If you correct for barometric pressure at high altitude. 11,000 feet to be exact, at above 3300 FPS the 100 grain scirocco .257 bullet does indeed have a B.C. of .8. Otherwise, back East at sea level that same bullet has a published B.C. of .429. But a lot of guys don't realize that bullets fly flatter when the air is thinner. Here CO Elk live primarily between 10,000 and 12,000 feet above sea level until the snow pushes them down. So that's a pretty realistic hunting scenario where I hunt. Everyone who lives here understands that the air is thinner and kickers can kick football's further in the thin Denver air. Same goes for bullets. Input barometric pressure to 24.0, humidity 30%, temperature 40 degrees above zero and you will see a corrected for atmosphere B.C. of .8 for a bullet that normally has a .429 B.C. at sea level. A lot of guys don't realize this.
.25 WSSM thread.. I'm starting over.
- Thread starter jeffreybehr
- Start date
I wish they made a .257 ABLR as well. That would be a winner. I've shot quite a few critters with 115 Bergers in .257 and they act just like any other match bullet does. They come apart. Which is less of a problem at a lower impact velocity, because they don't come apart as much the slower they're going. But if you're like me, you'll get a close shot. They perform an awful lot like a Vmax does, maybe a bit less explosive. They're only reliable when making long shots on game, not close shots. Especially when you need good penetration. If you're shooting a deer, or pronghorn they're adequate sometimes. But I've now seen two animals lost when hunting with those bullets. Both were shoulder shots. They're too soft when you hit something hard like a shoulder bone.
Yes bullets do perform better in high altitudes. That's no secret to long range shooters and hunters. You being a Colorado resident, I will not dispute your claim of elk primarily being in 10-12K elevations mostly. I however hunt Colorado and have never killed one past the 10k elevation. Typically our guys kill between 8-10k or lower. Never killed an elk above treeline. Pressured elk often do live up there but feed lower. You won't gain much from 10-12K in performance. There is a notable slight change when pushed faster but I've never seen published data of a BC change when used at higher elevations. The velocity increases due to that thinner air therefore changes the drop of the bullet. I'm not sure how to do an actual BC change from an increase in elevation. Typically velocity nodes for BC are published by the manufacturer from highest to average. They do not note that higher elevations will bring higher BCs. Atmospheric conditions and temp also changes a bullets rise or drop but it doesn't change it's BC. Your comparison is pretty spot on regarding what the ballistics of a .8 BC is for a .257 bullet at 800'asl. It mirrors a .485 BC bullet at 12000'asl when pushed 3300 fps. There's a 500 fps difference from 800' to 12000' asl. That certainly makes a huge difference in drop. My belief is that the velocity changes but the BC doesn't. Maybe I have alot more to learn but I think the bullet companies are pretty much on target.
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Try Shooters Calculator. It's an online ballistic calculator that allows you to correct for atmosphere. It will convert adjusted for atmosphere B.C.'s. I should say Elk primarily live at 10,000-12,000 feet above sea level when the habitat allows. Elk always gravitate towards the best available habitat in any given location. And yes with all the hunting pressure that's where the vast majority live until snow pushes them down. The grass is also typically better above treeline, which is
(Continued) Why they are there. Glad most flatlanders can't handle the thin air at those altitudes. But treeline changes depending on your correlation to the equator.
Yep I use several calculators. Altitude does increase performance.
Last time i was in Colorado, the elk & moose were at about the 10,000 ft level.
Couple of big fields covered by hundreds of elk 3rd week of Sept. About 3" of snow on the ground there. About 18" at 12,000 ft.
Personally, i use Strelok Pro. But that's just my preference.
Here in central/northern PA, we have what you would call steep sided rolling hills. Mountains to us.
Going up 1,000 ft in elevation has it's challenges here too. We have to deal with the humidity.
3rd week of Sept. with 18" of snow, we were in jackets (meaning not heavy coats) playing around for about 1-1/2 hours.
Till i found the tracks from a big cat. "Everyone back to the car!"
Get 18" of snow here, and your bundled up so much you can hardly move!
This "flatlander" knows to bring oxygen & eyedrops when out there.
After about 2 days my eyes were kill'n me!
Couple of big fields covered by hundreds of elk 3rd week of Sept. About 3" of snow on the ground there. About 18" at 12,000 ft.
Personally, i use Strelok Pro. But that's just my preference.
Here in central/northern PA, we have what you would call steep sided rolling hills. Mountains to us.
Going up 1,000 ft in elevation has it's challenges here too. We have to deal with the humidity.
3rd week of Sept. with 18" of snow, we were in jackets (meaning not heavy coats) playing around for about 1-1/2 hours.
Till i found the tracks from a big cat. "Everyone back to the car!"
Get 18" of snow here, and your bundled up so much you can hardly move!
This "flatlander" knows to bring oxygen & eyedrops when out there.
After about 2 days my eyes were kill'n me!
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I hate to hijack this guys post since I'm really excited to see how his 25 Wssm shoots. I think he's chosen a great cartridge, one that I've grown to love. I do love these mountains, but like you said the dry thin air causes problems! I just wanted to point out that in the thin air out west where you are most likely to shoot game at longer ranges the match bullets with high B.C.'s are not always necessary. In most cases they're not necessary at all. I actually just played around with shooters calculator and it looks like the .257 100 grain scirocco actually has a .744 B.C. when pushed to 3380 FPS at 40 degrees above zero. Barometric pressure 24.0, humidity 30%, elevation 11,000 feet. But it still has over 1,000 foot pounds of energy at 1,000 yards. Just thought that was a interesting data point. Not that energy alone kills, ask an archery hunter! But it doesn't quite have a .8 B.C.. So, I guess I was wrong.Last time i was in Colorado, the elk & moose were at about the 10,000 ft level.
Couple of big fields covered by hundreds of elk 3rd week of Sept. About 3" of snow on the ground there. About 18" at 12,000 ft.
Personally, i use Strelok Pro. But that's just my preference.
Here in central/northern PA, we have what you would call steep sided rolling hills. Mountains to us.
Going up 1,000 ft in elevation has it's challenges here too. We have to deal with the humidity.
3rd week of Sept. with 18" of snow, we were in jackets (meaning not heavy coats) playing around for about 1-1/2 hours.
Till i found the tracks from a big cat. "Everyone back to the car!"
Get 18" of snow here, and your bundled up so much you can hardly move!
This "flatlander" knows to bring oxygen & eyedrops when out there.
After about 2 days my eyes were kill'n me!
JohnMill
Gold $$ Contributor
Now there's an education I had not gotten b4.Thanks
Hope all is well with your surgery? Thought I'd chime in a little on post. I have started get parts together for my 25 wssm. Have 2k 135 Bergers, 400 new win brass, 28 inch 7.5 twist, reamer and gauges on the way had dies and expander and neck turning tools so i think its all in lol. I have had great luck with my ar 243 wssm with the 105s at mag length 26 inch tube running 3180 with es 19 and sd 7.6 out of a gasser 1/2 moa all day if I do my part. My Winchester 70 25 wssm runs factory 120s at 3k so I'd like to see what the new one will do
I'm back, sort of.. The shoulder surgery was succesful and just this week I got cleared to start shooting again.. BUT...I've turned into a fotografer again* and am enjoying that.. Meanwhile, lots of those 'vaporware' bullets turned real during my convalescence...
(I didn't intend to order so many Berger hunting bullets, but that's what happens when they take months to arrive AND one forgets what he has ordered. )
I'll get my rifle together in a month or two--the barrel FINALLY arrived a few weeks ago--and we'll see what happens.
And Stubby, TYVM for asking about my shoulder.
* I have two hobbies I biocycle thru, fotografy and rifle and pistol shooting.. After I ordered a barrel and quit shooting this summer, I restarted fotografy.. Look at
...for some of my pics.. Also, my wife of 37 years died in July after 8 years of fighting lung cancer, and my sister joined me from Ohio, so those rather disrupted life for a few months.
(I didn't intend to order so many Berger hunting bullets, but that's what happens when they take months to arrive AND one forgets what he has ordered. )
I'll get my rifle together in a month or two--the barrel FINALLY arrived a few weeks ago--and we'll see what happens.
And Stubby, TYVM for asking about my shoulder.
* I have two hobbies I biocycle thru, fotografy and rifle and pistol shooting.. After I ordered a barrel and quit shooting this summer, I restarted fotografy.. Look at
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I've kinda kelp up with this post.
I've shot a 25 wssm for the last 10 or 12... maybe
longer. It's just a little modle 70 win. but for a hunting gun, it shoots
real good. Killed several deer with it both with 100 gr. and 87 gr. bullets.
it feels as good as any rifle I've ever picked up, just fits me. I've loaded everything from 87 to 117 and found a good load for all of'em. Like was said in another post, only bullet I couldn't get to shoot was the 110 gr Accubond. Really wanted it to shoot'em but never found a load with'em it liked. Hope the op keeps this thread going.
Kermit
I've shot a 25 wssm for the last 10 or 12... maybe
longer. It's just a little modle 70 win. but for a hunting gun, it shoots
real good. Killed several deer with it both with 100 gr. and 87 gr. bullets.
it feels as good as any rifle I've ever picked up, just fits me. I've loaded everything from 87 to 117 and found a good load for all of'em. Like was said in another post, only bullet I couldn't get to shoot was the 110 gr Accubond. Really wanted it to shoot'em but never found a load with'em it liked. Hope the op keeps this thread going.
Kermit
Kermit,
Strangely, the Nosler Ballistic Tips shoot well in all my rifles. Ditto the AccuBond Long Range & Hornady's ELD bullets.
For some reason with the regular AccuBond it seems either your barrel really likes them, or it absolutely does not!
Mine did not.
I gave up on them several years ago.
Strangely, the Nosler Ballistic Tips shoot well in all my rifles. Ditto the AccuBond Long Range & Hornady's ELD bullets.
For some reason with the regular AccuBond it seems either your barrel really likes them, or it absolutely does not!
Mine did not.
I gave up on them several years ago.
Std7mag...the 87 gr speer hotcore shoot real good as good as anything I've tried. They do a good job on our deer and yotes.
I tried the 85 bts and they shot ok...but not as good as the 87s.
Kermit
I tried the 85 bts and they shot ok...but not as good as the 87s.
Kermit
Mounted the scope, a Zeiss V8 4.8-35X60 with 36mm tube. The 60mm objective lens and the 36mm tube diameter are the largest I've seen in a sporting scope. The front threads are filled with a 62mm Zeiss T* lens filter.. I'll do anything to avoid doing anything useful!
Left-arm carpal-tunnel-wrist and ulnar-nerve elbow-and-wrist surgery is tomorrow at 6:30AM
(YUK!!!!!!!!!!!!!!!!!!!!!!!!!), so I won't be shooting this for at least a month.. But that's probably OK, because it'll take about that long to remember how to load rifle cartridges.
Left-arm carpal-tunnel-wrist and ulnar-nerve elbow-and-wrist surgery is tomorrow at 6:30AM
(YUK!!!!!!!!!!!!!!!!!!!!!!!!!), so I won't be shooting this for at least a month.. But that's probably OK, because it'll take about that long to remember how to load rifle cartridges.
I don't see any 110 BIB's!!?I'm back, sort of.. The shoulder surgery was succesful and just this week I got cleared to start shooting again.. BUT...I've turned into a fotografer again* and am enjoying that.. Meanwhile, lots of those 'vaporware' bullets turned real during my convalescence...
View attachment 1298427
(I didn't intend to order so many Berger hunting bullets, but that's what happens when they take months to arrive AND one forgets what he has ordered. )
I'll get my rifle together in a month or two--the barrel FINALLY arrived a few weeks ago--and we'll see what happens.
And Stubby, TYVM for asking about my shoulder.
* I have two hobbies I biocycle thru, fotografy and rifle and pistol shooting.. After I ordered a barrel and quit shooting this summer, I restarted fotografy.. Look at
...for some of my pics.. Also, my wife of 37 years died in July after 8 years of fighting lung cancer and my sister joined me from Ohio, so those rather disrupted life for a few months.
There about as rare as hens teeth right now. Love to find a couple hundred tho.I don't see any 110 BIB's!!?
Hoot
Silver $$ Contributor
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