it’s really hard on the brass. Keep in mind that I am not using premium brass though. I only get 4 firings before the pockets come loose. But I have enough brass to last 2 barrels worth at that rate, so I’m not particularly concerned.
I have found nodes at 3080ish, 3125ish, and 3160ish as well. My biggest problem is that I finished this project about the time that powder disappeared and with absolutely ZERO load data to reference, I had very little idea on what powders I needed. So I only bought a couple pounds of a few things to try. About the time I really got a load dialed, I didn’t have enough powder to load for a match. Gambled a bit on a suspected flat spot with H100V and ended up with SD = 4, ES = 11 from 6 shots zeroing (3082fps).
I would expect 25-284 to at least equal these, if only because the bullet can be seated a bit more optimally (even without a SA constrained OAL). I won’t give my exact loads here on the thread, but if you can get 50-53gr of speed dirt into the case...
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Ok. My barrel is on the way. I should be testing by May. I have RL23/26. H4831sc and H4350. Thinking the RL23/26 will be the key powders. I'll be happy to get accuracy at 3150
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